Tachyonic field interacting with scalar (phantom) field
Chattopadhyay, Surajit; Debnath, Ujjal
2009-01-01
In this letter, we have considered the universe is filled with the mixture of tachyonic field and scalar or phantom field. If the tachyonic field interacts with scalar or phantom field, the interaction term decays with time and the energy for scalar field is transferred to tachyonic field or the energy for phantom field is transferred to tachyonic field. The tachyonic field and scalar field potentials always decrease, but phantom field potential always increases.
Huang, Ching-Yuan
2003-07-01
The asymptotically flat space-time with scalar fields is studied. It shows that the concepts of Bondi mass, Bondi mass loss, etc., are also applicable to other fields, although they were originally defined by gravity. The generating formulae of Bondi mass loss and angular momentum loss by a dynamics Hamiltonian over a hyperb oloid are given by the linearised theory.
Random scalar fields and hyperuniformity
Ma, Zheng; Torquato, Salvatore
2017-06-01
Disordered many-particle hyperuniform systems are exotic amorphous states of matter that lie between crystals and liquids. Hyperuniform systems have attracted recent attention because they are endowed with novel transport and optical properties. Recently, the hyperuniformity concept has been generalized to characterize two-phase media, scalar fields, and random vector fields. In this paper, we devise methods to explicitly construct hyperuniform scalar fields. Specifically, we analyze spatial patterns generated from Gaussian random fields, which have been used to model the microwave background radiation and heterogeneous materials, the Cahn-Hilliard equation for spinodal decomposition, and Swift-Hohenberg equations that have been used to model emergent pattern formation, including Rayleigh-Bénard convection. We show that the Gaussian random scalar fields can be constructed to be hyperuniform. We also numerically study the time evolution of spinodal decomposition patterns and demonstrate that they are hyperuniform in the scaling regime. Moreover, we find that labyrinth-like patterns generated by the Swift-Hohenberg equation are effectively hyperuniform. We show that thresholding (level-cutting) a hyperuniform Gaussian random field to produce a two-phase random medium tends to destroy the hyperuniformity of the progenitor scalar field. We then propose guidelines to achieve effectively hyperuniform two-phase media derived from thresholded non-Gaussian fields. Our investigation paves the way for new research directions to characterize the large-structure spatial patterns that arise in physics, chemistry, biology, and ecology. Moreover, our theoretical results are expected to guide experimentalists to synthesize new classes of hyperuniform materials with novel physical properties via coarsening processes and using state-of-the-art techniques, such as stereolithography and 3D printing.
Minimally coupled scalar field cosmology in anisotropic ...
Indian Academy of Sciences (India)
We study a spatially homogeneous and anisotropic cosmological model in the Einstein gravitational theory with a minimally coupled scalar field. We consider a non-interacting combination of scalar field and perfect fluid as the source of matter components which are separately conserved. The dynamics of cosmic scalar ...
Unified Dark Matter Scalar Field Models
Directory of Open Access Journals (Sweden)
Daniele Bertacca
2010-01-01
of a single scalar field accounts for a unified description of the Dark Matter and Dark Energy sectors, dubbed Unified Dark Matter (UDM models. In this framework, we consider the general Lagrangian of -essence, which allows to find solutions around which the scalar field describes the desired mixture of Dark Matter and Dark Energy. We also discuss static and spherically symmetric solutions of Einstein's equations for a scalar field with noncanonical kinetic term, in connection with galactic halo rotation curves.
Galactic collapse of scalar field dark matter
Energy Technology Data Exchange (ETDEWEB)
Alcubierre, Miguel [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, D-14476 Golm (Germany); Guzman, F Siddhartha [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, D-14476 Golm (Germany); Matos, Tonatiuh [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, AP 14-740, 07000 Mexico, DF (Mexico); Nunez, Dario [Centre for Gravitational Physics and Geometry, Penn State University, University Park, PA 16802 (United States); Urena-Lopez, L Arturo [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, AP 14-740, 07000 Mexico, DF (Mexico); Wiederhold, Petra [Departamento de Control Automatico, Centro de Investigacion y de Estudios Avanzados del IPN, AP 14-740, 07000 Mexico, DF (Mexico)
2002-10-07
We present a scenario for core galaxy formation based on the hypothesis of scalar field dark matter. We interpret galaxy formation through the collapse of a scalar field fluctuation. We find that a cosh potential for the self-interaction of the scalar field provides a reasonable scenario for the formation of a galactic core plus a remnant halo, which is in agreement with cosmological observations and phenomenological studies in galaxies.
Achasov, N. N.
2008-01-01
Outline: 1. Introduction, 2. Confinement, chiral dynamics and light scalar mesons, 3. Chiral shielding of \\sigma(600), chiral constraints, \\sigma(600), f_0(980) and their mixing in \\pi\\pi\\to\\pi\\pi, \\pi\\pi\\to K\\bar K, and \\phi\\to\\gamma\\pi0\\pi0, 4. The \\phi meson radiative decays on light scalar resonances. 5. Why a0(980) and f0(980) are not the K\\bar K molecules. 6. Light scalars in \\gamma\\gamma collisions. Evidence for four-quark components of light scalars is given. The priority of Quantum F...
Minimally coupled scalar field cosmology in anisotropic ...
Indian Academy of Sciences (India)
2017-01-03
Jan 3, 2017 ... modern cosmology to explain the early inflation and the late-time acceleration. The recent discovery of cosmic acceleration [3–7] has stimulated the interest to study cosmological models based on scalar fields. The cosmological models based on scalar fields have been discussed by many researchers for ...
Scalar field dark matter in hybrid approach
Friedrich, Pavel; Prokopec, Tomislav
2017-10-01
We develop a hybrid formalism suitable for modeling scalar field dark matter, in which the phase-space distribution associated with the real scalar field is modeled by statistical equal-time two-point functions and gravity is treated by two stochastic gravitational fields in the longitudinal gauge (in this work we neglect vector and tensor gravitational perturbations). Inspired by the commonly used Newtonian Vlasov-Poisson system, we firstly identify a suitable combination of equal-time two-point functions that defines the phase-space distribution associated with the scalar field and then derive both a kinetic equation that contains relativistic scalar matter corrections as well as linear gravitational scalar field equations whose sources can be expressed in terms of a momentum integral over the phase-space distribution function. Our treatment generalizes the commonly used classical scalar field formalism, in that it allows for modeling of (dynamically generated) vorticity and perturbations in anisotropic stresses of the scalar field. It also allows for a systematic inclusion of relativistic and higher-order corrections that may be used to distinguish different dark matter scenarios. We also provide initial conditions for the statistical equal-time two-point functions of the matter scalar field in terms of gravitational potentials and the scale factor.
scalar field dynamics on a brane
Indian Academy of Sciences (India)
power-law potential V ~φa is investigated. We describe solutions for which the scalar field energy density scales as a power-law of the scale factor. We also describe solutions existing in regions of the parameter space where these scaling solutions are unstable or do not exist. Keywords. Brane; scalar field; scaling solution.
Quantization of n coupled scalar field theory
Kim, Yong-Wan; Myung, Yun Soo; Park, Young-Jai
2013-10-01
We study a model of n coupled scalar fields in Minkowski spacetime in which all masses degenerate, which is considered as a toy model of polycritical gravity on anti-de Sitter spacetime. We quantize this model within the Becchi-Rouet-Stora-Tyutin scheme by introducing n Faddeev-Popov (FP) ghost fields. Extending a Becchi-Rouet-Stora-Tyutin quartet generated by two scalars and two FP ghosts to n scalars and n FP ghosts, there remains a physical subspace with positive norm for odd n, but there exists only the vacuum for even n. This clearly shows a nontriviality of odd higher-order derivative scalar field theories. This is helpful to understand the truncation mechanism, which is used to obtain a unitary conformal field theory dual to linearized polycritical gravity. It turns out that the truncation mechanism is nothing but a general quartet mechanism that appears when introducing the FP ghost action.
Exotic Material as Interactions Between Scalar Fields
Directory of Open Access Journals (Sweden)
Robertson G. A.
2006-04-01
Full Text Available Many theoretical papers refer to the need to create exotic materials with average negative energies for the formation of space propulsion anomalies such as "wormholes" and "warp drives". However, little hope is given for the existence of such material to resolve its creation for such use. From the standpoint that non-minimally coupled scalar fields to gravity appear to be the current direction mathematically. It is proposed that exotic material is really scalar field interactions. Within this paper the Ginzburg-Landau (GL scalar fields associated with superconductor junctions isinvestigated as a source for negative vacuum energy fluctuations, which could be used to study the interactions among energyfluctuations, cosmological scalar (i.e., Higgs fields, and gravity.
Gravitational Field Shielding by Scalar Field and Type II Superconductors
Directory of Open Access Journals (Sweden)
Zhang B. J.
2013-01-01
Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.
Kundt spacetimes minimally coupled to scalar field
Energy Technology Data Exchange (ETDEWEB)
Tahamtan, T. [Charles University, Institute of Theoretical Physics, Faculty of Mathematics and Physics, Prague 8 (Czech Republic); Astronomical Institute, Czech Academy of Sciences, Prague (Czech Republic); Svitek, O. [Charles University, Institute of Theoretical Physics, Faculty of Mathematics and Physics, Prague 8 (Czech Republic)
2017-06-15
We derive an exact solution belonging to the Kundt class of spacetimes both with and without a cosmological constant that are minimally coupled to a free massless scalar field. We show the algebraic type of these solutions and give interpretation of the results. Subsequently, we look for solutions additionally containing an electromagnetic field satisfying nonlinear field equations. (orig.)
Arbitrary scalar field and quintessence cosmological models
Harko, Tiberiu; Mak, M K
2014-01-01
The mechanism of the initial inflationary scenario of the universe and of its late-time acceleration can be described by assuming the existence of some gravitationally coupled scalar fields $\\phi $, with the inflaton field generating inflation and the quintessence field being responsible for the late accelerated expansion. Various inflationary and late-time accelerated scenarios are distinguished by the choice of an effective self-interaction potential $V(\\phi)$, which simulates a temporarily non-vanishing cosmological term. In this work, we present a new formalism for the analysis of scalar fields in flat isotropic and homogeneous cosmological models. The basic evolution equation of the models can be reduced to a first order non-linear differential equation. Approximate solutions of this equation can be constructed in the limiting cases of the scalar field kinetic energy and potential energy dominance, respectively, as well as in the intermediate regime. Moreover, we present several new accelerating and dece...
Extended solutions for the biadjoint scalar field
De Smet, Pieter-Jan; White, Chris D.
2017-12-01
Biadjoint scalar field theories are increasingly important in the study of scattering amplitudes in various string and field theories. Recently, some first exact nonperturbative solutions of biadjoint scalar theory were presented, with a pure power-like form corresponding to isolated monopole-like objects located at the origin of space. In this paper, we find a novel family of extended solutions, involving non-trivial form factors that partially screen the divergent field at the origin. All previous solutions emerge as special cases.
Renormalisation group improvement of scalar field inflation
Contillo, Adriano; Rahmede, Christoph
2011-01-01
We study quantum corrections to Friedmann-Robertson-Walker cosmology with a scalar field under the assumption that the dynamics are subject to renormalisation group improvement. We use the Bianchi identity to relate the renormalisation group scale to the scale factor and obtain the improved cosmological evolution equations. We study the solutions of these equations in the renormalisation group fixed point regime, obtaining the time-dependence of the scalar field strength and the Hubble parameter in specific models with monomial and trinomial quartic scalar field potentials. We find that power-law inflation can be achieved in the renormalisation group fixed point regime with the trinomial potential, but not with the monomial one. We study the transition to the quasi-classical regime, where the quantum corrections to the couplings become small, and find classical dynamics as an attractor solution for late times. We show that the solution found in the renormalisation group fixed point regime is also a cosmologic...
Exact solutions for the biadjoint scalar field
Energy Technology Data Exchange (ETDEWEB)
White, C.D., E-mail: Christopher.White@glasgow.ac.uk [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); Centre for Research in String Theory, Queen Mary University of London, London E1 4NS (United Kingdom)
2016-12-10
Biadjoint scalar theories are novel field theories that arise in the study of non-abelian gauge and gravity amplitudes. In this short paper, we present exact nonperturbative solutions of the field equations, and compare their properties with monopole-like solutions in non-abelian gauge theory. Our results may pave the way for nonperturbative studies of the double copy.
The scalar field kernel in cosmological spaces
Koksma, J.F.; Prokopec, T.|info:eu-repo/dai/nl/326113398; Rigopoulos, G.I.
2008-01-01
We construct the quantum mechanical evolution operator in the Functional Schrodinger picture - the kernel - for a scalar field in spatially homogeneous FLRW spacetimes when the field is a) free and b) coupled to a spacetime dependent source term. The essential element in the construction is the
Oscillating scalar fields in extended quintessence
Li, Dan; Pi, Shi; Scherrer, Robert J.
2018-01-01
We study a rapidly oscillating scalar field with potential V (ϕ )=k |ϕ |n nonminimally coupled to the Ricci scalar R via a term of the form (1 -8 π G0ξ ϕ2)R in the action. In the weak coupling limit, we calculate the effect of the nonminimal coupling on the time-averaged equation of state parameter γ =(p +ρ )/ρ . The change in ⟨γ ⟩ is always negative for n ≥2 and always positive for n values of n . Constraints on the time variation of G force this change to be infinitesimally small at the present time whenever the scalar field dominates the expansion, but constraints in the early universe are not as stringent. The rapid oscillation induced in G also produces an additional contribution to the Friedman equation that behaves like an effective energy density with a stiff equation of state, but we show that, under reasonable assumptions, this effective energy density is always smaller than the density of the scalar field itself.
Scalar fields in black hole spacetimes
Thuestad, Izak; Khanna, Gaurav; Price, Richard H.
2017-07-01
The time evolution of matter fields in black hole exterior spacetimes is a well-studied subject, spanning several decades of research. However, the behavior of fields in the black hole interior spacetime has only relatively recently begun receiving some attention from the research community. In this paper, we numerically study the late-time evolution of scalar fields in both Schwarzschild and Kerr spacetimes, including the black hole interior. We recover the expected late-time power-law "tails" on the exterior (null infinity, timelike infinity, and the horizon). In the interior region, we find an interesting oscillatory behavior that is characterized by the multipole index ℓ of the scalar field. In addition, we also study the extremal Kerr case and find strong indications of an instability developing at the horizon.
Nonequilibrium perturbation theory for complex scalar fields
Lawrie, I. D.; McKernan, D. B.
1996-01-01
Real-time perturbation theory is formulated for complex scalar fields away from thermal equilibrium in such a way that dissipative effects arising from the absorptive parts of loop diagrams are approximately resummed into the unperturbed propagators. Low order calculations of physical quantities then involve quasiparticle occupation numbers which evolve with the changing state of the field system, in contrast to standard perturbation theory, where these occupation numbers are frozen at their ...
Dynamics of Scalar field in a Brane World
Mizuno, Shuntaro; Maeda, Kei-ichi; Yamamoto, Kohta
2002-01-01
We study the dynamics of a scalar field in the brane cosmology. We assume that a scalar field is confined in our 4-dimensional world. As for the potential of the scalar field, we discuss three typical models: (1) a power-law potential, (2) an inverse-power-law potential, and (3) an exponential potential. We show that the behavior of the scalar field is very different from a conventional cosmology when the energy density square term is dominated.
Scalar-field theory of dark matter
Huang, Kerson; Zhao, Xiaofei
2013-01-01
We develop a theory of dark matter based on a previously proposed picture, in which a complex vacuum scalar field makes the universe a superfluid, with the energy density of the superfluid giving rise to dark energy, and variations from vacuum density giving rise to dark matter. We formulate a nonlinear Klein-Gordon equation to describe the superfluid, treating galaxies as external sources. We study the response of the superfluid to the galaxies, in particular, the emergence of the dark-matter galactic halo, contortions during galaxy collisions, and the creation of vortices due to galactic rotation.
Noncommutative Complex Scalar Field and Casimir Effect
Khelili, Farid
2012-06-01
Using the noncommutative deformed canonical commutation relations proposed by Carmona et al. [J. M. Carmona, J. L. Cortés, J. Gamboa, and F. Mendez, J. High Energy Phys.JHEPFG1029-8479 03 (2003) 058.10.1088/1126-6708/2003/03/058][J. Gamboa, J. Lopéz-Sarrion, and A. P. Polychronakos, Phys. Lett. B 634, 471 (2006).PYLBAJ0370-269310.1016/j.physletb.2006.02.014][J. M. Carmona, J. L. Cortés, Ashok Das, J. Gamboa, and F. Mendez, Mod. Phys. Lett. A 21, 883 (2006).MPLAEQ0217-732310.1142/S0217732306020111], a model describing the dynamics of the noncommutative complex scalar field is proposed. The noncommutative field equations are solved, and the vacuum energy is calculated to the second order in the parameter of noncommutativity. As an application to this model, the Casimir effect, due to the zero-point fluctuations of the noncommutative complex scalar field, is considered. It turns out that in spite of its smallness, the noncommutativity gives rise to a repulsive force at the microscopic level, leading to a modified Casimir potential with a minimum at the point amin=(5)/(84)πθ.
Scalar field dark matter and the Higgs field
Directory of Open Access Journals (Sweden)
O. Bertolami
2016-08-01
Full Text Available We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10−6–10−4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall–Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.
Massive basketball diagram for a thermal scalar field theory
Andersen, Jens O.; Braaten, Eric; Strickland, Michael
2000-08-01
The ``basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a φ4 interaction to three-loop order.
Neutron Star Structure in the Presence of Scalar Fields
Kazanas, Demosthenes
2004-01-01
Motivated by the possible presence of scalar fields on astrophysical scales, suggested by the apparent acceleration of the universe implied by the supernovae surveys, we present models of neutron star structure including the contribution of a (massless) scalar field to the stress energy momentum tensor, in addition to that made by the normal matter. To that end we solve the coupled Einstein -- scalar field -- hydrostatic balance equations to compute the effect of the presence of the scalar field on the neutron star structure. We find that the presence of the scalar field does change the structure of the neutron star, especially in cases of strong coupling between the scalar field and the matter density. We present the neutron star radius as a function of the matter--scalar field coupling constant for different values of the neutron star central density. The presence of the scalar field affects both the maximum neutron star mass and Its radius, the latter increasing with the value of the above coupling constant. We also compute particle and photon geodesics in the geometry of these neutron stars as well as to the geometry of black holes with different values of the scalar field. Our results may be testable with timing observations of accreting neutron stars.
Regular and Chaotic Regimes in Scalar Field Cosmology
Directory of Open Access Journals (Sweden)
Alexey V. Toporensky
2006-03-01
Full Text Available A transient chaos in a closed FRW cosmological model with a scalar field is studied. We describe two different chaotic regimes and show that the type of chaos in this model depends on the scalar field potential. We have found also that for sufficiently steep potentials or for potentials with large cosmological constant the chaotic behavior disappears.
Canonical Quantization of the Scalar Field: The Measure Theoretic Perspective
Velhinho, José
2015-01-01
This review is devoted to measure theoretical methods in the canonical quantization of scalar field theories. We present in some detail the canonical quantization of the free scalar field. We study the measures associated with the free fields and present two characterizations of the support of these measures. The first characterization concerns local properties of the quantum fields, whereas for the second one we introduce a sequence of variables that test the field behaviour at large distanc...
Effect of the chameleon scalar field on brane cosmological evolution
Directory of Open Access Journals (Sweden)
Y. Bisabr
2017-11-01
Full Text Available We have investigated a brane world model in which the gravitational field in the bulk is described both by a metric tensor and a minimally coupled scalar field. This scalar field is taken to be a chameleon with an appropriate potential function. The scalar field interacts with matter and there is an energy transfer between the two components. We find a late-time asymptotic solution which exhibits late-time accelerating expansion. We also show that the Universe recently crosses the phantom barrier without recourse to any exotic matter. We provide some thermodynamic arguments which constrain both the direction of energy transfer and dynamics of the extra dimension.
Effect of the chameleon scalar field on brane cosmological evolution
Bisabr, Y.; Ahmadi, F.
2017-11-01
We have investigated a brane world model in which the gravitational field in the bulk is described both by a metric tensor and a minimally coupled scalar field. This scalar field is taken to be a chameleon with an appropriate potential function. The scalar field interacts with matter and there is an energy transfer between the two components. We find a late-time asymptotic solution which exhibits late-time accelerating expansion. We also show that the Universe recently crosses the phantom barrier without recourse to any exotic matter. We provide some thermodynamic arguments which constrain both the direction of energy transfer and dynamics of the extra dimension.
A nonlinear dynamics for the scalar field in Randers spacetime
Energy Technology Data Exchange (ETDEWEB)
Silva, J.E.G. [Universidade Federal do Cariri (UFCA), Instituto de formação de professores, Rua Olegário Emídio de Araújo, Brejo Santo, CE, 63.260.000 (Brazil); Maluf, R.V. [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza, CE, C.P. 6030, 60455-760 (Brazil); Almeida, C.A.S., E-mail: carlos@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza, CE, C.P. 6030, 60455-760 (Brazil)
2017-03-10
We investigate the properties of a real scalar field in the Finslerian Randers spacetime, where the local Lorentz violation is driven by a geometrical background vector. We propose a dynamics for the scalar field by a minimal coupling of the scalar field and the Finsler metric. The coupling is intrinsically defined on the Randers spacetime, and it leads to a non-canonical kinetic term for the scalar field. The nonlinear dynamics can be split into a linear and nonlinear regimes, which depend perturbatively on the even and odd powers of the Lorentz-violating parameter, respectively. We analyze the plane-waves solutions and the modified dispersion relations, and it turns out that the spectrum is free of tachyons up to second-order.
Topological defect solutions for a system of three scalar fields
Niazian, M. R.; Amani, Ali R.
2015-06-01
In this paper, we studied on the defect structures as topological by non-linear three scalar fields. By using modified Adomian decomposition method (MADM), and Adomian decomposition method (ADM) we have found the solutions of three scalar fields. Then we compared the obtained results each other by numerical solution. Also, we consider the static case and draw ϕ(x), χ(x), and ρ(x) with the choice of different values for parameter r.
Cosmological Brane World Solutions with Bulk Scalar Fields
Davis, Stephen C.
2001-01-01
Cosmological brane world solutions are found for five-dimensional bulk spacetimes with a scalar field. A supergravity inspired method for obtaining static solutions is combined with a method for finding brane cosmologies with constant bulk energies. This provides a way to generate full (bulk and brane) cosmological solutions to brane worlds with bulk scalar fields. Examples of these solutions, and their cosmological evolution, are discussed.
Canonical Quantization of the Scalar Field: The Measure Theoretic Perspective
Directory of Open Access Journals (Sweden)
José Velhinho
2015-01-01
Full Text Available This review is devoted to measure theoretical methods in the canonical quantization of scalar field theories. We present in some detail the canonical quantization of the free scalar field. We study the measures associated with the free fields and present two characterizations of the support of these measures. The first characterization concerns local properties of the quantum fields, whereas for the second one we introduce a sequence of variables that test the field behaviour at large distances, thus allowing distinguishing between the typical quantum fields associated with different values of the mass.
Arbitrary scalar-field and quintessence cosmological models
Energy Technology Data Exchange (ETDEWEB)
Harko, Tiberiu [University College London, Department of Mathematics, London (United Kingdom); Lobo, Francisco S.N. [Centro de Astronomia e Astrofisica da Universidade de Lisboa, Lisbon (Portugal); Mak, M.K. [Hong Kong Institute of Vocational Education, Department of Computing and Information Management, Hong Kong (China)
2014-03-15
The mechanism of the initial inflationary scenario of the Universe and of its late-time acceleration can be described by assuming the existence of some gravitationally coupled scalar fields φ, with the inflaton field generating inflation and the quintessence field being responsible for the late accelerated expansion. Various inflationary and late-time accelerated scenarios are distinguished by the choice of an effective self-interaction potential V(φ), which simulates a temporarily non-vanishing cosmological term. In this work, we present a new formalism for the analysis of scalar fields in flat isotropic and homogeneous cosmological models. The basic evolution equation of the models can be reduced to a first-order non-linear differential equation. Approximate solutions of this equation can be constructed in the limiting cases of the scalar-field kinetic energy and potential energy dominance, respectively, as well as in the intermediate regime. Moreover, we present several new accelerating and decelerating exact cosmological solutions, based on the exact integration of the basic evolution equation for scalar-field cosmologies. More specifically, exact solutions are obtained for exponential, generalized cosine hyperbolic, and power-law potentials, respectively. Cosmological models with power-law scalar field potentials are also analyzed in detail. (orig.)
Thermodynamics of perfect fluids from scalar field theory
Ballesteros, Guillermo; Pilo, Luigi
2016-01-01
The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields. These scalars describe the embedding in spacetime of the medium and play the role of Stuckelberg fields for spontaneously broken spatial and time translations. Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar. We explore the relation between the field theory description of perfect fluids to thermodynamics. By drawing the correspondence between the allowed operators at leading order in derivatives and the thermodynamic variables, we find that a complete thermodynamic picture requires the four Stuckelberg fields. We show that thermodynamic stability plus the null energy condition imply dynamical stability. We also argue that a consistent thermodynamic interpretation is not possible if any of the shift symmetries is explicitly broken.
Small scale structures in coupled scalar field dark matter
Directory of Open Access Journals (Sweden)
J. Beyer
2014-11-01
Full Text Available We investigate structure formation for ultra-light scalar field dark matter coupled to quintessence, in particular the cosmon–bolon system. The linear power spectrum is computed by a numerical solution of the coupled field equations. We infer the substructure abundance within a Milky Way-like halo. Estimates of dark halo abundances from recent galaxy surveys imply a lower bound on the bolon mass of about 9×10−22 eV. This seems to exclude a possible detection of scalar field dark matter through time variation in pulsar timing signals in the near future.
Quantum Prisoners' Dilemma in Fluctuating Massless Scalar Field
Huang, Zhiming
2017-12-01
Quantum systems are easily affected by external environment. In this paper, we investigate the influences of external massless scalar field to quantum Prisoners' Dilemma (QPD) game. We firstly derive the master equation that describes the system evolution with initial maximally entangled state. Then, we discuss the effects of a fluctuating massless scalar field on the game's properties such as payoff, Nash equilibrium, and symmetry. We find that for different game strategies, vacuum fluctuation has different effects on payoff. Nash equilibrium is broken but the symmetry of the game is not violated.
Quantum Gravity Effects in Scalar, Vector and Tensor Field Propagation
Dutta, Anindita
Quantum theory of gravity deals with the physics of the gravitational field at Planck length scale (10-35 m). Even though it is experimentally hard to reach the Planck length scale, on can look for evidence of quantum gravity that is detectable in astrophysics. In this thesis, we try to find effects of loop quantum gravity corrections on observable phenomena. We show that the quantum fluctuation strain for LIGO data would be 10 -125 on the Earth. Th correction is, however, substantial near the black hole horizon. We discuss the effect of this for scalar field propagation followed by vector and tensor fields. For the scalar field, the correction introduces a new asymmetry; for the vector field, we found a new perturbation solution and for the tensor field, we found the corrected Einstein equations which are yet to solve. These will affect phenomena like Hawking radiation, black hole entropy and gravitational waves.
Polchinski ERG Equation in O(N) Scalar Field Theory
Kubyshin, Yuri; Neves, Rui; Potting, Robertus
We investigate the Polchinski ERG equation for d-dimensional O(N) scalar field theory. In the context of the non-pertubative derivative expansion we find families of regular solutions and establish their relation with the physical fixed points of the theory. Special emphasis is given to the limit N=∞ for which many properties can be studied analytically.
Polchinski ERG Equation in O(N) Scalar Field Theory
Kubyshin, Yuri; Neves, Rui; Potting, Robertus
2001-01-01
We investigate the Polchinski ERG equation for d-dimensional O(N) scalar field theory. In the context of the non-perturbative derivative expansion we find families of regular solutions and establish their relation with the physical fixed points of the theory. Special emphasis is given to the large N limit for which many properties can be studied analytically.
Eigenvalue Problem of Scalar Fields in BTZ Black Hole Spacetime
Kuwata, Maiko; Kenmoku, Masakatsu; Shigemoto, Kazuyasu
2008-01-01
We studied the eigenvalue problem of scalar fields in the (2+1)-dimensional BTZ black hole spacetime. The Dirichlet boundary condition at infinity and the Dirichlet or the Neumann boundary condition at the horizon are imposed. Eigenvalues for normal modes are characterized by the principal quantum number $(0
Effective action for a quantum scalar field in warped spaces
Energy Technology Data Exchange (ETDEWEB)
Hoff da Silva, J.M.; Mendonca, E.L.; Scatena, E. [Universidade Estadual Paulista ' ' Julio de Mesquita Filho' ' -UNESP, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil)
2015-11-15
We investigate the one-loop corrections, at zero as well as finite temperature, of a scalar field taking place in a braneworld motivated warped background. After to reach a well-defined problem, we calculate the effective action with the corresponding quantum corrections to each case. (orig.)
Anderson, David; Yunes, Nicolás
2017-09-01
Scalar-tensor theories of gravity modify general relativity by introducing a scalar field that couples nonminimally to the metric tensor, while satisfying the weak-equivalence principle. These theories are interesting because they have the potential to simultaneously suppress modifications to Einstein's theory on Solar System scales, while introducing large deviations in the strong field of neutron stars. Scalar-tensor theories can be classified through the choice of conformal factor, a scalar that regulates the coupling between matter and the metric in the Einstein frame. The class defined by a Gaussian conformal factor with a negative exponent has been studied the most because it leads to spontaneous scalarization (i.e. the sudden activation of the scalar field in neutron stars), which consequently leads to large deviations from general relativity in the strong field. This class, however, has recently been shown to be in conflict with Solar System observations when accounting for the cosmological evolution of the scalar field. We here study whether this remains the case when the exponent of the conformal factor is positive, as well as in another class of theories defined by a hyperbolic conformal factor. We find that in both of these scalar-tensor theories, Solar System tests are passed only in a very small subset of coupling parameter space, for a large set of initial conditions compatible with big bang nucleosynthesis. However, while we find that it is possible for neutron stars to scalarize, one must carefully select the coupling parameter to do so, and even then, the scalar charge is typically 2 orders of magnitude smaller than in the negative-exponent case. Our study suggests that future work on scalar-tensor gravity, for example in the context of tests of general relativity with gravitational waves from neutron star binaries, should be carried out within the positive coupling parameter class.
Scalar field localization on deformed extra space
Energy Technology Data Exchange (ETDEWEB)
Rubin, Sergey G. [National Research Nuclear University ' ' MEPhI' ' (Moscow Engineering Physics Institute), Moscow (Russian Federation)
2015-07-15
Field localization on 2-dim extra space is considered in the framework of f(R) gravity. It is shown that interference of the local matter energy distribution and the metric of the extra space forms a point-like defect - a 4-dim brane. The energy-momentum of the brane depends on the initial conditions, which could lead to an arbitrarily small cosmological Λ term. (orig.)
Scalar field localization on deformed extra space
Rubin, Sergey G
2015-01-01
Field localization on 2-dim extra space is considered in the framework of f(R) gravity. It is shown that an interference of local matter energy distribution and a metric of the extra space form a point-like defect - 4-dim brane. The energy-momentum of the brane depends on initial conditions that could lead to the cosmological $\\Lambda$ term being arbitrarily small.
Polchinski ERG equation and 2D scalar field theory
Kubyshin, Yuri; Neves, Rui; Potting, Robertus
1998-01-01
We investigate a $Z_2$-symmetric scalar field theory in two dimensions using the Polchinski exact renormalization group equation expanded to second order in the derivative expansion. We find preliminary evidence that the Polchinski equation is able to describe the non-perturbative infinite set of fixed points in the theory space, corresponding to the minimal unitary series of 2D conformal field theories. We compute the anomalous scaling dimension $\\eta$ and the correlation l...
Scalar field as a Bose-Einstein condensate?
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Castellanos, Elías; Escamilla-Rivera, Celia [Mesoamerican Centre for Theoretical Physics (ICTP regional headquarters in Central America, the Caribbean and Mexico), Universidad Autónoma de Chiapas, Carretera Zapata Km. 4, Real del Bosque (Terán), 29040, Tuxtla Gutiérrez, Chiapas (Mexico); Macías, Alfredo [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, Mexico D.F. 09340 (Mexico); Núñez, Darío, E-mail: ecastellanos@mctp.mx, E-mail: cescamilla@mctp.mx, E-mail: amac@xanum.uam.mx, E-mail: nunez@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U., A.P. 70-543, México D.F. 04510 (Mexico)
2014-11-01
We discuss the analogy between a classical scalar field with a self-interacting potential, in a curved spacetime described by a quasi-bounded state, and a trapped Bose-Einstein condensate. In this context, we compare the Klein-Gordon equation with the Gross-Pitaevskii equation. Moreover, the introduction of a curved background spacetime endows, in a natural way, an equivalence to the Gross-Pitaevskii equation with an explicit confinement potential. The curvature also induces a position dependent self-interaction parameter. We exploit this analogy by means of the Thomas-Fermi approximation, commonly used to describe the Bose-Einstein condensate, in order to analyze the quasi bound scalar field distribution surrounding a black hole.
Higgs particles interacting via a scalar Dark Matter field
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Bhattacharya Yajnavalkya
2016-01-01
Full Text Available We study a system of two Higgs particles, interacting via a scalar Dark Matter mediating field. The variational method in the Hamiltonian formalism of QFT is used to derive relativistic wave equations for the two-Higgs system, using a truncated Fock-space trial state. Approximate solutions of the two-body equations are used to examine the existence of Higgs bound states.
Constraints from high redshift supernovae upon scalar field cosmologies
Energy Technology Data Exchange (ETDEWEB)
Frieman, J.A. [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois60510 (United States)]|[Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois60637 (United States); Waga, I. [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ, 21945-970 (Brazil)
1998-04-01
Recent observations of high-redshift type Ia supernovae have placed stringent constraints on the cosmological constant {Lambda}. We explore the implications of these SNe observations for cosmological models in which a classically evolving scalar field currently dominates the energy density of the Universe. Such models have been shown to share the advantages of {Lambda} models: compatibility with the spatial flatness predicted by inflation; a Universe older than the standard Einstein{endash}de Sitter model; and, combined with cold dark matter, predictions for large-scale structure formation in good agreement with data from galaxy surveys. Compared to the cosmological constant, these scalar field models are consistent with the SNe observations for a lower matter density, {Omega}{sub m0}{approximately}0.2, and a higher age, H{sub 0}t{sub 0}{approx_gt}1. Combined with the fact that scalar field models imprint a distinctive signature on the cosmic microwave background anisotropy, they remain currently viable and should be testable in the near future. {copyright} {ital 1998} {ital The American Physical Society}
Galilean-invariant scalar fields can strengthen gravitational lensing.
Wyman, Mark
2011-05-20
The mystery of dark energy suggests that there is new gravitational physics on long length scales. Yet light degrees of freedom in gravity are strictly limited by Solar System observations. We can resolve this apparent contradiction by adding a Galilean-invariant scalar field to gravity. Called Galileons, these scalars have strong self-interactions near overdensities, like the Solar System, that suppress their dynamical effect. These nonlinearities are weak on cosmological scales, permitting new physics to operate. In this Letter, we point out that a massive-gravity-inspired coupling of Galileons to stress energy can enhance gravitational lensing. Because the enhancement appears at a fixed scaled location for dark matter halos of a wide range of masses, stacked cluster analysis of weak lensing data should be able to detect or constrain this effect.
Extension of warm inflation to non-canonical scalar fields
Zhang, Xiao-Min
2014-01-01
We extend the warm inflationary scenario to the case of the non-canonical scalar fields. The equation of motion and the other basic equations of this new scenario are obtained. The Hubble damped term is enhanced in non-canonical inflation. A linear stability analysis is performed to give the proper slow roll conditions in warm non-canonical inflation. We study the density fluctuations in the new picture and obtain an approximate analytic expression of the power spectrum. The energy scale at the horizon crossing is depressed by both non-canonical effect and thermal effect, so does the tensor-to-scalar ratio. Besides the synergy, the non-canonical effect and the thermal effect are competing in the case of the warm non-canonical inflation.
Varying vacuum energy of a self-interacting scalar field
Trachenko, K.
2015-11-01
Understanding mechanisms capable of altering the vacuum energy is currently of interest in field theories and cosmology. We consider an interacting scalar field and show that the vacuum energy naturally takes any value between its maximum and zero because interaction affects the number of operating field modes, the assertion that involves no assumptions or postulates. The mechanism is similar to the recently discussed temperature evolution of collective modes in liquids. The cosmological implication concerns the evolution of scalar field ϕ during the inflation of the Universe. ϕ starts with all field modes operating and maximal vacuum energy in the early inflation-dominated epoch. As a result of inflation, ϕ undergoes a dynamical crossover and arrives in the state with one long-wavelength longitudinal mode and small positive vacuum energy predicted to be asymptotically decreasing to zero in the late epoch. Accordingly, we predict that the currently observed cosmological constant will decrease in the future, and comment on the possibility of a cyclic Universe.
Visibility graphs of random scalar fields and spatial data
Lacasa, Lucas; Iacovacci, Jacopo
2017-07-01
We extend the family of visibility algorithms to map scalar fields of arbitrary dimension into graphs, enabling the analysis of spatially extended data structures as networks. We introduce several possible extensions and provide analytical results on the topological properties of the graphs associated to different types of real-valued matrices, which can be understood as the high and low disorder limits of real-valued scalar fields. In particular, we find a closed expression for the degree distribution of these graphs associated to uncorrelated random fields of generic dimension. This result holds independently of the field's marginal distribution and it directly yields a statistical randomness test, applicable in any dimension. We showcase its usefulness by discriminating spatial snapshots of two-dimensional white noise from snapshots of a two-dimensional lattice of diffusively coupled chaotic maps, a system that generates high dimensional spatiotemporal chaos. The range of potential applications of this combinatorial framework includes image processing in engineering, the description of surface growth in material science, soft matter or medicine, and the characterization of potential energy surfaces in chemistry, disordered systems, and high energy physics. An illustration on the applicability of this method for the classification of the different stages involved in carcinogenesis is briefly discussed.
Scalar field collapse in a conformally flat spacetime
Energy Technology Data Exchange (ETDEWEB)
Chakrabarti, Soumya; Banerjee, Narayan [Indian Institute of Science Education and Research, Kolkata, Department of Physical Sciences, Mohanpur, West Bengal (India)
2017-03-15
The collapse scenario of a scalar field along with a perfect fluid distribution was investigated for a conformally flat spacetime. The theorem for the integrability of an anharmonic oscillator has been utilized. For a pure power-law potential of the form φ{sup n+1}, it was found that a central singularity is formed which is covered by an apparent horizon for n > 0 and n < -3. Some numerical results have also been presented for a combination of two different powers of φ in the potential. (orig.)
Topological geons with self-gravitating phantom scalar field
Kratovitch, P. V.; Potashov, I. M.; Tchemarina, Ju V.; Tsirulev, A. N.
2017-12-01
A topological geon is the quotient manifold M/Z 2 where M is a static spherically symmetric wormhole having the reflection symmetry with respect to its throat. We distinguish such asymptotically at solutions of the Einstein equations according to the form of the time-time metric function by using the quadrature formulas of the so-called inverse problem for self-gravitating spherically symmetric scalar fields. We distinguish three types of geon spacetimes and illustrate them by simple examples. We also study possible observational effects associated with bounded geodesic motion near topological geons.
Stable cosmological models driven by a free quantum scalar field
Energy Technology Data Exchange (ETDEWEB)
Dappiaggi, C.; Pinamonti, N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Citta Univ., Roma (Italy). Istituto Nazionale di Alta Matematica ' ' F. Severi' ' - GNFM; Fredenhagen, K. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2008-01-15
In the mathematically rigorous analysis of semiclassical Einstein's equations, the renormalisation of the stress-energy tensor plays a crucial role. We address such a topic in the case of a scalar field with both arbitrary mass and coupling with gravity in the hypothesis that the underlying algebraic quantum state is of Hadamard type. Particularly, if we focus on highly symmetric solutions of the semiclassical Einstein's equations, the envisaged method displays a de Sitter type behaviour even without an a priori introduced cosmological constant. As a further novel result we shall show that these solutions turn out to be stable. (orig.)
Non-Gaussianity from Self-Ordering Scalar Fields
Figueroa, Daniel G; Kamionkowski, Marc
2010-01-01
The Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of matter to allow for direct detection. The non-Gaussian statistics of the density perturbations induced by these fields, however, permit a direct means to probe for these relics. Here we calculate the bispectrum that arises in models of self-ordered scalar fields. We find a compact analytic expression for the bispectrum, evaluate it numerically, and provide a simple approximation that may be useful for data analysis. The bispectrum is largest for triangles that are aligned (have edges $k_1\\simeq 2 k_2 \\simeq 2 k_3$) as opposed to the local-model bispectrum, which peaks for squeezed triangles ($k_1\\simeq k_2 \\gg k_3$), and the equilateral bispectrum, which peaks at $k_1\\simeq k_2 \\simeq k_3$. We estimate that this non-...
Massless Interacting Scalar Fields in de Sitter space
Directory of Open Access Journals (Sweden)
Nacir Diana López
2016-01-01
Full Text Available We present a method to compute the two-point functions for an O(N scalar field model in de Sitter spacetime, avoiding the well known infrared problems for massless fields. The method is based on an exact treatment of the Euclidean zero modes and a perturbative one of the nonzero modes, and involves a partial resummation of the leading secular terms. This resummation, crucial to obtain a decay of the correlation functions, is implemented along with a double expansion in an effective coupling constant √λ and in 1/N. The results reduce to those known in the leading infrared approximation and coincide with the ones obtained directly in Lorentzian de Sitter spacetime in the large N limit. The new method allows for a systematic calculation of higher order corrections both in √λ and in 1/N.
Massless Interacting Scalar Fields in de Sitter space
López Nacir, Diana
2016-10-28
We present a method to compute the two-point functions for an $O(N)$ scalar field model in de Sitter spacetime, avoiding the well known infrared problems for massless fields. The method is based on an exact treatment of the Euclidean zero modes and a perturbative one of the nonzero modes, and involves a partial resummation of the leading secular terms. This resummation, crucial to obtain a decay of the correlation functions, is implemented along with a double expansion in an effective coupling constant $\\sqrt\\lambda$ and in $1/N$. The results reduce to those known in the leading infrared approximation and coincide with the ones obtained directly in Lorentzian de Sitter spacetime in the large $N$ limit. The new method allows for a systematic calculation of higher order corrections both in $\\sqrt\\lambda$ and in $1/N$.
Group field theory for quantum gravity minimally coupled to a scalar field
Li, Yang; Oriti, Daniele; Zhang, Mingyi
2017-10-01
We construct a group field theory model for quantum gravity minimally coupled to relativistic scalar fields, defining as well a corresponding discrete gravity path integral (and, implicitly, a coupled spin foam model) in its Feynman expansion. We also analyze a number of variations of the same model, the corresponding discrete gravity path integrals, its generalization to the coupling of multiple scalar fields and discuss its possible applications to the extraction of effective cosmological dynamics from the full quantum gravity formalism, in the context of group field theory condensate cosmology.
Nandi, Debottam
2016-01-01
In this work, we present a consistent Hamiltonian analysis of cosmological perturbations for generalized non-canonical scalar fields. In order to do so, we introduce a new phase-space variable that is uniquely defined for different non-canonical scalar fields. We also show that this is the simplest and efficient way of expressing the Hamiltonian. We extend the Hamiltonian approach of [arXiv:1512.02539] to non-canonical scalar field and obtain a new definition of speed of sound in phase-space. In order to invert generalized phase-space Hamilton's equations to Euler-Lagrange equations of motion, we prescribe a general inversion formulae and show that our approach for non-canonical scalar field is consistent. We also obtain the third and fourth order interaction Hamiltonian for generalized non-canonical scalar fields and briefly discuss the extension of our method to generalized Galilean scalar fields.
AdS Black Hole with Phantom Scalar Field
Directory of Open Access Journals (Sweden)
Limei Zhang
2017-01-01
Full Text Available We present an AdS black hole solution with Ricci flat horizon in Einstein-phantom scalar theory. The phantom scalar fields just depend on the transverse coordinates x and y, which are parameterized by the parameter α. We study the thermodynamics of the AdS phantom black hole. Although its horizon is a Ricci flat Euclidean space, we find that the thermodynamical properties of the black hole solution are qualitatively the same as those of AdS Schwarzschild black hole. Namely, there exists a minimal temperature and the large black hole is thermodynamically stable, while the smaller one is unstable, so there is a so-called Hawking-Page phase transition between the large black hole and the thermal gas solution in the AdS space-time in Poincare coordinates. We also calculate the entanglement entropy for a strip geometry dual to the AdS phantom black holes and find that the behavior of the entanglement entropy is qualitatively the same as that of the black hole thermodynamical entropy.
Neutron Star Structure in the Presence of Conformally Coupled Scalar Fields
Sultana, Joseph; Bose, Benjamin; Kazanas, Demosthenes
2014-01-01
Neutron star models are studied in the context of scalar-tensor theories of gravity in the presence of a conformally coupled scalar field, using two different numerical equations of state (EoS) representing different degrees of stiffness. In both cases we obtain a complete solution by matching the interior numerical solution of the coupled Einstein-scalar field hydrostatic equations, with an exact metric on the surface of the star. These are then used to find the effect of the scalar field and its coupling to geometry, on the neutron star structure, particularly the maximum neutron star mass and radius. We show that in the presence of a conformally coupled scalar field, neutron stars are less dense and have smaller masses and radii than their counterparts in the minimally coupled case, and the effect increases with the magnitude of the scalar field at the center of the star.
Ignat'ev, Yu G
2016-01-01
In this paper we investigate the asymptotic behavior of the cosmological model based on phantom scalar field on the ground of qualitative analysis of the system of the cosmological model's differential equations and show that as opposed to models with classical scalar field, such models have stable asymptotic solutions with constant value of the potential both in infinite past and infinite future. We also develop numerical models of the cosmological evolution models with phantom scalar field in this paper. {\\bf keywords}: cosmological model, phantom scalar field, quality analysis, asymptotic behavior, numerical simulation, numerical gravitation.\\\\ {\\bf PACS}: 04.20.Cv, 98.80.Cq, 96.50.S 52.27.Ny
Nonequlibrium dynamics of scalar fields in a thermal bath
Energy Technology Data Exchange (ETDEWEB)
Anisimov, A.; Buchmueller, W.; Drewes, M.; Mendizabal, S.
2008-12-15
We study the approach to equilibrium for a scalar field which is coupled to a large thermal bath. Our analysis of the initial value problem is based on Kadanoff-Baym equations which are shown to be equivalent to a stochastic Langevin equation. The interaction with the thermal bath generates a temperature-dependent spectral density, either through decay and inverse decay processes or via Landau damping. In equilibrium, energy density and pressure are determined by the Bose-Einstein distribution function evaluated at a complex quasi-particle pole. The time evolution of the statistical propagator is compared with solutions of the Boltzmann equations for particles as well as quasi-particles. The dependence on initial conditions and the range of validity of the Boltzmann approximation are determined. (orig.)
On Naturalness of Scalar Fields and Standard Model
Pivovarov, Grigorii B
2008-01-01
We discuss how naturalness predicts the scale of new physics. Two conditions on the scale are considered. The first is the more conservative condition due to Veltman (Acta Phys. Polon. B 12, 437 (1981)). It requires that radiative corrections to the electroweak mass scale would be reasonably small. The second is the condition due to Barbieri and Giudice (Nucl. Phys. B 306, 63 (1988)), which is more popular lately. It requires that physical mass scale would not be oversensitive to the values of the input parameters. We show here that the above two conditions behave differently if higher order corrections are taken into account. Veltman's condition is robust (insensitive to higher order corrections), while Barbieri-Giudice condition changes qualitatively. We conclude that higher order perturbative corrections take care of the fine tuning problem, and, in this respect, scalar field is a natural system. We apply the Barbieri-Giudice condition with higher order corrections taken into account to the Standard Model,...
Qualitative analysis and characterization of two cosmologies including scalar fields
Leon, Genly
2014-01-01
The problem of dark energy can be roughly stated as the proposition and validation of a cosmological model that can explain the phenomenon of the accelerated expansion of the Universe. This problem is an open discussion topic in modern physics. One of the most common approaches is that of the "Dark Energy" (DE), a matter component still unknown, with repulsive character (to explain the accelerated expansion), which fills about 2/3 of the total content of the Universe. In this thesis are investigated two cosmological models, a non-minimally coupled quintessence field, based on a Scalar-Tensor Theory of gravity, formulated in the Einstein's frame, and a quintom dark energy model, based on General Relativity. A normalization and parametrization procedure is introduced for each model, in order to investigate the flow properties of an associated autonomous system of ordinary differential equations. In our study are combined topological, analytical and numerical techniques. We are mainly interested in the past dyna...
Gravitomagnetic effects in quadratic gravity with a scalar field
Finch, Andrew
2016-01-01
The two gravitomagnetic effects which influence bodies orbiting around a gravitational source are the geodetic effect and the Lense-Thirring effect. The former describes the precession angle of the axis of a spinning gyroscope while in orbit around a nonrotating gravitational source whereas the latter provides a correction for this angle in the case of a spinning source. In this paper we derive the relevant equations in quadratic gravity and relate them to their equivalents in general relativity. Starting with an investigation into Kepler's third law in quadratic gravity with a scalar field, the effects of an axisymmetric and rotating gravitational source on an orbiting body in a circular, equatorial orbit are introduced.
Scalar field dark matter in clusters of galaxies
Bernal, Tula; Robles, Victor H.; Matos, Tonatiuh
2017-07-01
One alternative to the cold dark matter (CDM) paradigm is the scalar field dark matter (SFDM) model, which assumes dark matter is a spin-0 ultra-light scalar field (SF) with a typical mass m ˜ 10-22 eV/c2 and positive self-interactions. Due to the ultra-light boson mass, the SFDM could form Bose-Einstein condensates (BEC) in the very early Universe, which are interpreted as the dark matter haloes. Although cosmologically the model behaves as CDM, they differ at small scales: SFDM naturally predicts fewer satellite haloes, cores in dwarf galaxies and the formation of massive galaxies at high redshifts. The ground state (or BEC) solution at zero temperature suffices to describe low-mass galaxies but fails for larger systems. A possible solution is adding finite-temperature corrections to the SF potential which allows combinations of excited states. In this work, we test the finite-temperature multistate SFDM solution at galaxy cluster scales and compare our results with the Navarro-Frenk-White (NFW) and BEC profiles. We achieve this by fitting the mass distribution of 13 Chandra X-ray clusters of galaxies, excluding the region of the brightest cluster galaxy. We show that the SFDM model accurately describes the clusters' DM mass distributions offering an equivalent or better agreement than the NFW profile. The complete disagreement of the BEC model with the data is also shown. We conclude that the theoretically motivated multistate SFDM profile is an interesting alternative to empirical profiles and ad hoc fitting-functions that attempt to couple the asymptotic NFW decline with the inner core in SFDM.
Scalar field coupling to Einstein tensor in regular black hole spacetime
Zhang, Chi; Wu, Chen
2018-02-01
In this paper, we study the perturbation property of a scalar field coupling to Einstein's tensor in the background of the regular black hole spacetimes. Our calculations show that the the coupling constant η imprints in the wave equation of a scalar perturbation. We calculated the quasinormal modes of scalar field coupling to Einstein's tensor in the regular black hole spacetimes by the 3rd order WKB method.
Uniqueness theorem for static wormholes in Einstein phantom scalar field theory
Yazadjiev, Stoytcho
2017-08-01
In the present paper we prove a uniqueness theorem for the regular static, traversable wormhole solutions to the Einstein phantom scalar field theory with two asymptotically flat regions (ends). We show that when a certain condition on the asymptotic values of the scalar field is imposed such solutions are uniquely specified by their mass M and the scalar charge D . The main arguments in the proof are based on the positive energy theorem.
Dănilă, Bogdan; Mak, Man Kwong; Pantaragphong, Praiboon; Sabau, Sorin
2016-01-01
We perform the study of the stability of the cosmological scalar field models, by using the Jacobi stability analysis, or the Kosambi-Cartan-Chern (KCC) theory. In the KCC approach we describe the time evolution of the scalar field cosmologies in geometric terms, by performing a "second geometrization", by considering them as paths of a semispray. By introducing a non-linear connection and a Berwald type connection associated to the Friedmann and Klein-Gordon equations, five geometrical invariants can be constructed, with the second invariant giving the Jacobi stability of the cosmological model. We obtain all the relevant geometric quantities, and we formulate the condition of the Jacobi stability for scalar field cosmologies in the second order formalism. As an application of the developed methods we consider the Jacobi stability properties of the scalar fields with exponential and Higgs type potential. We find that the Universe dominated by a scalar field exponential potential is in Jacobi unstable state, ...
Self-interacting scalar fields at high-temperature
Energy Technology Data Exchange (ETDEWEB)
Deur, Alexandre [University of Virginia, Charlottesville, VA (United States)
2017-06-15
We study two self-interacting scalar field theories in their high-temperature limit using path integrals on a lattice. We first discuss the formalism and recover known potentials to validate the method. We then discuss how these theories can model, in the high-temperature limit, the strong interaction and General Relativity. For the strong interaction, the model recovers the known phenomenology of the nearly static regime of heavy quarkonia. The model also exposes a possible origin for the emergence of the confinement scale from the approximately conformal Lagrangian. Aside from such possible insights, the main purpose of addressing the strong interaction here - given that more sophisticated approaches already exist - is mostly to further verify the pertinence of the model in the more complex case of General Relativity for which non-perturbative methods are not as developed. The results have important implications on the nature of Dark Matter. In particular, non-perturbative effects naturally provide flat rotation curves for disk galaxies, without need for non-baryonic matter, and explain as well other observations involving Dark Matter such as cluster dynamics or the dark mass of elliptical galaxies. (orig.)
Gravitational waves from self-ordering scalar fields
Fenu, Elisa; Durrer, Ruth; Garcia-Bellido, Juan
2009-01-01
Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as $\\Omega_{\\rm GW}(f) \\propto f^3$ with an amplitude much too small to be observable by gravitational wave observatories like LIGO, LISA or BBO. On the other hand, if the source is active for a much longer tim...
Scalar field self-force effects on a particle orbiting a Reissner-Nordstrom black hole
Bini, Donato; Geralico, Andrea
2016-01-01
Scalar field self-force effects on a scalar charge orbiting a Reissner-Nordstr\\"om black hole are investigated. The scalar wave equation is solved analytically in a post-Newtonian framework, and the solution is used to compute the self-field as well as the components of the self-force at the particle's location up to 7.5 post-Newtonian order. The energy fluxes radiated to infinity and down the hole are also evaluated. Comparison with previous numerical results in the Schwarzschild case shows a good agreement in both strong-field and weak-field regimes.
Directory of Open Access Journals (Sweden)
Nakwoo Kim
2015-03-01
Full Text Available We consider scalar fields which are coupled to Einstein gravity with a negative cosmological constant, and construct periodic solutions perturbatively. In particular, we study tachyonic scalar fields whose mass is at or above the Breitenlohner–Freedman bound in four, five, and seven spacetime dimensions. The critical amplitude of the leading order perturbation, for which the perturbative expansion breaks down, increases as we consider less massive fields. We present various examples including a model with a self-interacting scalar field which is derived from a consistent truncation of IIB supergravity.
Elperin, T; Kleeorin, N; Rogachevskii, I; Sokoloff, D
2001-08-01
Mean-field theory for turbulent transport of a passive scalar (e.g., particles and gases) is discussed. Equations for the mean number density of particles advected by a random velocity field, with a finite correlation time, are derived. Mean-field equations for a passive scalar comprise spatial derivatives of high orders due to the nonlocal nature of passive scalar transport in a random velocity field with a finite correlation time. A turbulent velocity field with a random renewal time is considered. This model is more realistic than that with a constant renewal time used by Elperin et al. [Phys. Rev. E 61, 2617 (2000)], and employs two characteristic times: the correlation time of a random velocity field tau(c), and a mean renewal time tau. It is demonstrated that the turbulent diffusion coefficient is determined by the minimum of the times tau(c) and tau. The mean-field equation for a passive scalar was derived for different ratios of tau/tau(c). The important role of the statistics of the field of Lagrangian trajectories in turbulent transport of a passive scalar, in a random velocity field with a finite correlation time, is demonstrated. It is shown that in the case tau(c)
arXiv Tensor to scalar ratio from single field magnetogenesis
Giovannini, Massimo
2017-08-10
The tensor to scalar ratio is affected by the evolution of the large-scale gauge fields potentially amplified during an inflationary stage of expansion. After deriving the exact evolution equations for the scalar and tensor modes of the geometry in the presence of dynamical gauge fields, it is shown that the tensor to scalar ratio is bounded from below by the dominance of the adiabatic contribution and it cannot be smaller than one thousands whenever the magnetogenesis is driven by a single inflaton field.
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar, E-mail: shaharhod@gmail.com [The Ruppin Academic Center, Emeq Hefer 40250 (Israel); The Hadassah Academic College, Jerusalem 91010 (Israel)
2017-05-10
We study analytically the characteristic resonance spectrum of charged massive scalar fields linearly coupled to a spherically symmetric charged reflecting shell. In particular, we use analytical techniques in order to solve the Klein–Gordon wave equation for the composed charged-shell–charged-massive-scalar-field system. Interestingly, it is proved that the resonant oscillation frequencies of this composed physical system are determined by the characteristic zeroes of the confluent hypergeometric function. Following this observation, we derive a remarkably compact analytical formula for the resonant oscillation frequencies which characterize the marginally-bound charged massive scalar field configurations. The analytically derived resonance spectrum is confirmed by numerical computations.
Evolution of perturbations in distinct classes of canonical scalar field models of dark energy
Jassal, H. K.
2009-01-01
Dark energy must cluster in order to be consistent with the equivalence principle. The background evolution can be effectively modelled by either a scalar field or by a barotropic fluid.The fluid model can be used to emulate perturbations in a scalar field model of dark energy, though this model breaks down at large scales. In this paper we study evolution of dark energy perturbations in canonical scalar field models: the classes of thawing and freezing models.The dark energy equation of stat...
Alhulaimi, B.; van den Hoogen, R. J.; Coley, A. A.
2017-12-01
Inflationary spatially homogeneous cosmological models within an Einstein-aether gravitational framework are investigated. The matter source is assumed to be a scalar field which is coupled to the aether field expansion and shear scalars through the generalized harmonic scalar field potential. The evolution equations are expressed in terms of expansion-normalized variables to produce an autonomous system of ordinary differential equations suitable for numerical and local stability analysis. An analysis of the local stability of the equilibrium points indicates that there exists a range of values of the parameters in which there exists an accelerating expansionary future attractor.
A late time accelerated FRW model with scalar and vector fields via Noether symmetry
Directory of Open Access Journals (Sweden)
Babak Vakili
2014-11-01
Full Text Available We study the evolution of a three-dimensional minisuperspace cosmological model by the Noether symmetry approach. The phase space variables turn out to correspond to the scale factor of a flat Friedmann–Robertson–Walker (FRW model, a scalar field with potential function V(ϕ with which the gravity part of the action is minimally coupled and a vector field of its kinetic energy is coupled with the scalar field by a coupling function f(ϕ. Then, the Noether symmetry of such a cosmological model is investigated by utilizing the behavior of the corresponding Lagrangian under the infinitesimal generator of the desired symmetry. We explicitly calculate the form of the coupling function between the scalar and the vector fields and also the scalar field potential function for which such symmetry exists. Finally, by means of the corresponding Noether current, we integrate the equations of motion and obtain exact solutions for the scale factor, scalar and vector fields. It is shown that the resulting cosmology is an accelerated expansion universe for which its expansion is due to the presence of the vector field in the early times, while the scalar field is responsible of its late time expansion.
A late time accelerated FRW model with scalar and vector fields via Noether symmetry
Energy Technology Data Exchange (ETDEWEB)
Vakili, Babak, E-mail: b-vakili@iauc.ac.ir
2014-11-10
We study the evolution of a three-dimensional minisuperspace cosmological model by the Noether symmetry approach. The phase space variables turn out to correspond to the scale factor of a flat Friedmann–Robertson–Walker (FRW) model, a scalar field with potential function V(ϕ) with which the gravity part of the action is minimally coupled and a vector field of its kinetic energy is coupled with the scalar field by a coupling function f(ϕ). Then, the Noether symmetry of such a cosmological model is investigated by utilizing the behavior of the corresponding Lagrangian under the infinitesimal generator of the desired symmetry. We explicitly calculate the form of the coupling function between the scalar and the vector fields and also the scalar field potential function for which such symmetry exists. Finally, by means of the corresponding Noether current, we integrate the equations of motion and obtain exact solutions for the scale factor, scalar and vector fields. It is shown that the resulting cosmology is an accelerated expansion universe for which its expansion is due to the presence of the vector field in the early times, while the scalar field is responsible of its late time expansion.
Ignat'ev, Yu G
2015-01-01
The article proposes generalizations of the macroscopic model of plasma of scalar charged particles to the cases of inter-particle interaction with multiple scalar fields and negative effective masses of these particles. The model is based on the microscopic dynamics of a particle at presence of scalar fields. The theory is managed to be generalized naturally having strictly reviewed a series of its key positions depending on a sign of particle masses. Thereby, it is possible to remove the artificial restriction contradicting the more fundamental principle of action functional additivity. Additionally, as a condition of internal consistency of the theory, particle effective mass function is found.
Black holes from multiplets of scalar fields in 2 + 1- and 3 + 1 dimensions
Energy Technology Data Exchange (ETDEWEB)
Mazharimousavi, S.H.; Halilsoy, M. [Eastern Mediterranean Univ., Gazimagusa (Turkey). Dept. of Physics
2016-08-15
We obtain classes of black hole solutions constructed from multiplets of scalar fields in 2 + 1/3 + 1 dimensions. The multi-component scalars do not undergo a symmetry breaking so that only the isotropic modulus is effective. The Lagrangian is supplemented by a self-interacting potential which plays significant role in obtaining the exact solutions. In 2 + 1/3 + 1 dimensions, a doublet/triplet of scalars is effective, which enriches the available black hole spacetimes and creates useful Liouville weighted field theoretic models. (orig.)
New class of cosmological solutions for a self-interacting scalar field
Chaadaev, A. A.; Chervon, S. V.
2013-12-01
New cosmological solutions are found to the system of Einstein scalar field equations using the scalar field φ as the argument. For a homogeneous and isotropic Universe, the system of equations is reduced to two equations, one of which is an equation of Hamilton-Jacobi type. Using the hyperbolically parameterized representation of this equation together with the consistency condition, explicit dependences of the potential V of the scalar field and the Hubble parameter H on φ are obtained. The dependences of the scalar field and the scale factor a on cosmic time t have also been found. It is shown that this scenario corresponds to the evolution of the Universe with accelerated expansion out to times distant from the initial singularity.
Spontaneous scalarization with an extremely massive field and heavy neutron stars
Morisaki, Soichiro; Suyama, Teruaki
2017-10-01
We investigate the internal structure and the mass-radius relation of neutron stars in a recently proposed scalar-tensor theory dubbed asymmetron in which a massive scalar field undergoes spontaneous scalarization inside neutron stars. We focus on the case where the Compton wavelength is shorter than 10 km, which has not been investigated in the literature. By solving the modified Einstein equations, either purely numerically or by partially using a semianalytic method, we find that not only the weakening of gravity by spontaneous scalarization but also the scalar force affect the internal structure significantly in the massive case. We also find that the maximum mass of neutron stars is larger for certain parameter sets than that in general relativity and reaches 2 M⊙ even if the effect of strange hadrons is taken into account. There is even a range of parameters where the maximum mass of neutron stars largely exceeds the threshold that violates the causality bound in general relativity.
Directory of Open Access Journals (Sweden)
Bogdan Dănilă
2016-01-01
Full Text Available We study the stability of the cosmological scalar field models by using the Jacobi stability analysis, or the Kosambi-Cartan-Chern (KCC theory. In this approach, we describe the time evolution of the scalar field cosmologies in geometric terms, by performing a “second geometrization” and considering them as paths of a semispray. By introducing a nonlinear connection and a Berwald-type connection associated with the Friedmann and Klein-Gordon equations, five geometrical invariants can be constructed, with the second invariant giving the Jacobi stability of the cosmological model. We obtain all the relevant geometric quantities, and we formulate the condition for Jacobi stability in scalar field cosmologies. We consider the Jacobi stability properties of the scalar fields with exponential and Higgs type potential. The Universe dominated by a scalar field exponential potential is in Jacobi unstable state, while the cosmological evolution in the presence of Higgs fields has alternating stable and unstable phases. We also investigate the stability of the phantom quintessence and tachyonic scalar field models, by lifting the first-order system to the tangent bundle. It turns out that in the presence of a power law potential both of these models are Jacobi unstable during the entire cosmological evolution.
Directory of Open Access Journals (Sweden)
Kazuharu Bamba
2014-10-01
Full Text Available We reconstruct scalar field theories to realize inflation compatible with the BICEP2 result as well as the Planck. In particular, we examine the chaotic inflation model, natural (or axion inflation model, and an inflationary model with a hyperbolic inflaton potential. We perform an explicit approach to find out a scalar field model of inflation in which any observations can be explained in principle.
Hawking radiation of five-dimensional charged black holes with scalar fields
Directory of Open Access Journals (Sweden)
Yan-Gang Miao
2017-09-01
Full Text Available We investigate the Hawking radiation cascade from the five-dimensional charged black hole with a scalar field coupled to higher-order Euler densities in a conformally invariant manner. We give the semi-analytic calculation of greybody factors for the Hawking radiation. Our analysis shows that the Hawking radiation cascade from this five-dimensional black hole is extremely sparse. The charge enhances the sparsity of the Hawking radiation, while the conformally coupled scalar field reduces this sparsity.
Wheeler-DeWitt equation and Lie symmetries in Bianchi scalar-field cosmology
Energy Technology Data Exchange (ETDEWEB)
Paliathanasis, A. [Universidad Austral de Chile, Instituto de Ciencias Fisicas y Matematicas, Valdivia (Chile); Karpathopoulos, L. [University of Athens, Faculty of Physics, Department of Astronomy-Astrophysics-Mechanics, Athens (Greece); Wojnar, A. [Institute for Theoretical Physics, Wroclaw (Poland); Universita' di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Complesso Universitario di Monte S. Angelo, Naples (Italy); Istituto Nazionale di Fisica Nucleare (INFN) Sez. di Napoli, Naples (Italy); Capozziello, S. [Universita' di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Complesso Universitario di Monte S. Angelo, Naples (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy); Istituto Nazionale di Fisica Nucleare (INFN) Sez. di Napoli, Naples (Italy)
2016-04-15
Lie symmetries are discussed for the Wheeler-De Witt equation in Bianchi Class A cosmologies. In particular, we consider general relativity, minimally coupled scalar-field gravity and hybrid gravity as paradigmatic examples of the approach. Several invariant solutions are determined and classified according to the form of the scalar-field potential. The approach gives rise to a suitable method to select classical solutions and it is based on the first principle of the existence of symmetries. (orig.)
Ignat'ev, Yurii
2014-01-01
In the article it is shown that at presence of fundamental scalar fields determining the masses of the scalar charged particles the global thermodynamic equilibrium (GTE) is compatible with a process of the cosmological expansion of the statistical system.
Superradiant instability of charged scalar field in stringy black hole mirror system
Energy Technology Data Exchange (ETDEWEB)
Li, Ran; Zhao, Junkun [Henan Normal University, Department of Physics, Xinxiang (China)
2014-09-15
It has been shown that the mass of a charged scalar field in the background of a charged stringy black hole is never able to generate a potential well outside the event horizon to trap the superradiant modes. This is to say that the charged stringy black hole is stable against massive charged scalar perturbations. In this paper we will study the superradiant instability of the massless scalar field in the background of charged stringy black hole due to a mirror-like boundary condition. The analytical expression of the frequencies of unstable superradiant modes is derived by using the asymptotic matching method. It is also pointed out that the black hole mirror system becomes extremely unstable for a large charge q of the scalar field and a small mirror radius r{sub m}. (orig.)
Slowly decaying resonances of massive scalar fields around Schwarzschild-de Sitter black holes
Toshmatov, Bobir; Stuchlík, Zdeněk
2017-07-01
We study in special limiting cases quasinormal modes of massive scalar fields in the Schwarzschild-de Sitter black hole backgrounds. We determine the lower limit on the mass parameter of the scalar field that allows the waves with quasinormal frequencies to propagate to infinity, showing that it depends on the spacetime parameters only. Then we discuss in the large multipole number limit quasinormal modes, whose frequencies can be directly related to the unstable circular photon geodesics. In the large scalar mass approximation, we demonstrate the new interesting phenomenon of slowly decaying resonances, that are strongly related to the maximum of the effective potential of the massive scalar field, which is located at the static radius of the Schwarzschild-de Sitter spacetimes, where the cosmic repulsion is just balanced by the black hole attraction.
Dark sector impact on gravitational collapse of an electrically charged scalar field
Energy Technology Data Exchange (ETDEWEB)
Nakonieczna, Anna [Institute of Physics, Maria Curie-Skłodowska University,Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin (Poland); Institute of Agrophysics, Polish Academy of Sciences,Doświadczalna 4, 20-290 Lublin (Poland); Rogatko, Marek [Institute of Physics, Maria Curie-Skłodowska University,Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin (Poland); Nakonieczny, Łukasz [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw,Pasteura 5, 02-093 Warszawa (Poland)
2015-11-04
Dark matter and dark energy are dominating components of the Universe. Their presence affects the course and results of processes, which are driven by the gravitational interaction. The objective of the paper was to examine the influence of the dark sector on the gravitational collapse of an electrically charged scalar field. A phantom scalar field was used as a model of dark energy in the system. Dark matter was modeled by a complex scalar field with a quartic potential, charged under a U(1)-gauge field. The dark components were coupled to the electrically charged scalar field via the exponential coupling and the gauge field-Maxwell field kinetic mixing, respectively. Complete non-linear simulations of the investigated process were performed. They were conducted from regular initial data to the end state, which was the matter dispersal or a singularity formation in a spacetime. During the collapse in the presence of dark energy dynamical wormholes and naked singularities were formed in emerging spacetimes. The wormhole throats were stabilized by the violation of the null energy condition, which occurred due to a significant increase of a value of the phantom scalar field function in its vicinity. The square of mass parameter of the dark matter scalar field potential controlled the formation of a Cauchy horizon or wormhole throats in the spacetime. The joint impact of dark energy and dark matter on the examined process indicated that the former decides what type of an object forms, while the latter controls the amount of time needed for the object to form. Additionally, the dark sector suppresses the natural tendency of an electrically charged scalar field to form a dynamical Reissner-Nordström spacetime during the gravitational collapse.
Equilibrium Statistical Thermodynamics of a Many-Particle System Coupled to an External Scalar Field
Salvino, R. E.
1990-01-01
The equilibrium thermodynamics of a many-particle assembly in the presence of an external scalar field is examined. Two types of scalar coupling are considered: an external field coupled to the particle density and an external scalar field coupled to the energy density. It is shown that the broken translational and rotational invariance of the system due to the external field is reflected in the macroscopic physics by loss of the usual extensivity property of the system and by means of anisotropy in the response of the system to changes in the system lengths or to the system shape. In addition, the assumptions used in local equilibrium analyses are shown to be incorrect in principle. Nonlocal effects due to the external field must be included in the determination of the equation of state. Simple model calculations for a system in an external gravitational field and an externally imposed temperature field are presented as illustrations.
Master formulas for the dressed scalar propagator in a constant field
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Aftab [Department of Physics, Gomal University, 29220 D.I. Khan, K.P.K (Pakistan); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia 58040, Michoacán (Mexico); Ahmadiniaz, Naser, E-mail: Ahmadiniaz@ibs.re.kr [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Department of Physics, Kunsan National University, Kunsan 54150 (Korea, Republic of); Corradini, Olindo [Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Via Campi 213/A, I-41125 Modena (Italy); INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Kim, Sang Pyo [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Department of Physics, Kunsan National University, Kunsan 54150 (Korea, Republic of); Schubert, Christian [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia 58040, Michoacán (Mexico)
2017-06-15
The worldline formalism has previously been used for deriving compact master formulas for the one-loop N-photon amplitudes in both scalar and spinor QED, and in the vacuum as well as in a constant external field. For scalar QED, there is also an analogous master formula for the propagator dressed with N photons in the vacuum. Here, we extend this master formula to include a constant field. The two-photon case is worked out explicitly, yielding an integral representation for the Compton scattering cross section in the field suitable for numerical integration in the full range of electric and magnetic field strengths.
Master formulas for the dressed scalar propagator in a constant field
Directory of Open Access Journals (Sweden)
Aftab Ahmad
2017-06-01
Full Text Available The worldline formalism has previously been used for deriving compact master formulas for the one-loop N-photon amplitudes in both scalar and spinor QED, and in the vacuum as well as in a constant external field. For scalar QED, there is also an analogous master formula for the propagator dressed with N photons in the vacuum. Here, we extend this master formula to include a constant field. The two-photon case is worked out explicitly, yielding an integral representation for the Compton scattering cross section in the field suitable for numerical integration in the full range of electric and magnetic field strengths.
Scalar-field quintessence by cosmic shear: CFHT data analysis and forecasts for DUNE
Energy Technology Data Exchange (ETDEWEB)
Schimd, C [DAPNIA, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Tereno, I [Argelander-Institut fuer Astronomie, Universitaet Bonn, 53121 Bonn (Germany)
2007-06-22
A light scalar field, minimally or not-minimally coupled to the metric field, is a well-defined candidate for the dark energy, alleviating the fine-tuning problem intrinsic to the cosmological constant and avoiding the difficulties of parameterizations. We present a general description of the weak gravitational lensing valid for every metric theory of gravity, including vector and tensor perturbations for a non-flat spatial metric. Based on this description, we investigate two minimally coupled scalar-field quintessence models using VIRMOS-Descart and CFHTLS cosmic-shear data, and forecast the constraints for the proposed space-borne wide-field imager DUNE.
Scalar field with the source in the form of the stress-energy tensor trace as a dark energy model
Dudko, I G
2016-01-01
We consider a scalar-tensor theory of gravitation with the scalar source being the trace of the stress-energy tensor of the scalar field itself and matter. We obtain an example of a numerical solution of the cosmological equations which shows that under some special choice of the scalar parameters, there exists a slow-roll regime in which the modern values of the Hubble and deceleration parameters may be obtained.
Dynamical system of scalar field from 2-dimension to 3-D and its cosmological implications
Fang, Wei; Tu, Hong; Huang, Jiasheng; Shu, Chenggang
2016-09-01
We give the three-dimensional dynamical autonomous systems for most of the popular scalar field dark energy models including (phantom) quintessence, (phantom) tachyon, K-essence, and general non-canonical scalar field models, change the dynamical variables from variables (x, y, λ ) to observable related variables (w_{φ }, Ω _{φ }, λ ), and show the intimate relationships between those scalar fields that the three-dimensional system of K-essence can reduce to (phantom) tachyon, general non-canonical scalar field can reduce to (phantom) quintessence and K-essence can also reduce to (phantom) quintessence for some special cases. For the applications of the three-dimensional dynamical systems, we investigate several special cases and give the exactly dynamical solutions in detail. In the end of this paper, we argue that it is more convenient and also has more physical meaning to express the differential equations of dynamical systems in (w_{φ }, Ω _{φ }, λ ) instead of variables (x, y, λ ) and to investigate the dynamical system in three dimensions instead of two dimensions. We also raise a question about the possibility of the chaotic behavior in the spatially flat single scalar field FRW cosmological models in the presence of ordinary matter.
Analytical study of a Kerr-Sen black hole and a charged massive scalar field
Bernard, Canisius
2017-11-01
It is reported that Kerr-Newman and Kerr-Sen black holes are unstable to perturbations of charged massive scalar field. In this paper, we study analytically the complex frequencies which characterize charged massive scalar fields in a near-extremal Kerr-Sen black hole. For near-extremal Kerr-Sen black holes and for charged massive scalar fields in the eikonal large-mass M ≫μ regime, where M is the mass of the black hole, and μ is the mass of the charged scalar field, we have obtained a simple expression for the dimensionless ratio ωI/(ωR-ωc) , where ωI and ωR are, respectively, the imaginary and real parts of the frequency of the modes, and ωc is the critical frequency for the onset of super-radiance. We have also found our expression is consistent with the result of Hod [Phys. Rev. D 94, 044036 (2016), 10.1103/PhysRevD.94.044036] for the case of a near-extremal Kerr-Newman black hole and the result of Zouros and Eardly [Ann. Phys. (N.Y.) 118, 139 (1979), 10.1016/0003-4916(79)90237-9] for the case of neutral scalar fields in the background of a near-extremal Kerr black hole.
Decoherence and disentanglement of qubits detecting scalar fields in an expanded universe
Li, Yujie; Shi, Yu
2016-01-01
We consider Unruh-Wald qubit detector model adopted for the far future region of an exactly solvable 1+1 dimensional scalar field theory in a Robertson-Walker expanding spacetime. It is shown that the expansion of the universe in its history enhances the decoherence of the qubit coupled with a scalar field. Moreover, we consider two entangled qubits, each locally coupled a scalar field. The expansion of the universe in its history degrades the entanglement between the qubits, and can lead to entanglement sudden death if the initial entanglement is small enough. The details depend on the parameters characterizing the expansion of the universe. This work, albeit on a toy model, suggests that the history of the universe might be probed through the coherent and entanglement behavior of future detectors of quantum fields.
Reconstruction of inflation from scalar field non-minimally coupled with the Gauss-Bonnet term
Sebastiani, Lorenzo; Myrzakul, Shynaray; Myrzakulov, Ratbay
2017-12-01
In this paper, we analyze the early time inflation in a scalar-tensor theory of gravity where the scalar field is minimally coupled with the Gauss-Bonnet four-dimensional topological invariant. The theory belongs to a class of Horndeski models where the field equations are at the second order, like in General Relativity. A viable inflationary scenario must correctly reproduce the last Plank satellite data. By starting from some simple assumptions on the field and on the coupling function between the field and the Gauss-Bonnet term, we derive the spectral index and the tensor-to-scalar ratio of the model. Once the model is viable, it is finally possible to fully reconstruct its Lagrangian.
Building a holographic superconductor with a scalar field coupled kinematically to Einstein tensor
Energy Technology Data Exchange (ETDEWEB)
Kuang, Xiao-Mei [Instituto de Física, Pontificia Universidad Católica de Valparaíso,Casilla 4059, Valparaíso (Chile); Papantonopoulos, Eleftherios [Physics Division, National Technical University of Athens,15780 Zografou Campus, Athens (Greece)
2016-08-29
We study the holographic dual description of a superconductor in which the gravity sector consists of a Maxwell field and a charged scalar field which except its minimal coupling to gravity it is also coupled kinematically to Einstein tensor. As the strength of the new coupling is increased, the critical temperature below which the scalar field condenses is lowering, the condensation gap decreases faster than the temperature, the width of the condensation gap is not proportional to the size of the condensate and at low temperatures the condensation gap tends to zero for the strong coupling. These effects which are the result of the presence of the coupling of the scalar field to the Einstein tensor in the gravity bulk, provide a dual description of impurities concentration in a superconducting state on the boundary.
Can LIGO Directly Detect the Scalar Field Dark Energy of 5D Gravity?
Zhang, Tianxi
2017-06-01
The observed acceleration of the present universe is commonly attributed to the existence of dark energy as a dominant component throughout the universe. A direct detection of dark energy has become one of the most important issues in the modern astrophysics and cosmology. Two widely accepted candidates of the dark energy are the cosmological constant Λ and the quintessence. Unlike the cosmological constant, the quintessence is a scalar field Φ that varies throughout spacetime, and has been modelled in various ways such as the four-dimensional (4D) Brans-Dicke scalar-tensor theory of gravitation and the five-dimensional (5D) Kaluza-Klein scalar-vector-tensor theory of gravitation. The scalar field of 5D gravity was shown to be capable of polarizing the space or vacuum and thus can extend the optical length of the path of a laser beam that passes through the polarized space or vacuum. Recently, the author, in terms of his 5D fully covariant Kaluza-Klein scalar-vector-tensor theory of gravitation, has quantitatively related the dielectric constant of the polarized vacuum (and thus the optical length of the path in the polarized vacuum) to the charge-mass ratio of a charged object. This study further demonstrates that the vacuum polarization by the scalar field dark energy of 5D gravity, when the object is highly charged, can be significant enough for the extremely accurate LIGO, which has recently detected first ever the gravitational waves from the binary black hole merger, to directly detect. It is shown that a some-thousand-kilogram sphere electrically charged to tens of kilovolts can polarize the vacuum by its scalar field dark energy and thus extend the optical path length of a laser beam that travels through one LIGO arm with some hundred reflections by approximately 10-18 m, which is one-order higher than that to be detected by the LIGO detectors. Therefore, being added a highly charged sphere into the experimental setup, LIGO may directly discover the
First scalar magnetic anomaly map from CHAMP satellite data indicates weak lithospheric field
DEFF Research Database (Denmark)
Maus, S.; Rother, M.; Holme, R.
2002-01-01
Satellite magnetic anomaly maps derived by different techniques from Magsat/POGO data vary by more than a factor of 2 in the deduced strength of the lithospheric magnetic field. Here, we present a first anomaly map from new CHAMP scalar magnetic field data. After subtracting a recent Ørsted main...
Closed star product on noncommutative ℝ 3 and scalar field dynamics
Jurić, Tajron; Poulain, Timothé; Wallet, Jean-Christophe
2016-01-01
We consider the noncommutative space $\\mathbb{R}^3_\\theta$, a deformation of $\\mathbb{R}^3$ for which the star product is closed for the trace functional. We study one-loop IR and UV properties of the 2-point function for real and complex noncommutative scalar field theories with quartic interactions and Laplacian on $\\mathbb{R}^3$ as kinetic operator. We find that the 2-point functions for these noncommutative scalar field theories have no IR singularities in the external momenta, indicating...
Scalar source in circular motion interacting with massive klein-gordon field in Minkowski spacetime
CRISPINO, Luís Carlos Bassalo; MEIRA FILHO, Damião Pedro
2005-01-01
We analyze the scalar radiation emitted by a source in uniform circular motion in Minkowski spacetime interacting with a massive Klein-Gordon field. We assume the source rotating around a central object due to a Newtonian force. By considering the canonical quantization of this field, we use perturbation theory to compute the radiation emitted at the tree level. Regarding the initial state of the field as being the Minkowski vacuum, we compute the emission amplitude for the rotating source, a...
Ultra-spinning exotic compact objects supporting static massless scalar field configurations
Hod, Shahar
2017-11-01
Horizonless spacetimes describing highly compact exotic objects with reflecting (instead of absorbing) surfaces have recently attracted much attention from physicists and mathematicians as possible quantum-gravity alternatives to canonical classical black-hole spacetimes. Interestingly, it has recently been proved that spinning compact objects with angular momenta in the sub-critical regime a bar ≡ J /M2 ≤ 1 are characterized by an infinite countable set of surface radii, {rc (a bar ; n) }n=1n=∞, that can support asymptotically flat static configurations made of massless scalar fields. In the present paper we study analytically the physical properties of ultra-spinning exotic compact objects with dimensionless angular momenta in the complementary regime a bar > 1. It is proved that ultra-spinning reflecting compact objects with dimensionless angular momenta in the super-critical regime √{ 1 -[ m / (l + 2) ] 2 } ≤ | a bar |-1 family of surface radii, {rc (a bar ; n) }n=1n=Nr, distributed symmetrically around r = M, that can support spatially regular static configurations of massless scalar fields (here the integers { l , m } are the harmonic indices of the supported static scalar field modes). Interestingly, the largest supporting surface radius rcmax (a bar) ≡maxn {rc (a bar ; n) } marks the onset of superradiant instabilities in the composed ultra-spinning-exotic-compact-object-massless-scalar-field system.
Höhn, P.A.|info:eu-repo/dai/nl/330827952; Kubalová, E.; Tsobanjan, A.
2011-01-01
We apply the effective approach to evaluating semiclassical relational dynamics to the closed Friedman–Robertson–Walker cosmological model filled with a minimally coupled massive scalar field. This model is interesting for studying relational dynamics in a more general setting because (i) it
Marunovic, A.; Prokopec, T.
2011-01-01
We calculate the one-loop graviton vacuum polarization induced by a massless, nonminimally coupled scalar field on Minkowski background. We make use of the Schwinger-Keldysh formalism, which allows us to study time dependent phenomena. As an application we compute the leading quantum correction to
Wormhole solutions with a complex ghost scalar field and their instability
Dzhunushaliev, Vladimir; Folomeev, Vladimir; Kleihaus, Burkhard; Kunz, Jutta
2018-01-01
We study compact configurations with a nontrivial wormholelike spacetime topology supported by a complex ghost scalar field with a quartic self-interaction. For this case, we obtain regular asymptotically flat equilibrium solutions possessing reflection symmetry. We then show their instability with respect to linear radial perturbations.
Anatomy of One-Loop Effective Action in Noncommutative Scalar Field Theories
Kiem, Youngjai; Sato, Haru-Tada; Yee, Jung-Tay; Kiem, Youngjai; Rey, Soo-Jong; Sato, Haru-Tada; Yee, Jung-Tay
2002-01-01
One-loop effective action of noncommutative scalar field theory with cubic self-interaction is studied. Utilizing worldline formulation, both planar and nonplanar part of the effective action are computed explicitly. We find complete agreement of the result with Seiberg-Witten limit of string worldsheet computation and standard Feynman diagrammatics. We prove that, at low-energy and large noncommutativity limit, nonplanar part of the effective action is simplified enormously and is resummable into a quadratic action of scalar open Wilson line operators.
Cosmological evolution of a complex scalar field with repulsive or attractive self-interaction
Suárez, Abril; Chavanis, Pierre-Henri
2017-03-01
We study the cosmological evolution of a complex scalar field with a self-interaction potential V (|φ |2) , possibly describing self-gravitating Bose-Einstein condensates, using a fully general relativistic treatment. We generalize the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field approximation developed in our previous paper [A. Suárez and P.-H. Chavanis, Phys. Rev. D 92, 023510 (2015), 10.1103/PhysRevD.92.023510]. We establish the general equations governing the evolution of a spatially homogeneous complex scalar field in an expanding background. We show how they can be simplified in the fast oscillation regime (equivalent to the Thomas-Fermi, or semiclassical, approximation) and derive the equation of state of the scalar field in parametric form for an arbitrary potential V (|φ |2) . We explicitly consider the case of a quartic potential with repulsive or attractive self-interaction. For repulsive self-interaction, the scalar field undergoes a stiff matter era followed by a pressureless dark matter era in the weakly self-interacting regime and a stiff matter era followed by a radiationlike era and a pressureless dark matter era in the strongly self-interacting regime. For attractive self-interaction, the scalar field undergoes an inflation era followed by a stiff matter era and a pressureless dark matter era in the weakly self-interacting regime and an inflation era followed by a cosmic stringlike era and a pressureless dark matter era in the strongly self-interacting regime (the inflation era is suggested, not demonstrated). We also find a peculiar branch on which the scalar field emerges suddenly at a nonzero scale factor with a finite energy density. At early times, it behaves as a gas of cosmic strings. At later times, it behaves as dark energy with an almost constant energy density giving rise to a de Sitter evolution. This is due to spintessence. We derive the effective cosmological constant produced by the scalar
Entanglement growth after a global quench in free scalar field theory
Energy Technology Data Exchange (ETDEWEB)
Cotler, Jordan S. [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University, Stanford, CA 94305 (United States); Hertzberg, Mark P. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Mezei, Márk [Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544 (United States); Mueller, Mark T. [Center for Theoretical Physics, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2016-11-28
We compute the entanglement and Rényi entropy growth after a global quench in various dimensions in free scalar field theory. We study two types of quenches: a boundary state quench and a global mass quench. Both of these quenches are investigated for a strip geometry in 1, 2, and 3 spatial dimensions, and for a spherical geometry in 2 and 3 spatial dimensions. We compare the numerical results for massless free scalars in these geometries with the predictions of the analytical quasiparticle model based on EPR pairs, and find excellent agreement in the limit of large region sizes. At subleading order in the region size, we observe an anomalous logarithmic growth of entanglement coming from the zero mode of the scalar.
Gesture Recognition using Latent-Dynamic based Conditional Random Fields and Scalar Features
Yulita, I. N.; Fanany, M. I.; Arymurthy, A. M.
2017-02-01
The need for segmentation and labeling of sequence data appears in several fields. The use of the conditional models such as Conditional Random Fields is widely used to solve this problem. In the pattern recognition, Conditional Random Fields specify the possibilities of a sequence label. This method constructs its full label sequence to be a probabilistic graphical model based on its observation. However, Conditional Random Fields can not capture the internal structure so that Latent-based Dynamic Conditional Random Fields is developed without leaving external dynamics of inter-label. This study proposes the use of Latent-Dynamic Conditional Random Fields for Gesture Recognition and comparison between both methods. Besides, this study also proposes the use of a scalar features to gesture recognition. The results show that performance of Latent-dynamic based Conditional Random Fields is not better than the Conditional Random Fields, and scalar features are effective for both methods are in gesture recognition. Therefore, it recommends implementing Conditional Random Fields and scalar features in gesture recognition for better performance
Anomalous scaling of a scalar field advected by turbulence
Energy Technology Data Exchange (ETDEWEB)
Kraichnan, R.H. [Robert H. Kraichnan, Inc., Santa Fe, NM (United States)
1995-12-31
Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.
Belotsky, K. M.; Golikova, Yu. A.; Rubin, S. G.
2017-07-01
It is shown that the formation of primordialmassive black holes may be accompanied by a local heating of matter. The proposed heating mechanism is based on the interaction of the Higgs field with a scalar field that is responsible for the formation of black holes.
In-Flight spacecraft magnetic field monitoring using scalar/vector gradiometry
DEFF Research Database (Denmark)
Primdahl, Fritz; Risbo, Torben; Merayo, José M.G.
2006-01-01
Earth magnetic field mapping from planetary orbiting satellites requires a spacecraft magnetic field environment control program combined with the deployment of the magnetic sensors on a boom in order to reduce the measurement error caused by the local spacecraft field. Magnetic mapping missions...... the spacecraft centre-of-gravity. In line with the classical dual vector sensors technique for monitoring the spacecraft magnetic field, this paper proposes and demonstrates that a similar combined scalar/vector gradiometry technique is feasible by using the measurements from the boom-mounted scalar and vector...... sensors onboard the Oersted satellite. For Oersted, a large difference between the pre-flight determined spacecraft magnetic field and the in-flight estimate exists causing some concern about the general applicability of the dual sensors technique....
PDF approach for turbulent scalar field: Some recent developments
Gao, Feng
1993-01-01
The probability density function (PDF) method has been proven a very useful approach in turbulence research. It has been particularly effective in simulating turbulent reacting flows and in studying some detailed statistical properties generated by a turbulent field There are, however, some important questions that have yet to be answered in PDF studies. Our efforts in the past year have been focused on two areas. First, a simple mixing model suitable for Monte Carlo simulations has been developed based on the mapping closure. Secondly, the mechanism of turbulent transport has been analyzed in order to understand the recently observed abnormal PDF's of turbulent temperature fields generated by linear heat sources.
Morales, Manuel D
2016-01-01
Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented in [J.M. Bardeen, O. Sarbach, and L.T. Buchman, Phys. Rev. D 83, 104045 (2011)] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of...
Matrix model approximations of fuzzy scalar field theories and their phase diagrams
Energy Technology Data Exchange (ETDEWEB)
Tekel, Juraj [Department of Theoretical Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynska Dolina, Bratislava, 842 48 (Slovakia)
2015-12-29
We present an analysis of two different approximations to the scalar field theory on the fuzzy sphere, a nonperturbative and a perturbative one, which are both multitrace matrix models. We show that the former reproduces a phase diagram with correct features in a qualitative agreement with the previous numerical studies and that the latter gives a phase diagram with features not expected in the phase diagram of the field theory.
On the scalar particle creation by electromagnetic fields in Robertson–Walker spacetime
Directory of Open Access Journals (Sweden)
Kenan Sogut
2015-12-01
Full Text Available In the present paper, we obtained the scalar particle creation number density by using the Klein–Gordon equation coupled to the electromagnetic fields in the Robertson–Walker spacetime with the help of the Bogoliubov transformation method. We analyzed the resulting expression for the effect of a time-dependent electric field and a constant magnetic field on the particle production rate and found that the strong time-dependent electric field amplifies the particle creation and the magnetic field reduces the rate, in accordance with the previous findings.
Bose-Einstein condensation and symmetry breaking of a complex charged scalar field
Energy Technology Data Exchange (ETDEWEB)
Matos, Tonatiuh [Centro de Investigacion y de Estudios Avanzados del IPN, Departamento de Fisica, Mexico, DF (Mexico); Castellanos, Elias [Centro de Investigacion y de Estudios Avanzados del IPN, Departamento de Fisica, Mexico, DF (Mexico); Universidad Autonoma de Chiapas, Mesoamerican Centre for Theoretical Physics, Tuxtla Gutierrez, Chiapas (Mexico); Suarez, Abril [Centro de Investigacion y de Estudios Avanzados del IPN, Departamento de Fisica, Mexico, DF (Mexico); Universidad Politecnica Metropolitana de Hidalgo, Departamento de Aeronautica, Tolcayuca, Hidalgo (Mexico)
2017-08-15
In this work the Klein-Gordon equation for a complex scalar field with U(1) symmetry endowed in a mexican-hat scalar field potential with thermal and electromagnetic contributions is written as a Gross-Pitaevskii (GP)-like equation. This equation is interpreted as a charged generalization of the GP equation at finite temperatures found in previous works. Its hydrodynamical representation is obtained and the corresponding thermodynamical properties are derived and related to measurable quantities. The condensation temperature in the non-relativistic regime associated with the aforementioned system within the semiclassical approximation is calculated. Also, a generalized equation for the conservation of energy for a charged bosonic gas is found when electromagnetic fields are introduced, and it is studied how under certain circumstances its breaking of symmetry can give some insight on the phase transition of the system not just into the condensed phase but also on other related systems. (orig.)
Global dynamics and asymptotics for monomial scalar field potentials and perfect fluids
Alho, Artur; Uggla, Claes
2015-01-01
We consider a minimally coupled scalar field with a monomial potential and a perfect fluid in flat FLRW cosmology. We apply local and global dynamical systems techniques to a new three-dimensional dynamical systems reformulation of the field equations on a compact state space. This leads to a visual global description of the solution space and asymptotic behavior. At late times we employ averaging techniques to prove statements about how the relationship between the equation of state of the fluid and the monomial exponent of the scalar field affects asymptotic source dominance and asymptotic manifest self-similarity breaking. We also situate the `attractor' solution in the three-dimensional state space and show that it corresponds to the one-dimensional unstable center manifold of a de Sitter fixed point, located on an unphysical boundary associated with the dynamics at early times. By deriving a center manifold expansion we obtain approximate expressions for the attractor solution. We subsequently improve th...
Local thermal behaviour of a massive scalar field near a reflecting wall
Energy Technology Data Exchange (ETDEWEB)
Lorenci, V.A. De [Instituto de Física e Química, Universidade Federal de Itajubá,Itajubá, MG 37500-903 (Brazil); Gomes, L.G.; Moreira, E.S. Jr. [Instituto de Matemática e Computação, Universidade Federal de Itajubá,Itajubá, MG 37500-903 (Brazil)
2015-03-19
The mean square fluctuation and the expectation value of the stress-energy-momentum tensor of a neutral massive scalar field at finite temperature are determined near an infinite plane Dirichlet wall, and also near an infinite plane Neumann wall. The flat background has an arbitrary number of dimensions and the field is arbitrarily coupled to the vanishing curvature. It is shown that, unlike vacuum contributions, thermal contributions are free from boundary divergences, and that the thermal behaviour of the scalar field near a Dirichlet wall differs considerably from that near a Neumann wall. Far from the wall the study reveals a local version of dimensional reduction, namely, corrections to familiar blackbody expressions are linear in the temperature, with the corresponding coefficients given only in terms of vacuum expectation values in a background with one less dimension. It is shown that such corrections are “classical” (i.e., not dependent on Planck’s constant) only if the scalar field is massless. A natural conjecture that arises is that the “local dimensional reduction” is universal since it operates for massless and massive fields alike and regardless of the boundary conditions.
The Modification of the Scalar Field in dense Nuclear Matter
Directory of Open Access Journals (Sweden)
Rożynek J.
2011-04-01
Full Text Available We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ρ. The nucleon deep inelastic structure function represents distribution of quarks as function of Björken variable x which measures the longitudinal fraction of momentum carried by them during the Deep Inelastic Scattering (DIS of electrons on nuclear targets. Starting with small density and negative pressure in Nuclear Matter (NM we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons.When the density approaches the saturation point, ρ = ρ0, we have no longer separate mesons and nucleons but eventually modified nucleon Structure Function (SF in medium. The ratio of nuclear to nucleon SF measured at saturation point is well known as “EMC effect”. For larger density, ρ > ρ0, when the localization of quarks is smaller then 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the Momentum Sum Rule (MSR of DIS. These modifications of the nucleon Structure Function (SF are calculated in the frame of the nuclear Relativistic Mean Field (RMF convolution model. The correction to the Fermi energy from term proportional to the pressure is very important and its inclusion modifies the Equation of State (EoS for nuclear matter.
Morales, Manuel D.; Sarbach, Olivier
2017-02-01
Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented by Bardeen, Sarbach, and Buchman [Phys. Rev. D 83, 104045 (2011), 10.1103/PhysRevD.83.104045] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of scalar field, part of which disperses to infinity and part of which is accreted by the black hole. As a nontrivial test, we study the tail decay of the scalar field along different curves, including one along the marginally trapped tube, one describing the world line of a timelike observer at a finite radius outside the horizon, and one corresponding to a generator of null infinity. Our results are in perfect agreement with the usual power-law decay discussed in previous work. This article also contains a detailed analysis for the asymptotic behavior and regularity of the lapse, conformal factor, extrinsic curvature and the Misner-Sharp mass function along constant mean curvature slices.
Decoherence and disentanglement of qubits detecting scalar fields in an expanded spacetime
Energy Technology Data Exchange (ETDEWEB)
Li, Yujie; Dai, Yue [Fudan University, Department of Physics and State Key Laboratory of Surface Physics, Shanghai (China); Shi, Yu [Fudan University, Department of Physics and State Key Laboratory of Surface Physics, Shanghai (China); Fudan University, Collaborative Innovation Center of Advanced Microstructures, Shanghai (China)
2017-09-15
We consider Unruh-Wald qubit detector model adopted for the far future region of an exactly solvable 1 + 1 dimensional scalar field theory in a toy model of Robertson-Walker expanding spacetime. It is shown that the expansion of the spacetime in its history enhances the decoherence of the qubit coupled with a scalar field. Moreover, we consider two entangled qubits, each locally coupled with a scalar field. The expansion of the spacetime in its history degrades the entanglement between the qubits, and it can lead to entanglement's sudden death if the initial entanglement is small enough. The details depend on the parameters characterizing the expansion of the spacetime. This work, on a toy model, suggests that the history of the spacetime might be probed through the coherent and entanglement behavior of the future detectors of quantum fields. In the present toy model, the two cosmological parameters can be determined from the quantum informational quantities of the detectors. (orig.)
The global rotating scalar field vacuum on anti-de Sitter space–time
Directory of Open Access Journals (Sweden)
Carl Kent
2015-01-01
Full Text Available We consider the definition of the global vacuum state of a quantum scalar field on n-dimensional anti-de Sitter space–time as seen by an observer rotating about the polar axis. Since positive (or negative frequency scalar field modes must have positive (or negative Klein–Gordon norm respectively, we find that the only sensible choice of positive frequency corresponds to positive frequency as seen by a static observer. This means that the global rotating vacuum is identical to the global nonrotating vacuum. For n≥4, if the angular velocity of the rotating observer is smaller than the inverse of the anti-de Sitter radius of curvature, then modes with positive Klein–Gordon norm also have positive frequency as seen by the rotating observer. We comment on the implications of this result for the construction of global rotating thermal states.
The global rotating scalar field vacuum on anti-de Sitter space–time
Energy Technology Data Exchange (ETDEWEB)
Kent, Carl, E-mail: c.kent@sheffield.ac.uk; Winstanley, Elizabeth, E-mail: e.winstanley@sheffield.ac.uk
2015-01-05
We consider the definition of the global vacuum state of a quantum scalar field on n-dimensional anti-de Sitter space–time as seen by an observer rotating about the polar axis. Since positive (or negative) frequency scalar field modes must have positive (or negative) Klein–Gordon norm respectively, we find that the only sensible choice of positive frequency corresponds to positive frequency as seen by a static observer. This means that the global rotating vacuum is identical to the global nonrotating vacuum. For n≥4, if the angular velocity of the rotating observer is smaller than the inverse of the anti-de Sitter radius of curvature, then modes with positive Klein–Gordon norm also have positive frequency as seen by the rotating observer. We comment on the implications of this result for the construction of global rotating thermal states.
Self-interacting scalar field trapped in a DGP brane: The dynamical systems perspective
Energy Technology Data Exchange (ETDEWEB)
Quiros, Israel [Departamento de Fisica, Universidad Central de Las Villas, 54830 Santa Clara (Cuba)], E-mail: israel@uclv.edu.cu; Garcia-Salcedo, Ricardo [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-Legaria del IPN, Mexico D.F. (Mexico)], E-mail: rigarcias@ipn.mx; Matos, Tonatiuh [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico)], E-mail: tmatos@fis.cinvestav.mx; Moreno, Claudia [Departamento de Fisica y Matematicas, Centro Universitario de Ciencias Exactas e Ingenierias, Corregidora 500 S.R., Universidad de Guadalajara, 44420 Guadalajara, Jalisco (Mexico)], E-mail: claudia.moreno@cucei.udg.mx
2009-01-05
We apply the dynamical systems tools to study the linear dynamics of a self-interacting scalar field trapped on a DGP brane. The simplest kinds of self-interaction potentials are investigated: (a) constant potential, and (b) exponential potential. It is shown that the dynamics of DGP models can be very rich and complex. One of the most interesting results of this study shows that dynamical screening of the scalar field self-interaction potential, occurring within the Minkowski cosmological phase of the DGP model and that mimics 4D phantom behaviour, is an attractor solution for a constant self-interaction potential but not for the exponential one. In the latter case gravitational screening is not even a critical point of the corresponding autonomous system of ordinary differential equations.
Generalized second law of thermodynamics for non-canonical scalar field model with corrected-entropy
Energy Technology Data Exchange (ETDEWEB)
Das, Sudipta; Mamon, Abdulla Al [Visva-Bharati, Department of Physics, Santiniketan (India); Debnath, Ujjal [Indian Institute of Engineering Science and Technology, Department of Mathematics, Shibpur, Howrah (India)
2015-10-15
In this work, we have considered a non-canonical scalar field dark energy model in the framework of flat FRW background. It has also been assumed that the dark matter sector interacts with the non-canonical dark energy sector through some interaction term. Using the solutions for this interacting non-canonical scalar field dark energy model, we have investigated the validity of generalized second law (GSL) of thermodynamics in various scenarios using first law and area law of thermodynamics. For this purpose, we have assumed two types of horizons viz apparent horizon and event horizon for the universe and using first law of thermodynamics, we have examined the validity of GSL on both apparent and event horizons. Next, we have considered two types of entropy-corrections on apparent and event horizons. Using the modified area law, we have examined the validity of GSL of thermodynamics on apparent and event horizons under some restrictions of model parameters. (orig.)
Energy exchange for homogeneous and isotropic universes with a scalar field coupled to matter
Energy Technology Data Exchange (ETDEWEB)
Giambo, Roberto [Department of Mathematics and Computer Science, University of Camerino 62032 Camerino (Italy); Miritzis, John, E-mail: roberto.giambo@unicam.i, E-mail: imyr@aegean.g [Department of Marine Sciences, University of the Aegean, University Hill, Mytilene 81100 (Greece)
2010-05-07
We study the late time evolution of flat and negatively curved Friedmann-Robertson-Walker (FRW) models with a perfect fluid matter source and a scalar field arising in the conformal frame of f(R) theories nonminimally coupled to matter. Under mild assumptions on the potential V we prove that equilibria corresponding to the non-negative local minima for V are asymptotically stable, as well as horizontal asymptotes approached from above by V. We classify all cases of the flat model where one of the matter components eventually dominates. In particular for a nondegenerate minimum of the potential with zero critical value we prove in detail that if gamma, the parameter of the equation of state, is larger than 1, then there is a transfer of energy from the fluid to the scalar field and the latter eventually dominates in a generic way.
The phase-space analysis of scalar fields with non-minimally derivative coupling
Energy Technology Data Exchange (ETDEWEB)
Huang, Yumei [Beijing Normal University, Department of Astronomy, Beijing (China); Gao, Qing; Gong, Yungui [Huazhong University of Science and Technology, MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Wuhan, Hubei (China)
2015-04-01
We perform a dynamical analysis for the exponential scalar field with non-minimally derivative coupling. For the quintessence case, the stable fixed points are the same with and without the non-minimally derivative coupling. For the phantom case, the attractor with dark energy domination exists for the minimal coupling only. For the non-minimally derivative coupling without the standard canonical kinetic term, only the de Sitter attractor exists, and the dark matter solution is unstable. (orig.)
On localization of universal scalar fields in a tachyonic de Sitter thick braneworld
Diaz-Furlong, Alfonso; Herrera-Aguilar, Alfredo(Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, México D.F., CP 09340, Mexico); Linares, Roman; Mora-Luna, Refugio Rigel; Morales-Tecotl, Hugo A.
2014-01-01
Braneworld models may yield interesting effects ranging from high-energy physics to cosmology, or even some low-energy physics. Their mode structure modifies standard results in these physical realms that can be tested and used to set bounds on the models parameters. Now, to define braneworld deviations from standard 4D physics, a notion of matter and gravity localization on the brane is crucial. In this work we investigate the localization of universal massive scalar fields in a de Sitter th...
Massless scalar field in de Sitter spacetime: unitary quantum time evolution
Cortez, Jerónimo; Martín-de Blas, Daniel; Mena Marugán, Guillermo A.; Velhinho, José M.
2013-04-01
We prove that, under the standard conformal scaling, a free scalar field in de Sitter spacetime admits an O(4)-invariant Fock quantization such that time evolution is unitarily implemented. Since this applies in particular to the massless case, this result disproves previous claims in the literature. We discuss the relationship between this quantization with unitary dynamics and the family of O(4)-invariant Hadamard states given by Allen and Folacci, as well as with the Bunch-Davies vacuum.
The phase diagram of scalar field theory on the fuzzy disc
Energy Technology Data Exchange (ETDEWEB)
Rea, Simone; Sämann, Christian [Maxwell Institute for Mathematical Sciences, Department of Mathematics,Heriot-Watt University,Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS (United Kingdom)
2015-11-17
Using a recently developed bootstrapping method, we compute the phase diagram of scalar field theory on the fuzzy disc with quartic even potential. We find three distinct phases with second and third order phase transitions between them. In particular, we find that the second order phase transition happens approximately at a fixed ratio of the two coupling constants defining the potential. We compute this ratio analytically in the limit of large coupling constants. Our results qualitatively agree with previously obtained numerical results.
LATTICEEASY A Program for Lattice Simulations of Scalar Fields in an Expanding Universe
Felder, G; Tkachev, Igor; Felder, Gary
2008-01-01
We describe a C++ program that we have written and made available for calculating the evolution of interacting scalar fields in an expanding universe. The program is particularly useful for the study of reheating and thermalization after inflation. The program and its full documentation are available on the Web at http://physics.stanford.edu/gfelder/latticeeasy. In this paper we provide a brief overview of what the program does and what it is useful for.
Quantization of Free Scalar Fields in the Presence of Natural Cutoffs
Directory of Open Access Journals (Sweden)
K. Nozari
2012-01-01
Full Text Available We construct a quantum theory of free scalar fields in (1+1-dimensions based on the deformed Heisenberg algebra x^,p^=iħ1-βp+2β2p2, that admits the existence of both a minimal measurable length and a maximal momentum, where β is a deformation parameter. We consider both canonical and path integral formalisms of the scenario. Finally a higher dimensional extension is easily performed in the path integral formalism.
Quantization of Free Scalar Fields in the Presence of Natural Cutoffs
Nozari, K.; Moafi, F.; Rezaee Balef, F.
2012-01-01
We construct a quantum theory of free scalar fields in (1+1)-dimensions based on the deformed Heisenberg algebra x^,p^=iħ1-βp+2β2p2, that admits the existence of both a minimal measurable length and a maximal momentum, where β is a deformation parameter. We consider both canonical and path integral formalisms of the scenario. Finally a higher dimensional extension is easily performed in the path integral formalism.
Continuum dynamics and the electromagnetic field in the scalar ether theory of gravitation
Arminjon Mayeul
2016-01-01
32 pages. V4: Introduction largely rewritten and expanded (new Refs.); some information added at beginning of Sect. 2 and in Sect. 5; some redactional improvements in Sects. 4 and 7.; An alternative, scalar theory of gravitation has been proposed, based on a mechanism/interpretation of gravity as being a pressure force: Archimedes' thrust. In it, the gravitational field affects the physical standards of space and time, but motion is governed by an extension of the relativistic form of Newton'...
On the critical behaviour of the 2-point function in scalar field theories
Energy Technology Data Exchange (ETDEWEB)
Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)
1999-09-01
By the use of a Mellin representation of Feynman integrals, a convergent asymptotic expansion for generic Feynman amplitudes for any set of invariants going to zero or to {infinity}, may be obtained. In the case of scalar field theories in Euclidean metric, we use this expansion to analyse the behaviour of the two-point function for small values of the mass parameter, for fixed external momentum. (author)
Global Stability for Charged Scalar Fields in an Asymptotically Flat Metric in Harmonic Gauge
Kauffman, Christopher
2018-01-01
We prove global stability for the Charge-Scalar Field system on a background metric which is close to 1+3-dimensional Minkowski space. In particular, we consider a class of background metrics which satisfy certain estimates consistent with the behavior of small-data solutions to Einstein's Vacuum Equations in harmonic coordinates. Our results are analogous to results obtained in Minkowski space by Lindblad and Sterbenz. The proof relies on a single-parameter modification of the standard Loren...
Real Scalar Field Scattering with Polynomial Approximation around Schwarzschild-de Sitter Black-hole
Liu, Molin; Liu, Hongya; Zhang, Jingfei; Yu, Fei
2008-01-01
As one of the fitting methods, the polynomial approximation is effective to process sophisticated problem. In this paper, we employ this approach to handle the scattering of scalar field around the Schwarzschild-de Sitter black-hole. The complex relationship between tortoise coordinate and radial coordinate is replaced by the approximate polynomial. The Schr$\\ddot{o}$dinger-like equation, the real boundary conditions and the polynomial approximation construct a full Sturm-Liouville type probl...
Global stability analysis for cosmological models with non-minimally coupled scalar fields
Skugoreva, Maria A; Vernov, Sergey Yu
2014-01-01
We explorer dynamics of cosmological models with a non-minimally coupled scalar field evolving on a spatially flat Friedmann-Lemaitre-Robertson-Walker background. We consider cosmological models including the Hilbert-Einstein curvature term and the $N$ degree monomial of the scalar field non-minimally coupled to gravity. The potential of the scalar field is the $n$ degree monomial or polynomial.We describe several qualitatively different types of dynamics depending on values of power indices $N$ and $n$. We identify that three main possible pictures correspond to $n2N$ cases. Some special features connected with the important cases of $N=n$ (including quadratic potential with quadratic coupling) and $n=2N$ (which share its asymptotics with the potential of the Higgs-driven inflation) are described separately. A global qualitative analysis allows us to cover most interesting cases of small $N$ and $n$ by a limiting number of phase-space diagrams. The influence of the cosmological constant to the global feature...
Hossienkhani, H.; Aghamohammadi, A.; Jafari, A.; Rabieei, S. W.; Refaei, A.
2017-12-01
A spatially homogeneous and anisotropic Bianchi type I universe is studied with the interacting holographic and new agegraphic scalar fields models of dark energy. Given, the framework of the anisotropic model, both the dynamics and potential of these scalar field models according to the evolutionary behavior of both dark energy models are reconstructed. We also investigate the cosmological evolution of interacting dark energy models, and compare it with observational data and schematic diagram. In order to do so, we focus on observational determinations of the expansion history H(z) . Next, we evaluate effects of anisotropy on various topics, such as evolution of the growth of perturbations in the linear regime, statefinder diagnostic, Sandage-Loeb (SL) test and distance modulus from holographic and new agegraphic dark energy models and compare with the results of the standard FRW, ΛCDM and wCDM models. Our numerical result shows the effects of the interaction and anisotropy on the evolutionary behavior the new agegraphic scalar field models.
A search for neutral Higgs bosons in the MSSM and models with two scalar field doublets
Ackerstaff, K.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Clarke, P.E.L.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Doucet, M.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Feld, L.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Foucher, M.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Hargrove, C.K.; Hart, P.A.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jawahery, A.; Jeffreys, P.W.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jones, M.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kirk, J.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Lellouch, D.; Letts, J.; Levinson, L.; List, B.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mincer, A.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Oldershaw, N.J.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Posthaus, A.; Rembser, C.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Rossi, A.M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schleper, P.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Springer, Robert Wayne; Sproston, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, David M.; Strohmer, R.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Utzat, P.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Vikas, P.; Vokurka, E.H.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.
1998-01-01
A search is described for the neutral Higgs bosons h^0 and A^0 predicted by models with two scalar field doublets and, in particular, the Minimal Supersymmetric Standard Model (MSSM). The search in the Z^0 h^0 and h^0 A^0 production channels is based on data corresponding to an integrated luminosity of 25 pb^{-1} from e^+e^- collisions at centre-of-mass energies between 130 and 172GeV collected with the OPAL detector at LEP. The observation of a number of candidates consistent with Standard Model background expectations is used in combination with earlier results from data collected at the Z^0 resonance to set limits on m_h and m_A in general models with two scalar field doublets and in the MSSM. For example, in the MSSM, for tan(beta) > 1, minimal and maximal scalar top quark mixing and soft SUSY-breaking masses of 1 TeV, the 95% confidence level limits m_h > 59.0 GeV and m_A > 59.5 GeV are obtained. For the first time, the MSSM parameter space is explored in a detailed scan.
Primordial black holes from scalar field evolution in the early universe
Cotner, Eric; Kusenko, Alexander
2017-11-01
Scalar condensates with large expectation values can form in the early universe, for example, in theories with supersymmetry. The condensate can undergo fragmentation into Q-balls before decaying. If the Q-balls dominate the energy density for some period of time, statistical fluctuations in their number density can lead to formation of primordial black holes (PBH). In the case of supersymmetry the mass range is limited from above by 1 023 g . For a general charged scalar field, this robust mechanism can generate black holes over a much broader mass range, including the black holes with masses of 1-100 solar masses, which is relevant for LIGO observations of gravitational waves. Topological defects can lead to formation of PBH in a similar fashion.
JDiffraction: A GPGPU-accelerated JAVA library for numerical propagation of scalar wave fields
Piedrahita-Quintero, Pablo; Trujillo, Carlos; Garcia-Sucerquia, Jorge
2017-05-01
JDiffraction, a GPGPU-accelerated JAVA library for numerical propagation of scalar wave fields, is presented. Angular spectrum, Fresnel transform, and Fresnel-Bluestein transform are the numerical algorithms implemented in the methods and functions of the library to compute the scalar propagation of the complex wavefield. The functionality of the library is tested with the modeling of easy to forecast numerical experiments and also with the numerical reconstruction of a digitally recorded hologram. The performance of JDiffraction is contrasted with a library written for C++, showing great competitiveness in the apparently less complex environment of JAVA language. JDiffraction also includes JAVA easy-to-use methods and functions that take advantage of the computation power of the graphic processing units to accelerate the processing times of 2048×2048 pixel images up to 74 frames per second.
Kuvshinov, A. V.; Poedjono, B.; Matzka, J.; Olsen, N.; Pai, S.; Samrock, F.
2013-12-01
Most marine EM studies are based on sea-bottom measurements which are expensive and logistically demanding. We propose a low-cost and easy-to-deploy magnetic survey concept which exploits sea surface measurements. It is assumed that the exciting source can be described by a plane wave. The concept is based on responses that relate variations of the scalar magnetic field at the survey sites with variations of the horizontal magnetic field at a base site. It can be shown that these scalar responses are a mixture of standard tipper responses and elements of the horizontal magnetic tensor and thus can be used to probe the electrical conductivity of the subsoil. This opens an avenue for sea-surface induction studies which so far was believed very difficult to conduct if conventional approaches based on vector measurements are invoked. We perform 3-D realistic model studies where the target region was Oahu Island and its surroundings, and USGS operated Honolulu geomagnetic observatory was chosen as the base site. We compare the predicted responses with the responses estimated from the scalar data collected at a few locations around Oahu Island by the unmanned, autonomous, wave and solar powered 'Wave Glider' developed and operated by Liquid Robotics Oil and Gas/Schlumberger. The marine robots observation platform is equipped with a tow Overhauser magnetometer (validated by USGS). The studies show an encouraging agreement between predictions and experiment in both components of the scalar response at all locations and we consider this as a proof of the suggested concept.
Ignat'ev, Yu G
2015-01-01
The article proposes generalizations of the macroscopic model of plasma of scalar charged particles to the cases of inter-particle interaction with multiple scalar fields and negative effective masses of these particles. The model is based on the microscopic dynamics of a particle at presence of scalar fields. The theory is managed to be generalized naturally having strictly reviewed a series of its key positions depending on the sign of particle masses. Thereby, it is possible to remove the artiicial restriction contradicting the more fundamental principle of action functional additivity.
Carvalho, P. R. S.; Sena-Junior, M. I.
2017-12-01
In this work, we compute analytically the infrared divergences of massless O(N) self-interacting scalar field theories with Lorentz violation, which are exact in the Lorentz-violating Kμν coefficients, for evaluating the corresponding next-to-leading order critical exponents. For that, we apply three distinct and independent field-theoretic renormalization group methods. We find that the outcomes for the critical exponents are the same in the three methods and, furthermore, are identical to their Lorentz invariant counterparts. We generalize the results for all loop levels by employing a general theorem arising from the exact procedure and give the corresponding physical interpretation.
Uniqueness of the Fock quantization of scalar fields in spatially flat cosmological spacetimes
Castelló Gomar, Laura; Cortez, Jerónimo; Martín-de Blas, Daniel; Mena Marugán, Guillermo A.; Velhinho, José M.
2012-11-01
We study the Fock quantization of scalar fields in (generically) time dependent scenarios, focusing on the case in which the field propagation occurs in -either a background or effective- spacetime with spatial sections of flat compact topology. The discussion finds important applications in cosmology, like e.g. in the description of test Klein-Gordon fields and scalar perturbations in Friedmann-Robertson-Walker spacetime in the observationally favored flat case. Two types of ambiguities in the quantization are analyzed. First, the infinite ambiguity existing in the choice of a Fock representation for the canonical commutation relations, understandable as the freedom in the choice of inequivalent vacua for a given field. Besides, in cosmological situations, it is customary to scale the fields by time dependent functions, which absorb part of the evolution arising from the spacetime, which is treated classically. This leads to an additional ambiguity, this time in the choice of a canonical pair of field variables. We show that both types of ambiguities are removed by the requirements of (a) invariance of the vacuum under the symmetries of the three-torus, and (b) unitary implementation of the dynamics in the quantum theory. In this way, one arrives at a unique class of unitarily equivalent Fock quantizations for the system. This result provides considerable robustness to the quantum predictions and renders meaningful the confrontation with observation.
Uniqueness of the Fock quantization of scalar fields in spatially flat cosmological spacetimes
Energy Technology Data Exchange (ETDEWEB)
Gomar, Laura Castelló [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Cortez, Jerónimo [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico D.F. 04510 (Mexico); Blas, Daniel Martín-de; Marugán, Guillermo A. Mena [Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Velhinho, José M., E-mail: laucaste@estumail.ucm.es, E-mail: jacq@ciencias.unam.mx, E-mail: daniel.martin@iem.cfmac.csic.es, E-mail: jvelhi@ubi.pt [Departamento de Física, Faculdade de Ciências, Universidade da Beira Interior, R. Marquês D' Ávila e Bolama, 6201-001 Covilhã (Portugal)
2012-11-01
We study the Fock quantization of scalar fields in (generically) time dependent scenarios, focusing on the case in which the field propagation occurs in –either a background or effective– spacetime with spatial sections of flat compact topology. The discussion finds important applications in cosmology, like e.g. in the description of test Klein-Gordon fields and scalar perturbations in Friedmann-Robertson-Walker spacetime in the observationally favored flat case. Two types of ambiguities in the quantization are analyzed. First, the infinite ambiguity existing in the choice of a Fock representation for the canonical commutation relations, understandable as the freedom in the choice of inequivalent vacua for a given field. Besides, in cosmological situations, it is customary to scale the fields by time dependent functions, which absorb part of the evolution arising from the spacetime, which is treated classically. This leads to an additional ambiguity, this time in the choice of a canonical pair of field variables. We show that both types of ambiguities are removed by the requirements of (a) invariance of the vacuum under the symmetries of the three-torus, and (b) unitary implementation of the dynamics in the quantum theory. In this way, one arrives at a unique class of unitarily equivalent Fock quantizations for the system. This result provides considerable robustness to the quantum predictions and renders meaningful the confrontation with observation.
Melek, M
2002-01-01
The sole influence of plane gravitational waves (PGW) on the magnitude of the gradient of a scalar field (MGSF) defined inside a medium, is calculated. The conditions on the relations between the fluctuations in the gradient of the scalar field (GSF) and PGW leading to increase or decrease of the GSF due to the sole influence of PGW, are given. Two special cases of laser interferometers and cryogenic bar detectors are presented as an application of the proposed approach.
Li, Ran; Zhao, Junkun
2016-01-01
Reissner-Nordstr\\"om Anti-de Sitter (RNAdS) black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon. We present the time domain analysis of charged scalar field perturbations in the RNAdS black hole background in general dimensions. We show that the instabilities of charged scalar field can be explicitly illustrated from the time profiles of evolving scalar field. By using the Prony method to fit the time evolution data, we confirm the mode that dominates the long time behavior of scalar field is in accordance with the quasinormal mode from the frequency domain analysis. The superradiance origin of the instability can also be demonstrated by comparing the real part of the dominant mode with the superradiant condition of charged scalar field. It is shown that all the unstable modes are superradiant, which is consistent with the analytical result in the frequency domain analysis. Furthermore, we also confirm there exists the rapid exponential growin...
Li, Bao-Fei; Bhattacharjee, Madhurima; Wang, Anzhong
2017-10-01
In this paper, we study the nonprojectable 2d Hořava gravity coupled with a nonrelativistic scalar field, where the coupling is, in general, nonminimal and of the form f (ϕ )R , where f (ϕ ) is an arbitrary function of the scalar field ϕ , and R denotes the 2d Ricci scalar. In particular, we first investigate the Hamiltonian structure and show that there are two first- and two second-class constraints, similar to the pure gravity case, but now the local degrees of freedom is one due to the presence of the scalar field. Then, we present various exact stationary solutions of this coupled system, and find that some of them represent black holes, but now with universal horizons as their boundaries. At these horizons, the Hawking radiation is thermal with temperatures proportional to their surface gravities, which normally depend on the nonlinear dispersion relations of the particles radiated, similar to the (3 +1 )-dimensional case.
Stability of Gauss-Bonnet black holes in Anti-de-Sitter space-time against scalar field condensation
Brihaye, Yves
2011-01-01
We study the stability of static, hyperbolic Gauss-Bonnet black holes in (4+1)-dimensional Anti-de-Sitter (AdS) space-time against the formation of scalar hair. Close to extremality the black holes possess a near-horizon topology of AdS_2 x H^3 such that within a certain range of the scalar field mass one would expect that they become unstable to the condensation of an uncharged scalar field. We confirm this numerically and observe that there exists a family of hairy black hole solutions labelled by the number of nodes of the scalar field function. We construct explicit examples of solutions with a scalar field that possesses zero nodes, one node and two nodes, respectively, and show that the solutions with nodes persist in the limit of Einstein gravity, i.e. for vanishing Gauss-Bonnet coupling. We observe that the interval of the mass for which scalar field condensation appears decreases with increasing Gauss-Bonnet coupling and/or with increasing node number.
Uniqueness of the Fock quantization of scalar fields in a Bianchi I cosmology with unitary dynamics
Cortez, Jerónimo; Navascués, Beatriz Elizaga; Martín-Benito, Mercedes; Mena Marugán, Guillermo A.; Olmedo, Javier; Velhinho, José M.
2016-11-01
The Fock quantization of free scalar fields is subject to an infinite ambiguity when it comes to choosing a set of annihilation and creation operators, a choice that is equivalent to the determination of a vacuum state. In highly symmetric situations, this ambiguity can be removed by asking vacuum invariance under the symmetries of the system. Similarly, in stationary backgrounds, one can demand time-translation invariance plus positivity of the energy. However, in more general situations, additional criteria are needed. For the case of free (test) fields minimally coupled to a homogeneous and isotropic cosmology, it has been proven that the ambiguity is resolved by introducing the criterion of unitary implementability of the quantum dynamics, as an endomorphism in Fock space. This condition determines a specific separation of the time dependence of the field, so that this splits into a very precise background dependence and a genuine quantum evolution. Furthermore, together with the condition of vacuum invariance under the spatial Killing symmetries, unitarity of the dynamics selects a unique Fock representation for the canonical commutation relations, up to unitary equivalence. In this work, we generalize these results to anisotropic spacetimes with shear, which are therefore not conformally symmetric, by considering the case of a free scalar field in a Bianchi I cosmology.
Energy Technology Data Exchange (ETDEWEB)
Hajj, G.A.
1988-01-01
The Gaussian effective potential (GEP), a non-perturbative approach to study quantum field theory, is applied to scalar and scalar-fermion models. We study the scalar {phi}{sup 6} field coupled to fermions through g{sub B}{phi}{psi}{psi} or g{sub B}{phi}{sup 2}{psi}{psi} in 2 and 3 space-time dimensions. In addition, we derive the finite temperature (T > 0) GEP from first principles and apply it to study these models at T > 0. Also the Autonomous {lambda}{phi}{sup 4}, coupled to fermions through a Yukawa term (g{sub B}{phi}{psi}{psi}), is examined in 4 dimensions at T > 0. In all these models, in order to obtain stable theories, it is found that g{sub B} must vanish as 1/log(M{sub uv}), 1/M{sub uv} or 1/M{sub uv}{sup 2} in 2, 3 or 4 dimensions respectively, M{sub uv} being an ultraviolet cutoff which is sent to infinity. The contribution of fermions to the GEP, however, is nonvanishing. It is also found that for the class of theories discussed, symmetry, if broken, is restored above a critical temperature. The coupling constant parameter space for each model is studied carefully, and regions where symmetry breaking occurs are determined both at zero and finite temperature.
Costa, João L.
2013-12-01
We review recent results concerning the spherically symmetric Einstein-scalar field system with positive cosmological constant. We do so by comparing with the classical results of Christodoulou concerning the asymptotically flat case (vanishing cosmological constant) and by discussing some of the issues which have emerged since the publication of our main results. Concerning the positive cosmological constant case, we also sketch an alternative proof of global in (Bondi) time existence, based on energy estimates, which is presumably more flexible and, consequently, amenable to generalizations; other potential improvements and generalizations of our main results are also discussed.
The classical wormhole solution and wormhole wavefunction with a nonlinear Born-Infeld scalar field
Lu, H. Q.; Shen, L. M.; Ji, P.; Ji, G. F.; Sun, N. J.
2002-01-01
On this paper we consider the classical wormhole solution of the Born-Infeld scalar field. The corresponding classical wormhole solution can be obtained analytically for both very small and large $\\dot{\\phi}$. At the extreme limits of small $\\dot{\\phi}$ the wormhole solution has the same format as one obtained by Giddings and Strominger[10]. At the extreme limits of large $\\dot{\\phi}$ the wormhole solution is a new one. The wormhole wavefunctions can also be obtained for both very small and l...
Kink dynamics in a system of two coupled scalar fields in two space-time dimensions
Alonso-Izquierdo, A.
2018-02-01
In this paper we examine the scattering processes among the members of a rich family of kinks which arise in a (1+1)-dimensional relativistic two scalar field theory. These kinks carry two different topological charges that determine the mutual interactions between the basic energy lumps (extended particles) described by these topological defects. Processes like topological charge exchange, kink-antikink bound state formation or kink repulsion emerge depending on the charges of the scattered particles. Two-bounce resonant windows have been found in the antikink-kink scattering processes, but not in the kink-antikink interactions.
Mass hierarchies and non-decoupling in multi-scalar field dynamics
Achúcarro, Ana; Hardeman, Sjoerd; Palma, Gonzalo A; Patil, Subodh P
2010-01-01
In this work we study the effects of field space curvature on scalar field perturbations around an arbitrary background field trajectory evolving in time. Non-trivial imprints of the `heavy' directions arise when the vacuum manifold of the potential does not coincide with the span of geodesics defined by the sigma model metric of the low energy effective theory. When the kinetic energy is small compared to the potential energy, the field traverses a curve close to the vacuum manifold of the potential. The curvature of the trajectory can still have a profound influence on the perturbations as modes parallel to the trajectory mix with those normal to the trajectory if the trajectory turns sharply enough. These effects could be important during inflation, which could lead to detectable effects in upcoming observations.
Guilleux, Maxime
2016-01-01
Nonperturbative renormalization group techniques have recently proven a powerful tool to tackle the nontrivial infrared dynamics of light scalar fields in de Sitter space. In the present article, we develop the formalism beyond the local potential approximation employed in earlier works. In particular, we consider the derivative expansion, a systematic expansion in powers of field derivatives, appropriate for long wavelength modes, that we generalize to the relevant case of a curved metric with Lorentzian signature. The method is illustrated with a detailed discussion of the so-called local potential approximation prime which, on the top of the full effective potential, includes a running (but field-independent) field renormalization. We explicitly compute the associated anomalous dimension for O(N) theories. We find that it can take large values along the flow, leading to sizable differences as compared to the local potential approximation. However, it does not prevent the phenomenon of gravitationally induc...
Approximate KMS states for scalar and spinor fields in Friedmann-Robertson-Walker spacetimes
Energy Technology Data Exchange (ETDEWEB)
Dappiaggi, Claudio; Hack, Thomas-Paul [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Pinamonti, Nicola [Roma ' ' Tor Vergata' ' Univ. (Italy). Dipt. di Matematica
2010-09-15
We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The states we obtain can be interpreted as being in thermal equilibrium at the time when the scale factor a has a specific value a = a{sub 0}. In the case a{sub 0} = 0, these states fulfil a strict KMS condition on the boundary of the spacetime, which is either a cosmological horizon, or a Big Bang hypersurface. Furthermore, in the conformally invariant case, they are conformal KMS states on the full spacetime. However, they provide a natural notion of an approximate KMS state also in the remaining cases, especially for massive fields. On the technical side, our results are based on a bulk-to-boundary reconstruction technique already successfully applied in the scalar case and here proven to be suitable also for spinor fields. The potential applications of the states we find range over a broad spectrum, but they appear to be suited to discuss in particular thermal phenomena such as the cosmic neutrino background or the quantum state of dark matter. (orig.)
Accretion of a symmetry-breaking scalar field by a Schwarzschild black hole.
Traykova, Dina; Braden, Jonathan; Peiris, Hiranya V
2018-03-06
We simulate the behaviour of a Higgs-like field in the vicinity of a Schwarzschild black hole using a highly accurate numerical framework. We consider both the limit of the zero-temperature Higgs potential and a toy model for the time-dependent evolution of the potential when immersed in a slowly cooling radiation bath. Through these numerical investigations, we aim to improve our understanding of the non-equilibrium dynamics of a symmetry-breaking field (such as the Higgs) in the vicinity of a compact object such as a black hole. Understanding this dynamics may suggest new approaches for studying properties of scalar fields using black holes as a laboratory.This article is part of the Theo Murphy meeting issue 'Higgs Cosmology'. © 2018 The Author(s).
Accretion of a symmetry-breaking scalar field by a Schwarzschild black hole
Traykova, Dina; Braden, Jonathan; Peiris, Hiranya V.
2018-01-01
We simulate the behaviour of a Higgs-like field in the vicinity of a Schwarzschild black hole using a highly accurate numerical framework. We consider both the limit of the zero-temperature Higgs potential and a toy model for the time-dependent evolution of the potential when immersed in a slowly cooling radiation bath. Through these numerical investigations, we aim to improve our understanding of the non-equilibrium dynamics of a symmetry-breaking field (such as the Higgs) in the vicinity of a compact object such as a black hole. Understanding this dynamics may suggest new approaches for studying properties of scalar fields using black holes as a laboratory. This article is part of the Theo Murphy meeting issue `Higgs Cosmology'.
Stable, Time-Dependent, Exact Solutions for Brane Models with a Bulk Scalar Field
Lee, S; Olive, Keith A; Kanti, Panagiota; Lee, Seokcheon; Olive, Keith A.
2003-01-01
We derive two classes of brane-world solutions arising in the presence of a bulk scalar field. For static field configurations, we adopt a time-dependent, factorizable metric ansatz that allows for radion stabilization. The solutions are characterized by a non-trivial warping along the extra dimension, even in the case of a vanishing bulk cosmological constant, and lead to a variety of inflationary, time-dependent solutions of the 3D scale factor on the brane. We also derive the constraints necessary for the stability of these solutions under time-dependent perturbations of the radion field, and we demonstrate the existence of phenomenologically interesting, stable solutions with a positive cosmological constant on the brane.
Diffusion of a passive scalar from a no-slip boundary into a two-dimensional chaotic advection field
Ghosh, S.; Leonard, A.; Wiggins, S.
1998-10-01
Using a time-periodic perturbation of a two-dimensional steady separation bubble on a plane no-slip boundary to generate chaotic particle trajectories in a localized region of an unbounded boundary layer flow, we study the impact of various geometrical structures that arise naturally in chaotic advection fields on the transport of a passive scalar from a local ‘hot spot’ on the no-slip boundary. We consider here the full advection-diffusion problem, though attention is restricted to the case of small scalar diffusion, or large Péclet number. In this regime, a certain one-dimensional unstable manifold is shown to be the dominant organizing structure in the distribution of the passive scalar. In general, it is found that the chaotic structures in the flow strongly influence the scalar distribution while, in contrast, the flux of passive scalar from the localized active no-slip surface is, to dominant order, independent of the overlying chaotic advection. Increasing the intensity of the chaotic advection by perturbing the velocity field further away from integrability results in more non-uniform scalar distributions, unlike the case in bounded flows where the chaotic advection leads to rapid homogenization of diffusive tracer. In the region of chaotic particle motion the scalar distribution attains an asymptotic state which is time-periodic, with the period the same as that of the time-dependent advection field. Some of these results are understood by using the shadowing property from dynamical systems theory. The shadowing property allows us to relate the advection-diffusion solution at large Péclet numbers to a fictitious zero-diffusivity or frozen-field solution, corresponding to infinitely large Péclet number. The zero-diffusivity solution is an unphysical quantity, but is found to be a powerful heuristic tool in understanding the role of small scalar diffusion. A novel feature in this problem is that the chaotic advection field is adjacent to a no
Cosmological dynamics of D-BIonic and DBI scalar field and coincidence problem of dark energy
Panpanich, Sirachak; Maeda, Kei-ichi; Mizuno, Shuntaro
2017-05-01
We study the cosmological dynamics of a D-BIonic and Dirac-Born-Infeld scalar field, which is coupled to matter fluid. For the exponential potential and the exponential couplings, we find a new analytic scaling solution yielding the accelerated expansion of the Universe. Since it is shown to be an attractor for some range of the coupling parameters, the density parameter of matter fluid can be the observed value, as in the coupled quintessence with a canonical scalar field. Contrary to the usual coupled quintessence, where the value of the matter coupling giving the observed density parameter is too large to satisfy the observational constraint from the cosmic microwave background, we show that the D-BIonic theory can give a similar solution with a much smaller value of matter coupling. As a result, together with the fact that the D-BIonic theory has a screening mechanism, the D-BIonic theory can solve the so-called coincidence problem as well as the dark energy problem.
Study of parametrized dark energy models with a general non-canonical scalar field
Mamon, Abdulla Al
2015-01-01
In this paper, we have considered various dark energy models in the framework of a non-canonical scalar field with a Lagrangian density of the form ${\\cal L}(\\phi , X)=f(\\phi)X{\\left(\\frac{X}{M^{4}_{Pl}}\\right)}^{\\alpha -1} - V(\\phi)$, which provides the standard canonical scalar field model for $\\alpha=1$ and $f(\\phi)=1$. We have then obtained cosmological solutions for constant as well as variable equation of state parameter ($\\omega_{\\phi}(z)$) for dark energy. We have also performed the data analysis for three different parametrizations of $\\omega_{\\phi}(z)$ by using the combination of SN Ia, BAO and CMB datasets. We have found that for all the parametrizations of $\\omega_{\\phi}(z)$, the SN Ia $+$ CMB/BAO dataset favors the past decelerated and recent accelerated expansion phase of the universe. Furthermore, using the combined dataset, we have observed that the reconstructed results of $\\omega_{\\phi}(z)$ and $q(z)$ are almost parametrization independent and the resulting cosmological scenarios are in good...
Nucleon form factors in dispersively improved chiral effective field theory: Scalar form factor
Alarcón, J. M.; Weiss, C.
2017-11-01
We propose a method for calculating the nucleon form factors (FFs) of G -parity-even operators by combining chiral effective field theory (χ EFT ) and dispersion analysis. The FFs are expressed as dispersive integrals over the two-pion cut at t >4 Mπ2 . The spectral functions are obtained from the elastic unitarity condition and expressed as products of the complex π π →N N ¯ partial-wave amplitudes and the timelike pion FF. χ EFT is used to calculate the ratio of the partial-wave amplitudes and the pion FF, which is real and free of π π rescattering in the t channel (N /D method). The rescattering effects are then incorporated by multiplying with the squared modulus of the empirical pion FF. The procedure results in a marked improvement compared to conventional χ EFT calculations of the spectral functions. We apply the method to the nucleon scalar FF and compute the scalar spectral function, the scalar radius, the t -dependent FF, and the Cheng-Dashen discrepancy. Higher-order chiral corrections are estimated through the π N low-energy constants. Results are in excellent agreement with dispersion-theoretical calculations. We elaborate several other interesting aspects of our method. The results show proper scaling behavior in the large-Nc limit of QCD because the χ EFT calculation includes N and Δ intermediate states. The squared modulus of the timelike pion FF required by our method can be extracted from lattice QCD calculations of vacuum correlation functions of the operator at large Euclidean distances. Our method can be applied to the nucleon FFs of other operators of interest, such as the isovector-vector current, the energy-momentum tensor, and twist-2 QCD operators (moments of generalized parton distributions).
Loran, Farhang
2004-11-01
We solve Klein-Gordon equation for massless scalars on (d + 1)-dimensional Minkowski (Euclidean) space in terms of the Cauchy data on the hypersurface t = 0. By inserting the solution into the action of massless scalars in Minkowski (Euclidean) space we obtain the action of dual theory on the boundary t = 0 which is exactly the holographic dual of conformally coupled scalars on (d + 1)-dimensional (Euclidean anti) de Sitter space obtained in (A)dS/CFT correspondence. The observed equivalence of dual theories is explained using the one-to-one map between conformally coupled scalar fields on Minkowski (Euclidean) space and (Euclidean anti) de Sitter space which is an isomorphism between the hypersurface t = 0 of Minkowski (Euclidean) space and the boundary of (A)dS space.
A uniqueness criterion for the Fock quantization of scalar fields with time-dependent mass
Cortez, Jerónimo; Mena Marugán, Guillermo A.; Olmedo, Javier; Velhinho, José M.
2011-09-01
A major problem in the quantization of fields in curved spacetimes is the ambiguity in the choice of a Fock representation for the canonical commutation relations. There exists infinite number of choices leading to different physical predictions. In stationary scenarios, a common strategy is to select a vacuum (or a family of unitarily equivalent vacua) by requiring invariance under the spacetime symmetries. When stationarity is lost, a natural generalization consists in replacing time invariance by unitarity in the evolution. We prove that when the spatial sections are compact, the criterion of a unitary dynamics, together with the invariance under the spatial isometries, suffices to select a unique family of Fock quantizations for a scalar field with time-dependent mass.
The edge of entanglement: getting the boundary right for non-minimally coupled scalar fields
Energy Technology Data Exchange (ETDEWEB)
Herzog, Christopher P. [C.N. Yang Institute for Theoretical Physics,Department of Physics and Astronomy, Stony Brook University,Stony Brook, NY 11794 (United States); Nishioka, Tatsuma [Department of Physics, Faculty of Science, The University of Tokyo,Bunkyo-ku, Tokyo 113-0033 (Japan)
2016-12-27
In entanglement computations for a free scalar field with coupling to background curvature, there is a boundary term in the modular Hamiltonian which must be correctly specified in order to get sensible results. We focus here on the entanglement in flat space across a planar interface and (in the case of conformal coupling) other geometries related to this one by Weyl rescaling of the metric. For these “half-space entanglement” computations, we give a new derivation of the boundary term and revisit how it clears up a number of puzzles in the literature, including mass corrections and twist operator dimensions. We also discuss how related boundary terms may show up in other field theories.
Dai, De-Chang; Stojkovic, Dejan
2012-10-01
We study a retarded potential solution of a massless scalar field in curved space-time. In a special ansatz for a particle at rest whose magnitude of the (scalar) charge is changing with time, we found an exact analytic solution. The solution indicates that the phase velocity of the retarded potential of a nonmoving scalar charge is position-dependent and may easily be greater than the speed of light at a given point. In the case of the Schwarzschild space-time, at the horizon, the phase velocity becomes infinitely faster than the coordinate speed of light at that point. Superluminal phase velocity is a relatively common phenomenon, with the phase velocity of the massive Klein-Gordon field as the best known example. We discuss why it is possible to have modes with superluminal phase velocity even for a massless field.
Experimental Investigation of Scalar Patterns in a Spatially Periodic Flow Field
Rajaei, Hadi; Baskan, Ozge; Speetjens, Michel; Clercx, Herman
2013-11-01
Spatially persisting patterns that form during the downstream evolution of passive scalars in three-dimensional (3D) spatially periodic flow fields is a fundamental aspect of industrial mixing processes that rely on the static mixing principle. Despite many numerical studies on 3D spatially periodic flow fields, a comprehensive experimental research on the periodic flow field is still scarce. This research focuses on a comparative analysis between laboratory experiments and numerical simulations on the evolution of the periodic flow field and coherent flow structures and concerns the effect of boundary (i.e. inlet) conditions on the periodicity of the flow field in a representative inline mixer consisting of spatially periodic internal elements. The experimental setup is composed of an optically accessible vertical test section with transparent internal elements which is fed by a pressure-driven pipe flow containing tracer particles. The 3D streamlines, hence, the flow field, are measured by 3D Particle-Tracking Velocimetry technique. The streamwise development of the periodicity within few internal elements regardless of the inlet conditions has been proven by preliminary studies.
Chen, Songbai; Liao, Hao
2015-01-01
We have investigated quantum entropy of a static black hole arising from the massless scalar field with Lorentz violation induced by the coupling to Einstein tensor. Our results show that the coupled massless scalar field contributes to the classical Bekenstein-Hawking term in the black hole entropy. The corrected classical Bekenstein-Hawking entropy is not one quarter of the event horizon area of the original background black hole, but of a corresponding effective metric related to the coupling. It means that the classical Bekenstein-Hawking entropy depends not only on the black hole parameter, but also on the coupling which reduces Lorentz violation.
Pavlov, Y V
2001-01-01
One derived expressions for the vacuum mean values of energy-momentum tensor of the scalar field with arbitrary relation to curvature in N-dimensional quasi-euclidean space-time for vacuum. One generalized n-wave procedure for multidimensional spaces. One calculated all counter-members for N=5 and for a conformal scalar field in N=6, 7. One determined the geometric structure of three first counter-members for N-dimensional spaces. All subtractions in 4-dimensional space-time and 3 first subtractions in multidimensional spaces are shown to correspond to renormalization of constants of priming and gravitational Lagrangian
Vacuum stress tensor of a scalar field in a rectangular waveguide
Energy Technology Data Exchange (ETDEWEB)
Rodrigues, R.B.; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]. E-mail: robson@cbpf.br; svaiter@lns.mit.edu; Paola, R.D.M. de [Escola Federal de Engenharia de Itajuba, MG (Brazil). Inst. de Ciencias]. E-mail: rpaola@efei.br
2001-11-01
Using the heat Kernel method and the analytical continuation of the zeta function, we calculate the canonical and improved vacuum stress tensors, {l_brace}T{sub {mu}}{sub {nu}}(vector x){r_brace} and {l_brace}{theta}{sub {mu}}{sub {nu}} (vector x){r_brace}, associated with a massless scalar field confined in the interior of an infinity long rectangular waveguide. The local depence of the renormalized energy for two special configurations when the total energy is positive and negative are presented using {l_brace}T{sub 00}(vector x){r_brace} and {l_brace}{theta}{sub 00}(vector x){r_brace}. From the stress tensors we obtain the local casimir forces in all walls by introducing a particular external configuration. It is hown that this external configuration cannot give account of the edge divergences of the local forces. The local form of the forces is obtained for three special configurations. (author)
Critical collapse of a rotating scalar field in 2 +1 dimensions
JałmuŻna, Joanna; Gundlach, Carsten
2017-04-01
We carry out numerical simulations of the collapse of a complex rotating scalar field of the form Ψ (t ,r ,θ )=ei m θΦ (t ,r ), giving rise to an axisymmetric metric, in 2 +1 spacetime dimensions with cosmological constant Λ 0 is very different from the case m =0 we have considered before: the thresholds for mass scaling and Ricci scaling are significantly different (for the same family); scaling stops well above the scale set by Λ , and the exponents depend strongly on the family. Hence, in contrast to the m =0 case, and to many other self-gravitating systems, there is only weak evidence for the collapse threshold being controlled by a self-similar critical solution and no evidence for it being universal.
Cosmological analysis of scalar field models in f(R, T) gravity
Energy Technology Data Exchange (ETDEWEB)
Sharif, M.; Nawazish, Iqra [University of the Punjab, Department of Mathematics, Lahore (Pakistan)
2017-03-15
This paper determines the existence of Noether symmetry in non-minimally coupled f(R, T) gravity admitting minimal coupling with scalar field models. We consider a generalized spacetime which corresponds to different anisotropic and homogeneous universe models. We formulate symmetry generators along with conserved quantities through Noether symmetry technique for direct and indirect curvature-matter coupling. For dust and perfect fluids, we evaluate exact solutions and construct their cosmological analysis through some cosmological parameters. We conclude that decelerated expansion is obtained for the quintessence model with a dust distribution, while a perfect fluid with dominating potential energy over kinetic energy leads to the current cosmic expansion for both phantom as well as quintessence models. (orig.)
C-metric solution for conformal gravity with a conformally coupled scalar field
Energy Technology Data Exchange (ETDEWEB)
Meng, Kun, E-mail: mengkun@tjpu.edu.cn [School of Science, Tianjin Polytechnic University, Tianjin 300387 (China); Zhao, Liu, E-mail: lzhao@nankai.edu.cn [School of Physics, Nankai University, Tianjin 300071 (China)
2017-02-15
The C-metric solution of conformal gravity with a conformally coupled scalar field is presented. The solution belongs to the class of Petrov type D spacetimes and is conformal to the standard AdS C-metric appeared in vacuum Einstein gravity. For all parameter ranges, we identify some of the physically interesting static regions and the corresponding coordinate ranges. The solution may contain a black hole event horizon, an acceleration horizon, either of which may be cut by the conformal infinity or be hidden behind the conformal infinity. Since the model is conformally invariant, we also discussed the possible effects of the conformal gauge choices on the structure of the spacetime.
Zhang, Xuefeng
2015-01-01
Motivated by cosmic censorship in general relativity and string theory, we extend Christodoulou's celebrated examples of naked singularity formation in the Einstein-massless scalar field system to include a positive or negative scalar potential of exponential forms, i.e., $V(\\phi)=\\pm\\exp(2\\phi/\\kappa)$ with a parameter $\\kappa$. Under spherical symmetry and a self-similar ansatz depending on $\\kappa$, we derive a 3-dimensional autonomous system of first-order ordinary differential equations, which incorporates the equations for massless scalar fields as a special case. Local behavior of the phase space is studied analytically with global solutions constructed numerically. Within the 3-dimensional solution manifold, we observe, for the negative potentials, naked singularity formation from nonsingular initial data for $\\kappa^2<1$. Meanwhile, transitions between solutions containing naked singularities and black holes are also identified. However, when the potential is taken positive, numerical evolutions r...
Continuum dynamics and the electromagnetic field in the scalar ether theory of gravitation
Arminjon, Mayeul
2016-01-01
An alternative, scalar theory of gravitation has been proposed, based on a mechanism/interpretation of gravity as being a pressure force: Archimedes' thrust. In it, the gravitational field affects the physical standards of space and time, but motion is governed by an extension of the relativistic form of Newton's second law. This implies Einstein's geodesic motion for free particles only in a constant gravitational field. In this work, equations governing the dynamics of a continuous medium subjected to gravitational and non-gravitational forces are derived. Then, the case where the non-gravitational force is the Lorentz force is investigated. The gravitational modification of Maxwell's equations is obtained under the requirement that a charged continuous medium, subjected to the Lorentz force, obeys the equation derived for continuum dynamics under external forces. These Maxwell equations are shown to be consistent with the dynamics of a "free" photon, and thus with the geometrical optics of this theory. However, these equations do not imply local charge conservation, except for a constant gravitational field.
Continuum dynamics and the electromagnetic field in the scalar ether theory of gravitation
Directory of Open Access Journals (Sweden)
Arminjon Mayeul
2016-01-01
Full Text Available An alternative, scalar theory of gravitation has been proposed, based on a mechanism/interpretation of gravity as being a pressure force: Archimedes’ thrust. In it, the gravitational field affects the physical standards of space and time, but motion is governed by an extension of the relativistic form of Newton’s second law. This implies Einstein’s geodesic motion for free particles only in a constant gravitational field. In this work, equations governing the dynamics of a continuous medium subjected to gravitational and non-gravitational forces are derived. Then, the case where the non-gravitational force is the Lorentz force is investigated. The gravitational modification of Maxwell’s equations is obtained under the requirement that a charged continuous medium, subjected to the Lorentz force, obeys the equation derived for continuum dynamics under external forces. These Maxwell equations are shown to be consistent with the dynamics of a “free” photon, and thus with the geometrical optics of this theory. However, these equations do not imply local charge conservation, except for a constant gravitational field.
On continuum dynamics and the electromagnetic field in the scalar ether theory of gravitation
Arminjon, Mayeul
2017-05-01
Our study of aspects of a scalar ether theory of gravitation is formulated in a preferred reference frame in a four-dimensional spacetime endowed with a curved “physical” metric. The dynamics of a test particle is defined by an extension of the special-relativistic form of Newton’s second law. This determines the dynamical equation verified by the energy-momentum tensor T of a “dust” continuum, also in the presence of a non-gravitational external force. The dynamical equation for T thus obtained is assumed valid for a general continuous medium or a system of fields. When the non-gravitational force is the Lorentz force, this equation in turn determines the Maxwell equations in a gravitational field for the present theory. They are consistent with the dynamics of photons i.e. with the geometrical optics of the theory. Except for a constant gravitational field, they seem to imply some local production or destruction of electric charge. The possible amounts are yet to be assessed.
Kleihaus, Burkhard; Yazadjiev, Stoytcho
2015-01-01
In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and ordinary hairy black holes. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
Achasov, N. N.; Kiselev, A. V.; Shestakov, G. N.
2008-01-01
Outline: 1. Introduction, 2. Confinement, chiral dynamics and light scalar mesons, 3. Chiral shielding of the \\sigma(600), chiral constraints (the CGL band), the \\sigma(600) and the f0(980) in \\pi\\pi->\\pi\\pi, \\pi\\pi->KKbar, \\phi->\\gamma\\pi0\\pi0, 4. The \\phi meson radiative decays on light scalar resonances, 5. Light scalars in \\gamma\\gamma collisions. Evidence for four-quark components of light scalars is given. The priority of Quantum Field Theory in revealing the light scalar mystery is emp...
Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space
Directory of Open Access Journals (Sweden)
Marcello Rotondo
2017-10-01
Full Text Available How precisely can we estimate cosmological parameters by performing a quantum measurement on a cosmological quantum state? In quantum estimation theory, the variance of an unbiased parameter estimator is bounded from below by the inverse of measurement-dependent Fisher information and ultimately by quantum Fisher information, which is the maximization of the former over all positive operator-valued measurements. Such bound is known as the quantum Cramer –Rao bound. We consider the evolution of a massless scalar field with Bunch–Davies vacuum in a spatially flat FLRW spacetime, which results in a two-mode squeezed vacuum out-state for each field wave number mode. We obtain the expressions of the quantum Fisher information as well as the Fisher informations associated to occupation number measurement and power spectrum measurement, and show the specific results of their evolution for pure de Sitter expansion and de Sitter expansion followed by a radiation-dominated phase as examples. We will discuss these results from the point of view of the quantum-to-classical transition of cosmological perturbations and show quantitatively how this transition and the residual quantum correlations affect the bound on the precision.
Solanke, D. T.; Karade, T. M.
2017-11-01
In f( R, T) theory of gravity, we have studied the interacting scalar and electromagnetic fields in Bianchi type I space-time, by considering the general cases f( R, T) = f 1( R) + λf 2( T), f( {R,T} ) = f1 ( R )f2 ( T ) and f( R) theory and its particular cases f( R, T) = R + λT, f( {R,T} ) = RT, f( R) = R. It is observed that, even though the cases of f( R, T) are distinct, the convergent and isotropic solution of metric functions can be evolved in each case along with the components of vector potential, corresponding to suitable integrable function in particular cases.
Interacting diffusive unified dark energy and dark matter from scalar fields
Energy Technology Data Exchange (ETDEWEB)
Benisty, David; Guendelman, E.I. [Ben Gurion University of the Negev, Department of Physics, Beersheba (Israel)
2017-06-15
Here we generalize ideas of unified dark matter-dark energy in the context of two measure theories and of dynamical space time theories. In two measure theories one uses metric independent volume elements and this allows one to construct unified dark matter-dark energy, where the cosmological constant appears as an integration constant associated with the equation of motion of the measure fields. The dynamical space-time theories generalize the two measure theories by introducing a vector field whose equation of motion guarantees the conservation of a certain Energy Momentum tensor, which may be related, but in general is not the same as the gravitational Energy Momentum tensor. We propose two formulations of this idea: (I) by demanding that this vector field be the gradient of a scalar, (II) by considering the dynamical space field appearing in another part of the action. Then the dynamical space time theory becomes a theory of Diffusive Unified dark energy and dark matter. These generalizations produce non-conserved energy momentum tensors instead of conserved energy momentum tensors which leads at the end to a formulation of interacting DE-DM dust models in the form of a diffusive type interacting Unified dark energy and dark matter scenario. We solved analytically the theories for perturbative solution and asymptotic solution, and we show that the ΛCDM is a fixed point of these theories at large times. Also a preliminary argument as regards the good behavior of the theory at the quantum level is proposed for both theories. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Nakonieczna, Anna [Institute of Physics, Maria Curie-Skłodowska University,Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin (Poland); Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin (Poland); Yeom, Dong-han [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University,No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)
2016-02-08
There does not exist a notion of time which could be transferred straightforwardly from classical to quantum gravity. For this reason, a method of time quantification which would be appropriate for gravity quantization is being sought. One of the existing proposals is using the evolving matter as an intrinsic ‘clock’ while investigating the dynamics of gravitational systems. The objective of our research was to check whether scalar fields can serve as time variables during a dynamical evolution of a coupled multi-component matter-geometry system. We concentrated on a neutral case, which means that the elaborated system was not charged electrically nor magnetically. For this purpose, we investigated a gravitational collapse of a self-interacting complex and real scalar fields in the Brans-Dicke theory using the 2+2 spacetime foliation. We focused mainly on the region of high curvature appearing nearby the emerging singularity, which is essential from the perspective of quantum gravity. We investigated several formulations of the theory for various values of the Brans-Dicke coupling constant and the coupling between the Brans-Dicke field and the matter sector of the theory. The obtained results indicated that the evolving scalar fields can be treated as time variables in close proximity of the singularity due to the following reasons. The constancy hypersurfaces of the Brans-Dicke field are spacelike in the vicinity of the singularity apart from the case, in which the equation of motion of the field reduces to the wave equation due to a specific choice of free evolution parameters. The hypersurfaces of constant complex and real scalar fields are spacelike in the regions nearby the singularities formed during the examined process. The values of the field functions change monotonically in the areas, in which the constancy hypersurfaces are spacelike.
Conformal Generally Covariant Quantum Field Theory: The Scalar Field and its Wick Products
Pinamonti, Nicola
2009-06-01
In this paper we generalize the construction of generally covariant quantum theories given in [BFV03] to encompass the conformal covariant case. After introducing the abstract framework, we discuss the massless conformally coupled Klein Gordon field theory, showing that its quantization corresponds to a functor between two certain categories. At the abstract level, the ordinary fields, could be thought of as natural transformations in the sense of category theory. We show that the Wick monomials without derivatives (Wick powers) can be interpreted as fields in this generalized sense, provided a non-trivial choice of the renormalization constants is given. A careful analysis shows that the transformation law of Wick powers is characterized by a weight, and it turns out that the sum of fields with different weights breaks the conformal covariance. At this point there is a difference between the previously given picture due to the presence of a bigger group of covariance. It is furthermore shown that the construction does not depend upon the scale μ appearing in the Hadamard parametrix, used to regularize the fields. Finally, we briefly discuss some further examples of more involved fields.
Holographic dark energy in Brans-Dicke theory with logarithmic form of scalar field
Singh, C P
2016-01-01
In this paper, an interacting holographic dark energy model with Hubble horizon as an infra-red cut-off is considered in the framework of Brans-Dicke theory. We propose a logarithmic form $\\phi \\propto ln(\\alpha+\\beta a)$ of the Brans-Dicke scalar field to alleviate the problems of interacting holographic dark energy models in Brans-Dicke theory. We find that the equation of state parameter $w_h$ and deceleration parameter $q$ are negative in the early time which shows the early time inflation. During the evolution the sign of parameter $q$ changes from negative to positive which means that the Universe expands with decelerated rate whereas the sign of $w_h$ may change or remain negative throughout the evolution depending on the values of parameters. It is also observed that $w_h$ may cross the phantom divide line in the late time evolution. The sign of $q$ changes from positive to negative during late time of evolution which explains the late time accelerated expansion of the Universe. Thus, we present a uni...
A Guide to Precision Calculations in Dyson's Hierarchical Scalar Field Theory
Godina, J J; Oktay, M B; Niermann, S M
1998-01-01
The goal of this article is to provide a practical method to calculate, in a scalar theory, accurate numerical values of the renormalized quantities which could be used to test any kind of approximate calculation. We use finite truncations of the Fourier transform of the recursion formula for Dyson's hierarchical model in the symmetric phase to perform high-precision calculations of the unsubtracted Green's functions at zero momentum in dimension 3, 4, and 5. We use the well-known correspondence between statistical mechanics and field theory in which the large cut-off limit is obtained by letting beta reach a critical value beta_c (with up to 16 significant digits in our actual calculations). We show that the round-off errors on the magnetic susceptibility grow like (beta_c -beta)^{-1} near criticality. We show that the systematic errors (finite truncations and volume) can be controlled with an exponential precision and reduced to a level lower than the numerical errors. We justify the use of the truncation f...
Kanti, P.; Pappas, T.; Pappas, N.
2014-12-01
In this paper, we consider the propagation of scalar particles in a higher-dimensional Schwarzschild-de Sitter black-hole spacetime, both on the brane and in the bulk. Our analysis applies for arbitrary partial modes and for both minimal and nonminimal coupling of the scalar field. A general expression for the greybody factor is analytically derived in each case, and its low-energy behavior is studied in detail. Its profile in terms of scalar properties (angular-momentum number and nonminimal coupling parameter) and spacetime properties (number of extra dimensions and cosmological constant) is thoroughly investigated. In contrast to previous studies, the effect of the cosmological constant is taken into account both close to and far away from the black-hole horizon. The dual role of the cosmological constant, that may act either as a helping agent to the emission of scalar particles or as a deterring effect depending on the value of the nonminimal coupling parameter, is also demonstrated.
A No-Chaos Theorem for Non-Minimally Coupled Scalar Field Cosmology and a New Cosmogenesis Scenario
Gunzig, E.; Brenig, L.; Figueiredo, A.; Filho, T. M. Rocha
A general dynamical system approach to classical self-consistent scalar field cosmology is presented in the framework of spatially flat FLRW space-times, for arbitrary potentials and arbitrary non-minimal coupling. We show that these universes cannot undergo chaotic behaviors, thus suggesting a possible new role of inflation in cosmology. An unexpectedly involved topology of the phase-portrait of the cosmological dynamics is exhibited: Dynamically forbidden regions, playing a crucial dynamical role, appear. A new exact critical solution, a heteroclinic orbit, connects two de Sitter inflationary regimes. We suggest a novel intriguing semiclassical cosmogenesis scenario in which the quantized scalar field could tunnel through the classically forbidden region, from the Minkowski space-time towards the nearest classically allowed solution: The critical one.
Is the cosmological dark sector better modeled by a generalized Chaplygin gas or by a scalar field?
Energy Technology Data Exchange (ETDEWEB)
Campo, Sergio del; Herrera, Ramon [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Valparaiso (Chile); Fabris, Julio C. [Universidade Federal do Espirito Santo, Departamento de Fisica, Vitoria, Espirito Santo (Brazil); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation); Zimdahl, Winfried [Universidade Federal do Espirito Santo, Departamento de Fisica, Vitoria, Espirito Santo (Brazil)
2017-07-15
Both scalar fields and (generalized) Chaplygin gases have been widely used separately to characterize the dark sector of the universe. Here we investigate the cosmological background dynamics for a mixture of both these components and quantify the fractional abundances that are admitted by observational data from supernovae of type Ia and from the evolution of the Hubble rate. Moreover, we study how the growth rate of (baryonic) matter perturbations is affected by the dark-sector perturbations. (orig.)
A new holographic dark energy model in Brans-Dicke theory with logarithmic scalar field
Sadri, Ehsan; Vakili, Babak
2018-01-01
We study a holographic dark energy model in the framework of Brans-Dicke (BD) theory with taking into account the interaction between dark matter and holographic dark energy. We use the recent observational data sets, namely SN Ia compressed Joint Light-Analysis (cJLA) compilation, Baryon Acoustic Oscillations (BAO) from BOSS DR12 and the Cosmic Microwave Background (CMB) of Planck 2015. After calculating the evolution of the equation of state as well as the deceleration parameters, we find that with a logarithmic form for the BD scalar field the phantom crossing can be achieved in the late time of cosmic evolution. Unlike the conventional theory of holographic dark energy in standard cosmology (ωD=0), our model results in a late time accelerated expansion. It is also shown that the cosmic coincidence problem may be resolved in the proposed model. We execute the statefinder and Om diagnostic tools and demonstrate that interaction term does not play a significant role. Based on the observational data sets used in this paper it seems that the best value with 1σ and 2σ confidence interval are Ωm=0.268^{+0.008 +0.010}_{-0.007 -0.009}, α =3.361^{+0.332 +0.483} _{-0.401 -0.522}, β =5.560^{+0.541 +0.780}_{-0.510 -0.729}, c=0.777^{+0.023 +0.029}_{-0.017 -0.023} and b2 =0.045, according to which we find that the proposed model in the presence of interaction is compatible with the recent observational data.
Non-minimal derivative coupling scalar field and bulk viscous dark energy
Energy Technology Data Exchange (ETDEWEB)
Mostaghel, Behrang [Shahid Beheshti University, Department of Physics, Tehran (Iran, Islamic Republic of); Moshafi, Hossein [Institute for Advanced Studies in Basic Sciences, Department of Physics, Zanjan (Iran, Islamic Republic of); Movahed, S.M.S. [Shahid Beheshti University, Department of Physics, Tehran (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Physics, Tehran (Iran, Islamic Republic of)
2017-08-15
Inspired by thermodynamical dissipative phenomena, we consider bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents phantom-crossing which avoids big-rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential leading to accelerated expansion of the Universe in the framework of bulk viscous dark energy model. In this approach, the coupling constant, κ, is related to viscosity coefficient, γ, and the present dark energy density, Ω{sub DE}{sup 0}. This coupling is bounded as κ element of [-1/9H{sub 0}{sup 2}(1 - Ω{sub DE}{sup 0}), 0]. We implement recent observational data sets including a joint light-curve analysis (JLA) for SNIa, gamma ray bursts (GRBs) for most luminous astrophysical objects at high redshifts, baryon acoustic oscillations (BAO) from different surveys, Hubble parameter from HST project, Planck CMB power spectrum and lensing to constrain model free parameters. The joint analysis of JLA + GRBs + BAO + HST shows that Ω{sub DE}{sup 0} = 0.696 ± 0.010, γ = 0.1404 ± 0.0014 and H{sub 0} = 68.1 ± 1.3. Planck TT observation provides γ = 0.32{sup +0.31}{sub -0.26} in the 68% confidence limit for the viscosity coefficient. The cosmographic distance ratio indicates that current observed data prefer to increase bulk viscosity. The competition between phantom and quintessence behavior of the viscous dark energy model can accommodate cosmological old objects reported as a sign of age crisis in the ΛCDM model. Finally, tension in the Hubble parameter is alleviated in this model. (orig.)
Non-minimal derivative coupling scalar field and bulk viscous dark energy
Mostaghel, Behrang; Moshafi, Hossein; Movahed, S. M. S.
2017-08-01
Inspired by thermodynamical dissipative phenomena, we consider bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents phantom-crossing which avoids big-rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential leading to accelerated expansion of the Universe in the framework of bulk viscous dark energy model. In this approach, the coupling constant, κ , is related to viscosity coefficient, γ , and the present dark energy density, Ω_DE^0. This coupling is bounded as κ \\in [-1/9H_0^2(1-Ω_DE^0), 0]. We implement recent observational data sets including a joint light-curve analysis (JLA) for SNIa, gamma ray bursts (GRBs) for most luminous astrophysical objects at high redshifts, baryon acoustic oscillations (BAO) from different surveys, Hubble parameter from HST project, Planck CMB power spectrum and lensing to constrain model free parameters. The joint analysis of JLA + GRBs + BAO + HST shows that Ω_DE^0=0.696± 0.010, γ =0.1404± 0.0014 and H_0=68.1± 1.3. Planck TT observation provides γ =0.32^{+0.31}_{-0.26} in the 68% confidence limit for the viscosity coefficient. The cosmographic distance ratio indicates that current observed data prefer to increase bulk viscosity. The competition between phantom and quintessence behavior of the viscous dark energy model can accommodate cosmological old objects reported as a sign of age crisis in the ΛCDM model. Finally, tension in the Hubble parameter is alleviated in this model.
Directory of Open Access Journals (Sweden)
Shahar Hod
2016-10-01
Full Text Available We determine the characteristic timescales associated with the linearized relaxation dynamics of the composed Reissner–Nordström-black-hole-charged-massive-scalar-field system. To that end, the quasinormal resonant frequencies {ωn(μ,q,M,Q}n=0n=∞ which characterize the dynamics of a charged scalar field of mass μ and charge coupling constant q in the charged Reissner–Nordström black-hole spacetime of mass M and electric charge Q are determined analytically in the eikonal regime 1≪Mμ
Energy Technology Data Exchange (ETDEWEB)
Cavalcanti, E.; Castro, E.; Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas/MCTI, Rio de Janeiro, RJ (Brazil); Linhares, C.A. [Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil)
2017-10-15
A scalar model is built, as a quantum field theory defined on a toroidal topology, to describe a phase transition in films subjected to periodic boundary conditions and influenced by an external and constant magnetic field. Criticality is studied and the relations between the critical temperature, the film thickness, the magnetic field strength and the chemical potential are investigated. Since the model describes a second-order phase transition a comparison with the Ginzburg-Landau theory is made. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)
2015-05-11
In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
Directory of Open Access Journals (Sweden)
Burkhard Kleihaus
2015-05-01
Full Text Available In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
Energy Technology Data Exchange (ETDEWEB)
Pashitskii, E. A., E-mail: pashitsk@iop.kiev.ua; Pentegov, V. I., E-mail: pentegov@iop.kiev.ua [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)
2017-03-15
We consider a possible scenario for the evolution of the early cold Universe born from a fairly large quantum fluctuation in a vacuum with a size a{sub 0} ≫ l{sub P} (where l{sub P} is the Planck length) and filled with both a nonlinear scalar field φ, whose potential energy density U(φ) determines the vacuum energy density λ, and a nonideal Fermi gas with short-range repulsion between particles, whose equation of state is characterized by the ratio of pressure P(n{sub F}) to energy density ε(n{sub F}) dependent on the number density of fermions n{sub F}. As the early Universe expands, the dimensionless quantity ν(n{sub F}) = P(n{sub F})/ε(n{sub F}) decreases with decreasing n{sub F} from its maximum value ν{sub max} = 1 for n{sub F} → ∞ to zero for n{sub F} → 0. The interaction of the scalar and gravitational fields, which is characterized by a dimensionless constant ξ, is proportional to the scalar curvature of four-dimensional space R = κ[3P(n{sub F})–ε(n{sub F})–4λ] (where κ is Einstein’s gravitational constant), and contains terms both quadratic and linear in φ. As a result, the expanding early Universe reaches the point of first-order phase transition in a finite time interval at critical values of the scalar curvature R = R{sub c} =–μ{sup 2}/ξ and radius a{sub c} ≫ a{sub 0}. Thereafter, the early closed Universe “rolls down” from the flat inflection point of the potential U(φ) to the zero potential minimum in a finite time. The release of the total potential energy of the scalar field in the entire volume of the expanding Universe as it “rolls down” must be accompanied by the production of a large number of massive particles and antiparticles of various kinds, whose annihilation plays the role of the Big Bang. We also discuss the fundamental nature of Newton’ gravitational constant G{sub N}.
Directory of Open Access Journals (Sweden)
Ran Li
2016-07-01
Full Text Available Reissner–Nordström Anti-de Sitter (RNAdS black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon. We present the time domain analysis of charged scalar field perturbations in the RNAdS black hole background in general dimensions. We show that the instabilities of charged scalar field can be explicitly illustrated from the time profiles of evolving scalar field. By using the Prony method to fit the time evolution data, we confirm the mode that dominates the long time behavior of scalar field is in accordance with the quasinormal mode from the frequency domain analysis. The superradiance origin of the instability can also be demonstrated by comparing the real part of the dominant mode with the superradiant condition of charged scalar field. It is shown that all the unstable modes are superradiant, which is consistent with the analytical result in the frequency domain analysis. Furthermore, we also confirm there exists the rapid exponential growing modes in the RNAdS case, which makes the RNAdS black hole a good test ground to investigate the nonlinear evolution of superradiant instability.
Energy Technology Data Exchange (ETDEWEB)
Li, Ran, E-mail: liran@htu.edu.cn [Department of Physics, Henan Normal University, Xinxiang 453007 (China); Zhang, Hongbao, E-mail: hzhang@vub.ac.be [Department of Physics, Beijing Normal University, Beijing 100875 (China); Theoretische Natuurkunde, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Zhao, Junkun, E-mail: zhaojkun1991@163.com [Department of Physics, Henan Normal University, Xinxiang 453007 (China)
2016-07-10
Reissner–Nordström Anti-de Sitter (RNAdS) black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon. We present the time domain analysis of charged scalar field perturbations in the RNAdS black hole background in general dimensions. We show that the instabilities of charged scalar field can be explicitly illustrated from the time profiles of evolving scalar field. By using the Prony method to fit the time evolution data, we confirm the mode that dominates the long time behavior of scalar field is in accordance with the quasinormal mode from the frequency domain analysis. The superradiance origin of the instability can also be demonstrated by comparing the real part of the dominant mode with the superradiant condition of charged scalar field. It is shown that all the unstable modes are superradiant, which is consistent with the analytical result in the frequency domain analysis. Furthermore, we also confirm there exists the rapid exponential growing modes in the RNAdS case, which makes the RNAdS black hole a good test ground to investigate the nonlinear evolution of superradiant instability.
Li, Ran; Zhang, Hongbao; Zhao, Junkun
2016-07-01
Reissner-Nordström Anti-de Sitter (RNAdS) black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon. We present the time domain analysis of charged scalar field perturbations in the RNAdS black hole background in general dimensions. We show that the instabilities of charged scalar field can be explicitly illustrated from the time profiles of evolving scalar field. By using the Prony method to fit the time evolution data, we confirm the mode that dominates the long time behavior of scalar field is in accordance with the quasinormal mode from the frequency domain analysis. The superradiance origin of the instability can also be demonstrated by comparing the real part of the dominant mode with the superradiant condition of charged scalar field. It is shown that all the unstable modes are superradiant, which is consistent with the analytical result in the frequency domain analysis. Furthermore, we also confirm there exists the rapid exponential growing modes in the RNAdS case, which makes the RNAdS black hole a good test ground to investigate the nonlinear evolution of superradiant instability.
Shao, Lijing; Sennett, Noah; Buonanno, Alessandra; Kramer, Michael; Wex, Norbert
2017-10-01
Pulsar timing and laser-interferometer gravitational-wave (GW) detectors are superb laboratories to study gravity theories in the strong-field regime. Here, we combine these tools to test the mono-scalar-tensor theory of Damour and Esposito-Farèse (DEF), which predicts nonperturbative scalarization phenomena for neutron stars (NSs). First, applying Markov-chain Monte Carlo techniques, we use the absence of dipolar radiation in the pulsar-timing observations of five binary systems composed of a NS and a white dwarf, and eleven equations of state (EOSs) for NSs, to derive the most stringent constraints on the two free parameters of the DEF scalar-tensor theory. Since the binary-pulsar bounds depend on the NS mass and the EOS, we find that current pulsar-timing observations leave scalarization windows, i.e., regions of parameter space where scalarization can still be prominent. Then, we investigate if these scalarization windows could be closed and if pulsar-timing constraints could be improved by laser-interferometer GW detectors, when spontaneous (or dynamical) scalarization sets in during the early (or late) stages of a binary NS (BNS) evolution. For the early inspiral of a BNS carrying constant scalar charge, we employ a Fisher-matrix analysis to show that Advanced LIGO can improve pulsar-timing constraints for some EOSs, and next-generation detectors, such as the Cosmic Explorer and Einstein Telescope, will be able to improve those bounds for all eleven EOSs. Using the late inspiral of a BNS, we estimate that for some of the EOSs under consideration, the onset of dynamical scalarization can happen early enough to improve the constraints on the DEF parameters obtained by combining the five binary pulsars. Thus, in the near future, the complementarity of pulsar timing and direct observations of GWs on the ground will be extremely valuable in probing gravity theories in the strong-field regime.
Directory of Open Access Journals (Sweden)
Lijing Shao
2017-10-01
Full Text Available Pulsar timing and laser-interferometer gravitational-wave (GW detectors are superb laboratories to study gravity theories in the strong-field regime. Here, we combine these tools to test the mono-scalar-tensor theory of Damour and Esposito-Farèse (DEF, which predicts nonperturbative scalarization phenomena for neutron stars (NSs. First, applying Markov-chain Monte Carlo techniques, we use the absence of dipolar radiation in the pulsar-timing observations of five binary systems composed of a NS and a white dwarf, and eleven equations of state (EOSs for NSs, to derive the most stringent constraints on the two free parameters of the DEF scalar-tensor theory. Since the binary-pulsar bounds depend on the NS mass and the EOS, we find that current pulsar-timing observations leave scalarization windows, i.e., regions of parameter space where scalarization can still be prominent. Then, we investigate if these scalarization windows could be closed and if pulsar-timing constraints could be improved by laser-interferometer GW detectors, when spontaneous (or dynamical scalarization sets in during the early (or late stages of a binary NS (BNS evolution. For the early inspiral of a BNS carrying constant scalar charge, we employ a Fisher-matrix analysis to show that Advanced LIGO can improve pulsar-timing constraints for some EOSs, and next-generation detectors, such as the Cosmic Explorer and Einstein Telescope, will be able to improve those bounds for all eleven EOSs. Using the late inspiral of a BNS, we estimate that for some of the EOSs under consideration, the onset of dynamical scalarization can happen early enough to improve the constraints on the DEF parameters obtained by combining the five binary pulsars. Thus, in the near future, the complementarity of pulsar timing and direct observations of GWs on the ground will be extremely valuable in probing gravity theories in the strong-field regime.
Fialko, O.; Opanchuk, B.; Sidorov, A. I.; Drummond, P. D.; Brand, J.
2017-01-01
The quantum decay of a relativistic scalar field from a metastable state (‘false vacuum decay’) is a fundamental idea in quantum field theory and cosmology. This occurs via local formation of bubbles of true vacuum with their subsequent rapid expansion. It can be considered as a relativistic analog of a first-order phase transition in condensed matter. Here we expand upon our recent proposal (Fialko O et al 2015 Europhys. Lett. 110 56001) for an experimental test of false vacuum decay using an ultra-cold spinor Bose gas. A false vacuum for the relative phase of two spin components, serving as the unstable scalar field, is generated by means of a modulated linear coupling of the spin components. We analyze the system theoretically using the functional integral approach and show that various microscopic degrees of freedom in the system, albeit leading to dissipation in the relative phase sector, will not hamper the observation of the false vacuum decay in the laboratory. This is well supported by numerical simulations demonstrating the spontaneous formation of true vacuum bubbles on millisecond time-scales in two-component 7Li or 41K bosonic condensates in one-dimensional traps of ∼ 100 μ {{m}} size.
Energy Technology Data Exchange (ETDEWEB)
Chattopadhyay, Surajit [Pailan College of Management and Technology, Kolkata (India); Pasqua, Antonio [University of Trieste, Department of Physics, Trieste (Italy); Khurshudyan, Martiros [Yerevan State University, Department of Theoretical Physics, Yerevan (Armenia); Potsdam-Golm Science Park, Max Planck Institute of Colloids and Interfaces, Potsdam (Germany)
2014-09-15
Motivated by the work of Yang et al. (Mod. Phys. Lett. A 26:191, 2011), we report on a study of the new holographic dark energy (NHDE) model with energy density given by ρ{sub D} = (3φ{sup 2})/(4ω)(μH{sup 2} + νH) in the framework of chameleon Brans-Dicke cosmology. We have studied the correspondence between the quintessence, the DBI-essence, and the tachyon scalar-field models with the NHDE model in the framework of chameleon Brans-Dicke cosmology. Deriving an expression of the Hubble parameter H and, accordingly, ρ{sub D} in the context of chameleon Brans-Dicke chameleon cosmology, we have reconstructed the potentials and dynamics for these scalar-field models. Furthermore, we have examined the stability for the obtained solutions of the crossing of the phantom divide under a quantum correction of massless conformally invariant fields, and we have seen that the quantum correction could be small when the phantom crossing occurs and the obtained solutions of the phantom crossing could be stable under the quantum correction. It has also been noted that the potential increases as the matter. chameleon coupling gets stronger with the evolution of the universe. (orig.)
Bouhmadi-López, Mariam; Marto, João; Morais, João; Zhuk, Alexander
2016-01-01
In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we can consider the Universe to be filled with dust-like matter in the form of discretely distributed galaxies, a $K$-essence scalar field, playing the role of dark energy, and radiation as matter sources. We investigate such a Universe in the mechanical approach. This means that the peculiar velocities of the inhomogeneities (in the form of galaxies) as well as the fluctuations of the other perfect fluids are non-relativistic. Such fluids are designated as coupled because they are concentrated around the inhomogeneities. In the present paper, we investigate the conditions under which the $K$-essence scalar field with the most general form for its action can become coupled. We investigate at the background level three particular examples of the $K$-essence models: (i) the pure kinetic $K$-essence field, (ii) a $K$-essence with a constant speed of sound and (iii) the $K$-essence m...
On Invariants and Scalar Chiral Correlation Functions in { n} = 1 Superconformal Field Theories
Knuth, Holger
A general expression for the four-point function with vanishing total R-charge of antichiral and chiral superfields in { N} = 1 superconformal theories is given. It is obtained by applying the exponential of a simple universal nilpotent differential operator to an arbitrary function of two cross-ratios. To achieve this the nilpotent superconformal invariants according to Park are focused. Several dependencies between these invariants are presented, so that eight nilpotent invariants and 27 monomials of these invariants of degree d > 1 are left being linearly independent. It is analyzed, how terms within the four-point function of general scalar superfields cancel in order to fulfill the chiral restrictions.
Nonuniversal anomaly-free U(1) model with three Higgs doublets and one singlet scalar field
Mantilla, S. F.; Martinez, R.
2017-11-01
The flavor problem, neutrino physics, and the fermion mass hierarchy are important motivations to extend the Standard Model to the TeV scale. A new family nonuniversal extension is presented with three Higgs doublets, one Higgs singlet, and one scalar dark matter candidate. Exotic fermions are included in order to cancel chiral anomalies and to allow family nonuniversal U(1 ) X charges. By implementing an additional Z2 symmetry, the Yukawa coupling terms are suited in such a way that the fermion mass hierarchy is obtained without fine-tuning. The neutrino sector includes Majorana fermions to implement the inverse seesaw mechanism. The effective mass matrix for Standard Model neutrinos is fitted to current neutrino oscillation data to check the consistency of the model with experimental evidence, obtaining that the normal-ordering scheme is preferred over the inverse ones, and the values of the neutrino Yukawa coupling constants are shown. Finally, the h →τ μ lepton-flavor-violation process is addressed with the rotation matrices of the C P -even scalars, left- and right-handed charged leptons, yielding definite regions where the model is consistent with CMS reports of BR (h →τ μ ).
Zero, normal and super-radiant modes for scalar and spinor fields in Kerr–anti de Sitter spacetime
Kenmoku, Masakatsu; Cho, Yongmin; Shigemoto, Kazuyasu; Yoon, Jong Hyuk
2017-11-01
We study zero and normal modes for scalar and spinor fields in Kerr–anti de Sitter spacetime as a bound state problem with Dirichlet and Neumann boundary conditions. Zero mode is defined as its momentum near the horizon to be zero: p_H=ω-Ω_Hm=0 , and is shown not to exist as a physical state for both scalar and spinor fields. Physical normal modes must satisfy the spectrum condition p_H>0 as results of (i) non-existence of zero mode and (ii) the analyticity with respect to the rotation parameter of Kerr–anti de Sitter spacetime. Under the spectrum condition, the super-radiant modes are shown to be type 2 super-radiance, which is characterized by negative frequency ω0 . The type 2 super-radiant modes are necessary for the completeness relation of normal modes and are stable. Applying the spectrum condition to black hole thermodynamics, the brick wall model is shown to be well-defined.
Nakonieczna, Anna
2015-01-01
There does not exist a notion of time which could be transferred straightforwardly from classical to quantum gravity. For this reason, a method of time quantification which would be appropriate for gravity quantization is being sought. One of the existing proposals is using the evolving matter as an intrinsic `clock' while investigating the dynamics of gravitational systems. The objective of our research was to check whether scalar fields can serve as time variables during a dynamical evolution of a coupled multi-component matter-geometry system. For this purpose, we investigated a gravitational collapse of a self-interacting complex and real scalar fields in the Brans-Dicke theory using the 2+2 spacetime foliation. We focused mainly on the region of high curvature appearing nearby the emerging singularity, which is essential from the perspective of quantum gravity. We investigated several formulations of the theory for various values of the Brans-Dicke coupling constant and the coupling between the Brans-Dic...
On a family of (1+1)-dimensional scalar field theory models: Kinks, stability, one-loop mass shifts
Energy Technology Data Exchange (ETDEWEB)
Alonso-Izquierdo, A., E-mail: alonsoiz@usal.es [Departamento de Matematica Aplicada and IUFFyM, Universidad de Salamanca (Spain); Mateos Guilarte, J. [Departamento de Fisica Fundamental and IUFFyM, Universidad de Salamanca (Spain)
2012-09-15
In this paper we construct a one-parametric family of (1+1)-dimensional one-component scalar field theory models supporting kinks. Inspired by the sine-Gordon and {phi}{sup 4} models, we look at all possible extensions such that the kink second-order fluctuation operators are Schroedinger differential operators with Poeschl-Teller potential wells. In this situation, the associated spectral problem is solvable and therefore we shall succeed in analyzing the kink stability completely and in computing the one-loop quantum correction to the kink mass exactly. When the parameter is a natural number, the family becomes the hierarchy for which the potential wells are reflectionless, the two first levels of the hierarchy being the sine-Gordon and {phi}{sup 4} models. - Highlights: Black-Right-Pointing-Pointer We construct a family of scalar field theory models supporting kinks. Black-Right-Pointing-Pointer The second-order kink fluctuation operators involve Poeschl-Teller potential wells. Black-Right-Pointing-Pointer We compute the one-loop quantum correction to the kink mass with different methods.
Computational study of scalar mixing in the field of a gaseous laminar line vortex
Basu, S.; Barber, T. J.; Cetegen, B. M.
2007-05-01
A computational study of scalar mixing in a laminar vortex is presented for vortices generated between two gas streams (one seeded and another unseeded) flowing parallel to each other in a rectangular flow channel. An isolated line vortex is initiated by momentarily increasing one of the stream velocities in relation to the other in otherwise equal velocity, co-flowing streams separated upstream by a splitter plate. A detailed parametric study was conducted to determine the effects of vortex strength, convection time, and nonuniform temperature on scalar mixing characteristics. A qualitative relationship was developed between the vortex and the convection Reynolds numbers to obtain a well-defined vortical structure. As it is well-known in the literature on mixing layers, the vortex initiation process creates an abundance of the fluid in the vortex core from the pulsed (or high speed) stream. Spatial mixing statistics are obtained in the vortex interaction domain by determining the scalar concentration probability density functions as well as the mean mixed fluid concentration and its variance. Computational results are found to be in excellent agreement with the experiments conducted in the same configuration by one of the authors. Both computations and experiments suggest that the interfacial area generation as a result of vortex interaction is primarily responsible for mixing augmentation at high vortex Reynolds numbers (Rev≥140). Effects of molecular diffusion become more important for weak vortices and at short convection times. Temperature (or density) ratio between co-flowing streams clearly affects the rate of growth of the vortices and this is consistent with the findings in nonuniform density mixing layers. Nonuniform temperatures result in a decrease of the mean mixed fluid concentration regardless of the stream from which the vortex is generated. The mean mixed fluid concentration in the vortex interaction region scales with the product of vortex
Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)
2017-05-15
The quasi-bound states of charged massive scalar fields in the near-extremal charged Reissner-Nordstroem black-hole spacetime are studied analytically. These discrete resonant modes of the composed black-hole-field system are characterized by the physically motivated boundary condition of ingoing waves at the black-hole horizon and exponentially decaying (bounded) radial eigenfunctions at spatial infinity. Solving the Klein-Gordon wave equation for the linearized scalar fields in the black-hole spacetime, we derive a remarkably compact analytical formula for the complex frequency spectrum which characterizes the quasi-bound state resonances of the composed Reissner-Nordstroem-black-hole-charged-massive-scalar-field system. (orig.)
Kofinas, Georgios; Lima, Nelson A.
2017-10-01
In this work we focus on a novel completion of the well-known Brans-Dicke theory that introduces an interaction between the dark energy and dark matter sectors, known as complete Brans-Dicke (CBD) theory. We obtain viable cosmological accelerating solutions that fit supernovae observations with great precision without any scalar potential V (ϕ ). We use these solutions to explore the impact of the CBD theory on the large scale structure by studying the dynamics of its linear perturbations. We observe a growing behavior of the lensing potential Φ+ at late-times, while the growth rate is actually suppressed relatively to Λ CDM , which allows the CBD theory to provide a competitive fit to current RSD measurements of f σ8. However, we also observe that the theory exhibits a pathological change of sign in the effective gravitational constant concerning the perturbations on subhorizon scales that could pose a challenge to its validity.
A New Fate of a Warped 5D FLRW Model with a U(1) Scalar Gauge Field
Slagter, Reinoud Jan; Pan, Supriya
2016-09-01
If we live on the weak brane with zero effective cosmological constant in a warped 5D bulk spacetime, gravitational waves and brane fluctuations can be generated by a part of the 5D Weyl tensor and carries information of the gravitational field outside the brane. We consider on a cylindrical symmetric warped FLRW background a U(1) self-gravitating scalar field coupled to a gauge field without bulk matter. It turns out that brane fluctuations can be formed dynamically, due to the modified energy-momentum tensor components of the scalar-gauge field ("cosmic string"). As a result, we find that the late-time behavior could significantly deviate from the standard evolution of the universe. The effect is triggered by the time-dependent warpfactor with two branches of the form ± 1/√{τ r}√{(c_1e^{√{2τ } t}+c_2e^{-√{2τ } t})(c_3e^{√{2τ } r}+c_4e^{-√{2τ } r})} ( with τ , c_i constants) and the modified brane equations comparable with a dark energy effect. This is a brane-world mechanism, not present in standard 4D FLRW, where the large disturbances are rapidly damped as the expansion proceed. Because gravity can propagate in the bulk, the cosmic string can build up a huge angle deficit (or mass per unit length) by the warpfactor and can induce massive KK-modes felt on the brane. Disturbances in the spatial components of the stress-energy tensor cause cylindrical symmetric waves, amplified due to the presence of the bulk space and warpfactor. They could survive the natural damping due to the expansion of the universe. It turns out that one of the metric components becomes singular at the moment the warp factor develops an extremum. This behavior could have influence on the possibility of a transition from acceleration to deceleration or vice versa.
Massive scalar counterpart of gravitational waves in scalarized neutron star binaries
Energy Technology Data Exchange (ETDEWEB)
Wang, Jing [Sun Yat-sen University, School of Physics and Astronomy, Guangzhou (China)
2017-09-15
In analogy with spontaneous magnetization of ferromagnets below the Curie temperature, a neutron star (NS), with a compactness above a certain critical value, may undergo spontaneous scalarization and exhibit an interior nontrivial scalar configuration. Consequently, the exterior spacetime is changed, and an external scalar field appears, which subsequently triggers a scalarization of its companion. The dynamical interplay produces a gravitational scalar counterpart of tensor gravitational waves. In this paper, we resort to scalar-tensor theory and demonstrate that the gravitational scalar counterpart from a double neutron star (DNS) and a neutron star-white dwarf (NS-WD) system become massive. We report that (1) a gravitational scalar background field, arising from convergence of external scalar fields, plays the role of gravitational scalar counterpart in scalarized DNS binary, and the appearance of a mass-dimensional constant in a Higgs-like gravitational scalar potential is responsible for a massive gravitational scalar counterpart with a mass of the order of the Planck scale; (2) a dipolar gravitational scalar radiated field, resulting from differing binding energies of NS and WD, plays the role of a gravitational scalar counterpart in scalarized orbital shrinking NS-WDs, which oscillates around a local and scalar-energy-density-dependent minimum of the gravitational scalar potential and obtains a mass of the order of about 10{sup -21} eV/c{sup 2}. (orig.)
Massive scalar counterpart of gravitational waves in scalarized neutron star binaries
Wang, Jing
2017-09-01
In analogy with spontaneous magnetization of ferromagnets below the Curie temperature, a neutron star (NS), with a compactness above a certain critical value, may undergo spontaneous scalarization and exhibit an interior nontrivial scalar configuration. Consequently, the exterior spacetime is changed, and an external scalar field appears, which subsequently triggers a scalarization of its companion. The dynamical interplay produces a gravitational scalar counterpart of tensor gravitational waves. In this paper, we resort to scalar-tensor theory and demonstrate that the gravitational scalar counterpart from a double neutron star (DNS) and a neutron star-white dwarf (NS-WD) system become massive. We report that (1) a gravitational scalar background field, arising from convergence of external scalar fields, plays the role of gravitational scalar counterpart in scalarized DNS binary, and the appearance of a mass-dimensional constant in a Higgs-like gravitational scalar potential is responsible for a massive gravitational scalar counterpart with a mass of the order of the Planck scale; (2) a dipolar gravitational scalar radiated field, resulting from differing binding energies of NS and WD, plays the role of a gravitational scalar counterpart in scalarized orbital shrinking NS-WDs, which oscillates around a local and scalar-energy-density-dependent minimum of the gravitational scalar potential and obtains a mass of the order of about 10^{-21} { {eV/c}}^2.
Uniqueness of the Fock quantization of a free scalar field on S1 with time dependent mass
Cortez, Jerónimo; Marugán, Guillermo A. Mena; Serôdio, Rogério; Velhinho, José M.
2009-04-01
We analyze the quantum description of a free scalar field on the circle in the presence of an explicitly time-dependent potential, also interpretable as a time-dependent mass. Classically, the field satisfies a linear wave equation of the form ξ¨-ξ''+f(t)ξ=0. We prove that the representation of the canonical commutation relations corresponding to the particular case of a massless free field (f=0) provides a unitary implementation of the dynamics for sufficiently general mass terms, f(t). Furthermore, this representation is uniquely specified, among the class of representations determined by S1-invariant complex structures, as the only one allowing a unitary dynamics. These conclusions can be extended in fact to fields on the two-sphere possessing axial symmetry. This generalizes a uniqueness result previously obtained in the context of the quantum field description of the Gowdy cosmologies, in the case of linear polarization and for any of the possible topologies of the spatial sections.
Directory of Open Access Journals (Sweden)
Shahar Hod
2015-07-01
Full Text Available The quasinormal resonance spectrum {ωn(μ,q,M,Q}n=0n=∞ of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime is studied analytically in the large-coupling regime qQ≫Mμ (here {μ,q} are respectively the mass and charge coupling constant of the field, and {M,Q} are respectively the mass and electric charge of the black hole. This physical system provides a striking illustration for the validity of the universal relaxation bound τ×T≥ħ/π in black-hole physics (here τ≡1/ℑω0 is the characteristic relaxation time of the composed black-hole-scalar-field system, and T is the Bekenstein–Hawking temperature of the black hole. In particular, it is shown that the relaxation dynamics of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime may saturate this quantum time-times-temperature inequality. Interestingly, we prove that potential violations of the bound by light scalar fields are excluded by the Schwinger-type pair-production mechanism (a vacuum polarization effect, a quantum phenomenon which restricts the physical parameters of the composed black-hole-charged-field system to the regime qQ≪M2μ2/ħ.
Excursion probabilities of non-homogeneous Gaussian scalar fields based on maxima considerations
DEFF Research Database (Denmark)
Nielsen, Michael Havbro Faber; Rackwitz, R.
1988-01-01
Many uncertain natural or technical phenomena are most realistically described by random fields. A typical example of a random field is the load effect in a floor slab which is loaded by a spatially distributed gravity load. Other examples of random fields include the sea-level around off-shore p...
National Research Council Canada - National Science Library
Miao, Yan-Gang; Xu, Zhen-Ming
2017-01-01
We investigate the $$P{-}V$$ P - V criticality and the Maxwell equal area law for a five-dimensional spherically symmetric AdS black hole with a scalar hair in the absence of and in the presence of a Maxwell field, respectively...
Reconstruction of scalar and vectorial components in X-ray dark-field tomography.
Bayer, Florian L; Hu, Shiyang; Maier, Andreas; Weber, Thomas; Anton, Gisela; Michel, Thilo; Riess, Christian P
2014-09-02
Grating-based X-ray dark-field imaging is a novel technique for obtaining image contrast for object structures at size scales below setup resolution. Such an approach appears particularly beneficial for medical imaging and nondestructive testing. It has already been shown that the dark-field signal depends on the direction of observation. However, up to now, algorithms for fully recovering the orientation dependence in a tomographic volume are still unexplored. In this publication, we propose a reconstruction method for grating-based X-ray dark-field tomography, which models the orientation-dependent signal as an additional observable from a standard tomographic scan. In detail, we extend the tomographic volume to a tensorial set of voxel data, containing the local orientation and contributions to dark-field scattering. In our experiments, we present the first results of several test specimens exhibiting a heterogeneous composition in microstructure, which demonstrates the diagnostic potential of the method.
On the backreaction of scalar and spinor quantum fields in curved spacetimes
Energy Technology Data Exchange (ETDEWEB)
Hack, Thomas-Paul
2010-10-15
In the first instance, the present work is concerned with generalising constructions and results in quantum field theory on curved spacetimes from the well-known case of the Klein-Gordon field to Dirac fields. To this end, the enlarged algebra of observables of the Dirac field is constructed in the algebraic framework. This algebra contains normal-ordered Wick polynomials in particular, and an extended analysis of one of its elements, the stress-energy tensor, is performed. Based on detailed calculations of the Hadamard coe?cients of the Dirac field, it is found that a local, covariant, and covariantly conserved construction of the stress-energy tensor is possible. Additionally, the mathematically sound Hadamard regularisation prescription of the stress-energy tensor is compared to the mathematically less rigorous DeWitt-Schwinger regularisation. It is found that both prescriptions are essentially equivalent, particularly, it turns out to be possible to formulate the DeWitt-Schwinger prescription in a well-defined way. While the aforementioned results hold in generic curved spacetimes, particular attention is also devoted to a specific class of Robertson-Walker spacetimes with a lightlike Big Bang hypersurface. Employing holographic methods, Hadamard states for the Klein-Gordon and the Dirac field are constructed. These states are preferred in the sense that they constitute asymptotic equilibrium states in the limit to the Big Bang hypersurface. Finally, solutions of the semiclassical Einstein equation for quantum fields of arbitrary spin are analysed in the flat Robertson-Walker case. One finds that these solutions explain the measured supernova Ia data as good as the {lambda}CDM model. Hence, one arrives at a natural explanation of dark energy and a simple quantum model of cosmological dark matter. (orig.)
A New Fate of a Warped 5D FRW Model with a U(1) Scalar Gauge Field
Slagter, Reinoud Jan
2015-01-01
If we live on the weak brane with zero effective cosmological constant in a warped 5D bulk spacetime , gravitational waves and brane fluctuations can be generated by a part of the 5D Weyl tensor and carries information of the gravitational field outside the brane. We consider on a cylindrical symmetric warped FRW background the U(1) self-gravitating scalar-gauge field without bulk matter. It turns out that "branons" can be formed dynamically, due to the modified energy-momentum tensor components of the cosmic string. As a result, we find that the late-time behavior could be significant deviate from the standard evolution of the universe. The effect is triggered by the time-dependent warp factor, of the form $\\sqrt{ae^{\\tau t}+be^{-\\tau t}}$ and the modified brane equations, comparable with a dark energy effect. This is a brane-world mechanism, not present is standard 4D FRW, where the large disturbances are rapidly damped as the expansion proceed. Because gravity can propagate in the bulk, the cosmic string c...
Directory of Open Access Journals (Sweden)
Katsuya Hashino
2017-03-01
Full Text Available We calculate the spectrum of gravitational waves originated from strongly first order electroweak phase transition in the extended Higgs model with a real singlet scalar field. In order to calculate the bubble nucleation rate, we perform a two-field analysis and evaluate bounce solutions connecting the true and the false vacua using the one-loop effective potential at finite temperatures. Imposing the Sakharov condition of the departure from thermal equilibrium for baryogenesis, we survey allowed regions of parameters of the model. We then investigate the gravitational waves produced at electroweak bubble collisions in the early Universe, such as the sound wave, the bubble wall collision and the plasma turbulence. We find that the strength at the peak frequency can be large enough to be detected at future space-based gravitational interferometers such as eLISA, DECIGO and BBO. Predicted deviations in the various Higgs boson couplings are also evaluated at the zero temperature, and are shown to be large enough too. Therefore, in this model strongly first order electroweak phase transition can be tested by the combination of the precision study of various Higgs boson couplings at the LHC, the measurement of the triple Higgs boson coupling at future lepton colliders and the shape of the spectrum of gravitational wave detectable at future gravitational interferometers.
Directory of Open Access Journals (Sweden)
Sergio Mendoza
2009-01-01
Full Text Available We present heuristic arguments suggesting that if EM waves with wavelengths somewhat larger than the Schwarzschild radius of a black hole were fully absorbed by it, the second law of thermodynamics would be violated, under the Bekenstein interpretation of the area of a black hole as a measure of its entropy. Thus, entropy considerations make the well known fact that large wavelengths are only marginally absorbed by black holes, a natural consequence of thermodynamics. We also study numerically the ingoing radial propagation of a scalar field wave in a Schwarzschild metric, relaxing the standard assumption which leads to the eikonal equation, that the wave has zero spatial extent. We find that if these waves have wavelengths larger that the Schwarzschild radius, they are very substantially reflected, fully to numerical accuracy. Interestingly, this critical wavelength approximately coincides with the one derived from entropy considerations of the EM field, and is consistent with well known limit results of scattering in the Schwarzschild metric. The propagation speed is also calculated and seen to differ from the value c, for wavelengths larger than Rs, in the vicinity of Rs. As in all classical wave phenomena, whenever the wavelength is larger or comparable to the physical size of elements in the system, in this case changes in the metric, the zero extent Ã¢Â€Â™particleÃ¢Â€Â™ description fails, and the wave nature becomes apparent.
Energy Technology Data Exchange (ETDEWEB)
Hashino, Katsuya, E-mail: hashino@jodo.sci.u-toyama.ac.jp [Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Kakizaki, Mitsuru, E-mail: kakizaki@sci.u-toyama.ac.jp [Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Kanemura, Shinya, E-mail: kanemu@sci.u-toyama.ac.jp [Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Ko, Pyungwon, E-mail: pko@kias.re.kr [School of Physics, KIAS, Seoul 02455 (Korea, Republic of); Matsui, Toshinori, E-mail: matsui@kias.re.kr [School of Physics, KIAS, Seoul 02455 (Korea, Republic of)
2017-03-10
We calculate the spectrum of gravitational waves originated from strongly first order electroweak phase transition in the extended Higgs model with a real singlet scalar field. In order to calculate the bubble nucleation rate, we perform a two-field analysis and evaluate bounce solutions connecting the true and the false vacua using the one-loop effective potential at finite temperatures. Imposing the Sakharov condition of the departure from thermal equilibrium for baryogenesis, we survey allowed regions of parameters of the model. We then investigate the gravitational waves produced at electroweak bubble collisions in the early Universe, such as the sound wave, the bubble wall collision and the plasma turbulence. We find that the strength at the peak frequency can be large enough to be detected at future space-based gravitational interferometers such as eLISA, DECIGO and BBO. Predicted deviations in the various Higgs boson couplings are also evaluated at the zero temperature, and are shown to be large enough too. Therefore, in this model strongly first order electroweak phase transition can be tested by the combination of the precision study of various Higgs boson couplings at the LHC, the measurement of the triple Higgs boson coupling at future lepton colliders and the shape of the spectrum of gravitational wave detectable at future gravitational interferometers.
Wang, R.; Demerdash, N. A.
1991-01-01
A method of combined use of magnetic vector potential based finite-element (FE) formulations and magnetic scalar potential (MSP) based formulations for computation of three-dimensional magnetostatic fields is introduced. In this method, the curl-component of the magnetic field intensity is computed by a reduced magnetic vector potential. This field intensity forms the basic of a forcing function for a global magnetic scalar potential solution over the entire volume of the region. This method allows one to include iron portions sandwiched in between conductors within partitioned current-carrying subregions. The method is most suited for large-scale global-type 3-D magnetostatic field computations in electrical devices, and in particular rotating electric machinery.
Phase-space representation of non-classical behaviour of scalar wave-fields
Energy Technology Data Exchange (ETDEWEB)
Canas-Cardona, Gustavo; Castaneda, Roman [Physics School, Universidad Nacional de Colombia Sede Medellin, A.A. 3840 Medellin (Colombia); Vinck-Posada, Herbert, E-mail: gcanas@unal.edu.co [Physics Department, Universidad Nacional de Colombia Sede Bogota, Bogota D.C (Colombia)
2011-01-01
The modelling of optical fields by using radiant and virtual point sources for the spatial coherence wavelets in the phase-space representation evidences some effects, conventionally attributed to non-classical correlations of light, although such type of correlations are not explicitly included in the model. Specifically, a light state is produced that has similar morphology to the Wigner Distribution Function of the well-known quantum Schroedinger cat and squeezed states.
Quantization of a scalar field in two Poincaré patches of anti-de Sitter space and AdS/CFT
Directory of Open Access Journals (Sweden)
Ippei Fujisawa
2014-09-01
Full Text Available Two sets of modes of a massive free scalar field are quantized in a pair of Poincaré patches of Lorentzian anti-de Sitter (AdS space, AdSd+1 (d≥2. It is shown that in Poincaré coordinates (r,t,x→, the two boundaries at r=±∞ are connected. When the scalar mass m satisfies a condition 0<ν=(d2/4+(mℓ2<1, there exist two sets of mode solutions to Klein–Gordon equation, with distinct fall-off behaviors at the boundary. By using the fact that the boundaries at r=±∞ are connected, a conserved Klein–Gordon norm can be defined for these two sets of scalar modes, and these modes are canonically quantized. Energy is also conserved. A prescription within the approximation of semi-classical gravity is presented for computing two- and three-point functions of the operators in the boundary CFT, which correspond to the two fall-off behaviours of scalar field solutions.
Rybnikov, A. K.
2017-01-01
The paper is devoted to the investigation, using the method of Cartan-Laptev, of the differential-geometric structure associated with a Lagrangian L, depending on a function z of the variables t, x 1,..., x n and its partial derivatives. Lagrangians of this kind are considered in theoretical physics (in field theory). Here t is interpreted as time, and x 1,..., x n as spatial variables. The state of the field is characterized by a function z( t, x 1,..., x n ) (a field function) satisfying the Euler equation, which corresponds to the variational problem for the action integral. In the present paper, the variables z( t, x 1,..., x n are regarded as adapted local coordinates of a bundle of general type M with n-dimensional fibers and 1-dimensional base (here the variable t is simultaneously a local coordinate on the base). If we agree to call t time, and a typical fiber an n-dimensional space, then M can be called the spatiotemporal bundle manifold. We consider the variables t, x 1,..., x n , z (i.e., the variables t, x 1,..., x n with the added variable z) as adapted local coordinates in the bundle H over the fibered base M. The Lagrangian L, which is a coefficient in the differential form of the variational action integral in the integrand, is a relative invariant given on the manifold J 1 H (the manifold of 1-jets of the bundle H). In the present paper, we construct a tensor with components Λ00, Λ0 i , Λ ij (Λ ij = Λ ji ) which is generated by the fundamental object of the structure associated with the Lagrangian. This tensor is an invariant (with respect to admissible transformations the variables t, x 1,..., x n , z) analog of the energy-momentum tensor of the classical theory of physical fields. We construct an invariant I, a vector G i , and a bivalent tensor G jk generated by the Lagrangian. We also construct a relative invariant of E (in the paper, we call it the Euler relative invariant) such that the equation E = 0 is an invariant form of the Euler
Miao, Yan-Gang; Xu, Zhen-Ming
2017-06-01
We investigate the P{-}V criticality and the Maxwell equal area law for a five-dimensional spherically symmetric AdS black hole with a scalar hair in the absence of and in the presence of a Maxwell field, respectively. Especially in the charged case, we give the exact P{-}V critical values. More importantly, we analyze the validity and invalidity of the Maxwell equal area law for the AdS hairy black hole in the scenarios without and with charges, respectively. Within the scope of validity of the Maxwell equal area law, we point out that there exists a representative van der Waals-type oscillation in the P{-}V diagram. This oscillating part, which indicates the phase transition from a small black hole to a large one, can be replaced by an isobar. The small and large black holes have the same Gibbs free energy. We also give the distribution of the critical points in the parameter space both without and with charges, and we obtain for the uncharged case the fitting formula of the co-existence curve. Meanwhile, the latent heat is calculated, which gives the energy released or absorbed between the small and large black hole phases in the isothermal-isobaric procedure.
Energy Technology Data Exchange (ETDEWEB)
Huang, Zhiming, E-mail: 465609785@qq.com [School of Economics and Management, Wuyi University, Jiangmen 529020 (China); Situ, Haozhen, E-mail: situhaozhen@gmail.com [College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642 (China)
2017-02-15
In this article, the dynamics of quantum correlation and coherence for two atoms interacting with a bath of fluctuating massless scalar field in the Minkowski vacuum is investigated. We firstly derive the master equation that describes the system evolution with initial Bell-diagonal state. Then we discuss the system evolution for three cases of different initial states: non-zero correlation separable state, maximally entangled state and zero correlation state. For non-zero correlation initial separable state, quantum correlation and coherence can be protected from vacuum fluctuations during long time evolution when the separation between the two atoms is relatively small. For maximally entangled initial state, quantum correlation and coherence overall decrease with evolution time. However, for the zero correlation initial state, quantum correlation and coherence are firstly generated and then drop with evolution time; when separation is sufficiently small, they can survive from vacuum fluctuations. For three cases, quantum correlation and coherence first undergo decline and then fluctuate to relatively stable values with the increasing distance between the two atoms. Specially, for the case of zero correlation initial state, quantum correlation and coherence occur periodically revival at fixed zero points and revival amplitude declines gradually with increasing separation of two atoms.
Energy Technology Data Exchange (ETDEWEB)
Rejon-Barrera, Fernando [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, 1090 GL, Amsterdam (Netherlands); Robbins, Daniel [Department of Physics, Texas A& M University,TAMU 4242, College Station, TX 77843 (United States)
2016-01-22
We work out all of the details required for implementation of the conformal bootstrap program applied to the four-point function of two scalars and two vectors in an abstract conformal field theory in arbitrary dimension. This includes a review of which tensor structures make appearances, a construction of the projectors onto the required mixed symmetry representations, and a computation of the conformal blocks for all possible operators which can be exchanged. These blocks are presented as differential operators acting upon the previously known scalar conformal blocks. Finally, we set up the bootstrap equations which implement crossing symmetry. Special attention is given to the case of conserved vectors, where several simplifications occur.
Hod, Shahar
2015-01-01
The quasinormal resonance spectrum $\\{\\omega_n(\\mu,q,M,Q)\\}_{n=0}^{n=\\infty}$ of charged massive scalar fields in the charged Reissner-Nordstr\\"om black-hole spacetime is studied {\\it analytically} in the large-coupling regime $qQ\\gg M\\mu$ (here $\\{\\mu, q\\}$ are respectively the mass and charge coupling constant of the field, and $\\{M,Q\\}$ are respectively the mass and electric charge of the black hole). This physical system provides a striking illustration for the validity of the universal relaxation bound $\\tau \\times T \\geq \\hbar/\\pi$ in black-hole physics (here $\\tau\\equiv 1/\\Im\\omega_0$ is the characteristic relaxation time of the composed black-hole-scalar-field system, and $T$ is the Bekenstein-Hawking temperature of the black hole). In particular, it is shown that the relaxation dynamics of charged massive scalar fields in the charged Reissner-Nordstr\\"om black-hole spacetime may {\\it saturate} this quantum time-times-temperature inequality. Interestingly, we prove that potential violations of the bou...
González, P. A.; Konoplya, R. A.; Vásquez, Yerko
2017-06-01
It has recently been found that quasinormal modes of asymptotically anti-de Sitter (AdS) black holes in theories with higher curvature corrections may help to describe the regime of intermediate 't Hooft coupling in the dual field theory. Here, we consider quasinormal modes of a scalar field in the background of spherical Gauss-Bonnet-anti-de Sitter (AdS) black holes. In general, the eigenvalues of wave equations are found here numerically, but at a fixed Gauss-Bonnet constant α =R2/2 (where R is the AdS radius), an exact solution of the scalar field equation has been obtained. Remarkably, the purely imaginary modes, which are usually appropriate only to some gravitational perturbations, were found here even for a test scalar field. These purely imaginary modes of the Einstein-Gauss-Bonnet theory do not have the Einsteinian limits, because their damping rates grow, when α is decreasing. Thus, these modes are nonperturbative in α . The real oscillation frequencies of the perturbative branch are linearly related to their Schwarzschild-AdS limits Re (ωG B)=Re (ωSAdS)(1 +K (D )(α /R2)) , where D is the number of spacetime dimensions. Comparison of the analytical formula with the frequencies found by the shooting method allows us to test the latter. In addition, we found exact solutions to the master equations for gravitational perturbations at α =R2/2 and observed that for the scalar type of gravitational perturbations an eikonal instability develops.
Jurcisinová, E; Jurcisin, M
2008-01-01
The influence of uniaxial small-scale anisotropy on the stability of the scaling regimes and on the anomalous scaling of the structure functions of a passive scalar advected by a Gaussian solenoidal velocity field with finite correlation time is investigated by the field theoretic renormalization group and operator product expansion within one-loop approximation. Possible scaling regimes are found and classified in the plane of exponents epsilon-eta , where epsilon characterizes the energy spectrum of the velocity field in the inertial range E proportional, variantk;{1-2epsilon} , and eta is related to the correlation time of the velocity field at the wave number k which is scaled as k;{-2+eta} . It is shown that the presence of anisotropy does not disturb the stability of the infrared fixed points of the renormalization group equations, which are directly related to the corresponding scaling regimes. The influence of anisotropy on the anomalous scaling of the structure functions of the passive scalar field is studied as a function of the fixed point value of the parameter u , which represents the ratio of turnover time of scalar field and velocity correlation time. It is shown that the corresponding one-loop anomalous dimensions, which are the same (universal) for all particular models with a concrete value of u in the isotropic case, are different (nonuniversal) in the case with the presence of small-scale anisotropy and they are continuous functions of the anisotropy parameters, as well as the parameter u . The dependence of the anomalous dimensions on the anisotropy parameters of two special limits of the general model, namely, the rapid-change model and the frozen velocity field model, are found when u-->infinity and u-->0 , respectively.
Bittencourt, E; Novello, M; Toniato, J D
2016-01-01
We discuss a class of models for gravity based on a scalar field. The models include and generalize the old approach by Nordstr\\"om which predated and in some way inspired General Relativity. The class include also a model that we have recently introduced and discussed in its cosmological aspects (GSG). We present here a complete characterisation of the Schwarschild geometry as a vacuum solution of GSG and sketch a discussion of the first Post-Newtonian approximation.
Schwarzschild black holes can wear scalar wigs.
Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-08-24
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.
Scalar fluctuations in dilatonic brane-worlds
Bozza, Valerio; Veneziano, Gabriele
2001-01-01
We derive and solve the full set of scalar perturbation equations for a class of five-dimensional brane--world solutions, with a dilaton scalar field coupled to the bulk cosmological constant and to a 3-brane. The spectrum contains one localized massless scalar mode, to be interpreted as an effective dilaton on the brane, inducing long--range scalar interactions. Two massive scalar modes yield corrections to Newton's law at short distances, which persist even in the limit of vanishing dilaton (namely, in the standard Randall--Sundrum configuration).
Inflation and the Higgs Scalar
Energy Technology Data Exchange (ETDEWEB)
Green, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2014-12-05
This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A simple scalar model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.
Burns, Sean P.; Sun, Jielun; Lenschow, D.H.; Oncley, S.P.; Stephens, B.B.; Yi, C.; Anderson, D.E.; Hu, Jiawen; Monson, Russell K.
2011-01-01
Air temperature Ta, specific humidity q, CO2 mole fraction ??c, and three-dimensional winds were measured in mountainous terrain from five tall towers within a 1 km region encompassing a wide range of canopy densities. The measurements were sorted by a bulk Richardson number Rib. For stable conditions, we found vertical scalar differences developed over a "transition" region between 0.05 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability. The relationships q and ??c have with Rib are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO2 near the ground being 5-7 ??mol mol-1 larger than aloft, even with strong above-canopy winds (near-neutral conditions). We found Rib-binning to be a useful tool for evaluating vertical scalar mixing; however, additional information (e.g., pressure gradients, detailed vegetation/topography, etc.) is needed to fully explain the subcanopy wind patterns. Implications of our results for CO2 advection over heterogenous, complex terrain are discussed. ?? 2010 Springer Science+Business Media B.V.
Axially symmetric static scalar solitons and black holes with scalar hair
Energy Technology Data Exchange (ETDEWEB)
Kleihaus, Burkhard, E-mail: kleihaus@theorie.physik.uni-oldenburg.de; Kunz, Jutta; Radu, Eugen; Subagyo, Bintoro
2013-10-01
We construct static, asymptotically flat black hole solutions with scalar hair. They evade the no-hair theorems by having a scalar potential which is not strictly positive. By including an azimuthal winding number in the scalar field ansatz, we find hairy black hole solutions which are static but axially symmetric only. These solutions possess a globally regular limit, describing scalar solitons. A branch of axially symmetric black holes is found to possess a positive specific heat.
The first search for sub-eV scalar fields via four-wave mixing at a quasi-parallel laser collider
Homma, Kensuke; Kume, Kazuki
2014-01-01
A search for sub-eV scalar fields coupling to two photons has been performed via four-wave mixing at a quasi-parallel laser collider for the first time. The experiment demonstrates the novel approach to search for resonantly produced sub-eV scalar fields by combining two-color laser fields in the vacuum. The aim of this paper is to provide the concrete experimental setup and the analysis method based on specific combinations of polarization states between incoming and outgoing photons, which is extendable to higher intensity laser systems operated at high repetition rates. No significant signal of four-wave mixing was observed by combining a $0.2\\mu$J/0.75ns pulse laser and a 2mW CW laser on the same optical axis. Based on the prescription developed for this particular experimental approach, we obtained the upper limit at a confidence level of 95% on the coupling-mass relation.
Dai, Yue; Shi, Yu
2015-01-01
We consider quantum entanglement of three accelerating qubits, each of which is locally coupled with a real scalar field, without causal influence among the qubits or among the fields. The initial state is assumed to be the GHZ or the W state, the two representative three-partite entangled states. For each initial state, we study how various kinds of entanglement depend on the accelerations of the three qubits. All kinds of entanglement eventually suddenly die if at least two of three qubits have large enough accelerations. This result implies eventual sudden death of all kinds of entanglement among field-coupled particles sufficiently close to the horizon of a black hole, which is thus an entanglement shield.
Demerdash, N. A.; Wang, R.; Secunde, R.
1992-01-01
A 3D finite element (FE) approach was developed and implemented for computation of global magnetic fields in a 14.3 kVA modified Lundell alternator. The essence of the new method is the combined use of magnetic vector and scalar potential formulations in 3D FEs. This approach makes it practical, using state of the art supercomputer resources, to globally analyze magnetic fields and operating performances of rotating machines which have truly 3D magnetic flux patterns. The 3D FE-computed fields and machine inductances as well as various machine performance simulations of the 14.3 kVA machine are presented in this paper and its two companion papers.
Alonso, Rodrigo; Manohar, Aneesh V.
2016-01-01
The $S$-matrix of a quantum field theory is unchanged by field redefinitions, and so only depends on geometric quantities such as the curvature of field space. Whether the Higgs multiplet transforms linearly or non-linearly under electroweak symmetry is a subtle question since one can make a coordinate change to convert a field that transforms linearly into one that transforms non-linearly. Renormalizability of the Standard Model (SM) does not depend on the choice of scalar fields or whether the scalar fields transform linearly or non-linearly under the gauge group, but only on the geometric requirement that the scalar field manifold ${\\mathcal M}$ is flat. We explicitly compute the one-loop correction to scalar scattering in the SM written in non-linear Callan-Coleman-Wess-Zumino (CCWZ) form, where it has an infinite series of higher dimensional operators, and show that the $S$-matrix is finite. Standard Model Effective Field Theory (SMEFT) and Higgs Effective Field Theory (HEFT) have curved ${\\mathcal M}$, ...
Scalar scattering via conformal higher spin exchange
Energy Technology Data Exchange (ETDEWEB)
Joung, Euihun [School of Physics and Astronomy,Seoul National University, Seoul 151-747 (Korea, Republic of); Gauge, Gravity & Strings, Center for Theoretical Physics of the Universe,Institute for Basic Sciences, Daejeon 34047 (Korea, Republic of); Nakach, Simon; Tseytlin, Arkady A. [Theoretical physics group, Blackett Laboratory,Imperial College London, SW7 2AZ (United Kingdom)
2016-02-18
Theories containing infinite number of higher spin fields require a particular definition of summation over spins consistent with their underlying symmetries. We consider a model of massless scalars interacting (via bilinear conserved currents) with conformal higher spin fields in flat space. We compute the tree-level four-scalar scattering amplitude using a natural prescription for summation over an infinite set of conformal higher spin exchanges and find that it vanishes. Independently, we show that the vanishing of the scalar scattering amplitude is, in fact, implied by the global conformal higher spin symmetry of this model. We also discuss one-loop corrections to the four-scalar scattering amplitude.
Rodríguez, Yeinzon; Navarro, Andrés A.
2017-03-01
An alternative for the construction of fundamental theories is the introduction of Galileons. These are fields whose action leads to non higher than second-order equations of motion. As this is a necessary but not sufficient condition to make the Hamiltonian bounded from below, as long as the action is not degenerate, the Galileon construction is a way to avoid pathologies both at the classical and quantum levels. Galileon actions are, therefore, of great interest in many branches of physics, specially in high energy physics and cosmology. This proceedings contribution presents the generalities of the construction of both scalar and vector Galileons following two different but complimentary routes.
Saharian, Aram; Kotanjyan, Anna; Sargsyan, Hayk; Simonyan, David
2016-07-01
The models with compact spatial dimensions appear in a number of fundamental physical theories. In particular, the idea of compactified dimensions has been extensively used in supergravity and superstring theories. In quantum field theory, the modification of the vacuum fluctuations spectrum by the periodicity conditions imposed on the field operator along compact dimensions leads to a number of interesting physical effects. A well known example of this kind, demonstrating the close relation between quantum phenomena and global geometry, is the topological Casimir effect. In models with extra compact dimensions, the Casimir energy creates a nontrivial potential for the compactification radius. This can serve as a stabilization mechanism for moduli fields and for the effective gauge couplings. The Casimir effect has also been considered as a possible origin for the dark energy in Kaluza-Klein-type and braneworld models. In the resent presentation we investigate the effects of the gravity and topology on the local properties of the quantum vacuum for a charged scalar field in the presence of a classical gauge field. Vacuum expectation value of the energy-momentum tensor and current density are investigated for a charged scalar field in dS spacetime with toroidally compact spatial dimensions in the presence of a classical constant gauge field. Due to the nontrivial topology, the latter gives rise to Aharonov-Bohm-like effect on the vacuum characteristics. The vacuum current density, energy density and stresses are even periodic functions of the magnetic flux enclosed by compact dimensions. For small values of the comoving lengths of compact dimensions, compared with the dS curvature radius, the effects of gravity on the topological contributions are small and the expectation values are expressed in terms of the corresponding quantities in the Minkowski bulk by the standard conformal relation. For large values of the comoving lengths, depending on the field mass, two
Scalar strong interaction hadron theory
Hoh, Fang Chao
2015-01-01
The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.
Solano-Altamirano, J. M.; Hernández-Pérez, Julio M.
2015-11-01
DensToolKit is a suite of cross-platform, optionally parallelized, programs for analyzing the molecular electron density (ρ) and several fields derived from it. Scalar and vector fields, such as the gradient of the electron density (∇ρ), electron localization function (ELF) and its gradient, localized orbital locator (LOL), region of slow electrons (RoSE), reduced density gradient, localized electrons detector (LED), information entropy, molecular electrostatic potential, kinetic energy densities K and G, among others, can be evaluated on zero, one, two, and three dimensional grids. The suite includes a program for searching critical points and bond paths of the electron density, under the framework of Quantum Theory of Atoms in Molecules. DensToolKit also evaluates the momentum space electron density on spatial grids, and the reduced density matrix of order one along lines joining two arbitrary atoms of a molecule. The source code is distributed under the GNU-GPLv3 license, and we release the code with the intent of establishing an open-source collaborative project. The style of DensToolKit's code follows some of the guidelines of an object-oriented program. This allows us to supply the user with a simple manner for easily implement new scalar or vector fields, provided they are derived from any of the fields already implemented in the code. In this paper, we present some of the most salient features of the programs contained in the suite, some examples of how to run them, and the mathematical definitions of the implemented fields along with hints of how we optimized their evaluation. We benchmarked our suite against both a freely-available program and a commercial package. Speed-ups of ˜2×, and up to 12× were obtained using a non-parallel compilation of DensToolKit for the evaluation of fields. DensToolKit takes similar times for finding critical points, compared to a commercial package. Finally, we present some perspectives for the future development and
Energy Technology Data Exchange (ETDEWEB)
Alonso, Rodrigo [Department of Physics, University of California at San Diego,La Jolla, CA 92093 (United States); Jenkins, Elizabeth E.; Manohar, Aneesh V. [Department of Physics, University of California at San Diego,La Jolla, CA 92093 (United States); CERN TH Division,CH-1211 Geneva 23 (Switzerland)
2016-08-17
The S-matrix of a quantum field theory is unchanged by field redefinitions, and so it only depends on geometric quantities such as the curvature of field space. Whether the Higgs multiplet transforms linearly or non-linearly under electroweak symmetry is a subtle question since one can make a coordinate change to convert a field that transforms linearly into one that transforms non-linearly. Renormalizability of the Standard Model (SM) does not depend on the choice of scalar fields or whether the scalar fields transform linearly or non-linearly under the gauge group, but only on the geometric requirement that the scalar field manifold M is flat. Standard Model Effective Field Theory (SMEFT) and Higgs Effective Field Theory (HEFT) have curved M, since they parametrize deviations from the flat SM case. We show that the HEFT Lagrangian can be written in SMEFT form if and only if M has a SU(2){sub L}×U(1){sub Y} invariant fixed point. Experimental observables in HEFT depend on local geometric invariants of M such as sectional curvatures, which are of order 1/Λ{sup 2}, where Λ is the EFT scale. We give explicit expressions for these quantities in terms of the structure constants for a general G→H symmetry breaking pattern. The one-loop radiative correction in HEFT is determined using a covariant expansion which preserves manifest invariance of M under coordinate redefinitions. The formula for the radiative correction is simple when written in terms of the curvature of M and the gauge curvature field strengths. We also extend the CCWZ formalism to non-compact groups, and generalize the HEFT curvature computation to the case of multiple singlet scalar fields.
Pair condensation in massless scalar electrodynamics
Hey, Anthony J. G.; Mandula, Jeffrey E.
1982-05-01
Motivated by the instabilities of the vacuum to bound-state pair production at large coupling in both abelian and non-abelian gauge theories, we examine the stability of the vacuum of a constrained version of massless scalar electrodynamics to the formation of a scalar pair condensate. The trial states are constructed by analogy with the BCS ground state of super-conductivity and are such that the vacuum expectation value of the scalar field vanishes. Analysis of the minimization equation for the energy density indicates that there are two phases as a function of the coupling constant. Under the constraint that the vacuum expectation value of the scalar field be zero, we find what, for small coupling, the perturbative vacuum minimizes the energy, while for large coupling a condensate of particle-antiparticle pairs is energetically favored. After discussing the relation of our results to the phase structure of unconstrained scalar electrodynamics, we speculate on possible implications for QCD.
Pair condensation in massless scalar electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Hey, A.J.G. (Southampton Univ. (UK). Dept. of Physics); Mandula, J.E. (Washington Univ., St. Louis, MO (USA). Dept. of Physics)
1982-05-03
Motivated by the instabilities of the vacuum to bound-state pair production at large coupling in both abelian and non-abelian gauge theories, we examine the stability of the vacuum of a constrained version of massless scalar electrodynamics to the formation of a scalar pair condensate. The trial states are constructed by analogy with the BCS ground state of super-conductivity and are such that the vacuum expectation value of the scalar field vanishes. Analysis of the minimization equation for the energy density indicates that there are two phases as a function of the coupling constant. Under the constraint that the vacuum expectation value of the scalar field be zero, we find that, for small coupling, the perturbative vacuum minimizes the energy, while for large coupling a condensate of particle-antiparticle pairs is energetically favored. After discussing the relation of our results to the phase structure of unconstrained scalar electrodynamics, we speculate on possible implications for QCD.
Compressibility Effects on the Passive Scalar Flux Within Homogeneous Turbulence
Blaisdell, G. A.; Mansour, N. N.; Reynolds, W. C.
1994-01-01
Compressibility effects on turbulent transport of a passive scalar are studied within homogeneous turbulence using a kinematic decomposition of the velocity field into solenoidal and dilatational parts. It is found that the dilatational velocity does not produce a passive scalar flux, and that all of the passive scalar flux is due to the solenoidal velocity.
Castañeda, Román; Cañas, Gustavo; Vinck-Posada, Herbert
2012-04-01
The border between the descriptions of the classical optical fields in any state of spatial coherence and the quantum coherence state of light is revisited in the framework of the phase-space representation. Although it is established that such descriptions are not completely equivalent, the exact calculation of the marginal power spectrum leads to new analogies that suggest that some features exclusively attributed to quantum states of light can be also shared by classical optical fields due to their spatial coherence state.
Cortez, Jerónimo; Mena Marugán, Guillermo A.; Olmedo, Javier; Velhinho, José M.
2012-11-01
We consider the quantization of scalar fields in spacetimes such that, by means of a suitable scaling of the field by a time dependent function, the field equation can be regarded as that of a field with a time dependent mass propagating in an auxiliary ultrastatic static background. For Klein-Gordon fields, it is well known that there exist an infinite number of nonequivalent Fock representations of the canonical commutation relations and, therefore, of inequivalent quantum theories. A context in which this kind of ambiguities arises and prevents the derivation of robust results is, e.g., in the quantum analysis of cosmological perturbations. In these situations, typically, a suitable scaling of the field by a time dependent function leads to a description in an auxiliary static background, though the nonstationarity still shows up in a time dependent mass. For such a field description, and assuming the compactness of the spatial sections, we recently proved in three or less spatial dimensions that the criteria of a natural implementation of the spatial symmetries and of a unitary time evolution are able to select a unique class of unitarily equivalent vacua, and hence of Fock representations. In this work, we succeed to extend our uniqueness result to the consideration of all possible field descriptions that can be reached by a time dependent canonical transformation which, in particular, involves a scaling of the field by a function of time. These kinds of canonical transformations modify the dynamics of the system and introduce a further ambiguity in its quantum description, exceeding the choice of a Fock representation. Remarkably, for any compact spatial manifold in less than four dimensions, we show that our criteria eliminate any possible nontrivial scaling of the field other than that leading to the description in an auxiliary static background. Besides, we show that either no time dependent redefinition of the field momentum is allowed or, if this may
Wang, Ren H.
1991-01-01
A method of combined use of magnetic vector potential (MVP) based finite element (FE) formulations and magnetic scalar potential (MSP) based FE formulations for computation of three-dimensional (3D) magnetostatic fields is developed. This combined MVP-MSP 3D-FE method leads to considerable reduction by nearly a factor of 3 in the number of unknowns in comparison to the number of unknowns which must be computed in global MVP based FE solutions. This method allows one to incorporate portions of iron cores sandwiched in between coils (conductors) in current-carrying regions. Thus, it greatly simplifies the geometries of current carrying regions (in comparison with the exclusive MSP based methods) in electric machinery applications. A unique feature of this approach is that the global MSP solution is single valued in nature, that is, no branch cut is needed. This is again a superiority over the exclusive MSP based methods. A Newton-Raphson procedure with a concept of an adaptive relaxation factor was developed and successfully used in solving the 3D-FE problem with magnetic material anisotropy and nonlinearity. Accordingly, this combined MVP-MSP 3D-FE method is most suited for solution of large scale global type magnetic field computations in rotating electric machinery with very complex magnetic circuit geometries, as well as nonlinear and anisotropic material properties.
Cortez, Jerónimo; Mena Marugán, Guillermo A.; Velhinho, José M.
2010-02-01
We study the Fock description of a quantum free field on the three-sphere with a mass that depends explicitly on time, also interpretable as an explicitly time dependent quadratic potential. We show that, under quite mild restrictions on the time dependence of the mass, the specific Fock representation of the canonical commutation relations which is naturally associated with a massless free field provides a unitary dynamics even when the time varying mass is present. Moreover, we demonstrate that this Fock representation is the only acceptable one, up to unitary equivalence, if the vacuum has to be SO(4)-invariant (i.e., invariant under the symmetries of the field equation) and the dynamics is required to be unitary. In particular, the analysis and uniqueness of the quantization can be applied to the treatment of cosmological perturbations around Friedmann-Robertson-Walker spacetimes with the spatial topology of the three-sphere, like e.g. for gravitational waves (tensor perturbations). In addition, we analyze the extension of our results to free fields with a time dependent mass defined on other compact spatial manifolds. We prove the uniqueness of the Fock representation in the case of a two-sphere as well, and discuss the case of a three-torus.
Universal effective coupling constant ratios of 3D scalar ϕ4 field theory and pseudo-ϵ expansion
Directory of Open Access Journals (Sweden)
Sokolov A. I.
2016-01-01
Full Text Available The ratios R2k = g2k/gk − 14 of renormalized coupling constants g2k entering the small-field equation of state approach universal values R*2k at criticality. They are calculated for the three-dimensional λϕ4 field theory within the pseudo-ϵ expansion approach. Pseudo-ϵ expansions for R*6, R*8, R*10 are derived in the five-loop approximation, numerical estimates are obtained with a help of the Padé–Borel–Leroy resummation technique. Its use gives R*6 = 1.6488, the number which perfectly agrees with the most recent lattice result R*6 = 1.649. For the octic coupling the pseudo-ϵ expansion is less favorable numerically. Nevertheless the Padé–Borel–Leroy resummation leads to the estimate R*8 = 0.890 close to the values R*8 = 0.87, R*8 = 0.857 extracted from the lattice and field-theoretical calculations. The pseudo-ϵ expansion for R*10 turns out to have big and rapidly increasing coefficients. This makes correspondent estimates strongly dependent on the Borel–Leroy shift parameter b and prevents proper evaluation of R*10
Energy Technology Data Exchange (ETDEWEB)
Miao, Yan-Gang; Xu, Zhen-Ming [Nankai University, School of Physics, Tianjin (China)
2017-06-15
We investigate the P - V criticality and the Maxwell equal area law for a five-dimensional spherically symmetric AdS black hole with a scalar hair in the absence of and in the presence of a Maxwell field, respectively. Especially in the charged case, we give the exact P - V critical values. More importantly, we analyze the validity and invalidity of the Maxwell equal area law for the AdS hairy black hole in the scenarios without and with charges, respectively. Within the scope of validity of the Maxwell equal area law, we point out that there exists a representative van der Waals-type oscillation in the P - V diagram. This oscillating part, which indicates the phase transition from a small black hole to a large one, can be replaced by an isobar. The small and large black holes have the same Gibbs free energy. We also give the distribution of the critical points in the parameter space both without and with charges, and we obtain for the uncharged case the fitting formula of the co-existence curve. Meanwhile, the latent heat is calculated, which gives the energy released or absorbed between the small and large black hole phases in the isothermal-isobaric procedure. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Ngampitipan, Tritos, E-mail: tritos.ngampitipan@gmail.com [Faculty of Science, Chandrakasem Rajabhat University, Ratchadaphisek Road, Chatuchak, Bangkok 10900 (Thailand); Particle Physics Research Laboratory, Department of Physics, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Boonserm, Petarpa, E-mail: petarpa.boonserm@gmail.com [Department of Mathematics and Computer Science, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Chatrabhuti, Auttakit, E-mail: dma3ac2@gmail.com [Particle Physics Research Laboratory, Department of Physics, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand); Visser, Matt, E-mail: matt.visser@msor.vuw.ac.nz [School of Mathematics, Statistics, and Operations Research, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand)
2016-06-02
Hawking radiation is the evidence for the existence of black hole. What an observer can measure through Hawking radiation is the transmission probability. In the laboratory, miniature black holes can successfully be generated. The generated black holes are, most commonly, Myers-Perry black holes. In this paper, we will derive the rigorous bounds on the transmission probabilities for massless scalar fields of non-negative-angular-momentum modes emitted from a generated Myers-Perry black hole in six, seven, and eight dimensions. The results show that for low energy, the rigorous bounds increase with the increase in the energy of emitted particles. However, for high energy, the rigorous bounds decrease with the increase in the energy of emitted particles. When the black holes spin faster, the rigorous bounds decrease. For dimension dependence, the rigorous bounds also decrease with the increase in the number of extra dimensions. Furthermore, as comparison to the approximate transmission probability, the rigorous bound is proven to be useful.
Maccari, Attilio
2000-10-01
A weakly nonlinear Lorentz invariant complex field model in 3+1 dimensions is studied by an asymptotic perturbation method, based on Fourier expansion and spatio-temporal rescaling. It is shown that a nonlinear system of partial differential equations describes oscillation amplitudes of Fourier modes. This system is C-integrable, i.e., can be linearized through a suitable transformation of the dependent and independent variables. We resolve the Cauchy problem and demonstrate that localized nondispersive waves (envelope solitons) with finite energy exist under appropriate initial conditions. These particle-like solutions propagate with the group velocity of their carrier wave. During a collision solitons maintain their shape, because the only change is a phase shift. Energy E and momentum p of solitons are identical to those of a relativistic particle. If the Planck constant is connected to the spatial dimension of the envelope soliton, then we obtain at the lowest order of approximation the quantum relations E=ℏ ω, λ= h/ p, where λ and ω are wavelength and frequency of the carrier wave. This work represents a possible way to achieve the Einstein-de Broglie soliton-particle concept.
Czajka, Alina; Jeon, Sangyong
2017-06-01
In this paper we provide a quantum field theoretical study on the shear and bulk relaxation times. First, we find Kubo formulas for the shear and the bulk relaxation times, respectively. They are found by examining response functions of the stress-energy tensor. We use general properties of correlation functions and the gravitational Ward identity to parametrize analytical structures of the Green functions describing both sound and diffusion mode. We find that the hydrodynamic limits of the real parts of the respective energy-momentum tensor correlation functions provide us with the method of computing both the shear and bulk viscosity relaxation times. Next, we calculate the shear viscosity relaxation time using the diagrammatic approach in the Keldysh basis for the massless λ ϕ4 theory. We derive a respective integral equation which enables us to compute η τπ and then we extract the shear relaxation time. The relaxation time is shown to be inversely related to the thermal width as it should be.
Minazzoli, Olivier
2013-01-01
The post-Newtonian parameter \\gamma\\ resulting from a universal scalar/matter coupling is investigated in Brans-Dicke-like Scalar-Tensor theories where the scalar potential is assumed to be negligible. Conversely to previous studies, we use a perfect fluid formalism in order to get the explicit scalar-field equation. It is shown that the metric can be put in its standard post-Newtonian form. However, it is pointed out that 1-\\gamma\\ could be either positive, null or negative for finite value of \\omega_0, depending on the coupling function; while Scalar-Tensor theories without coupling always predict \\gamma<1 for finite value of \\omega_0.
Dynamical scalar hair formation around a Schwarzschild black hole
Benkel, Robert; Sotiriou, Thomas P.; Witek, Helvi
2016-12-01
Scalar fields coupled to the Gauss-Bonnet invariant evade the known no-hair theorems and have nontrivial configurations around black holes. We focus on a scalar field that couples linearly to the Gauss-Bonnet invariant and hence exhibits shift symmetry. We study its dynamical evolution and the formation of scalar hair in a Schwarzschild background. We show that the evolution eventually settles to the known static hairy solutions in the appropriate limit.
Adler, Stephen L.
2017-07-01
We continue our study of Coleman-Weinberg symmetry breaking induced by a third rank antisymmetric tensor scalar, in the context of the SU(8) model (Adler 2014 Int. J. Mod. Phys. A 29 1450130) we proposed earlier. We focus in this paper on qualitative features that will determine whether the model can make contact with the observed particle spectrum. We discuss the mechanism for giving the spin \\frac{3}{2} field a mass by the BEH mechanism, and analyze the remaining massless spin \\frac{1}{2} fermions, the global chiral symmetries, and the running couplings after symmetry breaking. We note that the smallest gluon mass matrix eigenvalue has an eigenvector suggestive of U(1) B-L , and conjecture that the theory runs to an infrared fixed point at which there is a massless gluon with 3 to -1 ratios in generator components. Assuming this, we discuss a mechanism for making contact with the standard model, based on a conjectured asymmetric breaking of Sp(4) to SU(2) subgroups, one of which is the electroweak SU(2), and the other of which is a ‘technicolor’ group that binds the original SU(8) model fermions, which play the role of ‘preons’, into composites. Quarks can emerge as 5 preon composites and leptons as 3 preon composites, with consequent stability of the proton against decay to a single lepton plus a meson. A composite Higgs boson can emerge as a two preon composite. Since anomaly matching for the relevant conserved global symmetry current is not obeyed by three fermion families, emergence of three composite families requires formation of a Goldstone boson with quantum numbers matching this current, which can be a light dark matter candidate.
Spherically symmetric scalar field collapse
Indian Academy of Sciences (India)
2013-03-01
Mar 1, 2013 ... Vaidya metric at the hypersurface and the appropriate junction conditions are obtained. Keywords. Gravitational ... a perfect fluid. As the final stages of collapse might involve dissipative processes as well, ... by Christodoulou [5], Goswami and Joshi [6], Giambo [7] and also by numerical work of. Choptuik [3] ...
Spherically symmetric scalar field collapse
Indian Academy of Sciences (India)
Author Affiliations. Koyel Ganguly1 2 Narayan Banerjee3. Relativity and Cosmology Research Centre, Department of Physics, Jadavpur University, Kolkata 700 032, India; St. Xavier's College, 30 Mother Teresa Sarani, Kolkata 700 016, India; IISER-Kolkata, Mohanpur Campus, P.O. BCKV Main Office, Nadia 741 252, India ...
Fundamental and composite scalars from extra dimensions
Energy Technology Data Exchange (ETDEWEB)
Aranda, Alfredo [Dual C-P Institute of High Energy Physics, Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima, Colima (Mexico)], E-mail: fefo@ucol.mx; Diaz-Cruz, J.L. [Dual C-P Institute of High Energy Physics, Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima, Colima (Mexico); Dual C-P Institute of High Energy Physics, Facultad de Ciencias Fisico-Matematicas, BUAP, Apdo. Postal 1364, C.P. 72000 Puebla, Pue (Mexico)], E-mail: lorenzo.diaz@fcfm.buap.mx; Hernandez-Sanchez, J. [Dual C-P Institute of High Energy Physics, Centro de Investigacion en Matematicas, Universidad Autonoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo km. 4.5, C.P. 42184, Pachuca, Hidalgo (Mexico)], E-mail: jaimeh@uaeh.edu.mx; Noriega-Papaqui, R. [Dual C-P Institute of High Energy Physics, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 Mexico D.F. (Mexico)], E-mail: rnoriega@fisica.unam.mx
2007-12-13
We discuss a scenario consisting of an effective 4D theory containing fundamental and composite fields. The strong dynamics sector responsible for the compositeness is assumed to be of extra dimensional origin. In the 4D effective theory the SM fermion and gauge fields are taken as fundamental fields. The scalar sector of the theory resembles a bosonic topcolor in the sense there are two scalar Higgs fields, a composite scalar field and a fundamental gauge-Higgs unification scalar. A detailed analysis of the scalar spectrum is presented in order to explore the parameter space consistent with experiment. It is found that, under the model assumptions, the acceptable parameter space is quite constrained. As a part of our phenomenological study of the model, we evaluate the branching ratio of the lightest Higgs boson and find that our model predicts a large FCNC mode h{yields}tc, which can be as large as O(10{sup -3}). Similarly, a large BR for the top FCNC decay is obtained, namely BR(t{yields}c+H){approx_equal}10{sup -4}.
Li, Bohua; Shapiro, Paul R.; Rindler-Daller, Tanja
2017-09-01
We consider an alternative to weakly interacting massive particle (WIMP) cold dark matter (CDM)—ultralight bosonic dark matter (m ≳10-22 eV /c2) described by a complex scalar field (SFDM) with a global U (1 ) symmetry—for which the comoving particle number density or charge density is conserved after particle production during standard reheating. We allow for a repulsive self-interaction. In a Λ SFDM universe, SFDM starts out relativistic, evolving from stiff (w =1 ) to radiation-like (w =1 /3 ), before becoming nonrelativistic at late times (w =0 ). Thus, before the familiar radiation-dominated era, there is an earlier era of stiff-SFDM domination. During both the stiff-SFDM-dominated and radiation-dominated eras, the expansion rate is higher than in Λ CDM . The SFDM particle mass m and quartic self-interaction coupling strength λ are therefore constrained by cosmological observables, particularly Neff, the effective number of neutrino species during big bang nucleosynthesis, and zeq, the redshift of matter-radiation equality. Furthermore, since the stochastic gravitational-wave background (SGWB) from inflation is amplified during the stiff-SFDM-dominated era, it can contribute a radiation-like component large enough to affect these observables by further boosting the expansion rate after the stiff era ends. Remarkably, this same amplification makes detection of the SGWB possible at high frequencies by current laser interferometer experiments, e.g., aLIGO/Virgo and LISA. For SFDM particle parameters that satisfy these cosmological constraints, the amplified SGWB is detectable by LIGO for a broad range of reheat temperatures Treheat, for values of the tensor-to-scalar ratio r currently allowed by cosmic microwave background polarization measurements. For a given r and λ /(m c2)2, the marginally allowed Λ SFDM model for each Treheat has the smallest m that satisfies the cosmological constraints, and maximizes the present SGWB energy density for that
Ignat'ev, Yu G
2013-01-01
On the basis of the relativistic kinetic theory the mathematical model of cosmological plasmas with an attraction of the like charged scalar particles is formulated. It is shown, that cosmological the model, based on a classical scalar field with an attraction, is unsatisfactory, that leads to necessity of attraction of phantom models of a scalar field for systems with an attraction.
Effective action model of dynamically scalarizing binary neutron stars
Sennett, Noah; Shao, Lijing; Steinhoff, Jan
2017-10-01
Gravitational waves can be used to test general relativity (GR) in the highly dynamical strong-field regime. Scalar-tensor theories of gravity are natural alternatives to GR that can manifest nonperturbative phenomena in neutron stars (NSs). One such phenomenon, known as dynamical scalarization, occurs in coalescing binary NS systems. Ground-based gravitational-wave detectors may be sensitive to this effect, and thus could potentially further constrain scalar-tensor theories. This type of analysis requires waveform models of dynamically scalarizing systems; in this work we devise an analytic model of dynamical scalarization using an effective action approach. For the first time, we compute the Newtonian-order Hamiltonian describing the dynamics of a dynamically scalarizing binary in a self-consistent manner. Despite only working to leading order, the model accurately predicts the frequency at which dynamical scalarization occurs. In conjunction with Landau theory, our model allows one to definitively establish dynamical scalarization as a second-order phase transition. We also connect dynamical scalarization to the related phenomena of spontaneous scalarization and induced scalarization; these phenomena are naturally encompassed into our effective action approach.
The Statistical Model with Interpartial Scalar Conformally Invariant Interaction
Ignat'ev, Yurii
2015-01-01
A closed mathematical model of the statistical self-gravitating system of scalar charged particles for conformal invariant scalar interactions is constructed on the basis of relativistic kinetics and gravitation theory. Asymptotic properties of the model are investigated in the ultrarelativistic limit. It is shown, that scalar charge density automatically generates scalar field effective mass and the value of this mass is found. In the paper it is proved the asymptotic conformal invariance of constitutive equations in case of homogenous isotropic Universe. Also it is proved the asymptotic conformal invariance of field equations at the early stages of cosmological evolution.
Kerr-Newman black holes with scalar hair
Delgado, Jorge F. M.; Herdeiro, Carlos A. R.; Radu, Eugen; Rúnarsson, Helgi
2016-10-01
We construct electrically charged Kerr black holes (BHs) with scalar hair. Firstly, we take an uncharged scalar field, interacting with the electromagnetic field only indirectly, via the background metric. The corresponding family of solutions, dubbed Kerr-Newman BHs with ungauged scalar hair, reduces to (a sub-family of) Kerr-Newman BHs in the limit of vanishing scalar hair and to uncharged rotating boson stars in the limit of vanishing horizon. It adds one extra parameter to the uncharged solutions: the total electric charge. This leading electromagnetic multipole moment is unaffected by the scalar hair and can be computed by using Gauss's law on any closed 2-surface surrounding (a spatial section of) the event horizon. By contrast, the first sub-leading electromagnetic multipole - the magnetic dipole moment -, gets suppressed by the scalar hair, such that the gyromagnetic ratio is always smaller than the Kerr-Newman value (g = 2). Secondly, we consider a gauged scalar field and obtain a family of Kerr-Newman BHs with gauged scalar hair. The electrically charged scalar field now stores a part of the total electric charge, which can only be computed by applying Gauss' law at spatial infinity and introduces a new solitonic limit - electrically charged rotating boson stars. In both cases, we analyze some physical properties of the solutions.
Spectra of turbulently advected scalars that have small Schmidt number
Hill, Reginald J.
2017-09-01
Exact statistical equations are derived for turbulent advection of a passive scalar having diffusivity much larger than the kinematic viscosity, i.e., small Schmidt number. The equations contain all terms needed for precise direct numerical simulation (DNS) quantification. In the appropriate limit, the equations reduce to the classical theory for which the scalar spectrum is proportional to the energy spectrum multiplied by k-4, which, in turn, results in the inertial-diffusive range power law, k-17 /3. The classical theory was derived for the case of isotropic velocity and scalar fields. The exact equations are simplified for less restrictive cases: (1) locally isotropic scalar fluctuations at dissipation scales with no restriction on symmetry of the velocity field, (2) isotropic velocity field with averaging over all wave-vector directions with no restriction on the symmetry of the scalar, motivated by that average being used for DNS, and (3) isotropic velocity field with axisymmetric scalar fluctuations, motivated by the mean-scalar-gradient-source case. The equations are applied to recently published DNSs of passive scalars for the cases of a freely decaying scalar and a mean-scalar-gradient source. New terms in the exact equations are estimated for those cases and are found to be significant; those terms cause the deviations from the classical theory found by the DNS studies. A new formula for the mean-scalar-gradient case explains the variation of the scalar spectra for the DNS of the smallest Schmidt-number cases. Expansion in Legendre polynomials reveals the effect of axisymmetry. Inertial-diffusive-range formulas for both the zero- and second-order Legendre contributions are given. Exact statistical equations reveal what must be quantified using DNS to determine what causes deviations from asymptotic relationships.
Direct numerical simulation of a passive scalar with imposed mean gradient in isotropic turbulence
Overholt, M. R.; Pope, S. B.
1996-11-01
Mixing of a passive scalar in statistically homogeneous, isotropic, and stationary turbulence with a mean scalar gradient is investigated via direct numerical simulation, for Taylor-scale Reynolds numbers, Rλ, from 28 to 185. Multiple independent simulations are performed to get confidence intervals, and local regression smoothing is used to further reduce statistical fluctuations. The scalar fluctuation field, φ(x,t), is initially zero, and develops to a statistically stationary state after about four eddy turnover times. Quantities investigated include the dissipation of scalar flux, which is found to be significant; probability density functions (pdfs) and joint-pdfs of the scalar, its derivatives, scalar dissipation, and mechanical dissipation; and conditional expectations of scalar mixing, ∇2φ. A linear model for scalar mixing jointly conditioned on the scalar and v-velocity is developed, and reproduces the data quite well. Also considered is scalar mixing jointly conditioned on the scalar and scalar dissipation. Terms appearing in the balance equation for the pdf of φ are examined. From a solution of the scalar pdf equation two sufficient conditions arise for the scalar pdf to be Gaussian. These are shown to be well satisfied for moderate values of the scalar, and approximately so for large fluctuations. Many correlations are also presented, including ρ(v,φ), which changes during the evolution of the scalar from a value of unity when initialized to the stationary value of 0.5-0.6.
Stochastic inflationary scalar electrodynamics
Prokopec, T.; Tsamis, N.C.; Woodard, R.P.
2008-01-01
We stochastically formulate the theory of scalar quantum electrodynamics on a de Sitter background. This reproduces the leading infrared logarithms at each loop order. It also allows one to sum the series of leading infrared logarithms to obtain explicit, nonperturbative results about the late time
Semi-analytic stellar structure in scalar-tensor gravity
Horbatsch, M. W.; Burgess, C. P.
2011-08-01
Precision tests of gravity can be used to constrain the properties of hypothetical very light scalar fields, but these tests depend crucially on how macroscopic astrophysical objects couple to the new scalar field. We study the equations of stellar structure using scalar-tensor gravity, with the goal of seeing how stellar properties depend on assumptions made about the scalar coupling at a microscopic level. In order to make the study relatively easy for different assumptions about microscopic couplings, we develop quasi-analytic approximate methods for solving the stellar-structure equations rather than simply integrating them numerically. (The approximation involved assumes the dimensionless scalar coupling at the stellar center is weak, and we compare our results with numerical integration in order to establish its domain of validity.) We illustrate these methods by applying them to Brans-Dicke scalars, and their generalization in which the scalar-matter coupling slowly runs — or `walks' — as a function of the scalar field: a(phi) simeq as+bsphi. (Such couplings can arise in extra-dimensional applications, for instance.) The four observable parameters that characterize the fields external to a spherically symmetric star are the stellar radius, R, mass, M, scalar `charge', Q, and the scalar's asymptotic value, phi∞. These are subject to two relations because of the matching to the interior solution, generalizing the usual mass-radius, M(R), relation of General Relativity. Since phi∞ is common to different stars in a given region (such as a binary pulsar), all quantities can be computed locally in terms of the stellar masses. We identify how these relations depend on the microscopic scalar couplings, agreeing with earlier workers when comparisons are possible. Explicit analytical solutions are obtained for the instructive toy model of constant-density stars, whose properties we compare to more realistic equations of state for neutron star models.
Variational method for objective analysis of scalar variable and its ...
Indian Academy of Sciences (India)
In regard to variational optimization of meteoro- logical parameter a given measure of the 'distance' between the variational scalar analysis and the standard scalar analysis is minimized. The varia- tional analysed field must at the same time satisfy some constraint. The constraint is that the differ- ence between derivative of ...
Finsler metrics with constant (or scalar) flag curvature
Indian Academy of Sciences (India)
of new Finsler metrics of constant (or scalar) flag curvature and determine their scalar curvature. Keywords. ... For instance, Li, Chang and Mo related some Killing fields of Finsler metrics to the symmetry of very ...... [13] Shen Z, Differential Geometry of Spray and Finsler Spaces (Kluwer Academic Publish- ers) (2001) 258 ...
CMB bounds on tensor-scalar-scalar inflationary correlations
Shiraishi, Maresuke; Liguori, Michele; Fergusson, James R.
2018-01-01
The nonlinear interaction between one graviton and two scalars is enhanced in specific inflationary models, potentially leading to distinguishable signatures in the bispectrum of the cosmic microwave background (CMB) anisotropies. We develop the tools to examine such bispectrum signatures, and show a first application using WMAP temperature data. We consider several l-ranges, estimating the gtss amplitude parameter, by means of the so-called separable modal methodology. We do not find any evidence of a tensor-scalar-scalar signal at any scale. Our tightest bound on the size of the tensor-scalar-scalar correlator is derived from our measurement including all the multipoles in the range 2 first direct observational constraint on the primordial tensor-scalar-scalar correlation, and it will be cross-checked and improved by applying the same pipeline to high-resolution temperature and polarization data from Planck and forthcoming CMB experiments.
Ignat'ev, Yu G
2013-01-01
On the basis of Hamilton a formalism the dynamic equations of movement scalar charged particles in a classical scalar field are formulated. Unlike earlier published works of the author the model with zero own weight of particles is considered. Linear integrals of movement are found and ambiguity of communication between kinematic speed and an impulse of particles is specified.
Vast Antimatter Regions and Scalar Condensate Baryogenesis
Kirilova, D.; Panayotova, M.; Valchanov, T
2002-01-01
The possibility of natural and abundant creation of antimatter in the Universe in a SUSY-baryogenesis model with a scalar field condensate is described. This scenario predicts vast quantities of antimatter, corresponding to galaxy and galaxy cluster scales today, separated from the matter ones by baryonically empty voids. Theoretical and observational constraints on such antimatter regions are discussed.
Update on scalar singlet dark matter
Cline, J.M.; Scott, P.; Kainulainen, K.; Weniger, C.
2013-01-01
One of the simplest models of dark matter is where a scalar singlet field S comprises some or all of the dark matter and interacts with the standard model through an vertical bar H vertical bar S-2(2) coupling to the Higgs boson. We update the present limits on the model from LHC searches for
Scalar operators in solid-state NMR
Energy Technology Data Exchange (ETDEWEB)
Sun, Boqin [Univ. of California, Berkeley, CA (United States)
1991-11-01
Selectivity and resolution of solid-state NMR spectra are determined by dispersion of local magnetic fields originating from relaxation effects and orientation-dependent resonant frequencies of spin nuclei. Theoretically, the orientation-dependent resonant frequencies can be represented by a set of irreducible tensors. Among these tensors, only zero rank tensors (scalar operators) are capable of providing high resolution NMR spectra. This thesis presents a series of new developments in high resolution solid-state NMR concerning the reconstruction of various scalar operators motion in solid C_{60} is analyzed.
Scalar Calibration of Vector Magnetometers
DEFF Research Database (Denmark)
Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz
2000-01-01
The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...... of a magnetic field, three scale factors for normalization of the axes and three non-orthogonality angles which build up an orthogonal system intrinsically in the sensor. The advantage of this method compared with others lies in its linear least squares estimator, which finds independently and uniquely...... the parameters for a given data set. Therefore, a magnetometer may be characterized inexpensively in the Earth's magnetic-field environment. This procedure has been used successfully in the pre-flight calibration of the state-of-the-art magnetometers on board the magnetic mapping satellites Orsted, Astrid-2...
Scalar dissipation rate statistics in turbulent swirling jets
Stetsyuk, V.; Soulopoulos, N.; Hardalupas, Y.; Taylor, A. M. K. P.
2016-07-01
The scalar dissipation rate statistics were measured in an isothermal flow formed by discharging a central jet in an annular stream of swirling air flow. This is a typical geometry used in swirl-stabilised burners, where the central jet is the fuel. The flow Reynolds number was 29 000, based on the area-averaged velocity of 8.46 m/s at the exit and the diameter of 50.8 mm. The scalar dissipation rate and its statistics were computed from two-dimensional imaging of the mixture fraction fields obtained with planar laser induced fluorescence of acetone. Three swirl numbers, S, of 0.3, 0.58, and 1.07 of the annular swirling stream were considered. The influence of the swirl number on scalar mixing, unconditional, and conditional scalar dissipation rate statistics were quantified. A procedure, based on a Wiener filter approach, was used to de-noise the raw mixture fraction images. The filtering errors on the scalar dissipation rate measurements were up to 15%, depending on downstream positions from the burner exit. The maximum of instantaneous scalar dissipation rate was found to be up to 35 s-1, while the mean dissipation rate was 10 times smaller. The probability density functions of the logarithm of the scalar dissipation rate fluctuations were found to be slightly negatively skewed at low swirl numbers and almost symmetrical when the swirl number increased. The assumption of statistical independence between the scalar and its dissipation rate was valid for higher swirl numbers at locations with low scalar fluctuations and less valid for low swirl numbers. The deviations from the assumption of statistical independence were quantified. The conditional mean of the scalar dissipation rate, the standard deviation of the scalar dissipation rate fluctuations, the weighted probability of occurrence of the mean conditional scalar dissipation rate, and the conditional probability are reported.
Search for scalar top and scalar bottom quarks at LEP
Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Elfgren, E.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kruger, K.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trefzger, T.; Tricoli, A.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija
2002-01-01
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb-1 at centre-of-mass energies of sqrt(s) = 192 - 209 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level lower limit on the scalar top quark mass is 97.6 GeV if the mixing angle between the supersymmetric partners of the left- and right-handed states of the top quark is zero. When the scalar top quark decouples from the Z0 boson, the lower limit is 95.7 GeV. These limits were obtained assuming that the scalar top quark decays into a charm quark and the lightest neutralino, and that the mass difference between the scalar top quark and the lightest neutralino is larger than 10 GeV. The complementary decay mode of the scalar top quark decaying into a bottom quark, a charged lepton and a scalar neutrino has also been studied. The lower limit on the scalar top quark mass is 93.0 GeV for this decay mode, if the mass difference between the scalar top quark a...
Iso-scalar surfaces, mixing and reaction in turbulent flows
Dopazo, César; Martín, Jesús; Hierro, Juan
2006-08-01
Turbulent scalar mixing with chemical reaction is investigated in terms of the local geometrical features of the iso-scalar surfaces—'scalar field topologies'—, using Direct Numerical Simulation data. Two scalars with identical initial distribution, one inert and the other obeying a prescribed Arrhenius-like chemical reaction, evolve in homogeneous isotropic turbulence with a mesh size 256 3. The two local principal curvatures, k and k, of the iso-scalar surface at each point are straightforwardly obtained from the curvature tensor, n, whose elements are the spatial derivatives of the unit vector normal to the iso-surface. The scalar diffusive flux is decomposed into a 'flat-front' contribution plus a curvature induced molecular transport. Expressions for the normal propagating velocity relative to the fluid of iso-surfaces, of both the inert and the reactive scalar fields, are provided making use of the previous decomposition. The 'flat-front' and the curvature induced contributions to the diffusive fluxes, beside to the chemical reaction rate, are correlated with the principal curvatures. Results, including the joint statistics of the principal curvatures and their correlations with the scalar dissipation, are also presented. To cite this article: C. Dopazo et al., C. R. Mecanique 334 (2006).
Kerr black holes with scalar hair.
Herdeiro, Carlos A R; Radu, Eugen
2014-06-06
We present a family of solutions of Einstein's gravity minimally coupled to a complex, massive scalar field, describing asymptotically flat, spinning black holes with scalar hair and a regular horizon. These hairy black holes (HBHs) are supported by rotation and have no static limit. Besides mass M and angular momentum J, they carry a conserved, continuous Noether charge Q measuring the scalar hair. HBHs branch off from the Kerr metric at the threshold of the superradiant instability and reduce to spinning boson stars in the limit of vanishing horizon area. They overlap with Kerr black holes for a set of (M, J) values. A single Killing vector field preserves the solutions, tangent to the null geodesic generators of the event horizon. HBHs can exhibit sharp physical differences when compared to the Kerr solution, such as J/M^{2}>1, a quadrupole moment larger than J^{2}/M, and a larger orbital angular velocity at the innermost stable circular orbit. Families of HBHs connected to the Kerr geometry should exist in scalar (and other) models with more general self-interactions.
Brief History of Ultra-light Scalar Dark Matter Models
Lee Jae-Weon
2018-01-01
This is a review on the brief history of the scalar field dark matter model also known as fuzzy dark matter, BEC dark matter, wave dark matter, or ultra-light axion. In this model ultra-light scalar dark matter particles with mass m = O(10-22)eV condense in a single Bose-Einstein condensate state and behave collectively like a classical wave. Galactic dark matter halos can be described as a self-gravitating coherent scalar field configuration called boson stars. At the scale larger than ga...
Brief History of Ultra-light Scalar Dark Matter Models
Lee Jae-Weon
2018-01-01
This is a review on the brief history of the scalar field dark matter model also known as fuzzy dark matter, BEC dark matter, wave dark matter, or ultra-light axion. In this model ultra-light scalar dark matter particles with mass $m = O(10^{-22})eV$ condense in a single Bose-Einstein condensate state and behave collectively like a classical wave. Galactic dark matter halos can be described as a self-gravitating coherent scalar field configuration called boson stars. At the scale larger than ...
Brief History of Ultra-light Scalar Dark Matter Models
Lee, Jae-Weon
2017-01-01
This is an ongoing review on the brief history of the scalar field dark matter model also known as fuzzy dark matter, BEC dark matter, wave dark matter, or ultra-light axion. In this model ultra-light scalar dark matter particles with mass $m = O(10^{-22})eV$ condense in a single Bose-Einstein condensate state and behave collectively like a classical wave. Galactic dark matter halos can be described as a self-gravitating coherent scalar field configuration called boson stars. At the scale lar...
High-Range Scalar Helium Magnetometer (HSHM) Project
National Aeronautics and Space Administration — This SBIR Phase I proposal describes development of a conceptual design for a High-range Scalar Helium Magnetometer (HSHM) for the field range +/-16 Gauss. The HSHM...
DEFF Research Database (Denmark)
Sannino, Francesco
2016-01-01
We construct effective Lagrangians, and corresponding counting schemes, valid to describe the dynamics of the lowest lying large N stable massive composite state emerging in strongly coupled theories. The large N counting rules can now be employed when computing quantum corrections via an effective...... at the electroweak scale. To illustrate the formalism we consider the possibility that the Higgs emerges as: the lightest glueball of a new composite theory; the large N scalar meson in models of dynamical electroweak symmetry breaking; the large N pseudodilaton useful also for models of near-conformal dynamics...
Brans-Dicke type teleparallel scalar-tensor theory
Salti, Mustafa; Aydogdu, Oktay; Yanar, Hilmi; Binbay, Figen
2017-11-01
The teleparallel alternative of general relativity which is based on torsion instead of curvature is considered as the gravitational sector to explore the dark universe. Inspired from the well-known Brans-Dicke gravity, here, we introduce a new proposal for the galactic dark energy effect. The new model includes a scalar field with self-interacting potential and a non-minimal coupling between the gravity and scalar field. Additionally, we analyze the idea via the Noether symmetry approach and thermodynamics.
Electrically charged Kerr black holes with scalar hair
Delgado, Jorge F M; Radu, Eugen; Runarsson, Helgi
2016-01-01
We construct electrically charged Kerr black holes (BHs) with scalar hair. Firstly, we take an uncharged scalar field, interacting with the electromagnetic field only indirectly, via the background metric. The corresponding family of solutions, dubbed Kerr-Newman BHs with ungauged scalar hair, reduces to (a sub-family of) Kerr-Newman BHs in the limit of vanishing scalar hair and to uncharged rotating boson stars in the limit of vanishing horizon. It adds one extra parameter to the uncharged solutions: the total electric charge. This leading electromagnetic multipole moment is unaffected by the scalar hair and can be computed by using Gauss's law on any closed 2-surface surrounding (a spatial section of) the event horizon. By contrast, the first sub-leading electromagnetic multipole -- the magnetic dipole moment --, gets suppressed by the scalar hair, such that the gyromagnetic ratio is always smaller than the Kerr-Newman value ($g=2$). Secondly, we consider a gauged scalar field and obtain a family of Kerr-Ne...
Scalar transport in inline mixers with spatially periodic flows
Baskan, Ozge; Rajaei, Hadi; Speetjens, Michel F. M.; Clercx, Herman J. H.
2017-01-01
Spatially persisting patterns form during the downstream evolution of passive scalars in three-dimensional (3D) spatially periodic flows due to the coupled effect of stretching and folding mechanisms of the flow field. This has been investigated in many computational and theoretical studies of 2D time-periodic and 3D spatially periodic flow fields. However, experimental studies, to date, have mainly focused on flow visualization with streaks of dye rather than fully 3D scalar field measurements. Our study employs 3D particle tracking velocimetry and 3D laser-induced fluorescence to analyze the evolution of 3D flow and scalar fields and the correlation between the coherent flow/scalar field structures in a representative inline mixer, the Quatro static mixer. For this purpose an experimental setup that consists of an optically accessible test section with transparent internal elements accommodating a pressure-driven pipe flow has been built. The flow and scalar fields clearly underline the complementarity of the experimental results with numerical simulations and provide validation of the periodicity assumption needed in numerical studies. The experimental procedure employed in this investigation, which allows studying the scalar transport in the advective limit, demonstrates the suitability of the present method for exploratory mixing studies of a variety of mixing devices, beyond the Quatro static mixer.
Holographic quantum phase transitions and interacting bulk scalars
Directory of Open Access Journals (Sweden)
Pankaj Chaturvedi
2014-12-01
Full Text Available We consider a system of two massive, mutually interacting probe real scalar fields, in zero temperature holographic backgrounds. The system does not have any continuous symmetry. For a suitable range of the interaction parameters adhering to the interaction potential between the bulk scalars, we have shown that as one turns on the source for one scalar field, the system may go through a second order quantum critical phase transition across which the second scalar field forms a condensate. We have looked at the resulting phase diagram and numerically computed the condensate. We have also investigated our system in two different backgrounds: AdS4 and AdS soliton, and got similar phase structure.
Dark energy in scalar-tensor theories
Energy Technology Data Exchange (ETDEWEB)
Moeller, J.
2007-12-15
We investigate several aspects of dynamical dark energy in the framework of scalar-tensor theories of gravity. We provide a classification of scalar-tensor coupling functions admitting cosmological scaling solutions. In particular, we recover that Brans-Dicke theory with inverse power-law potential allows for a sequence of background dominated scaling regime and scalar field dominated, accelerated expansion. Furthermore, we compare minimally and non-minimally coupled models, with respect to the small redshift evolution of the dark energy equation of state. We discuss the possibility to discriminate between different models by a reconstruction of the equation-of-state parameter from available observational data. The non-minimal coupling characterizing scalar-tensor models can - in specific cases - alleviate fine tuning problems, which appear if (minimally coupled) quintessence is required to mimic a cosmological constant. Finally, we perform a phase-space analysis of a family of biscalar-tensor models characterized by a specific type of {sigma}-model metric, including two examples from recent literature. In particular, we generalize an axion-dilaton model of Sonner and Townsend, incorporating a perfect fluid background consisting of (dark) matter and radiation. (orig.)
Scalar geons in Born-Infeld gravity
Afonso, V. I.; Olmo, Gonzalo J.; Rubiera-Garcia, D.
2017-08-01
The existence of static, spherically symmetric, self-gravitating scalar field solutions in the context of Born-Infeld gravity is explored. Upon a combination of analytical approximations and numerical methods, the equations for a free scalar field (without a potential term) are solved, verifying that the solutions recover the predictions of General Relativity far from the center but finding important new effects in the central regions. We find two classes of objects depending on the ratio between the Schwarzschild radius and a length scale associated to the Born-Infeld theory: massive solutions have a wormhole structure, with their throat at r≈ 2M, while for the lighter configurations the topology is Euclidean. The total energy density of these solutions exhibits a solitonic profile with a maximum peaked away from the center, and located at the throat whenever a wormhole exists. The geodesic structure and curvature invariants are analyzed for the various configurations considered.
Electroweak Baryogenesis and Colored Scalars
Energy Technology Data Exchange (ETDEWEB)
Cohen, Timothy; /SLAC /Michigan U., MCTP; Pierce, Aaron; /Michigan U., MCTP
2012-02-15
We consider the 2-loop finite temperature effective potential for a Standard Model-like Higgs boson, allowing Higgs boson couplings to additional scalars. If the scalars transform under color, they contribute 2-loop diagrams to the effective potential that include gluons. These 2-loop effects are perhaps stronger than previously appreciated. For a Higgs boson mass of 115 GeV, they can increase the strength of the phase transition by as much as a factor of 3.5. It is this effect that is responsible for the survival of the tenuous electroweak baryogenesis window of the Minimal Supersymmetric Standard Model. We further illuminate the importance of these 2-loop diagrams by contrasting models with colored scalars to models with singlet scalars. We conclude that baryogenesis favors models with light colored scalars. This motivates searches for pair-produced di-jet resonances or jet(s) + = E{sub T}.
The Effective Hamiltonian in the Scalar Electrodynamics
Dineykhan, M D; Zhaugasheva, S A; Sakhyev, S K
2002-01-01
On the basis of an investigation of the asymptotic behaviour of the polarization loop for the scalar particles in the external electromagnetic field the relativistic corrections to the Hamiltonian are determined. The constituent mass of the particles in the bound state is analytically derived. It is shown that the constituent mass of the particles differs from the mass of the particles in the free state. The corrections connected with the Thomas precession have been calculated.
Wave propagation and shock formation in the most general scalar-tensor theories
Tanahashi, Norihiro; Ohashi, Seiju
2017-11-01
This work studies wave propagation in the most general covariant scalar-tensor theories with second-order field equations, particularly focusing on the causal structure realized in these theories and also the shock formation process induced by nonlinear effects. For these studies we use the Horndeski theory and its generalization to the two scalar field case. We show that propagation speeds of the gravitational wave and scalar field wave in these theories may differ from the light speed depending on background field configuration, and find that a Killing horizon becomes a boundary of causal domain if the scalar fields share the symmetry of the background spacetime. With regard to the shock formation, we focus on transport of discontinuity in second derivatives of the metric and scalar field in the shift-symmetric Horndeski theory. We find that amplitude of the discontinuity generically diverges within finite time, which corresponds to shock formation. It turns out that the canonical scalar field and the scalar DBI model, among other theories described by the Horndeski theory, are free from such shock formation even when the background geometry and scalar field configuration are nontrivial. We also observe that the gravitational wave is protected against shock formation when the background has some symmetries at least. This fact may indicate that the gravitational wave in this theory is more well-behaved compared to the scalar field, which typically suffers from shock formation.
Anderson, David; Yunes, Nicolás; Barausse, Enrico
2016-11-01
Certain scalar-tensor theories of gravity that generalize Jordan-Fierz-Brans-Dicke theory are known to predict nontrivial phenomenology for neutron stars. In these theories, first proposed by Damour and Esposito-Farèse, the scalar field has a standard kinetic term and couples conformally to the matter fields. The weak equivalence principle is therefore satisfied, but scalar effects may arise in strong-field regimes, e.g., allowing for violations of the strong equivalence principle in neutron stars ("spontaneous scalarization") or in sufficiently tight binary neutron-star systems ("dynamical/induced scalarization"). The original scalar-tensor theory proposed by Damour and Esposito-Farèse is in tension with Solar System constraints (for couplings that lead to scalarization), if one accounts for cosmological evolution of the scalar field and no mass term is included in the action. We extend here the conformal coupling of that theory, in order to ascertain if, in this way, Solar System tests can be passed, while retaining a nontrivial phenomenology for neutron stars. We find that, even with this generalized conformal coupling, it is impossible to construct a theory that passes both big bang nucleosynthesis and Solar System constraints, while simultaneously allowing for scalarization in isolated/binary neutron stars.
Solution of the Higgs scalar-tensor theory without Higgs particles for static stars
Rekowski, Oleg von Styp; Frommert, Hartmut
1996-01-01
Within the scalar-tensor theory of gravity with Higgs mechanism without Higgs particles, we prove that the excited Higgs potential (the scalar field) vanishs inside and outside of the stellar matter for static spherically symmetric configurations. The field equation for the metric (the tensorial gravitational field) turns out to be essentially the Einsteinian one.
Late Inspiral and Merger of Binary Black Holes in Scalar-Tensor Theories of Gravity
Healy, James; Bode, Tanja; Haas, Roland; Pazos, Enrique; Laguna, Pablo; Shoemaker, Deirdre M.; Yunes, Nicolás
2011-01-01
Gravitational wave observations will probe non-linear gravitational interactions and thus enable strong tests of Einstein's theory of general relativity. We present a numerical relativity study of the late inspiral and merger of binary black holes in scalar-tensor theories of gravity. We consider black hole binaries in an inhomogeneous scalar field, specifically binaries inside a scalar field bubble, in some cases with a potential. We calculate the emission of dipole radiation. We also show h...
Effects of scalar mesons in a Skyrme model with hidden local symmetry
He, Bing-Ran; Ma, Yong-Liang; Harada, Masayasu
2015-10-01
We study the effects of light scalar mesons on the Skyrmion properties by constructing and examining a mesonic model including pion, rho meson, and omega meson fields as well as two-quark and four-quark scalar meson fields. In our model, the physical scalar mesons are defined as mixing states of the two- and four-quark fields. We first omit the four-quark scalar meson field from the model and find that when there is no direct coupling between the two-quark scalar meson and the vector mesons, the soliton mass is smaller and the soliton size is larger for lighter scalar mesons; when direct coupling is switched on, as the coupling strength increases, the soliton becomes heavy, and the radius of the baryon number density becomes large as the repulsive force arising from the ω meson becomes strong. We then include the four-quark scalar meson field in the model and find that mixing between the two-quark and four-quark components of the scalar meson fields also affects the properties of the soliton. When the two-quark component of the lighter scalar meson is increased, the soliton mass decreases and the soliton size increases.
Small vacuum energy from small equivalence violation in scalar gravity
Agrawal, Prateek; Sundrum, Raman
2017-05-01
The theory of scalar gravity proposed by Nordström, and refined by Einstein and Fokker, provides a striking analogy to general relativity. In its modern form, scalar gravity appears as the low-energy effective field theory of the spontaneous breaking of conformal symmetry within a CFT, and is AdS/CFT dual to the original Randall-Sundrum I model, but without a UV brane. Scalar gravity faithfully exhibits several qualitative features of the cosmological constant problem of standard gravity coupled to quantum matter, and the Weinberg no-go theorem can be extended to this case as well. Remarkably, a solution to the scalar gravity cosmological constant problem has been proposed, where the key is a very small violation of the scalar equivalence principle, which can be elegantly formulated as a particular type of deformation of the CFT. In the dual AdS picture this involves implementing Goldberger-Wise radion stabilization where the Goldberger-Wise field is a pseudo-Nambu Goldstone boson. In quantum gravity however, global symmetries protecting pNGBs are not expected to be fundamental. We provide a natural six-dimensional gauge theory origin for this global symmetry and show that the violation of the equivalence principle and the size of the vacuum energy seen by scalar gravity can naturally be exponentially small. Our solution may be of interest for study of non-supersymmetric CFTs in the spontaneously broken phase.
Structure function of passive scalars in two-dimensional turbulence
Eckhardt, B; Eckhardt, Bruno; Schumacher, Joerg
1999-01-01
The structure function of a scalar $\\theta({\\bf x},t)$, passively advected in a two-dimensional turbulent flow ${\\bf u}({\\bf x},t)$, is discussed by means of the fractal dimension $\\delta^{(1)}_g$ of the passive scalar graph. A relation between $\\delta^{(1)}_g$, the scaling exponent $\\zeta_1^{(\\theta)}$ of the scalar structure function $D_1^{(\\theta)}(r)$, and the structure function $D_2(r)$ of the underlying flow field is derived. Different from the 3-d case, the 2-d structure function also depends on an additional parameter, characteristic of the driving of the passive scalar. In the enstrophy inertial subrange a mean field approximation for the velocity structure function gives a scaling of the passive scalar graph with $\\delta^{(1)}_g<2$ for intermediate and large values of the Prandtl number $Pr$. In the energy inertial subrange a model for the energy spectrum and thus $D_2(r)$ gives a passive scalar graph scaling with exponent $\\delta^{(1)}_g=5/3$. Finally, we discuss an application to recent observa...
Cortez, Jerónimo; Mena Marugán, Guillermo A.; Velhinho, José M.
The canonical quantization of midisuperspace gravitational models is a particular case of the quantization of fields. Typically, the requirement of symmetries other than homogeneity reduces the phase space of full General Relativity, but still leaves an infinite number of degrees of freedom, encoded in some fields which parametrize the metric components and are subject to constraints. Since the total Hamiltonian vanishes, and constraints are all that there is l, a peculiar situation occurs in the quantization of these models. On the one hand, it is tempting to solve at the classical level as many constraints as possible, e.g. by gauge fixing or other means. On the other hand, if all the constraints were to be solved, one would be l just with the infinite dimensional reduced phase space of the model, and no extra structure to guide us through the quantization process.
Scalar perturbation produced at the pre-inflationary stage in Eddington-inspired Born-Infeld gravity
Energy Technology Data Exchange (ETDEWEB)
Cho, Inyong; Singh, Naveen K. [Seoul National University of Science and Technology, Institute of Convergence Fundamental Studies, School of Liberal Arts, Seoul (Korea, Republic of)
2015-06-15
We investigate the scalar perturbation produced at the pre-inflationary stage driven by a massive scalar field in Eddington-inspired Born-Infeld gravity. The scalar power spectrum exhibits a peculiar rise for low k-modes. The tensor-to-scalar ratio can be significantly lowered compared with that in the standard chaotic inflation model in general relativity. This result is very affirmative considering the recent dispute on the detection of gravitational wave radiation between PLANCK and BICEP2. (orig.)
Topological Aharonov-Bohm Effect of Neutral Scalar Particle on Noncommutative Space
Wang, Ya-Hui; Wang, Jian-Hua; Ma, Kai
2017-12-01
We study the interactions between a neutral scalar particle and electromagnetic fields on noncommutative space. Because of the noncommutativity of space, neutral particle can couple to electromagnetic fields at the tree level, and the interaction strength is represented by a new coupling constant. We find that on noncommtuative space the topological Aharonov-Bohm effect is nontrivial even for neutral scalar particle.
DEFF Research Database (Denmark)
Kuvshinov, Alexey; Matzka, Jürgen; Poedjono, Benny
2016-01-01
-keeping platform. The concept exploits scalar magnetic responses that relate variations of the scalar magnetic field at the survey sites with variations of the horizontal magnetic field at a reference site. A 3-D model study offshore Oahu Island (Hawaii) demonstrates that these responses are sensitive...
Curvature Perturbation and Domain Wall Formation with Pseudo Scaling Scalar Dynamics
Ema, Yohei; Takimoto, Masahiro
2015-01-01
Cosmological dynamics of scalar field with a monomial potential $\\phi^{n}$ with a general background equation of state is revisited. It is known that if $n$ is smaller than a critical value, the scalar field exhibits a coherent oscillation and if $n$ is larger it obeys a scaling solution without oscillation. We study in detail the case where $n$ is equal to the critical value, and find a peculiar scalar dynamics which is neither oscillating nor scaling solution, and we call it a pseudo scaling solution. We also discuss cosmological implications of a pseudo scaling scalar dynamics, such as the curvature perturbation and the domain wall problem.
Energy Technology Data Exchange (ETDEWEB)
Sainath, Kamalesh, E-mail: sainath.1@osu.edu [The Ohio State University, Electroscience Laboratory, 1330 Kinnear Road, Columbus, OH 43212 (United States); Teixeira, Fernando L., E-mail: teixeira@ece.osu.edu [The Ohio State University, Electroscience Laboratory, 1330 Kinnear Road, Columbus, OH 43212 (United States); Donderici, Burkay, E-mail: Burkay.Donderici@Halliburton.com [Halliburton, Sensor Physics and Technology, 3000 N. Sam Houston Pkwy E, Houston, TX 77032 (United States)
2014-07-15
We propose the complex-plane generalization of a powerful algebraic sequence acceleration algorithm, the method of weighted averages (MWA), to guarantee exponential-cum-algebraic convergence of Fourier and Fourier–Hankel (F–H) integral transforms. This “complex-plane” MWA, effected via a linear-path detour in the complex plane, results in rapid, absolute convergence of field and potential solutions in multi-layered environments regardless of the source-observer geometry and anisotropy/loss of the media present. In this work, we first introduce a new integration path used to evaluate the field contribution arising from the radiation spectra. Subsequently, we (1) exhibit the foundational relations behind the complex-plane extension to a general Levin-type sequence convergence accelerator, (2) specialize this analysis to one member of the Levin transform family (the MWA), (3) address and circumvent restrictions, arising for two-dimensional integrals associated with wave dynamics problems, through minimal complex-plane detour restrictions and a novel partition of the integration domain, (4) develop and compare two formulations based on standard/real-axis MWA variants, and (5) present validation results and convergence characteristics for one of these two formulations.
Fluctuations of a passive scalar in a turbulent mixing layer
Attili, Antonio
2013-09-19
The turbulent flow originating downstream of the Kelvin-Helmholtz instability in a mixing layer has great relevance in many applications, ranging from atmospheric physics to combustion in technical devices. The mixing of a substance by the turbulent velocity field is usually involved. In this paper, a detailed statistical analysis of fluctuations of a passive scalar in the fully developed region of a turbulent mixing layer from a direct numerical simulation is presented. Passive scalar spectra show inertial ranges characterized by scaling exponents −4/3 and −3/2 in the streamwise and spanwise directions, in agreement with a recent theoretical analysis of passive scalar scaling in shear flows [Celani et al., J. Fluid Mech. 523, 99 (2005)]. Scaling exponents of high-order structure functions in the streamwise direction show saturation of intermittency with an asymptotic exponent ζ∞=0.4 at large orders. Saturation of intermittency is confirmed by the self-similarity of the tails of the probability density functions of the scalar increments at different scales r with the scaling factor r−ζ∞ and by the analysis of the cumulative probability of large fluctuations. Conversely, intermittency saturation is not observed for the spanwise increments and the relative scaling exponents agree with recent results for homogeneous isotropic turbulence with mean scalar gradient. Probability density functions of the scalar increments in the three directions are compared to assess anisotropy.
Cosmological evolution and Solar System consistency of massive scalar-tensor gravity
de Pirey Saint Alby, Thibaut Arnoulx; Yunes, Nicolás
2017-09-01
The scalar-tensor theory of Damour and Esposito-Farèse recently gained some renewed interest because of its ability to suppress modifications to general relativity in the weak field, while introducing large corrections in the strong field of compact objects through a process called scalarization. A large sector of this theory that allows for scalarization, however, has been shown to be in conflict with Solar System observations when accounting for the cosmological evolution of the scalar field. We here study an extension of this theory by endowing the scalar field with a mass to determine whether this allows the theory to pass Solar System constraints upon cosmological evolution for a larger sector of coupling parameter space. We show that the cosmological scalar field goes first through a quiescent phase, similar to the behavior of a massless field, but then it enters an oscillatory phase, with an amplitude (and frequency) that decays (and grows) exponentially. We further show that after the field enters the oscillatory phase, its effective energy density and pressure are approximately those of dust, as expected from previous cosmological studies. Due to these oscillations, we show that the scalar field cannot be treated as static today on astrophysical scales, and so we use time-dependent perturbation theory to compute the scalar-field-induced modifications to Solar System observables. We find that these modifications are suppressed when the mass of the scalar field and the coupling parameter of the theory are in a wide range, allowing the theory to pass Solar System constraints, while in principle possibly still allowing for scalarization.
Dolan, Sam R
2010-01-01
To model the radiative evolution of extreme mass-ratio binary inspirals (a key target of the LISA mission), the community needs efficient methods for computation of the gravitational self-force (SF) on the Kerr spacetime. Here we further develop a practical `$m$-mode regularization' scheme for SF calculations, and give details of a first implementation. The key steps in the method are (i) removal of a singular part of the perturbation field with a suitable `puncture' to leave a sufficiently regular residual within a finite worldtube surrounding the particle's worldline, (ii) decomposition in azimuthal ($m$-)modes, (iii) numerical evolution of the $m$-modes in 2+1D with a finite difference scheme, and (iv) reconstruction of the SF from the mode sum. The method relies on a judicious choice of puncture, based on the Detweiler--Whiting decomposition. We give a working definition for the `order' of the puncture, and show how it determines the convergence rate of the $m$-mode sum. The dissipative piece of the SF di...
Scalar boundary conditions in hyperscaling violating geometry
Directory of Open Access Journals (Sweden)
Jian-Pin Wu
2016-02-01
Full Text Available We study the possible boundary conditions of scalar field modes in a hyperscaling violation (HV geometry with Lifshitz dynamical exponent z (z≥1 and hyperscaling violation exponent θ (θ≠0. For the case with θ>0, we show that in the parameter range 1≤z≤2, −z+d−12, −z+d−10, which has been addressed in Ref. [1]. Meanwhile, we also carry out the parallel investigation in the case with θ0, only one type is available.
Scalar - vector soliton fiber lasers
Wu, Zhichao; Li, Lei; Luo, Yiyang; Tang, Dingyuan; Shen, Deyuan; Tang, Ming; Fu, Songnian; Zhao, Luming
2016-01-01
Rapid progress in passively mode-locked fiber lasers is currently driven by the recent discovery of vector feature of mode-locking pulses, namely, the group velocity-locked vector solitons, the phase locked vector solitons, and the high-order vector solitons. Those vector solitons are fundamentally different from the previously known scalar solitons. Here, we report a fiber laser where the mode-locked pulse evolves as a vector soliton in the strong birefringent segment and is transformed into a regular scalar soliton after the polarizer within the laser cavity. The existence of solutions in a polarization-dependent cavity comprising a periodic combination of two distinct nonlinear waves is novel and likely to be applicable to various other nonlinear systems. For very large local birefringence, our laser approaches the working regime of vector soliton lasers, while it approaches scalar soliton fiber lasers under the conditions of very small birefringence.
Scalar multiplet recombination at large N and holography
Energy Technology Data Exchange (ETDEWEB)
Bashmakov, Vladimir [SISSA and INFN, Via Bonomea 265, I-34136 Trieste (Italy); Bertolini, Matteo [SISSA and INFN, Via Bonomea 265, I-34136 Trieste (Italy); ICTP, Strada Costiera 11, I-34014 Trieste (Italy); Pietro, Lorenzo Di [Weizmann Institute of Science, Rehovot 7610001 (Israel); Raj, Himanshu [SISSA and INFN, Via Bonomea 265, I-34136 Trieste (Italy)
2016-05-31
We consider the coupling of a free scalar to a single-trace operator of a large N CFT in d dimensions. This is equivalent to a double-trace deformation coupling two primary operators of the CFT, in the limit when one of the two saturates the unitarity bound. At leading order, the RG-flow has a non-trivial fixed point where multiplets recombine. We show this phenomenon in field theory, and provide the holographic dual description. Free scalars correspond to singleton representations of the AdS algebra. The double-trace interaction is mapped to a boundary condition mixing the singleton with the bulk field dual to the single-trace operator. In the IR, the singleton and the bulk scalar merge, providing just one long representation of the AdS algebra.
Brief History of Ultra-light Scalar Dark Matter Models
Lee, Jae-Weon
2018-01-01
This is a review on the brief history of the scalar field dark matter model also known as fuzzy dark matter, BEC dark matter, wave dark matter, or ultra-light axion. In this model ultra-light scalar dark matter particles with mass m = O(10-22)eV condense in a single Bose-Einstein condensate state and behave collectively like a classical wave. Galactic dark matter halos can be described as a self-gravitating coherent scalar field configuration called boson stars. At the scale larger than galaxies the dark matter acts like cold dark matter, while below the scale quantum pressure from the uncertainty principle suppresses the smaller structure formation so that it can resolve the small scale crisis of the conventional cold dark matter model.
Unified cosmology with scalar-tensor theory of gravity
Energy Technology Data Exchange (ETDEWEB)
Tajahmad, Behzad [Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of); Sanyal, Abhik Kumar [Jangipur College, Department of Physics, Murshidabad (India)
2017-04-15
Unlike the Noether symmetry, a metric independent general conserved current exists for non-minimally coupled scalar-tensor theory of gravity if the trace of the energy-momentum tensor vanishes. Thus, in the context of cosmology, a symmetry exists both in the early vacuum and radiation dominated era. For slow roll, symmetry is sacrificed, but at the end of early inflation, such a symmetry leads to a Friedmann-like radiation era. Late-time cosmic acceleration in the matter dominated era is realized in the absence of symmetry, in view of the same decayed and redshifted scalar field. Thus, unification of early inflation with late-time cosmic acceleration with a single scalar field may be realized. (orig.)
SCALAR AND VECTOR IN COMPULATION
Directory of Open Access Journals (Sweden)
Valery F. Ochkov
2013-01-01
Full Text Available The article deals with two fundamental data types – scalar and vector (array, without the ability of working with them one cannot solve using computer school or university tasks in mathematics, physics, chemistry and other technical training courses. Some fundamentals of teaching computer science at school and university are covered as well.
Veltman, M.J.G.; Hooft, G. 't
1979-01-01
The completely general one-loop scalar one-, two-, three- and four-point functions are studied. Also an integral occurring in connection with soft bremsstrahlung is considered. Formulas in terms of Spence functions are given. An expansion for Spence functions with complex argument is presented.
Scalar magnetometers for space applications
DEFF Research Database (Denmark)
Primdahl, Fritz
magnetometer, offer stability and resolution well suited for the calibration purposes. Recent developments are discussed. The metastable Helium magnetometer also offers quasi-absolute scalar measurements, and the use of semiconductor tuned lasers replacing an RF-excited Helium lamp holds great promise...
Charged black holes in a generalized scalar-tensor gravity model
Brihaye, Yves; Hartmann, Betti
2017-09-01
We study 4-dimensional charged and static black holes in a generalized scalar-tensor gravity model, in which a shift symmetry for the scalar field exists. For vanishing scalar field the solution corresponds to the Reissner-Nordström (RN) solution, while solutions of the full scalar-gravity model have to be constructed numerically. We demonstrate that these black holes support Galilean scalar hair up to a maximal value of the scalar-tensor coupling that depends on the value of the charge and can be up to roughly twice as large as that for uncharged solutions. The Hawking temperature TH of the hairy black holes at maximal scalar-tensor coupling decreases continuously with the increase of the charge and reaches TH = 0 for the highest possible charge that these solutions can carry. However, in this limit, the scalar-tensor coupling needs to vanish. The limiting solution hence corresponds to the extremal RN solution, which does not support regular Galilean scalar hair due to its AdS2 ×S2 near-horizon geometry.
Unique Fock quantization of scalar cosmological perturbations
Fernández-Méndez, Mikel; Mena Marugán, Guillermo A.; Olmedo, Javier; Velhinho, José M.
2012-05-01
We investigate the ambiguities in the Fock quantization of the scalar perturbations of a Friedmann-Lemaître-Robertson-Walker model with a massive scalar field as matter content. We consider the case of compact spatial sections (thus avoiding infrared divergences), with the topology of a three-sphere. After expanding the perturbations in series of eigenfunctions of the Laplace-Beltrami operator, the Hamiltonian of the system is written up to quadratic order in them. We fix the gauge of the local degrees of freedom in two different ways, reaching in both cases the same qualitative results. A canonical transformation, which includes the scaling of the matter-field perturbations by the scale factor of the geometry, is performed in order to arrive at a convenient formulation of the system. We then study the quantization of these perturbations in the classical background determined by the homogeneous variables. Based on previous work, we introduce a Fock representation for the perturbations in which: (a) the complex structure is invariant under the isometries of the spatial sections and (b) the field dynamics is implemented as a unitary operator. These two properties select not only a unique unitary equivalence class of representations, but also a preferred field description, picking up a canonical pair of field variables among all those that can be obtained by means of a time-dependent scaling of the matter field (completed into a linear canonical transformation). Finally, we present an equivalent quantization constructed in terms of gauge-invariant quantities. We prove that this quantization can be attained by a mode-by-mode time-dependent linear canonical transformation which admits a unitary implementation, so that it is also uniquely determined.
Unique Fock quantization of scalar cosmological perturbations
Fernández-Méndez, Mikel; Olmedo, Javier; Velhinho, José M
2012-01-01
We investigate the ambiguities in the Fock quantization of the scalar perturbations of a Friedmann-Lema\\^{i}tre-Robertson-Walker model with a massive scalar field as matter content. We consider the case of compact spatial sections (thus avoiding infrared divergences), with the topology of a three-sphere. After expanding the perturbations in series of eigenfunctions of the Laplace-Beltrami operator, the Hamiltonian of the system is written up to quadratic order in them. We fix the gauge of the local degrees of freedom in two different ways, reaching in both cases the same qualitative results. A canonical transformation, which includes the scaling of the matter field perturbations by the scale factor of the geometry, is performed in order to arrive at a convenient formulation of the system. We then study the quantization of these perturbations in the classical background determined by the homogeneous variables. Based on previous work, we introduce a Fock representation for the perturbations in which: (a) the co...
Passive Scalar Evolution in Peripheral Region
Lebedev, V. V.; Turitsyn, K. S.
2003-01-01
We consider evolution of a passive scalar (concentration of pollutants or temperature) in a chaotic (turbulent) flow. A universal asymptotic behavior of the passive scalar decay (homogenization) related to peripheral regions (near walls) is established. The passive scalar moments and its pair correlation function in the peripheral region are analyzed. A special case investigated in our paper is the passive scalar decay along a pipe.
Search for Scalar Leptons and Scalar Quarks at LEP
Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.
2004-01-01
Scalar partners of quarks and leptons, predicted in supersymmetric models, are searched for in e^+e^- collisions at centre-of-mass energies between 192GeV and 209GeV at LEP. No evidence for any such particle is found in a data sample of 450 pb^-1. Upper limits on their production cross sections are set and lower limits on their masses are derived in the framework of the Minimal Supersymmetric Standard Model.
Galileons as the Scalar Analogue of General Relativity
Klein, Remko; Ozkan, Mehmet; Roest, Diederik
2016-01-01
We establish a correspondence between general relativity with diffeomorphism invariance and scalar field theories with Galilean invariance: notions such as the Levi-Civita connection and the Riemann tensor have a Galilean counterpart. This suggests Galilean theories as the unique nontrivial
Two loop stress-energy tensor for inflationary scalar electrodynamics
Prokopec, T.; Tsamis, N.C.; Woodard, R.P.
2008-01-01
We calculate the expectation value of the coincident product of two field strength tensors at two loop order in scalar electrodynamics on de Sitter background. The result agrees with the stochastic formulation which we have developed in a companion paper [2] for the nonperturbative resummation of
Brief History of Ultra-light Scalar Dark Matter Models
Directory of Open Access Journals (Sweden)
Lee Jae-Weon
2018-01-01
dark matter, BEC dark matter, wave dark matter, or ultra-light axion. In this model ultra-light scalar dark matter particles with mass m = O(10-22eV condense in a single Bose-Einstein condensate state and behave collectively like a classical wave. Galactic dark matter halos can be described as a self-gravitating coherent scalar field configuration called boson stars. At the scale larger than galaxies the dark matter acts like cold dark matter, while below the scale quantum pressure from the uncertainty principle suppresses the smaller structure formation so that it can resolve the small scale crisis of the conventional cold dark matter model.
Statistical Cosmological Fermion Systems With Interparticle Fantom Scalar Interaction
Ignat'ev, Yurii; Ignatyev, Dmitry
2016-01-01
The article represents a research of the cosmological evolution of fermion statistical systems with fantom scalar interaction where "kinetic" term's contribution to the total energy of a scalar field is negative. As a result of analytical and numerical simulation of such systems it has been revealed a existence of four possible scenarios depending on parameters of the system and initial conditions. Among these scenarios there are scenarios with an early, intermediate and late non-relativistic stages of the cosmological evolution, all of which also have necessary inflation stage.
Scalar ether theory of gravity: a modification that seems needed
Arminjon, Mayeul
2004-01-01
The construction of the scalar theory based on the concept of gravity as Archimedes' thrust is briefly summarized, emphasizing the two (extreme) possibilities that result from this concept for the gravitational rod contraction: it can either occur in only one direction, or be isotropic. A modified equation for the scalar field is stated for the new, isotropic case. The reasons to consider this case are: i) it is almost as natural as the other case, and ii) it should avoid the violation of the...
Inert scalars and vacuum metastability around the electroweak scale
Energy Technology Data Exchange (ETDEWEB)
Świeżewska, Bogumiła [Faculty of Physics, University of Warsaw,Pasteura 5, 02-093 Warsaw (Poland)
2015-07-22
We analyse effective potential around the electroweak (EW) scale in the Standard Model (SM) extended with a heavy scalar doublet. We show that the additional scalars can have a strong impact on vacuum stability. Although the additional heavy scalars may improve the behaviour of running Higgs self-coupling at large field values, we prove that they can destabilise the vacuum due to EW-scale effects. A new EW symmetry conserving minimum of the effective potential can appear rendering the electroweak symmetry breaking (EWSB) minimum meta- or unstable. However, for the case of the inert doublet model (IDM) with a 125 GeV Higgs boson we demonstrate that the parameter space region where the vacuum is meta- or unstable cannot be reconciled with the constraints from perturbative unitarity, electroweak precision tests (EWPT) and dark matter relic abundance measurements.
Bounded Scalar Perturbations in Bouncing Brane World Cosmologies
Maier, Rodrigo; Soares, Ivano Damião
2013-01-01
We examine the dynamics of scalar perturbations in closed Friedmann-Lema\\^itre-Robertson- Walker (FLRW) universes in the framework of Brane World theory with a timelike extra dimension. In this scenario, the unperturbed Friedmann equations contain additional terms arising from the bulk-brane interaction that implement non-singular bounces in the models with a cosmological constant and non-interacting perfect fluids. The structure of the phase-space of the models allows for two basic configurations, namely, one bounce solutions or eternal universes. Assuming that the matter content of the model is given by dust and radiation, we derive the dynamical field equations for scalar hydrodynamical perturbations considering either a conformally flat (de Sitter) bulk or a perturbed bulk. We perform a numerical analysis which can shed some light on the study of cosmological scalar perturbations in bouncing brane world models. From a mathematical point of view we show that although the bounce enhances the amplitudes of s...
CP violating scalar Dark Matter
Energy Technology Data Exchange (ETDEWEB)
Cordero-Cid, A.; Hernández-Sánchez, J. [Instituto de Física and Facultad de Ciencias de la Electrónica, Benemérita Universidad Autónoma de Puebla, Apdo. Postal 542, C.P. 72570 Puebla (Mexico); Keus, V. [Department of Physics and Helsinki Institute of Physics, University of Helsinki, Gustaf Hallstromin katu 2, Helsinki, FIN-00014 (Finland); School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); King, S.F. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Moretti, S. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Particle Physics Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX (United Kingdom); Rojas, D. [Instituto de Física and Facultad de Ciencias de la Electrónica, Benemérita Universidad Autónoma de Puebla, Apdo. Postal 542, C.P. 72570 Puebla (Mexico); Sokołowska, D. [Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland)
2016-12-05
We study an extension of the Standard Model (SM) in which two copies of the SM scalar SU(2) doublet which do not acquire a Vacuum Expectation Value (VEV), and hence are inert, are added to the scalar sector. We allow for CP-violation in the inert sector, where the lightest inert state is protected from decaying to SM particles through the conservation of a Z{sub 2} symmetry. The lightest neutral particle from the inert sector, which has a mixed CP-charge due to CP-violation, is hence a Dark Matter (DM) candidate. We discuss the new regions of DM relic density opened up by CP-violation, and compare our results to the CP-conserving limit and the Inert Doublet Model (IDM). We constrain the parameter space of the CP-violating model using recent results from the Large Hadron Collider (LHC) and DM direct and indirect detection experiments.
Self-Gravitating Spherically Symmetric Solutions in Scalar-Torsion Theories
Kofinas, Georgios; Saridakis, Emmanuel N
2015-01-01
We studied spherically symmetric solutions in scalar-torsion gravity theories in which a scalar field is coupled to torsion with a derivative coupling. We obtained the general field equations from which we extracted a decoupled master equation, the solution of which leads to the specification of all other unknown functions. We first obtained an exact solution which represents a new wormhole-like solution dressed with a regular scalar field. Then, we found large distance linearized spherically symmetric solutions in which the space asymptotically is AdS.
Energy Technology Data Exchange (ETDEWEB)
Foda, O. [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)], E-mail: foda@ms.unimelb.edu.au; Wheeler, M. [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)], E-mail: mwheeler@ms.unimelb.edu.au; Zuparic, M. [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)], E-mail: mzup@ms.unimelb.edu.au
2009-10-21
Using a Jacobi-Trudi-type identity, we show that the scalar product of a general state and a Bethe eigenstate in a finite-length XXZ spin-1/2 chain is (a restriction of) a KP {tau} function. This leads to a correspondence between the eigenstates and points on Sato's Grassmannian. Each of these points is a function of the rapidities of the corresponding eigenstate, the inhomogeneity variables of the spin chain and the crossing parameter.
Convergence of scalar-tensor theories towards general relativity and primordial nucleosynthesis
Serna, A; Navarro, A
2002-01-01
In this paper, we analyse the conditions for convergence towards general relativity of scalar-tensor gravity theories defined by an arbitrary coupling function alpha (in the Einstein frame). We show that, in general, the evolution of the scalar field (phi) is governed by two opposite mechanisms: an attraction mechanism which tends to drive scalar-tensor models towards Einstein's theory, and a repulsion mechanism which has the contrary effect. The attraction mechanism dominates the recent epochs of the universe evolution if, and only if, the scalar field and its derivative satisfy certain boundary conditions. Since these conditions for convergence towards general relativity depend on the particular scalar-tensor theory used to describe the universe evolution, the nucleosynthesis bounds on the present value of the coupling function, alpha sub 0 , strongly differ from some theories to others. For example, in theories defined by alpha propor to |phi| analytical estimates lead to very stringent nucleosynthesis bou...
Growth of spherical overdensities in scalar-tensor cosmologies
Nazari-Pooya, N; Pace, F; Jassur, D Mohammad-Zadeh
2016-01-01
The accelerated expansion of the universe is a rather established fact in cosmology and many different models have been proposed as a viable explanation. Many of these models are based on the standard general relativistic framework of non-interacting fluids or more recently of coupled (interacting) dark energy models, where dark energy (the scalar field) is coupled to the dark matter component giving rise to a fifth-force. An interesting alternative is to couple the scalar field directly to the gravity sector via the Ricci scalar. These models are dubbed non-minimally coupled models and give rise to a time-dependent gravitational constant. In this work we study few models falling into this category and describe how observables depend on the strength of the coupling. We extend recent work on the subject by taking into account also the effects of the perturbations of the scalar field and showing their relative importance on the evolution of the mass function. By working in the framework of the spherical collaps...
Accelerating Universe and the Scalar-Tensor Theory
Directory of Open Access Journals (Sweden)
Yasunori Fujii
2012-10-01
Full Text Available To understand the accelerating universe discovered observationally in 1998, we develop the scalar-tensor theory of gravitation originally due to Jordan, extended only minimally. The unique role of the conformal transformation and frames is discussed particularly from a physical point of view. We show the theory to provide us with a simple and natural way of understanding the core of the measurements, Λobs ∼ t0−2 for the observed values of the cosmological constant and today’s age of the universe both expressed in the Planckian units. According to this scenario of a decaying cosmological constant, Λobs is this small only because we are old, not because we fine-tune the parameters. It also follows that the scalar field is simply the pseudo Nambu–Goldstone boson of broken global scale invariance, based on the way astronomers and astrophysicists measure the expansion of the universe in reference to the microscopic length units. A rather phenomenological trapping mechanism is assumed for the scalar field around the epoch of mini-inflation as observed, still maintaining the unmistakable behavior of the scenario stated above. Experimental searches for the scalar field, as light as ∼ 10−9 eV, as part of the dark energy, are also discussed.
Myers–Perry black holes with scalar hair and a mass gap
Energy Technology Data Exchange (ETDEWEB)
Brihaye, Yves [Physique–Mathématique, Universite de Mons-Hainaut, Mons (Belgium); Herdeiro, Carlos; Radu, Eugen [Departamento de Física da Universidade de Aveiro and I3N, Campus de Santiago, 3810-183 Aveiro (Portugal)
2014-12-12
We construct a family of asymptotically flat, rotating black holes with scalar hair and a regular horizon, within five dimensional Einstein's gravity minimally coupled to a complex, massive scalar field doublet. These solutions are supported by rotation and have no static limit. They are described by their mass M, two equal angular momenta J{sub 1}=J{sub 2}≡J and a conserved Noether charge Q, measuring the scalar hair. For vanishing horizon size the solutions reduce to five dimensional boson stars. In the limit of vanishing Noether charge density, the scalar field becomes point-wise arbitrarily small and the geometry becomes, locally, arbitrarily close to that of a specific set of Myers–Perry black holes (MPBHs); but there remains a global difference with respect to the latter, manifest in a finite mass gap. Thus, the scalar hair never becomes a linear perturbation of MPBHs. This is a qualitative difference when compared to Kerr black holes with scalar hair [1]. Whereas the existence of the latter can be anticipated in linear theory, from the existence of scalar bound states on the Kerr geometry (i.e. scalar clouds), the hair of these MPBHs is intrinsically non-linear.
Myers–Perry black holes with scalar hair and a mass gap
Directory of Open Access Journals (Sweden)
Yves Brihaye
2014-12-01
Full Text Available We construct a family of asymptotically flat, rotating black holes with scalar hair and a regular horizon, within five dimensional Einstein's gravity minimally coupled to a complex, massive scalar field doublet. These solutions are supported by rotation and have no static limit. They are described by their mass M, two equal angular momenta J1=J2≡J and a conserved Noether charge Q, measuring the scalar hair. For vanishing horizon size the solutions reduce to five dimensional boson stars. In the limit of vanishing Noether charge density, the scalar field becomes point-wise arbitrarily small and the geometry becomes, locally, arbitrarily close to that of a specific set of Myers–Perry black holes (MPBHs; but there remains a global difference with respect to the latter, manifest in a finite mass gap. Thus, the scalar hair never becomes a linear perturbation of MPBHs. This is a qualitative difference when compared to Kerr black holes with scalar hair [1]. Whereas the existence of the latter can be anticipated in linear theory, from the existence of scalar bound states on the Kerr geometry (i.e. scalar clouds, the hair of these MPBHs is intrinsically non-linear.
Leading-twist distribution amplitudes of scalar and vector mesons
Energy Technology Data Exchange (ETDEWEB)
Li, B. -L.; Chang, L.; Ding, M.; Roberts, C. D.; Zong, H. -S.
2016-11-01
A symmetry-preserving truncation of the two-body light-quark bound-state problem in relativistic quantum field theory is used to calculate the leading-twist parton distribution amplitudes (PDAs) of scalar systems, both ground-state and radial excitations, and the radial excitations of vector mesons. Owing to the fact that the scale-independent leptonic decay constant of a scalar meson constituted from equal-mass valence-constituents vanishes, it is found that the PDA of a given scalar system possesses one more zero than that of an analogous vector meson. Consequently, whereas the mean light-front relative momentum of the valence-constituents within a vector meson is zero, that within a scalar meson is large, an outcome which hints at a greater role for light-front angular momentum in systems classified as P-wave in quantum mechanical models. Values for the scale-dependent decay constants of ground-state scalar and vector systems are a by-product of this analysis, and they turn out to be roughly equal, viz. ≃ 0.2 GeV at an hadronic scale. In addition, it is confirmed that the dilation characterising ground-state PDAs is manifest in the PDAs of radial excitations too. The impact of SU(3)-flavour symmetry breaking is also considered. When compared with pseudoscalar states, it is a little stronger in scalar systems, but the size is nevertheless determined by the flavour-dependence of dynamical chiral symmetry breaking and the PDAs are still skewed toward the heavier valence-quark in asymmetric systems.
Shell model for time-correlated random advection of passive scalars
DEFF Research Database (Denmark)
Andersen, Ken Haste; Muratore-Ginanneschi, P.
1999-01-01
We study a minimal shell model for the advection of a passive scalar by a Gaussian time-correlated velocity field. The anomalous scaling properties of the white noise limit are studied analytically. The effect of the time correlations are investigated using perturbation theory around the white...... noise limit and nonperturbatively by numerical integration. The time correlation of the velocity field is seen to enhance the intermittency of the passive scalar. [S1063-651X(99)07711-9]....
A new approach to exact solutions construction in scalar cosmology with a Gauss-Bonnet term
Fomin, I. V.; Chervon, S. V.
2017-08-01
We study the cosmological model based on Einstein-Gauss-Bonnet gravity with non-minimal coupling of a scalar field to a Gauss-Bonnet term in four-dimensional (4D) Friedmann universe. We show how constructing the exact solutions by the method based on a confrontation of the Hubble parameter in the model under consideration is achieved with that in a standard scalar field inflationary cosmology.
Low energy constraints and scalar leptoquarks⋆
Directory of Open Access Journals (Sweden)
Fajfer Svjetlana
2014-01-01
Full Text Available The presence of a colored weak doublet scalar state with mass below 1 TeV can provide an explanation of the observed branching ratios in B → D(∗τντ decays. Constraints coming from Z → bb̄, muon g − 2, lepton flavor violating decays are derived. The colored scalar is accommodated within 45 representation of SU(5 group of unification. We show that presence of color scalar can improve mass relations in the up-type quark sector mass. Impact of the colored scalar embedding in 45-dimensional representation of SU(5 on low-energy phenomenology is also presented.
Charged composite scalar dark matter
Balkin, Reuven; Ruhdorfer, Maximilian; Salvioni, Ennio; Weiler, Andreas
2017-11-01
We consider a composite model where both the Higgs and a complex scalar χ, which is the dark matter (DM) candidate, arise as light pseudo Nambu-Goldstone bosons (pNGBs) from a strongly coupled sector with TeV scale confinement. The global symmetry structure is SO(7)/SO(6), and the DM is charged under an exact U(1)DM ⊂ SO(6) that ensures its stability. Depending on whether the χ shift symmetry is respected or broken by the coupling of the top quark to the strong sector, the DM can be much lighter than the Higgs or have a weak-scale mass. Here we focus primarily on the latter possibility. We introduce the lowest-lying composite resonances and impose calculability of the scalar potential via generalized Weinberg sum rules. Compared to previous analyses of pNGB DM, the computation of the relic density is improved by fully accounting for the effects of the fermionic top partners. This plays a crucial role in relaxing the tension with the current DM direct detection constraints. The spectrum of resonances contains exotic top partners charged under the U(1)DM, whose LHC phenomenology is analyzed. We identify a region of parameters with f = 1.4 TeV and 200 GeV ≲ m χ ≲ 400 GeV that satisfies all existing bounds. This DM candidate will be tested by XENON1T in the near future.
Scalar conservation and boundedness in simulations of compressible flow
Subbareddy, Pramod K.; Kartha, Anand; Candler, Graham V.
2017-11-01
With the proper combination of high-order, low-dissipation numerical methods, physics-based subgrid-scale models, and boundary conditions it is becoming possible to simulate many combustion flows at relevant conditions. However, non-premixed flows are a particular challenge because the thickness of the fuel/oxidizer interface scales inversely with Reynolds number. Sharp interfaces can also be present in the initial or boundary conditions. When higher-order numerical methods are used, there are often aphysical undershoots and overshoots in the scalar variables (e.g. passive scalars, species mass fractions or progress variable). These numerical issues are especially prominent when low-dissipation methods are used, since sharp jumps in flow variables are not always coincident with regions of strong variation in the scalar fields: consequently, special detection mechanisms and dissipative fluxes are needed. Most numerical methods diffuse the interface, resulting in artificial mixing and spurious reactions. In this paper, we propose a numerical method that mitigates this issue. We present methods for passive and active scalars, and demonstrate their effectiveness with several examples.
Cosmological Evolution of Statistical System of Scalar Charged Particles
Ignat'ev, Yurii; Mikhailov, Mikhail; Ignatyev, Dmitry
2014-01-01
In the paper we consider the macroscopic model of plasma of scalar charged particles, obtained by means of the statistical averaging of the microscopic equations of particle dynamics in a scalar field. On the basis of kinetic equations, obtained from averaging, and their strict integral consequences, a self-consistent set of equations is formulated which describes the self-gravitating plasma of scalar charged particles. It was obtained the corresponding closed cosmological model which also was numerically simulated for the case of one-component degenerated Fermi gas and two-component Boltzmann system. It was shown that results depend weakly on the choice of a statistical model. Two specific features of cosmological evolution of a statistical system of scalar charged particles were obtained with respect to cosmological evolution of the minimal interaction models: appearance of giant bursts of invariant cosmological acceleration $\\Omega$ at the time interval $8\\cdot10^3\\div2\\cdot10^4 t_{Pl}$ and strong heating ...
Subfilter scalar-flux vector orientation in homogeneous isotropic turbulence.
Verma, Siddhartha; Blanquart, G
2014-06-01
The geometric orientation of the subfilter-scale scalar-flux vector is examined in homogeneous isotropic turbulence. Vector orientation is determined using the eigenframe of the resolved strain-rate tensor. The Schmidt number is kept sufficiently large so as to leave the velocity field, and hence the strain-rate tensor, unaltered by filtering in the viscous-convective subrange. Strong preferential alignment is observed for the case of Gaussian and box filters, whereas the sharp-spectral filter leads to close to a random orientation. The orientation angle obtained with the Gaussian and box filters is largely independent of the filter width and the Schmidt number. It is shown that the alignment direction observed numerically using these two filters is predicted very well by the tensor-diffusivity model. Moreover, preferred alignment of the scalar gradient vector in the eigenframe is shown to mitigate any probable issues of negative diffusivity in the tensor-diffusivity model. Consequentially, the model might not suffer from solution instability when used for large eddy simulations of scalar transport in homogeneous isotropic turbulence. Further a priori tests indicate poor alignment of the Smagorinsky and stretched vortex model predictions with the exact subfilter flux. Finally, strong filter dependence of subfilter scalar-flux orientation suggests that explicit filtering may be preferable to implicit filtering in large eddy simulations.
Probing Scalar Couplings Through Tests Of The Equivalence Principle
Chen, J
2005-01-01
It could be that our universe contains one or more nearly-massless neutral scalars, either as low energy relics of the UV complete theory, or as dynamical dark energy as called upon by observations. Here we discuss phenomenological ramifications of the coupling of a light scalar to the Standard Model. More precisely, we argue that low energy effects of this scalar are dominated by its linear couplings to gauge field kinetic terms and to fermion mass terms, which could then source fifth forces and induce variations in the 'constants.' We determine the limits on each of these couplings, first by determining the strength of the source from each sector. We find that couplings to the gluon kinetic term and to the strange quark mass term are most constrained by current null results for long range composition dependent fifth forces. Should such as detection occur, it would most likely arise from couplings to these sectors. If we are fortunate enough to make multiple measurements of scalar forces with test body pairs...
Scalar resonances as two-quark systems
Energy Technology Data Exchange (ETDEWEB)
Shabalin, E.P.
1985-07-01
On the basis of a theory with an effective U(3)xU(3)-symmetric chiral Lagrangian it is possible to determine the properties of two-quark scalar mesons and to show that the scalar resonances delta(980) and k(1240) can be treated as P-wave states of the q-barq system.
Psycholinguistic and Neurolinguistic Investigations of Scalar Implicature
Politzer-Ahles, Stephen
2013-01-01
The present study examines the representation and composition of meaning in scalar implicatures. Scalar implicature is the phenomenon whereby the use of a less informative term (e.g., "some") is inferred to mean the negation of a more informative term (e.g., to mean "not all"). The experiments reported here investigate how the…
Scalar Potential Model of light
Hodge, John
2008-04-01
Some observations of light are inconsistent with a wave--like model. Other observations of light are inconsistent with a particle--like model. A model of light is proposed wherein Newton's and Democritus's speculations are combined with the cosmological scalar potential model (SPM). The SPM was tested by confrontation with observations of galaxy HI rotation curves (RCs), asymmetric RCs, redshift, discrete redshift, galaxy central mass, and central velocity dispersion; and with observations of the Pioneer Anomaly. The resulting model of light will be tested by numerical simulation of a photon behaving in a wave-like manner such as diffusion, interference, reflection, spectrography, and the Afshar experiment. Although the SPM light model requires more work, early results are beginning to emerge that suggest possible tests because a few predictions are inconsistent with both the current particle and wave models of light and that suggest a re-interpretation of the equations of quantum mechanics.
Phase space analysis for a scalar-tensor model with kinetic and Gauss-Bonnet couplings
Granda, L N
2016-01-01
We study the phase space for an scalar-tensor string inspired model of dark energy with non minimal kinetic and Gauss Bonnet couplings. The form of the scalar potential and of the coupling terms is of the exponential type, which give rise to appealing cosmological solutions. The critical points describe a variety of cosmological scenarios that go from matter or radiation dominated universe to dark energy dominated universe. There were found trajectories in the phase space departing from unstable or saddle fixed points and arriving to the stable scalar field dominated point corresponding to late-time accelerated expansion.
Quantum tunneling from rotating black holes with scalar hair in three dimensions
Energy Technology Data Exchange (ETDEWEB)
Sakalli, I.; Gursel, H. [Eastern Mediterranean University, Department of Physics, Mersin-10 (Turkey)
2016-06-15
We study the Hawking radiation of scalar and Dirac particles (fermions) emitted from a rotating scalar hair black hole (RSHBH) within the context of three dimensional (3D) Einstein gravity using non-minimally coupled scalar field theory. Amalgamating the quantum tunneling approach with the Wentzel-Kramers-Brillouin approximation, we obtain the tunneling rates of the outgoing particles across the event horizon. Inserting the resultant tunneling rates into the Boltzmann formula, we then obtain the Hawking temperature (T{sub H}) of the 3D RSHBH. (orig.)
Scalar Aharonov–Bohm Phase in Ramsey Atom Interferometry under Time-Varying Potential
Directory of Open Access Journals (Sweden)
Atsuo Morinaga
2016-08-01
Full Text Available In a Ramsey atom interferometer excited by two electromagnetic fields, if atoms are under a time-varying scalar potential during the interrogation time, the phase of the Ramsey fringes shifts owing to the scalar Aharonov–Bohm effect. The phase shift was precisely examined using a Ramsey atom interferometer with a two-photon Raman transition under the second-order Zeeman potential, and a formula for the phase shift was derived. Using the derived formula, the frequency shift due to the scalar Aharonov–Bohm effect in the frequency standards utilizing the Ramsey atom interferometer was discussed.
Subgrid-scale stresses and scalar fluxes constructed by the multi-scale turnover Lagrangian map
AL-Bairmani, Sukaina; Li, Yi; Rosales, Carlos; Xie, Zheng-tong
2017-04-01
The multi-scale turnover Lagrangian map (MTLM) [C. Rosales and C. Meneveau, "Anomalous scaling and intermittency in three-dimensional synthetic turbulence," Phys. Rev. E 78, 016313 (2008)] uses nested multi-scale Lagrangian advection of fluid particles to distort a Gaussian velocity field and, as a result, generate non-Gaussian synthetic velocity fields. Passive scalar fields can be generated with the procedure when the fluid particles carry a scalar property [C. Rosales, "Synthetic three-dimensional turbulent passive scalar fields via the minimal Lagrangian map," Phys. Fluids 23, 075106 (2011)]. The synthetic fields have been shown to possess highly realistic statistics characterizing small scale intermittency, geometrical structures, and vortex dynamics. In this paper, we present a study of the synthetic fields using the filtering approach. This approach, which has not been pursued so far, provides insights on the potential applications of the synthetic fields in large eddy simulations and subgrid-scale (SGS) modelling. The MTLM method is first generalized to model scalar fields produced by an imposed linear mean profile. We then calculate the subgrid-scale stress, SGS scalar flux, SGS scalar variance, as well as related quantities from the synthetic fields. Comparison with direct numerical simulations (DNSs) shows that the synthetic fields reproduce the probability distributions of the SGS energy and scalar dissipation rather well. Related geometrical statistics also display close agreement with DNS results. The synthetic fields slightly under-estimate the mean SGS energy dissipation and slightly over-predict the mean SGS scalar variance dissipation. In general, the synthetic fields tend to slightly under-estimate the probability of large fluctuations for most quantities we have examined. Small scale anisotropy in the scalar field originated from the imposed mean gradient is captured. The sensitivity of the synthetic fields on the input spectra is assessed by
Stability equation and two-component Eigenmode for domain walls in scalar potential model
Energy Technology Data Exchange (ETDEWEB)
Dias, G.S.; Graca, E.L.; Rodrigues, R. de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]. E-mail: dias@cbpf.br; rafaelr@cbpf.br
2002-08-01
Supersymmetric quantum mechanics involving a two-component representation and two-component eigenfunctions is applied to obtain the stability equation associated to a potential model formulated in terms of two coupled real scalar fields. We investigate the question of stability by introducing an operator technique for the Bogomol'nyi-Prasad-Sommerfield (BPS) and non-BPS states on two domain walls in a scalar potential model with minimal N 1-supersymmetry. (author)
Vaithianathan, T.; Xia, Yanjun; Collins, Lance R.
2011-11-01
Xia and Collins [Physics of Fluids 23 (6):065107, 2011] developed the Bounded Stochastic Shell Mixing (BSSM) model that takes into account the multi-scale nature of the turbulent mixing process. They successfully applied the model to mixing of isotropic scalars with an initial double-delta probability density function (PDF). To enforce the scalar bounds, they introduced a novel ``zeroth mode'' that precisely cancels the inherently non-conservative random terms in the formulation. The extension of the model to the mixing of inhomogeneous scalar fields uses notional particles that move with a fluctuating velocity that is chosen to conform with the underlying turbulent energy spectrum. A consistency condition further requires the particle motion in the direction of the mean scalar gradient be carefully connected to the generation of the scalar fluctuation. The appropriate constraint has been derived and is enforced by the numerical algorithm. This new formulation has been applied to turbulent mixing of a scalar slab of specified thickness. (In the limit of zero thickness, this reduces to the classical ``line source'' problem.) We analyze multiple scalars so that differential diffusion can be considered as well as the effect of the thickness of the slab (relative to the turbulence length scales). The predictions of the BSSM model compare well with direct numerical simulations.
Gotoh, Toshiyuki
2012-11-01
Spectrum of passive scalar variance at very high Schmidt number up to 1000 in isotropic steady turbulence has been studied by using very high resolution DNS. Gaussian random force and scalar source which are isotropic and white in time are applied at low wavenumber band. Since the Schmidt number is very large, the system was integrated for 72 large eddy turn over time for the system to forgot the initial state. It is found that the scalar spectrum attains the asymptotic k-1 spectrum in the viscous-convective range and the constant CB is found to be 5.7 which is larger than 4.9 obtained by DNS under the uniform mean scalar gradient. Reasons for the difference are inferred as the Reynolds number effect, anisotropy, difference in the scalar injection, duration of time average, and the universality of the constant is discussed. The constant CB is also compared with the prediction by the Lagrangian statistical theory for the passive scalar. The scalar spectrum in the far diffusive range is found to be exponential, which is consistent with the Kraichnan's spectrum. However, the Kraichnan spectrum was derived under the assumption that the velocity field is white in time, therefore theoretical explanation of the agreement needs to be explored. Grant-in-Aid for Scientific Research No. 21360082, Ministry of Education, Culture, Sports, Science and Technology of Japan.
Gradient trajectory analysis of the scalar superlayer in a jet flow
Gampert, Markus; Schaefer, Philip; Peters, Norbert
2012-11-01
Based on planar high-speed Rayleigh scattering measurements of the mass fraction of propane discharging from a turbulent round jet into co-flowing carbon dioxide at nozzle based Reynolds numbers Re0 = 3 , 000 - 8 , 600 , we investigate the scalar superlayer. The latter is located between the fully turbulent part of the jet and the outer flow and has the so called turbulent/non-turbulent interface embedded within it. It is termed in analogy to the laminar superlayer introduced by Corrsin and Kistler (NACA Report 1244, 1955). Using scalar gradient trajectories, we partition the turbulent scalar field into the afore mentioned three regions according to an approach developed by Mellado et al. (J. Fluid Mech. 626:333-365, 2009) based on which we in a next step investigate conditioned zonal statistics of the scalar pdf as well as the scalar difference along the trajectory and its mean scalar value. Finally, we relate our results for the scalar superlayer on the one hand to the findings made in other experimental and numerical studies of the turbulent/non-turbulent interface and discuss them on the other hand in the context of the flamelet approach in turbulent non-premixed combustion. This work was funded by the Cluster of Excellence ``Tailor-Made Fuels from Biomass,'' which is funded by the Excellence Initiative of the German federal state governments to promote science and research at German universities.
Mixing among light scalar mesons and L=1 qq-bar scalar mesons
Energy Technology Data Exchange (ETDEWEB)
Teshima, T. [Department of Applied Physics, Chubu University, Kasugai (Japan)]. E-mail: teshima@isc.chubu.ac.jp; Kitamura, I.; Morisita, N. [Department of Applied Physics, Chubu University, Kasugai (Japan)
2002-06-01
Following the re-establishment of the {sigma}(500) and the {kappa}(900), the light scalar mesons a{sub 0}(980) and f{sub 0}(980) together with the {sigma}(500) and the {kappa}(900) are considered as the chiral scalar partner of pseudoscalar nonet in SU(3) chiral symmetry, and the high mass scalar mesons a{sub 0}(1450), K*{sub 0}(1430), f{sub 0}(1370) and f{sub 0}(1710) turned out to be considered as the L=1 qq-bar scalar mesons. We assume that the high mass of the L=1 qq-bar scalar mesons is caused by the mixing with the light scalar mesons. For the structure of the light scalar mesons, we adopted the qqq-barq-bar model in order to explain the 'scalar meson puzzle'. The inter-mixing between the light scalar nonet and the high mass L=1 qq-bar nonet and the intra-mixing among each nonet are analysed by including the glueball into the high mass scalar nonet. (author)
Scalar QED, NLO and PHOTOS Monte Carlo
Nanava, G.; Was, Z.
2006-01-01
Recently, QED bremsstrahlung in $B$-meson decays into pair of scalars (\\pi's and/or K's) is of interest. If experimental acceptance must be taken into account, PHOTOS Monte Carlo is often used in experimental simulations. We will use scalar QED to benchmark PHOTOS, even though this theory is of limited use for complex objects. We present the analytical form of the kernel used in the older versions of PHOTOS, and the new, exact (scalar QED) one. Matrix element and phase-space Jacobians are sep...
Structures and Intermittency in a Passive Scalar Model
Vergassola, M.; Mazzino, A.
1997-09-01
Perturbative expansions for intermittency scaling exponents in the Kraichnan passive scalar model [Phys. Rev. Lett. 72, 1016 (1994)] are investigated. A one-dimensional compressible model is considered for this purpose. High resolution Monte Carlo simulations using an Ito approach adapted to an advecting velocity field with a very short correlation time are performed and lead to clean scaling behavior for passive scalar structure functions. Perturbative predictions for the scaling exponents around the Gaussian limit of the model are derived as in the Kraichnan model. Their comparison with the simulations indicates that the scale-invariant perturbative scheme correctly captures the inertial range intermittency corrections associated with the intense localized structures observed in the dynamics.
Stationary scalar clouds around a BTZ black hole
Ferreira, Hugo R. C.; Herdeiro, Carlos A. R.
2017-10-01
We establish the existence of stationary clouds of massive test scalar fields around BTZ black holes. These clouds are zero-modes of the superradiant instability and are possible when Robin boundary conditions (RBCs) are considered at the AdS boundary. These boundary conditions are the most general ones that ensure the AdS space is an isolated system, and include, as a particular case, the commonly considered Dirichlet or Neumann-type boundary conditions (DBCs or NBCs). We obtain an explicit, closed form, resonance condition, relating the RBCs that allow the existence of normalizable (and regular on and outside the horizon) clouds to the system's parameters. Such RBCs never include pure DBCs or NBCs. We illustrate the spatial distribution of these clouds, their energy and angular momentum density for some cases. Our results show that BTZ black holes with scalar hair can be constructed, as the non-linear realization of these clouds.
Entangled scalar and tensor fluctuations during inflation
Energy Technology Data Exchange (ETDEWEB)
Collins, Hael; Vardanyan, Tereza [Department of Physics, Carnegie Mellon University,5000 Forbes Avenue, Pittsburgh, Pennsylvania (United States)
2016-11-29
We show how the choice of an inflationary state that entangles scalar and tensor fluctuations affects the angular two-point correlation functions of the T, E, and B modes of the cosmic microwave background. The propagators for a state starting with some general quadratic entanglement are solved exactly, leading to predictions for the primordial scalar-scalar, tensor-tensor, and scalar-tensor power spectra. These power spectra are expressed in terms of general functions that describe the entangling structure of the initial state relative to the standard Bunch-Davies vacuum. We illustrate how such a state would modify the angular correlations in the CMB with a simple example where the initial state is a small perturbation away from the Bunch-Davies state. Because the state breaks some of the rotational symmetries, the angular power spectra no longer need be strictly diagonal.
Symmetry Breaking in a random passive scalar
Kilic, Zeliha; McLaughlin, Richard; Camassa, Roberto
2017-11-01
We consider the evolution of a decaying passive scalar in the presence of a gaussian white noise fluctuating shear flow. We focus on deterministic initial data and establish the short, intermediate, and long time symmetry properties of the evolving point wise probability measure for the random passive scalar. Analytical results are compared directly to Monte Carlo simulations. Time permitting we will compare the predictions to experimental observations.
Numerical simulations of stellar collapse in scalar-tensor theories of gravity
Gerosa, Davide; Ott, Christian D
2016-01-01
We present numerical-relativity simulations of spherically symmetric core collapse and compact-object formation in scalar-tensor theories of gravity. The additional scalar degree of freedom introduces a propagating monopole gravitational-wave mode. Detection of monopole scalar waves with current and future gravitational-wave experiments may constitute smoking gun evidence for strong-field modifications of General Relativity. We collapse both polytropic and more realistic pre-supernova profiles using a high-resolution shock-capturing scheme and an approximate prescription for the nuclear equation of state. The most promising sources of scalar radiation are protoneutron stars collapsing to black holes. In case of a Galactic core collapse event forming a black hole, Advanced LIGO may be able to place independent constraints on the parameters of the theory at a level comparable to current Solar-System and binary-pulsar measurements. In the region of the parameter space admitting spontaneously scalarised stars, tr...
Two component WIMP-FImP dark matter model with singlet fermion, scalar and pseudo scalar
Energy Technology Data Exchange (ETDEWEB)
Dutta Banik, Amit; Pandey, Madhurima; Majumdar, Debasish [Saha Institute of Nuclear Physics, HBNI, Astroparticle Physics and Cosmology Division, Kolkata (India); Biswas, Anirban [Harish Chandra Research Institute, Allahabad (India)
2017-10-15
We explore a two component dark matter model with a fermion and a scalar. In this scenario the Standard Model (SM) is extended by a fermion, a scalar and an additional pseudo scalar. The fermionic component is assumed to have a global U(1){sub DM} and interacts with the pseudo scalar via Yukawa interaction while a Z{sub 2} symmetry is imposed on the other component - the scalar. These ensure the stability of both dark matter components. Although the Lagrangian of the present model is CP conserving, the CP symmetry breaks spontaneously when the pseudo scalar acquires a vacuum expectation value (VEV). The scalar component of the dark matter in the present model also develops a VEV on spontaneous breaking of the Z{sub 2} symmetry. Thus the various interactions of the dark sector and the SM sector occur through the mixing of the SM like Higgs boson, the pseudo scalar Higgs like boson and the singlet scalar boson. We show that the observed gamma ray excess from the Galactic Centre as well as the 3.55 keV X-ray line from Perseus, Andromeda etc. can be simultaneously explained in the present two component dark matter model and the dark matter self interaction is found to be an order of magnitude smaller than the upper limit estimated from the observational results. (orig.)
Cosmological Dynamics of f(R) Gravity Scalar Degree of Freedom in Einstein Frame
Goswami, Umananda Dev; Deka, Kabita
2013-12-01
f(R) gravity models belong to an important class of modified gravity models where the late time cosmic accelerated expansion is considered as a manifestation of the large scale modification of the force of gravity. f(R) gravity models can be expressed in terms of a scalar degree of freedom by redefinition of model's variable. The conformal transformation of the action from Jordan frame to Einstein frame makes the scalar degree of freedom more explicit and can be studied conveniently. We have investigated the features of the scalar degree of freedoms and the consequent cosmological implications of the power-law (ξRn) and the Starobinsky (disappearing cosmological constant) f(R) gravity models numerically in the Einstein frame. Both the models show interesting behavior of their scalar degree of freedom and could produce the accelerated expansion of the universe in the Einstein frame with the negative equation of state of the scalar field. However, the scalar field potential for the power-law model is the well-behaved function of the field, whereas the potential becomes flat for higher value of field in the case of the Starobinsky model. Moreover, the equation of state of the scalar field for the power-law model is always negative and less than -1/3, which corresponds to the behavior of the dark energy, that produces the accelerated expansion of the universe. This is not always the case for the Starobinsky model. At late times, the Starobinsky model behaves as cosmological constant Λ as behaves by power-law model for the values of n → 2 at all times.
Bounded scalar perturbations in bouncing brane world cosmologies
Maier, Rodrigo; Pace, Francesco; Soares, Ivano Damião
2013-11-01
We examine the dynamics of scalar perturbations in closed Friedmann-Lemaître-Robertson-Walker universes in the framework of brane world theory with a timelike extra dimension. In this scenario, the unperturbed Friedmann equations contain additional terms arising from the bulk-brane interaction that implement nonsingular bounces in the models with a cosmological constant and noninteracting perfect fluids. The structure of the phase space of the models allows for two basic configurations, namely, one bounce solutions and eternal universes. Assuming that the matter content of the model is given by dust and radiation, we derive the dynamical field equations for scalar hydrodynamical perturbations considering either a conformally flat (de Sitter) bulk or a perturbed bulk. The dynamical system built with these equations is extremely involved. Nevertheless, in this paper we perform a numerical analysis which can shed some light on the study of cosmological scalar perturbations in bouncing brane world models. From a mathematical point of view we show that although the bounce enhances the amplitudes of scalar perturbations for one bounce models in the case of a de Sitter bulk, the amplitudes of the perturbations remain sufficiently small and bounded relative to the background values up to a certain scale. For one bounce models in the case of a perturbed bulk the amplitudes of all perturbations (apart from the Weyl fluid energy density) remain sufficiently small and bounded relative to the background values for any scale of the perturbations. We also discuss and compare the stability and bounded behavior of the perturbations in the late accelerated phase of one bounce solutions. For eternal universes we argue that some of these features are maintained only for early times (typically of the order of the first bounce). In this sense we show that eternal solutions are highly unstable configurations considering the background model of this paper.
Immirzi parameter without Immirzi ambiguity: Conformal loop quantization of scalar-tensor gravity
Veraguth, Olivier J.; Wang, Charles H.-T.
2017-10-01
Conformal loop quantum gravity provides an approach to loop quantization through an underlying conformal structure i.e. conformally equivalent class of metrics. The property that general relativity itself has no conformal invariance is reinstated with a constrained scalar field setting the physical scale. Conformally equivalent metrics have recently been shown to be amenable to loop quantization including matter coupling. It has been suggested that conformal geometry may provide an extended symmetry to allow a reformulated Immirzi parameter necessary for loop quantization to behave like an arbitrary group parameter that requires no further fixing as its present standard form does. Here, we find that this can be naturally realized via conformal frame transformations in scalar-tensor gravity. Such a theory generally incorporates a dynamical scalar gravitational field and reduces to general relativity when the scalar field becomes a pure gauge. In particular, we introduce a conformal Einstein frame in which loop quantization is implemented. We then discuss how different Immirzi parameters under this description may be related by conformal frame transformations and yet share the same quantization having, for example, the same area gaps, modulated by the scalar gravitational field.
Construction and physical properties of Kerr black holes with scalar hair
Herdeiro, Carlos
2015-01-01
Kerr black holes with scalar hair are solutions of the Einstein-Klein-Gordon field equations describing regular (on and outside an event horizon), asymptotically flat black holes with scalar hair (arXiv:1403.2757). These black holes interpolate continuously between the Kerr solution and rotating boson stars in D=4 spacetime dimensions. Here we provide details on their construction, discussing properties of the ansatz, the field equations, the boundary conditions and the numerical strategy. Then, we present an overview of the parameter space of the solutions, and describe in detail the space-time structure of the black holes exterior geometry and of the scalar field for a sample of reference solutions. Phenomenological properties of potential astrophysical interest are also discussed, and the stability properties and possible generalizations are commented on. As supplementary material to this paper we make available numerical data files for the sample of reference solutions discussed, for public use.
Quartet-metric general relativity: scalar graviton, dark matter, and dark energy
Energy Technology Data Exchange (ETDEWEB)
Pirogov, Yury F. [SRC Institute for High Energy Physics of NRC Kurchatov Institute, Protvino (Russian Federation)
2016-04-15
General relativity extended through a dynamical scalar quartet is proposed as a theory of the scalar-vector-tensor gravity, generically describing the unified gravitational dark matter (DM) and dark energy (DE). The implementation in the weak-field limit of the Higgs mechanism for the extended gravity, with a redefinition of metric field, is exposed in a generally covariant form. Under a natural restriction on the parameters, the redefined theory possesses in the linearized approximation a residual transverse-diffeomorphism invariance, and consistently comprises the massless tensor graviton and a massive scalar one as a DM particle. The number of adjustable parameters in the full nonlinear theory and a partial decoupling of the latter from its weak-field limit noticeably extend the perspectives for the unified description of the gravity DM and DE in the various phenomena at the different scales. (orig.)
One-loop renormalization of Resonance Chiral Theory: scalar and pseudoscalar resonances
Energy Technology Data Exchange (ETDEWEB)
Rosell, Ignasi [Departament de FIsica Teorica, IFIC, CSIC - Universitat de Valencia, Edifici d' Instituts de Paterna, Apt. Correus 22085, E-46071 Valencia (Spain); Ruiz-FemenIa, Pedro [Theory Division, Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Portoles, Jorge [Departament de FIsica Teorica, IFIC, CSIC - Universitat de Valencia, Edifici d' Instituts de Paterna, Apt. Correus 22085, E-46071 Valencia (Spain)
2005-12-15
We consider the Resonance Chiral Theory with one multiplet of scalar and pseudoscalar resonances, up to bilinear couplings in the resonance fields, and evaluate its {beta}-function at one-loop with the use of the background field method. Thus we also provide the full set of operators that renormalize the theory at one loop and render it finite.
Oscillation modes of rapidly rotating neutron stars in scalar-tensor theories of gravity
Yazadjiev, Stoytcho S.; Doneva, Daniela D.; Kokkotas, Kostas D.
2017-09-01
We perform the first study of the oscillation frequencies of rapidly rotating neutron stars in alternative theories of gravity, focusing mainly on the fundamental f modes. We concentrated on a particular class of alternative theories—the (massive) scalar-tensor theories. The generalization to rapid rotation is important because on one hand the rapid rotation can magnify the deviations from general relativity compared to the static case and on the other hand some of the most efficient emitters of gravitational radiation, such as the binary neutron star merger remnants, are supposed to be rotating close to their Kepler (mass-shedding) limits shortly after their formation. We have constructed several sequences of models starting from the nonrotating case and reaching up to the Kepler limit, with different values of the scalar-tensor theory coupling constant and the scalar field mass. The results show that the deviations from pure Einstein's theory can be significant, especially in the case of nonzero scalar field mass. An important property of the oscillation modes of rapidly rotating stars is that they can become secularly unstable due to the emission of gravitational radiation, the so-called Chandrasekhar-Friedman-Schutz instability. Such unstable modes are efficient emitters of gravitational radiation. Our studies show that the inclusion of a nonzero scalar field would decrease the threshold value of the normalized angular momentum where this instability starts to operate, but the growth time of the instability seems to be increased compared to pure general relativity.
Spinning scalar solitons in anti-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Radu, Eugen, E-mail: eugen.radu@uni-oldenburg.de [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Subagyo, Bintoro [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany)
2012-10-31
We present spinning Q-balls and boson stars in four-dimensional anti-de Sitter spacetime. These are smooth, horizonless solutions for gravity coupled to a massive complex scalar field with a harmonic dependence on time and the azimuthal angle. Similar to the flat spacetime configurations, the angular momentum is quantized. We find that a class of solutions with a self-interaction potential has a limit corresponding to static solitons with axial symmetry only. An exact solution describing spherically symmetric Q-balls in a fixed AdS background is also discussed.
The cosmological backreaction: gauge (in)dependence, observers and scalars
Energy Technology Data Exchange (ETDEWEB)
Marozzi, G., E-mail: giovanni.marozzi@college-de-france.fr [Collège de France, 11 Place M. Berthelot, 75005 Paris (France)
2011-01-01
We discuss several issues related to a recent proposal for defining classical spatial averages to be used in the so-called cosmological backreaction problem. In the large averaging-volume limit all gauge dependence disappears and different averages can be univocally characterized by the observers associated with different scalar fields. The relation between such averaging procedure and the standard one is emphasized and a gauge invariant way to select different observers is presented. For finite averaging volumes we show that, within our proposal, a residual gauge dependence is left, but is suppressed by several effects.
Dimensionality influence on passive scalar transport
Energy Technology Data Exchange (ETDEWEB)
Iovieno, M; Ducasse, L; Tordella, D, E-mail: michele.iovieno@polito.it [Dipartimento di Ingegneria Aeronautica e Spaziale, Politecnico di Torino (Italy)
2011-12-22
We numerically investigate the advection of a passive scalar through an interface placed inside a decaying shearless turbulent mixing layer. We consider the system in both two and three dimensions. The dimensionality produces a different time scaling of the diffusion, which is faster in the two-dimensional case. Two intermittent fronts are generated at the margins of the mixing layer. During the decay these fronts present a sort of propagation in both the direction of the scalar flow and the opposite direction. In two dimensions, the propagation of the fronts exhibits a significant asymmetry with respect to the initial position of the interface and is deeper for the front merged in the high energy side of the mixing. In three dimensions, the two fronts remain nearly symmetrically placed. Results concerning the scalar spectra exponents are also presented.
New Experimental limit on Optical Photon Coupling to Neutral, Scalar Bosons
Energy Technology Data Exchange (ETDEWEB)
Afanaciev, Andrei; Afanasev, Andrei; Afanaciev, Andrei; Afanasev, Andrei; Baker, O.; Beard, Kevin; Biallas, George; Boyce, James; Minarni, Minarni; Ramdon, Roopchan; Michelle D. Shinn; Slocum, P.
2008-09-01
We report on the first results of a sensitive search for scalar coupling of photons to a light neutral boson in the mass range of approximately 1.0 milli-electron volts and coupling strength greater than 10$^-6$ GeV$^-1$ using optical photons. This was a photon regeneration experiment using the "light shining through a wall" technique in which laser light was passed through a strong magnetic field upstream of an optical beam dump; regenerated laser light was then searched for downstream of a second magnetic field region optically shielded from the former. Our results show no evidence for scalar coupling in this region of parameter space.
CSW rules for a massive scalar
DEFF Research Database (Denmark)
Boels, Rutger Herman; Schwinn, Christian
2008-01-01
We derive the analog of the Cachazo-Svrcek-Witten (CSW) diagrammatic Feynman rules for four-dimensional Yang-Mills gauge theory coupled to a massive colored scalar. The mass term is shown to give rise to a new tower of vertices in addition to the CSW vertices for massless scalars in non......-supersymmetric theories. The rules are derived directly from an action, once through a canonical transformation within light-cone Yang-Mills and once by the construction of a twistor action. The rules are tested against known results in several examples and are used to simplify the proof of on-shell recursion relations...
Fast and slow thermal processes in harmonic scalar lattices
Kuzkin, V. A.; Krivtsov, A. M.
2017-12-01
An approach for analytical description of thermal processes in harmonic lattices is presented. We cover longitudinal and transverse vibrations of chains and out-of-plane vibrations of two-dimensional lattices with interactions of an arbitrary number of neighbors. The motion of each particle is governed by a single scalar equation and therefore the notion ‘scalar lattice’ is used. The evolution of initial temperature field in an infinite lattice is investigated. An exact equation describing the evolution is derived. Continualization of this equation with respect to spatial coordinates is carried out. The resulting continuum equation is solved analytically. The solution shows that the kinetic temperature is represented as the sum of two terms, one describing short time behavior, the other large time behavior. At short times, the temperature performs high-frequency oscillations caused by redistribution of energy among kinetic and potential forms (fast process). Characteristic time of this process is of the order of ten periods of atomic vibrations. At large times, changes of the temperature are caused by ballistic heat transfer (slow process). The temperature field is represented as a superposition of waves having the shape of initial temperature distribution and propagating with group velocities dependent on the wave vector. Expressions describing fast and slow processes are invariant with respect to substitution t by -t . However, examples considered in the paper demonstrate that these processes are irreversible. Numerical simulations show that presented theory describes the evolution of temperature field at short and large time scales with high accuracy.
Four-dimensional black holes with scalar hair in nonlinear electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Barrientos, Jose [Universidad de Concepcion, Departamento de Fisica, Concepcion (Chile); Universidad Catolica del Norte, Departamento de Ensenanza de las Ciencias Basicas, Coquimbo (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica y Astronomia, Facultad de Ciencias, La Serena (Chile)
2016-12-15
We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and a U(1) nonlinear electromagnetic field. Solving analytically and numerically the coupled system for both power-law and Born-Infeld type electrodynamics, we find charged hairy black hole solutions. Then we study the thermodynamics of these solutions and we find that at a low temperature the topological charged black hole with scalar hair is thermodynamically preferred, whereas the topological charged black hole without scalar hair is thermodynamically preferred at a high temperature for power-law electrodynamics. Interestingly enough, these phase transitions occur at a fixed critical temperature and do not depend on the exponent p of the nonlinear electrodynamics. (orig.)
Examples of reflection positive field theories
Trinchero, R.
The requirement of reflection positivity (RP) for Euclidean field theories is considered. This is done for the cases of a scalar field, a higher derivative scalar field theory and the scalar field theory defined on a non-integer dimensional space (NIDS). It is shown that regarding RP, the analytical structure of the corresponding Schwinger functions plays an important role. For the higher derivative scalar field theory, RP does not hold. However for the scalar field theory on a NIDS, RP holds in a certain range of dimensions where the corresponding Minkowskian field is defined on a Hilbert space with a positive definite scalar product that provides a unitary representation of the Poincaré group. In addition, and motivated by the last example, it is shown that, under certain conditions, one can construct non-local reflection positive Euclidean field theories starting from the corrected two point functions of interacting local field theories.
A consistent scalar-tensor cosmology for inflation, dark energy and the Hubble parameter
Energy Technology Data Exchange (ETDEWEB)
Wang, C.H.-T., E-mail: c.wang@abdn.ac.uk [Department of Physics, University of Aberdeen, King' s College, Aberdeen AB24 3UE (United Kingdom); Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Reid, J.A. [Department of Physics, University of Aberdeen, King' s College, Aberdeen AB24 3UE (United Kingdom); Murphy, A.St.J. [School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Rodrigues, D.; Al Alawi, M. [Department of Physics, University of Aberdeen, King' s College, Aberdeen AB24 3UE (United Kingdom); Bingham, R. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Mendonça, J.T. [IPFN, Instituto Superior Técnico, 1049-001 Lisboa (Portugal); Davies, T.B. [Department of Physics, University of Aberdeen, King' s College, Aberdeen AB24 3UE (United Kingdom)
2016-11-25
A Friedman cosmology is investigated based on scalar-tensor gravitation with general metric coupling and scalar potential functions. We show that for a broad class of such functions, the scalar field can be dynamically trapped using a recently suggested mechanism. The trapped scalar can drive inflation and accelerated cosmic expansion, compatible with standard requirements. The inflationary phase admits a natural exit with a value of the Hubble parameter dictated by the duration of inflation in a parameter independent manner. For inflationary duration consistent with the GUT description, the resulting Hubble parameter is found to be consistent with its observed value. - Highlights: • First model for inflation and dark energy in cosmology and core-collapse supernovae in astronomy to be unified under the same theory. • Achieved with a natural simple extension of Einstein's General Relativity using a new scalar field. • Potentially far-researching consequences in cosmology for dark matter, dark energy and inflation, testable through core-collapse supernovae.
Analysis of soft wall AdS/QCD potentials to obtain the melting temperature of scalar hadrons
Vega, Alfredo; Ibañez, Adolfo
2017-11-01
We consider an analysis of potentials related to Schrödinger-type equations for scalar fields in a 5D AdS black hole background with dilaton in order to obtain melting temperatures for different hadrons in a thermal bath. The approach does not consider calculations of spectral functions, and it is easy to yield results for hadrons with an arbitrary number of constituents. We present results for scalar mesons, glueballs, hybrid mesons and tetraquarks, and we show that mesons are more resistant to being melted in a thermal bath than other scalar hadrons, and in general the melting temperature increases when hadrons contain heavy quarks.
Scalar absorption by charged rotating black holes
Leite, Luiz C. S.; Benone, Carolina L.; Crispino, Luís C. B.
2017-08-01
We compute numerically the absorption cross section of planar massless scalar waves impinging upon a Kerr-Newman black hole with different incidence angles. We investigate the influence of the black hole electric charge and angular momentum in the absorption spectrum, comparing our numerical computations with analytical results for the limits of high and low frequency.
Brane solutions sourced by a scalar with vanishing potential and classification of scalar branes
Energy Technology Data Exchange (ETDEWEB)
Cadoni, Mariano [Dipartimento di Fisica, Università di Cagliari,Cittadella Universitaria, 09042 Monserrato (Italy); INFN, Sezione di Cagliari,Cagliari (Italy); Franzin, Edgardo [Dipartimento di Fisica, Università di Cagliari,Cittadella Universitaria, 09042 Monserrato (Italy); INFN, Sezione di Cagliari,Cagliari (Italy); CENTRA, Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa,Avenida Rovisco Pais 1, 1049 Lisboa (Portugal); Serra, Matteo [Dipartimento di Matematica, Sapienza Università di Roma,Piazzale Aldo Moro 2, 00185 Roma (Italy)
2016-01-20
We derive exact brane solutions of minimally coupled Einstein-Maxwell-scalar gravity in d+2 dimensions with a vanishing scalar potential and we show that these solutions are conformal to the Lifshitz spacetime whose dual QFT is characterized by hyperscaling violation. These solutions, together with the AdS brane and the domain wall sourced by an exponential potential, give the complete list of scalar branes sourced by a generic potential having simple (scale-covariant) scaling symmetries not involving Galilean boosts. This allows us to give a classification of both simple and interpolating brane solution of minimally coupled Einstein-Maxwell-scalar gravity having no Schrödinger isometries, which may be very useful for holographic applications.
Scalar Implicatures: The psychological reality of scales
Directory of Open Access Journals (Sweden)
Alex de Carvalho
2016-10-01
Full Text Available Scalar implicatures, the phenomena where a sentence like The pianist played some Mozart sonatas is interpreted as The pianist did not play all Mozart sonatas have been given two different analyses. Neo-Griceans claim that this interpretation is based on lexical scales (e.g. , where the stronger term (e.g. all implies the weaker term (e.g. some, but the weaker term (e.g., some implicates the negation of the stronger term (i.e., some = not all. Post-Griceans deny that this is the case and offer a context-based inferential account for scalar implicatures. While scalar implicatures have been extensively investigated, with results apparently in favor of post-Gricean accounts, the psychological reality of lexical scales has not been put to the test. This is what we have done in the present experiment, with a lexical decision task using lexical scales in a masked priming paradigm. While Post-Gricean accounts do not attribute any role for lexical scales in the computation of scalar implicatures, Neo-Gricean accounts suggest that lexical scales are the core mechanism behind the computation of scalar implicatures, and predict that weaker terms in a scale should prime stronger terms more than the reverse because stronger words are necessary to the interpretation of weaker words, while stronger words can be interpreted independently of weaker words. Our results provided evidence in favor of the psychological existence of scales, leading to the first clear experimental support for the Neo-Gricean account.
Absorption of scalars by extremal black holes in string theory
Moura, Filipe
2017-09-01
We show that the low frequency absorption cross section of minimally coupled test massless scalar fields by extremal spherically symmetric black holes in d dimensions is equal to the horizon area, even in the presence of string-theoretical α ' corrections. Classically one has the relation σ = 4 GS between that absorption cross section and the black hole entropy. By comparing in each case the values of the horizon area and Wald's entropy, we discuss the validity of such relation in the presence of higher derivative corrections for extremal black holes in many different contexts: in the presence of electric and magnetic charges; for nonsupersymmetric and supersymmetric black holes; in d=4 and d=5 dimensions. The examples we consider seem to indicate that this relation is not verified in the presence of α ' corrections in general, although being valid in some specific cases (electrically charged maximally supersymmetric black holes in d=5). We argue that the relation σ = 4 GS should in general be valid for the absorption cross section of scalar fields which, although being independent from the black hole solution, have their origin from string theory, and therefore are not minimally coupled.
Tracking our universe to de Sitter by a Horndeski scalar
Germani, Cristiano; Martín-Moruno, Prado
2017-12-01
Assuming both that our Universe is evolving into a de Sitter space and a vanishing cosmological constant, leaves only the option that the observed acceleration is provided by a "kinetic" energy of a scalar field. From an effective field theory point of view, the absence of Ostrogradsky instabilities restricts the choice to shift-symmetric Horndeski theories. Within these theories, we find the conditions for the existence of a de Sitter critical point in a universe filled by matter, radiation and a Horndeski scalar. Moreover, we show that this point is a universal attractor and we provide the tracking trajectory. Therefore, if a de Sitter fixed point exists within these models, our Universe will eventually evolve into a de Sitter space. As an example, we have discussed the case of the combined Galileon-Slotheon system, in which the Galileon is kinetically non-minimal coupled to the Einstein tensor. Interestingly, we have also found that the tracker trajectory of this system does not follow previous literature assumptions.
One-loop renormalization of a gravity-scalar system
Energy Technology Data Exchange (ETDEWEB)
Park, I.Y. [Philander Smith College, Department of Applied Mathematics, Little Rock, AR (United States)
2017-05-15
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the ''mass'' term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information. (orig.)
Athermal fiber laser for the SWARM absolute scalar magnetometer
Fourcault, W.; Léger, J.-M.; Costes, V.; Fratter, I.; Mondin, L.
2017-11-01
The Absolute Scalar Magnetometer (ASM) developed by CEA-LETI/CNES is an optically pumped 4He magnetic field sensor based on the Zeeman effect and an electronic magnetic resonance whose effects are amplified by a laser pumping process [1-2]. Consequently, the role of the laser is to pump the 4He atoms at the D0 transition as well as to allow the magnetic resonance signal detection. The ASM will be the scalar magnetic reference instrument of the three ESA Swarm satellites to be launched in 2012 in order to carry out the best ever survey of the Earth magnetic field and its temporal evolution. The sensitivity and accuracy of this magnetometer based on 4He optical pumping depend directly on the characteristics of its light source, which is the key sub-system of the sensor. We describe in this paper the selected fiber laser architecture and its wavelength stabilization scheme. Its main performance in terms of spectral emission, optical power at 1083 nm and intensity noise characteristics in the frequency bands used for the operation of the magnetometer, are then presented. Environmental testing results (thermal vacuum cycling, vibrations, shocks and ageing) are also reported at the end of this paper.
Black holes with surrounding matter in scalar-tensor theories.
Cardoso, Vitor; Carucci, Isabella P; Pani, Paolo; Sotiriou, Thomas P
2013-09-13
We uncover two mechanisms that can render Kerr black holes unstable in scalar-tensor gravity, both associated with the presence of matter in the vicinity of the black hole and the fact that this introduces an effective mass for the scalar. Our results highlight the importance of understanding the structure of spacetime in realistic, astrophysical black holes in scalar-tensor theories.
Chameleons with Field Dependent Couplings
Brax, Philippe; Mota, David F; Nunes, Nelson J; Winther, Hans A
2010-01-01
Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power run-away potentials and field independent couplings to matter. In this paper we investigate field-theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for E\\"ot-Wash experiments, fifth-force searches and Casimir force experiments. Requiring that the scalar-field evades gravitational tests, we find that the coupling is sensitive to a mass-scale which is of order of the Hubble scale today.
Measurements of Scalar Power Spectra in High Schmidt Number Turbulent Jets
1992-11-09
1975). 6 Gibson, C. H.. "IKohnogorov similarity hy!potheses for scalar fields: sampling intermittent turbulent mixing in the ocean and galaxy ," Proc...34 J. Geophys. Res. 92, C5 , 5383-5404 (1987). 13 Komori, S.. Kanzaki, T., Murakami, Y., and Ueda, H., "Simultaneous measure- ments of instantaneous
Scalar perturbation in warm tachyon inflation in LQC in light of Plank and BICEP2
Directory of Open Access Journals (Sweden)
M.R. Setare
2014-12-01
Full Text Available We study warm-tachyon inflationary universe model in the context of the effective field theory of loop quantum cosmology. In slow-roll approximation the primordial perturbation spectrums for this model are calculated. We also obtain the general expressions of the tensor-to-scalar ratio and scalar spectral index. We develop this model by using exponential potential, the characteristics of this model are presented in great details. The parameters of the model are restricted by recent observational data from Planck, WMAP9 and BICEP2.
Analysis of CHAMP scalar magnetic data to identify ocean circulation signals
DEFF Research Database (Denmark)
Manoj, C.; Maus, S.; Kuvshinov, Alexei
signals at satellite altitude. We predict annual variation amplitudes in the scalar anomaly of the order of 0.3 nT. We compare these predictions with the particularly quiet CHAMP night-time scalar data, subtracting core, mantle, crustal, ocean tidal, and magnetospheric contributions to the field....... The residuals were further screened with Kp and Dst indices. Comparing the seasonal and annual harmonics of the predictions and observations, we find that the amplitude of the CHAMP residuals (about 0.5 nT) is already quite close to the prediction, with stronger signals over oceanic regions than over land...
Application of Arbitrary-Order Hilbert Spectral Analysis to Passive Scalar Turbulence
Energy Technology Data Exchange (ETDEWEB)
Huang, Y X; Lu, Z M; Liu, Y L [Shanghai Key Laboratory of Mechanics in Energy and Environment Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072 (China); Schmitt, F G [CNRS, Laboratory of Oceanology and Geosciences, UMR 8187, F-62930 Wimereux (France); Gagne, Y, E-mail: yongxianghuang@gmail.com [LEGI, CNRS/UJF/INPG, UMR 5519, 38041 Grenoble (France)
2011-12-22
In previous work [Huang et al., PRE 82, 26319, 2010], we found that the passive scalar turbulence field maybe less intermittent than what we believed before. Here we apply the same method, namely arbitrary-order Hilbert spectral analysis, to a passive scalar (temperature) time series with a Taylor's microscale Reynolds number Re{sub {lambda}} {approx_equal} 3000. We find that with increasing Reynolds number, the discrepancy of scaling exponents between Hilbert {xi}{sub {theta}}(q) and Kolmogorov-Obukhov-Corrsin (KOC) theory is increasing, and consequently the discrepancy between Hilbert and structure function could disappear at infinite Reynolds number.
Hydrogen Burning in Low Mass Stars Constrains Scalar-Tensor Theories of Gravity.
Sakstein, Jeremy
2015-11-13
The most general scalar-tensor theories of gravity predict a weakening of the gravitational force inside astrophysical bodies. There is a minimum mass for hydrogen burning in stars that is set by the interplay of plasma physics and the theory of gravity. We calculate this for alternative theories of gravity and find that it is always significantly larger than the general relativity prediction. The observation of several low mass red dwarf stars therefore rules out a large class of scalar-tensor gravity theories and places strong constraints on the cosmological parameters appearing in the effective field theory of dark energy.
Gravitino and scalar {tau}-lepton decays in supersymmetric models with broken R-parity
Energy Technology Data Exchange (ETDEWEB)
Hajer, Jan
2010-06-15
Mildly broken R-parity is known to provide a solution to the cosmological gravitino problem in supergravity extensions of the Standard Model. In this work we consider new effects occurring in the R-parity breaking Minimal Supersymmetric Standard Model including right-handed neutrino superfields. We calculate the most general vacuum expectation values of neutral scalar fields including left- and right-handed scalar neutrinos. Additionally, we derive the corresponding mass mixing matrices of the scalar sector. We recalculate the neutrino mass generation mechanisms due to right- handed neutrinos as well as by cause of R-parity breaking. Furthermore, we obtain a, so far, unknown formula for the neutrino masses for the case where both mechanisms are effective. We then constrain the couplings to bilinear R-parity violating couplings in order to accommodate R-parity breaking to experimental results. In order to constrain the family structure with a U(1){sub Q} flavor symmetry we furthermore embed the particle content into an SU(5) Grand Unified Theory. In this model we calculate the signal of decaying gravitino dark matter as well as the dominant decay channel of a likely NLSP, the scalar {tau}-lepton. Comparing the gravitino signal with results of the Fermi Large Area Telescope enables us to find a lower bound on the decay length of scalar {tau}-leptons in collider experiments. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan); Kume, Etsuo; Adachi, Masaaki; Ogasawara, Shinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan); Kawai, Wataru; Nemoto, Toshiyuki; Kawasaki, Nobuo; Ishizuki, Shigeru [Fujitsu Ltd., Tokyo (Japan)
2000-12-01
Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization part on scalar processors and the porting part. In this report, we describe the parallelization on scalar processors. In this parallelization on scalar processors part, the parallelization of Nucleon Meson Transport Code (NMTC), Differential Algebraic VLASOV code (DA-VLASOV) and Monte Carlo N-Particle transport code (MCNP4B2) on the Paragon system are described. (author)
Conformally coupled scalars, instantons and vacuum instability in AdS{sub 4}
Energy Technology Data Exchange (ETDEWEB)
De Haro, S. [King' s College London (United Kingdom). Dept. of Mathematics; Papadimitriou, I. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Petkou, A.C. [Crete Univ., Keraklion (Greece). Dept. of Physics
2006-11-15
We show that a scalar field conformally coupled to AdS gravity in four dimensions with a quartic self-interaction can be embedded into M-theory. The holographic effective action and effective potential are exactly calculated, allowing us to study non-perturbatively the stability of AdS{sub 4} in the presence of the conformally coupled scalar. It is shown that there exists a one-parameter family of conformal scalar boundary conditions for which the boundary theory has an unstable vacuum. In this case, the bulk theory has instanton solutions that mediate the decay of the AdS{sub 4} space. These results match nicely with the vacuum structure and the existence of instantons in an effective three-dimensional boundary model.
Gravitational localization of scalar zero modes in S U (5 )×Z2 branes
Pantoja, Nelson; Rojas, Rossana
2017-02-01
The fluctuations of five-dimensional self-gravitating non-Abelian kinks which arise from the breaking of the S U (5 )×Z2 -symmetric theory are analyzed within the context of braneworlds. While tensor and vector sectors of these fluctuations behave like its counterparts in the standard Abelian Z2 kinks, the mixing between the field excitations of the non-Abelian kink and the scalar components of the metric makes the pure scalar sector of the theory very interesting. The spectrum of these scalar fluctuations, which includes gravitationally trapped massless modes on the core of the wall associated with the broken symmetries, is discussed for the two classes of kinks that break S U (5 ) into its maximal subgroups.
Anisotropic Bulk Viscous String Cosmological Model in a Scalar-Tensor Theory of Gravitation
Directory of Open Access Journals (Sweden)
D. R. K. Reddy
2013-01-01
Full Text Available Spatially homogeneous, anisotropic, and tilted Bianchi type-VI0 model is investigated in a new scalar-tensor theory of gravitation proposed by Saez and Ballester (1986 when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. Exact solution of the highly nonlinear field equations is obtained using the following plausible physical conditions: (i scalar expansion of the space-time which is proportional to the shear scalar, (ii the barotropic equations of state for pressure and energy density, and (iii a special law of variation for Hubble’s parameter proposed by Berman (1983. Some physical and kinematical properties of the model are also discussed.
SuperDARN scalar radar equations
Berngardt, O I; Potekhin, A P
2016-01-01
The quadratic scalar radar equations are obtained for SuperDARN radars that are suitable for the analysis and interpretation of experimental data. The paper is based on a unified approach to the obtaining radar equations for the monostatic and bistatic sounding with use of hamiltonian optics and ray representation of scalar Green's function and without taking into account the polarization effects. The radar equation obtained is the sum of several terms corresponding to the propagation and scattering over the different kinds of trajectories, depending on their smoothness and the possibility of reflection from the ionosphere. It is shown that the monostatic sounding in the media with significant refraction, unlike the case of refraction-free media, should be analyzed as a combination of monostatic and bistatic scattering. This leads to strong dependence of scattering amplitude on background ionospheric density due to focusing mechanism and appearance of new (bistatic) areas of effective scattering with signific...
The light scalar mesons as tetraquarks
Directory of Open Access Journals (Sweden)
Gernot Eichmann
2016-02-01
Full Text Available We present a numerical solution of the four-quark Bethe–Salpeter equation for ground-state scalar tetraquarks with JPC=0++. We find that the four-body equation dynamically generates pseudoscalar-meson poles in the Bethe–Salpeter amplitude. The resulting tetraquarks are genuine four-quark states that are dominated by pseudoscalar meson–meson correlations. Diquark–antidiquark contributions are subleading because of their larger mass scale. In the light quark sector, the sensitivity of the tetraquark wave function to the pion poles leads to an isoscalar tetraquark mass Mσ∼350 MeV which is comparable to that of the σ/f0(500. The masses of its multiplet partners κ and a0/f0 follow a similar pattern. This provides support for a tetraquark interpretation of the light scalar meson nonet in terms of ‘meson molecules’.
Astrophysical constraints on singlet scalars at LHC
Hertzberg, Mark P.; Masoumi, Ali
2017-04-01
We consider the viability of new heavy gauge singlet scalar particles at colliders such as the LHC . Our original motivation for this study came from the possibility of a new heavy particle of mass ~ TeV decaying significantly into two photons at colliders, such as LHC, but our analysis applies more broadly. We show that there are significant constraints from astrophysics and cosmology on the simplest UV complete models that incorporate such new particles and its associated collider signal. The simplest and most obvious UV complete model that incorporates such signals is that it arises from a new singlet scalar (or pseudo-scalar) coupled to a new electrically charged and colored heavy fermion. Here we show that these new fermions (and anti-fermions) would be produced in the early universe, then form new color singlet heavy mesons with light quarks, obtain a non-negligible freeze-out abundance, and remain in kinetic equilibrium until decoupling. These heavy mesons possess interesting phenomenology, dependent on their charge, including forming new bound states with electrons and protons. We show that a significant number of these heavy states would survive for the age of the universe and an appreciable number would eventually be contained within the earth and solar system. We show that this leads to detectable consequences, including the production of highly energetic events from annihilations on earth, new spectral lines, and, spectacularly, the destabilization of stars. The lack of detection of these consequences rules out such simple UV completions, putting pressure on the viability of such new particles at LHC . To incorporate such a scalar would require either much more complicated UV completions or even further new physics that provides a decay channel for the associated fermion.
Search for Ultralight Scalar Dark Matter with Atomic Spectroscopy.
Van Tilburg, Ken; Leefer, Nathan; Bougas, Lykourgos; Budker, Dmitry
2015-07-03
We report new limits on ultralight scalar dark matter (DM) with dilatonlike couplings to photons that can induce oscillations in the fine-structure constant α. Atomic dysprosium exhibits an electronic structure with two nearly degenerate levels whose energy splitting is sensitive to changes in α. Spectroscopy data for two isotopes of dysprosium over a two-year span are analyzed for coherent oscillations with angular frequencies below 1 rad s-1. No signal consistent with a DM coupling is identified, leading to new constraints on dilatonlike photon couplings over a wide mass range. Under the assumption that the scalar field comprises all of the DM, our limits on the coupling exceed those from equivalence-principle tests by up to 4 orders of magnitude for masses below 3×10(-18) eV. Excess oscillatory power, inconsistent with fine-structure variation, is detected in a control channel, and is likely due to a systematic effect. Our atomic spectroscopy limits on DM are the first of their kind, and leave substantial room for improvement with state-of-the-art atomic clocks.
Reopening the Higgs portal for single scalar dark matter
Casas, J. A.; Cerdeño, D. G.; Moreno, J. M.; Quilis, J.
2017-05-01
A real singlet scalar, connected to the Standard Model sector through a portal with the Higgs boson, is one of the simplest and most popular models for dark matter (DM). However, the experimental advances in direct and indirect DM searches, together with the latest results from the LHC, have ruled out vast areas of the parameter space of this scenario; and are expected to probe it completely within the next years, ruling it out if no signal is found. Motivated by the simplicity of this model, in this article we address a minimal, renormalizable extension that could evade detection, consisting of the addition of an extra real singlet scalar field in the dark sector. We analyze the physical constraints on the model and show that the new annihilation and/or coannihilation channels involving the extra singlet allow to reproduce the correct DM relic abundance while avoiding the bounds from direct and indirect searches for any DM mass above 50 GeV. We also show that, in some interesting regions of the parameter space, the extra particle can be integrated-out, leaving a "clever" effective theory (just involving the DM particle and the Higgs), that essentially reproduces the results.
Trace anomaly, massless scalars, and the gravitational coupling of QCD
Armillis, Roberta; Corianò, Claudio; Delle Rose, Luigi
2010-09-01
The anomalous effective action describing the coupling of gravity to a non-Abelian gauge theory can be determined by a variational solution of the anomaly equation, as shown by Riegert long ago. It is given by a nonlocal expression, with the nonlocal interaction determined by the Green’s function of a conformally covariant operator of fourth order. In recent works it has been shown that this interaction is mediated by a simple pole in an expansion around a Minkowski background, coupled in the infrared in the massless fermion limit. This result relies on the local formulation of the original action in terms of two auxiliary fields, one physical scalar and one ghost, which take the role of massless composite degrees of freedom. In the gravity case, the two scalars have provided ground in favor of some recent proposals of an infrared approach to the solution of the dark energy problem, entirely based on the behavior of the vacuum energy at the QCD phase transition. As a test of this general result, we perform a complete one-loop computation of the effective action describing the coupling of a non-Abelian gauge theory to gravity. We confirm the appearance of an anomaly pole which contributes to the trace part of the TJJ correlator and of extra poles in its trace-free part, in the quark and gluon sectors, describing the coupling of the energy-momentum tensor (T) to two non-Abelian gauge currents (J).
Weakly dynamic dark energy via metric-scalar couplings with torsion
Sur, Sourav; Singh Bhatia, Arshdeep
2017-07-01
We study the dynamical aspects of dark energy in the context of a non-minimally coupled scalar field with curvature and torsion. Whereas the scalar field acts as the source of the trace mode of torsion, a suitable constraint on the torsion pseudo-trace provides a mass term for the scalar field in the effective action. In the equivalent scalar-tensor framework, we find explicit cosmological solutions representing dark energy in both Einstein and Jordan frames. We demand the dynamical evolution of the dark energy to be weak enough, so that the present-day values of the cosmological parameters could be estimated keeping them within the confidence limits set for the standard LCDM model from recent observations. For such estimates, we examine the variations of the effective matter density and the dark energy equation of state parameters over different redshift ranges. In spite of being weakly dynamic, the dark energy component differs significantly from the cosmological constant, both in characteristics and features, for e.g. it interacts with the cosmological (dust) fluid in the Einstein frame, and crosses the phantom barrier in the Jordan frame. We also obtain the upper bounds on the torsion mode parameters and the lower bound on the effective Brans-Dicke parameter. The latter turns out to be fairly large, and in agreement with the local gravity constraints, which therefore come in support of our analysis.
Motion of Passive Scalar by Elasticity-Induced Instability in Curved Microchannel
Directory of Open Access Journals (Sweden)
Xiao-Bin Li
2014-08-01
Full Text Available This paper presented a direct numerical simulation (DNS study on the elasticity-induced irregular flow, passive mixing, and scalar evolution in the curvilinear microchannel. The mixing enhancement was achieved at vanishingly low-Reynolds-number chaotic flow raised by elastic instabilities. Along with the mixing process, the passive scalar transportation carried by the flow was greatly affected by the flow structure and the underlying interaction between microstructures of viscoelastic fluid and flow structure itself. The simulations are conducted for a wide range of viscoelasticity. As the elastic effect exceeds the critical value, the flow tends to a chaotic state, while the evolution of scalar gets strong and fast, showing excellent agreement with experimental results. For the temporal changing of scalar gradients, they vary rapidly in the form of isosurfaces, with the shape of “rolls” in the bulk and evolving into “threads” near the wall. That indicates that the flow fields should be related to the deformation of viscoelastic micromolecules. The probability distribution function analysis between micromolecular deformation and flow field deformation shows that the main direction of molecular stretching is perpendicular to the main direction of flow field deformation. It implies they are weakly correlated, due to the confinement of channel wall.
Scalar scattering from charged black holes on the brane
de Oliveira, Ednilton S.
2018-03-01
The differential scattering cross section of massless scalar fields localized on the 3-brane of charged static black holes in the ADD model is analyzed. While results valid over the entire range of the scattering angle can be obtained only via a numerical approach, analytical results can be obtained via the geodesic, Born and glory approximations. Comparison between numerical and analytical results leads to excellent agreement. The increase of the charge intensity has the consequence of increasing the width of the interference fringes in the scattering cross section. Its influence on the intensity of the scattered flux, however, depends on the dimensionality of the spacetime. Analyses for the special cases of uncharged and extremely charged black holes are included.
The Cauchy problem of scalar-tensor theories of gravity
Energy Technology Data Exchange (ETDEWEB)
Salgado, Marcelo [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-543 Mexico 04510 DF (Mexico)
2006-07-21
The 3 + 1 formulation of scalar-tensor theories of gravity (STT) is obtained in the physical (Jordan) frame departing from the 4 + 0 covariant field equations. Contrary to common belief (folklore), the new system of ADM-like equations shows that the Cauchy problem of STT is well formulated (in the sense that the whole system of evolution equations is of first order in the time derivative). This is the first step towards a full first-order (in time and space) formulation from which a subsequent hyperbolicity analysis (a well-posedness determination) can be performed. Several gauge (lapse and shift) conditions are considered and implemented for STT. In particular, a generalization of the harmonic gauge for STT allows us to prove the well posedness of the STT using a second-order analysis which is very similar to the one employed in general relativity. Several appendices complement the ideas of the main part of the paper.
Mono-jet signatures of gluphilic scalar dark matter
Godbole, Rohini M.; Mendiratta, Gaurav; Shivaji, Ambresh; Tait, Tim M. P.
2017-09-01
A gluphilic scalar dark matter (GSDM) model has recently been proposed as an interesting vision for WIMP dark matter communicating dominantly with the Standard Model via gluons. We discuss the collider signature of a hard jet recoiling against missing momentum (;mono-jet;) in such a construction, whose leading contribution is at one-loop. We compare the full one-loop computation with an effective field theory (EFT) treatment, and find (as expected) that EFT does not accurately describe regions of parameter space where mass of the colored mediator particles are comparable to the experimental cuts on the missing energy. We determine bounds (for several choices of SU(3) representation of the mediator) from the √{ s} = 8 TeV data, and show the expected reach of the √{ s} = 13 TeV LHC and a future 100 TeV pp collider to constrain or discover GSDM models.
Black hole accretion in scalar-tensor-vector gravity
John, Anslyn J
2016-01-01
We examine the accretion of matter onto a black hole in scalar--tensor--vector gravity (STVG). The gravitational constant is $G=G_{N} (1 + \\alpha)$ where $\\alpha$ is a parameter taken to be constant for static black holes in the theory. The STVG black hole is spherically symmetric and characterised by two event horizons. The matter falling into the black hole obeys the polytrope equation of state and passes through two critical points before entering the outer horizon. We obtain analytical expressions for the mass accretion rate as well as for the outer critical point, critical velocity and critical sound speed. Our results complement existing strong field tests like lensing and orbital motion and could be used in conjunction to determine observational constraints on STVG.
Primordial GWs from universality classes of pseudo-scalar inflation
Pieroni, M.
2017-05-01
In this contribution we discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudo-scalar inflaton to some Abelian gauge fields. This analysis is performed by dividing inflationary models into universality classes. We find that of the most promising scenario is a Starobinsky-like model, which may lead to the generation of observational signatures both in upcoming CMB detectors as well as for direct GW detectors. The signal which can be produced in these models would both be observable in ground-based detectors, such as advanced LIGO, and in space-based detectors, such as LISA. The complementarity between the CMB and direct GW detection may be used to extract informations on the microphysics of inflation. Interestingly the mechanism discussed in this contribution may also be relevant for the generation of Primordial Black Holes (PBHs).
Effective long wavelength scalar dynamics in de Sitter
Moss, Ian
2016-01-01
We discuss the effective infrared theory governing a light scalar's long wavelength dynamics in de Sitter spacetime. We show how the separation of scales around the physical curvature radius $k/a \\sim H$ can be performed consistently with a window function and how short wavelengths can be integrated out in the Schwinger-Keldysh path integral formalism. At leading order, and for time scales $\\Delta t \\gg H^{-1}$, this results in the well-known Starobinsky stochastic evolution. Our approach allows for the computation of quantum UV corrections, generating an effective potential on which the stochastic dynamics takes place, as well as the description of dynamics on spatial and temporal scales comparable to $H^{-1}$ and above. We further elaborate on the use of a Wigner function to evaluate the non-perturbative expectation values of field correlators and the stress-energy tensor of $\\phi$ within the stochastic formalism.
Mono-jet signatures of gluphilic scalar dark matter
Directory of Open Access Journals (Sweden)
Rohini M. Godbole
2017-09-01
Full Text Available A gluphilic scalar dark matter (GSDM model has recently been proposed as an interesting vision for WIMP dark matter communicating dominantly with the Standard Model via gluons. We discuss the collider signature of a hard jet recoiling against missing momentum (“mono-jet” in such a construction, whose leading contribution is at one-loop. We compare the full one-loop computation with an effective field theory (EFT treatment, and find (as expected that EFT does not accurately describe regions of parameter space where mass of the colored mediator particles are comparable to the experimental cuts on the missing energy. We determine bounds (for several choices of SU(3 representation of the mediator from the s=8 TeV data, and show the expected reach of the s=13 TeV LHC and a future 100 TeV pp collider to constrain or discover GSDM models.
Chiral effective theory with a light scalar and lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Soto, J., E-mail: joan.soto@ub.edu [Departament d' Estructura i Constituents de la Materia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Institut de Ciencies del Cosmos, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Talavera, P., E-mail: pere.talavera@icc.ub.edu [Institut de Ciencies del Cosmos, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Comte Urgell 187, E-08036 Barcelona (Spain); Tarrus, J., E-mail: tarrus@ecm.ub.es [Departament d' Estructura i Constituents de la Materia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Catalonia (Spain); Institut de Ciencies del Cosmos, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona, Catalonia (Spain)
2013-01-21
We extend the usual chiral perturbation theory framework ({chi}PT) to allow the inclusion of a light dynamical isosinglet scalar. Using lattice QCD results, and a few phenomenological inputs, we explore the parameter space of the effective theory. We discuss the S-wave pion-pion scattering lengths, extract the average value of the two light quark masses and evaluate the impact of the dynamical singlet field in the low-energy constants l{sup Macron }{sub 1}, l{sup Macron }{sub 3} and l{sup Macron }{sub 4} of {chi}PT. We also show how to extract the mass and width of the sigma resonance from chiral extrapolations of lattice QCD data.
Search for Scalar Top and Scalar Bottom Quarks at $\\sqrt{s}$ = 189 GeV at LEP
Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Blobel, V.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hoch, M.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.
1999-01-01
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 182 pb-1 at a centre-of-mass energy of 189 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level lower limit on the scalar top quark mass is 90.3 GeV if the mixing angle between the supersymmetric partners of the left- and right-handed states of the top quark is zero. In the worst case, when the scalar top quark decouples from the Z boson, the lower limit is 87.2 GeV. These limits were obtained assuming that the scalar top quark decays into a charm quark and the lightest neutralino, and that the mass difference between the scalar top quark and the lightest neutralino is larger than 10 GeV. The complementary decay mode of the scalar top quark decaying into a bottom quark, a charged lepton and a scalar neutrino has also been studied. From a search for the scalar bottom quark, a mass limit of 88.6 GeV was obtained if the mass difference between the scalar bottom...
Scalar Potential Model of photon diffraction
Hodge, John
2011-04-01
Some observations of light are inconsistent with a wave-like model. Other observations of light are inconsistent with a traditional particle-like model. A single model of light has remained a mystery. Newton's speculations, Democritus's speculations, the Bohm interpretation, and the fractal philosophy are combined with the cosmological Scalar Potential Model (SPM). The resulting model of photon structure and dynamics is tested by a toy computer experiment. The simulations included light from a distance and Young's experiment. The patterns on the screens showed diffraction wave patterns fit by the Fresnel equation. The model is consistent with the Afshar experiment and with the concepts of Bohmian mechanics.
Inflation and reheating in scale-invariant scalar-tensor gravity
Tambalo, Giovanni
2016-01-01
We consider the scale-invariant inflationary model studied in [1]. The Lagrangian includes all the scale-invariant operators that can be built with combinations of $R, R^{2}$ and one scalar field. The equations of motion show that the symmetry is spontaneously broken after an arbitrarily long inflationary period and a fundamental mass scale is generated. Upon symmetry breaking, and in the Jordan frame, both Hubble function and the scalar field undergo damped oscillations that can eventually amplify Standard Model fields and reheat the Universe. In the present work, we study in detail inflation and the reheating mechanism of this model in the Einstein frame and we compare some of the results with the latest observational data.
Floating and sinking: the imprint of massive scalars around rotating black holes.
Cardoso, Vitor; Chakrabarti, Sayan; Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo
2011-12-09
We study the coupling of massive scalar fields to matter in orbit around rotating black holes. It is generally expected that orbiting bodies will lose energy in gravitational waves, slowly inspiraling into the black hole. Instead, we show that the coupling of the field to matter leads to a surprising effect: because of superradiance, matter can hover into "floating orbits" for which the net gravitational energy loss at infinity is entirely provided by the black hole's rotational energy. Orbiting bodies remain floating until they extract sufficient angular momentum from the black hole, or until perturbations or nonlinear effects disrupt the orbit. For slowly rotating and nonrotating black holes floating orbits are unlikely to exist, but resonances at orbital frequencies corresponding to quasibound states of the scalar field can speed up the inspiral, so that the orbiting body sinks. These effects could be a smoking gun of deviations from general relativity.
Structure scalars and evolution equations in f( G) cosmology
Sharif, M.; Fatima, H. Ismat
2017-01-01
In this paper, we study the dynamics of self-gravitating fluid using structure scalars for spherical geometry in the context of f( G) cosmology. We construct structure scalars through orthogonal splitting of the Riemann tensor and deduce a complete set of equations governing the evolution of dissipative anisotropic fluid in terms of these scalars. We explore different causes of density inhomogeneity which turns out to be a necessary condition for viable models. It is explicitly shown that anisotropic inhomogeneous static spherically symmetric solutions can be expressed in terms of these scalar functions.
Light Higgs from Scalar See-Saw in Technicolor
DEFF Research Database (Denmark)
Foadi, Roshan; Frandsen, Mads Toudal
2012-01-01
We consider a TeV scale see-saw mechanism leading to light scalar resonances in models with otherwise intrinsically heavy scalars. The mechanism can provide a 125 GeV technicolor Higgs in e.g. two-scale TC models......We consider a TeV scale see-saw mechanism leading to light scalar resonances in models with otherwise intrinsically heavy scalars. The mechanism can provide a 125 GeV technicolor Higgs in e.g. two-scale TC models...
Spontaneous breakdown and the scalar nonet
Energy Technology Data Exchange (ETDEWEB)
Scadron, M.D.
1982-07-01
In the context of the QCD quark model and on the basis of dynamical Bethe-Salpeter ladder graphs, we suggest that (i) the existence of the scalar q-barq hadron multiplet, like the pseudoscalar q-barq multiplet, is a direct consequence of dynamical spontaneous breakdown of chiral symmetry with a chiral-limiting nonstrange mass scale of m/sub sigmaNS//sup CL/ = 2m/sub dyn/ roughly-equal630 MeV, (ii) the lifting of the nonstrange sigma-delta degeneracy is expected from the s-wave quark-gluon annihilation diagram, and (iii) the observed sigma-S* mixing follows from the existence of the p-wave scalar quark-annihilation diagram. The resulting predicted 0q-barq nonet is then sigma(750 MeV), kappa(800), S*(980), and delta(985), in agreement with data for the resonant masses, the mixing angle, and also decay widths except for the kappa(800).
Study of WIMP annihilations into a pair of on-shell scalar mediators
Jia, Lian-Bao
2016-11-01
In this article, we focus on new scalar ϕ mediated scalar/vectorial weakly interacting massive particles (WIMPs) with ϕ 's mass slightly below the WIMP mass. To explain the Galactic center 1-3 GeV gamma-ray excess, here we consider the case that a WIMP pair predominantly annihilates into an on-shell ϕ ϕ pair with ϕ mainly decaying to τ τ ¯. The masses of WIMPs are in a range about 14-22 GeV, and the annihilations of WIMPs are phase space suppressed today. In this annihilation scheme, the couplings of the ϕ -standard model (SM) particles are almost arbitrarily small, and the WIMP-nucleus spin-independent scattering can be tolerant by the present dark matter (DM) direct detections. A scalar mediator-Higgs field mixing is introduced, which is small and available. The lower limit on the couplings of the ϕ -SM particles set by the thermal equilibrium in the early Universe is derived, and this constraint is above the neutrino background for scalar DM in direct detections. The WIMPs may be detectable at the upgraded DM direct detection experiment in the next few years, and the exotic decay h →ϕ ϕ , the production of ϕ may be observable at the future high-luminosity e+e- collider.
More exact tunneling solutions in scalar field theory
Energy Technology Data Exchange (ETDEWEB)
Dutta, Koushik; Hector, Cecelie; Vaudrevange, Pascal M.; Westphal, Alexander
2011-11-15
We present exact bounce solutions and amplitudes for tunneling in (i) a piecewise linear-quartic potential and (ii) a piecewise quartic-quartic potential. We cross check their correctness by comparing with results obtained through the thin-wall approximation and with a piecewise linear-linear potential. We briefly comment on applications in cosmology. (orig.)
''Superluminal'' scalar fields and cosmology
Energy Technology Data Exchange (ETDEWEB)
Vikman, A. [LMU-ASC, Muenchen (Germany)
2007-07-01
It is well known that in manifestly Lorentz invariant theories with non-trivial kinetic terms, perturbations around some classical dynamical backgrounds can travel faster than light. These exotic ''superluminal'' models may have interesting consequences for cosmology and astrophysics. I begin my talk by explaining how a nonlinearity of equations of motion can yield a superluminal propagation. Further I consider an inflationary model with the sound speed larger than the speed of light. The most interesting property of the model is a higher, in comparison to the standard chaotic inflation, amount of gravitational waves produced during inflation. Finally I discuss causality and stability of these models. (orig.)
Analysis of Scalar Field Cosmology with Phase Space Deformations
Directory of Open Access Journals (Sweden)
Sinuhe Perez-Payan
2014-01-01
modifying the symplectic structure of the minisuperspace variables. The effects of the deformation are studied in the “C-frame” and the “NC-frame.” In order to remove the ambiguities of working on different frames, a new principle is introduced. When we impose that both frames should be physically equivalent, we conclude that the only possibility for this model, is to have an effective cosmological constant Λeff≥0. Finally we bound the parameter space for θ and β.
Analysis of solutions of a nonlinear scalar field differential equation
Muhamadiev, E. M.; Naimov, A. N.
2017-10-01
We consider a nonlinear differential equation arising in mathematical models of elementary particle theory. For this equation, we examine questions of the extendability of solutions, the boundedness of solutions at infinity, and the search for new conditions for the existence of a positive particle-like solution.
Resolvent estimates for scalar fields with electromagnetic perturbation
Directory of Open Access Journals (Sweden)
Mirko Tarulli
2004-12-01
Full Text Available In this note we prove some estimates for the resolvent of the operator $-Delta$ perturbed by the differential operator $$ V(x,D=ia(xcdot abla+V(xquad hbox{in }mathbb{R}^3,. $$ This differential operator is of short range type and a compact perturbation of the Laplacian on $mathbb{R}^3$. Also we find estimates in the space-time norm for the solution of the wave equation with such perturbation.
Resolvent estimates for scalar fields with electromagnetic perturbation
Mirko Tarulli
2004-01-01
In this note we prove some estimates for the resolvent of the operator $-Delta$ perturbed by the differential operator $$ V(x,D)=ia(x)cdot abla+V(x)quad hbox{in }mathbb{R}^3,. $$ This differential operator is of short range type and a compact perturbation of the Laplacian on $mathbb{R}^3$. Also we find estimates in the space-time norm for the solution of the wave equation with such perturbation.
Versatile rogue waves in scalar, vector, and multidimensional nonlinear systems
Chen, Shihua; Baronio, Fabio; Soto-Crespo, Jose M.; Grelu, Philippe; Mihalache, Dumitru
2017-11-01
This review is dedicated to recent progress in the active field of rogue waves, with an emphasis on the analytical prediction of versatile rogue wave structures in scalar, vector, and multidimensional integrable nonlinear systems. We first give a brief outline of the historical background of the rogue wave research, including referring to relevant up-to-date experimental results. Then we present an in-depth discussion of the scalar rogue waves within two different integrable frameworks—the infinite nonlinear Schrödinger (NLS) hierarchy and the general cubic-quintic NLS equation, considering both the self-focusing and self-defocusing Kerr nonlinearities. We highlight the concept of chirped Peregrine solitons, the baseband modulation instability as an origin of rogue waves, and the relation between integrable turbulence and rogue waves, each with illuminating examples confirmed by numerical simulations. Later, we recur to the vector rogue waves in diverse coupled multicomponent systems such as the long-wave short-wave equations, the three-wave resonant interaction equations, and the vector NLS equations (alias Manakov system). In addition to their intriguing bright–dark dynamics, a series of other peculiar structures, such as coexisting rogue waves, watch-hand-like rogue waves, complementary rogue waves, and vector dark three sisters, are reviewed. Finally, for practical considerations, we also remark on higher-dimensional rogue waves occurring in three closely-related (2 + 1)D nonlinear systems, namely, the Davey–Stewartson equation, the composite (2 + 1)D NLS equation, and the Kadomtsev–Petviashvili I equation. As an interesting contrast to the peculiar X-shaped light bullets, a concept of rogue wave bullets intended for high-dimensional systems is particularly put forward by combining contexts in nonlinear optics.
Kuvshinov, Alexey; Matzka, Jürgen; Poedjono, Benny; Samrock, Friedemann; Olsen, Nils; Pai, Sudhir
2016-11-01
The electric conductivity distribution of the Earth's crust and upper mantle provides a key to unraveling its structure. Information can be obtained from vector data time series of the natural variations of the magnetic and electric field in a directional stable reference frame. Applying this method, known as magnetotellurics, to oceanic regions is challenging since only vector instruments placed at the sea bottom can provide such data. Here, we discuss a concept of marine induction surveying which is based on sea-surface scalar magnetic field measurements from a modern position-keeping platform. The concept exploits scalar magnetic responses that relate variations of the scalar magnetic field at the survey sites with variations of the horizontal magnetic field at a reference site. A 3-D model study offshore Oahu Island (Hawaii) demonstrates that these responses are sensitive to the conductivity structure beneath the ocean. We conclude that the sensitivity, depending on the bathymetry gradient, is typically largest near the coast offshore. We show that such sea-surface marine induction surveys can be performed with the Wave Glider, an easy-to-deploy, autonomous, energy-harvesting floating platform with position-keeping capability.[Figure not available: see fulltext.
Directory of Open Access Journals (Sweden)
John McDonald
2016-10-01
Full Text Available The 750 GeV resonance observed by ATLAS and CMS may be explained by a gauge singlet scalar. This would provide an ideal candidate for a gauge singlet scalar alternative to Higgs Inflation, known as S-inflation. Here we discuss the relevant results of S-inflation in the context of the 750 GeV resonance. In particular, we show that a singlet scalar, if it is real, has a major advantage over the Higgs boson with regard to unitarity violation during inflation. This is because it is possible to restrict the large non-minimal coupling required for inflation, ξ∼105, to the real singlet scalar, with all other scalars having ξ∼1. In this case the scale of unitarity violation Λ is much larger than the inflaton field during inflation. This protects the inflaton effective potential from modification by the new physics or strong coupling which is necessary to restore unitarity, which would otherwise invalidate the perturbative effective potential based on Standard Model physics. This is in contrast to the case of Higgs Inflation or models based on complex singlet scalars, where the unitarity violation scale during inflation is less than or of the order of the inflaton field. Therefore if the 750 GeV resonance is the inflaton, it must be a non-minimally coupled real singlet scalar.
Experimental Limit on Optical-Photon Coupling to Light Neutral Scalar Bosons
Energy Technology Data Exchange (ETDEWEB)
Afanaciev, Andrei; Afanasev, Andrei; Baker, O.; Beard, Kevin; Biallas, George; Boyce, James; Minarni, Minarni; Ramdon, Roopchan; Michelle D. Shinn; Slocum, P.
2008-09-01
DOI: http://dx.doi.org/10.1103/PhysRevLett.101.120401
We report on the first results of a sensitive search for scalar coupling of photons to a light neutral boson in the mass range of approximately 1.0 meV (milli-electron volts) and coupling strength greater than 10^-6 GeV^-1 using optical photons. This was a photon regeneration experiment using the "light shining through a wall" technique in which laser light was passed through a strong magnetic field upstream of an optical beam dump; regenerated laser light was then searched for downstream of a second magnetic field region optically shielded from the former. Our results show no evidence for scalar coupling in this region of parameter space.
Scalar resonant frequencies and Hawking effect of an f(R) global monopole
Vieira, H. S.; Morais Graça, J. P.; Bezerra, V. B.
2017-09-01
Massive scalar fields are considered in the gravitational field produced by a Schwarzschild black hole with a global monopole in f(R) gravity. The exact solution of the radial part of the Klein-Gordon equation in this background is obtained and is given in terms of the general Heun functions. We apply the properties of the general Heun functions to study the Hawking radiation and the resonant frequencies of scalar particles. H.S.V. is funded by the Brazilian research agencies CNPq (research Project No. 140612/2014-9) and CAPES (PDSE Process No. 88881.133092/2016-01). J.P.M.G. is funded by the CNPq through the research Project No. 150565/2016-0. V.B.B. is partially supported by the CNPq through the research Project No. 304553/2010-7
Variational method for objective analysis of scalar variable and its ...
Indian Academy of Sciences (India)
It has been found that objectively analysed scalar ﬁeld obtained using standard method is superior to the scalar ﬁeld derived by the triangle method,whereas the derivative ﬁelds produced by triangle method are superior to the derivative ﬁelds produced using standard method. A variational objective analysis scheme has ...
Collisionless self-gravitating statistical systems of scalar interacting particles
Ignat'ev, Yu G
2015-01-01
This paper is devoted to consideration of the theory of collisionless statistical systems with interparticle scalar interaction. The mathematical model of such systems is constructed and the exact solution of Vlasov equation for isotropic homogenous model of the Universe is found. Asymptotic solutions of self-consistent Vlasov - Einstein model for conformally invariant scalar interactions are found.
LIPSS results for photons coupling to light neutral scalar bosons
Energy Technology Data Exchange (ETDEWEB)
Andrei Afanasev; Oliver K. Baker; Kevin Beard; George Biallas; James Boyce; Minarni Minarni; Roopchan Ramdon; Michelle D. Shinn; Penny Slocum
2008-06-01
The LIPSS search for a light neutral scalar boson coupling to optical photons is reported. The search covers a region of parameter space of approximately 1.0 meV and coupling strength greater than 10^-6 GeV^-1. The LIPSS results show no evidence for scalar coupling in this region of parameter space.
Small visible energy scalar top iterative discriminant analysis
Indian Academy of Sciences (India)
The search for scalar top quarks and the determination of their parameters in the framework of supersymmetric models are important aspects of the linear collider physics programme. The lightest neutralino with a small mass difference (∆m) to the scalar top quark is a candidate for dark matter in the Universe [1]. The.
Visualization of Scalar Adaptive Mesh Refinement Data
Energy Technology Data Exchange (ETDEWEB)
VACET; Weber, Gunther; Weber, Gunther H.; Beckner, Vince E.; Childs, Hank; Ligocki, Terry J.; Miller, Mark C.; Van Straalen, Brian; Bethel, E. Wes
2007-12-06
Adaptive Mesh Refinement (AMR) is a highly effective computation method for simulations that span a large range of spatiotemporal scales, such as astrophysical simulations, which must accommodate ranges from interstellar to sub-planetary. Most mainstream visualization tools still lack support for AMR grids as a first class data type and AMR code teams use custom built applications for AMR visualization. The Department of Energy's (DOE's) Science Discovery through Advanced Computing (SciDAC) Visualization and Analytics Center for Enabling Technologies (VACET) is currently working on extending VisIt, which is an open source visualization tool that accommodates AMR as a first-class data type. These efforts will bridge the gap between general-purpose visualization applications and highly specialized AMR visual analysis applications. Here, we give an overview of the state of the art in AMR scalar data visualization research.
Abelian scalar theory at large global charge
Energy Technology Data Exchange (ETDEWEB)
Loukas, Orestis [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern (Switzerland)
2017-09-15
We elaborate on Abelian complex scalar models, which are dictated by natural actions (all couplings are of order one), at fixed and large global U(1) charge in an arbitrary number of dimensions. The ground state vertical stroke v right angle is coherently constructed by the zero modes and the appearance of a centrifugal potential is quantum mechanically verified. Using the path integral formulation we systematically analyze the quantum fluctuations around vertical stroke v right angle in order to derive an effective action for the Goldstone mode, which becomes perturbatively meaningful when the charge is large. In this regime we explicitly show, by computing the first few loop corrections, that the whole construction is stable against quantum effects, in the sense that any higher derivative couplings to Goldstone's tree-level action are suppressed by appropriate powers of the large charge. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Observability of inert scalars at the LHC
Energy Technology Data Exchange (ETDEWEB)
Hashemi, Majid [Shiraz University, Physics Department, College of Sciences, Shiraz (Iran, Islamic Republic of); Najjari, Saereh [University of Warsaw, Faculty of Physics, Warsaw (Poland)
2017-09-15
In this work we investigate the observability of inert doublet model scalars at the LHC operating at the center of mass energy of 14 TeV. The signal production process is pp → AH{sup ±} → ZHW{sup ±}H leading to two different final states of l{sup +}l{sup -}HjjH and l{sup +}l{sup -}Hl{sup ±}νH based on the hadronic and leptonic decay channels of the W boson. All the relevant background processes are considered and an event selection is designed to distinguish the signal from the large Standard Model background. We found that signals of the selected search channels are well observable at the LHC with an integrated luminosity of 300 fb{sup -1}. (orig.)
LHC constraints on color octet scalars
Hayreter, Alper; Valencia, German
2017-08-01
We extract constraints on the parameter space of the Manohar and Wise model by comparing the cross sections for dijet, top-pair, dijet-pair, t t ¯t t ¯ and b b ¯b b ¯ productions at the LHC with the strongest available experimental limits from ATLAS or CMS at 8 or 13 TeV. Overall we find mass limits around 1 TeV in the most sensitive regions of parameter space, and lower elsewhere. This is at odds with generic limits for color octet scalars often quoted in the literature where much larger production cross sections are assumed. The constraints that can be placed on coupling constants are typically weaker than those from existing theoretical considerations, with the exception of the parameter ηD.
The BEH mechanism and its scalar bosons
CERN. Geneva
2014-01-01
In the beginning of the 1960’s, the long range interactions within our universe were well understood from the laws of classical general relativity, Einstein’s generalisation of Newtonian gravity, and of quantum electrodynamics, the quantum version of Maxwell’s electromagnetic theory. But there was no hints of how to formulate consistent fundamental theories of short range interactions. A solution to this problem was proposed by Robert Brout and me, and independently by Peter Higgs. I shall explain our motivations for constructing this BEH mechanism and discuss its content. I will comment on how the magnificent ATLAS and CMS discovery at CERN of the scalar boson predicted by the mechanism confirms its validity and may have implications on structures at yet unexplored energies.
Scalar dark matter with type II seesaw
Directory of Open Access Journals (Sweden)
Arnab Dasgupta
2014-12-01
Full Text Available We study the possibility of generating tiny neutrino mass through a combination of type I and type II seesaw mechanism within the framework of an abelian extension of standard model. The model also provides a naturally stable dark matter candidate in terms of the lightest neutral component of a scalar doublet. We compute the relic abundance of such a dark matter candidate and also point out how the strength of type II seesaw term can affect the relic abundance of dark matter. Such a model which connects neutrino mass and dark matter abundance has the potential of being verified or ruled out in the ongoing neutrino, dark matter, as well as accelerator experiments.
Motion of particles on a Four-Dimensional Asymptotically AdS Black Hole with Scalar Hair
Gonzalez, P A; Vasquez, Yerko
2015-01-01
Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields in the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss about the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar h...
Motion of particles on a four-dimensional asymptotically AdS black hole with scalar hair
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, P.A.; Olivares, Marco [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)
2015-10-15
Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields on the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light, and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar hair, in order to explain the discrepancy between the theory and the observations, for the perihelion precession of Mercury and light deflection. (orig.)
Cha, Chong M.; de Bruyn Kops, Stephen M.; Mortensen, Mikael
2006-06-01
The double scalar mixing layer (DSML) is a canonical problem for studying the mixing of multiple streams and, with reaction, combustion of the partially premixed type. In a DSML, a third stream consisting of a premixture of the reactants is introduced in between the pure fuel and air streams of the classic twin-feed or binary mixing problem. The well-known presumed probability density function (PDF), such as the β-PDF, can adequately model passive scalar mixing for the binary mixing problem on which state-of-the-art turbulent combustion models such as conditional moment closure and flamelet approaches rely. However, the β-PDF model, now a standard in CFD simulation, cannot describe turbulent mixing involving multiple streams; e.g., the asymmetric three-stream mixing characterizing the DSML. In this paper, direct numerical simulations of the DSML are performed to make available a high-fidelity database for developing more general, fine-scale mixing models required to compute turbulent combustion problems of practical engineering interest, which usually involve mixing between multiple streams. In this first part of two investigations, nonreacting numerical experiments are presented with emphasis on the nontrivial distributions of the passive scalar and its dissipation rate. Mapping closure modeling is applied to describe the PDFs and conditional dissipation rates of a single mixture fraction.
Joint Scalar versus Joint Velocity-Scalar PDF Simulations of Bluff-Body Stabilized Flames with REDIM
Merci, B.; Naud, B.; Roekaerts, D.; Maas, U.
2008-01-01
Two transported PDF strategies, joint velocity-scalar PDF (JVSPDF) and joint scalar PDF (JSPDF), are investigated for bluff-body stabilized jet-type turbulent diffusion flames with a variable degree of turbulence–chemistry interaction. Chemistry is modeled by means of the novel reaction-diffusion
Kerr black holes with self-interacting scalar hair: hairier but not heavier
Herdeiro, Carlos A R; Rúnarsson, Helgi
2015-01-01
The maximal ADM mass for (mini-)boson stars (BSs) -- gravitating solitons of Einstein's gravity minimally coupled to a free, complex, mass $\\mu$, Klein-Gordon field -- is $M_{\\rm ADM}^{\\rm max}\\sim M_{Pl}^2/\\mu$. Adding quartic self-interactions to the scalar field theory, described by the Lagrangian $\\mathcal{L}_I=\\lambda |\\Psi|^4$, the maximal ADM mass becomes $M_{\\rm ADM}^{\\rm max}\\sim \\sqrt{\\lambda}M_{Pl}^3/\\mu^2$. Thus, for mini-BSs, astrophysically interesting masses require ultra-light scalar fields, whereas self-interacting BSs can reach such values for bosonic particles with Standard Model range masses. We investigate how these same self-interactions affect Kerr black holes with scalar hair (KBHsSH) [1], which can be regarded as (spinning) BSs in stationary equilibrium with a central horizon. Remarkably, whereas the ADM mass scales in the same way as for BSs, the \\textit{horizon mass} $M_H$ does not increases with the coupling $\\lambda$, and, for fixed $\\mu$, it is maximized at the "Hod point", corre...
Experimental Investigation of Spatially-Periodic Scalar Patterns in an Inline Mixer
Baskan, Ozge; Speetjens, Michel F. M.; Clercx, Herman J. H.
2015-11-01
Spatially persisting patterns with exponentially decaying intensities form during the downstream evolution of passive scalars in three-dimensional (3D) spatially periodic flows due to the coupled effect of the chaotic nature of the flow and the diffusivity of the material. This has been investigated in many computational and theoretical studies on 3D spatially-periodic flow fields. However, in the limit of zero-diffusivity, the evolution of the scalar fields results in more detailed structures that can only be captured by experiments due to limitations in the computational tools. Our study employs the-state-of-the-art experimental methods to analyze the evolution of 3D advective scalar field in a representative inline mixer, called Quatro static mixer. The experimental setup consists of an optically accessible test section with transparent internal elements, accommodating a pressure-driven pipe flow and equipped with 3D Laser-Induced Fluorescence. The results reveal that the continuous process of stretching and folding of material creates finer structures as the flow progresses, which is an indicator of chaotic advection and the experiments outperform the simulations by revealing far greater level of detail.
Energy Technology Data Exchange (ETDEWEB)
Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)
2016-10-15
We apply the confluent Heun functions to study the resonant frequencies (quasispectrum), the Hawking radiation and the scattering process of scalar waves, in a class of spacetimes, namely, the ones generated by a Kerr–Newman–Kasuya spacetime (dyon black hole) and a Reissner–Nordström black hole surrounded by a magnetic field (Ernst spacetime). In both spacetimes, the solutions for the angular and radial parts of the corresponding Klein–Gordon equations are obtained exactly, for massive and massless fields, respectively. The special cases of Kerr and Schwarzschild black holes are analyzed and the solutions obtained, as well as in the case of a Schwarzschild black hole surrounded by a magnetic field. In all these special situations, the resonant frequencies, Hawking radiation and scattering are studied. - Highlights: • Charged massive scalar field in the dyon black hole and massless scalar field in the Ernst spacetime are analyzed. • The confluent Heun functions are applied to obtain the solution of the Klein–Gordon equation. • The resonant frequencies are obtained. • The Hawking radiation and the scattering process of scalar waves are examined.
Non-commutative gauge gravity: second-order correction and scalar particle creation
Energy Technology Data Exchange (ETDEWEB)
Zaim, Slimane [Departement de Physique, Faculte des Sciences, Universite de Batna (Algeria); Khodja, Lamine, E-mail: zaimslimane@yahoo.f [Departement de Physique, Faculte des Sciences Exactes, Universite Mentouri, Constantine (Algeria)
2010-05-01
We construct a non-commutative gauge theory for a charged scalar field and verify its invariance under local Poincare and general coordinate transformations. We derive a general Klein-Gordon equation up to the second order of the non-commutativity parameter using the general modified field equation. As an application, we choose the Bianchi I universe and use the Seiberg-Witten maps to obtain the deformed non-commutative metric and study a particle production process. We show that non-commutativity plays the same role as an electric field, gravity and chemical potential.
Equivalence of cosmological observables in conformally related scalar tensor theories
Rondeau, François; Li, Baojiu
2017-12-01
Scalar tensor theories can be expressed in different frames, such as the commonly used Einstein and Jordan frames, and it is generally accepted that cosmological observables are the same in these frames. We revisit this by making a detailed side-by-side comparison of the quantities and equations in two conformally related frames, from the actions and fully covariant field equations to the linearized equations in both real and Fourier spaces. This confirms that the field and conservation equations are equivalent in the two frames, in the sense that we can always re-express equations in one frame using relevant transformations of variables to derive the corresponding equations in the other. We show, with both analytical derivation and a numerical example, that the line-of-sight integration to calculate CMB temperature anisotropies can be done using either Einstein frame or Jordan frame quantities, and the results are identical, provided the correct redshift is used in the Einstein frame (1 +z ≠1 /a ).
Evolution of scalar and velocity dynamics in planar shock-turbulence interaction
Boukharfane, R.; Bouali, Z.; Mura, A.
2018-01-01
passive (i.e., chemically inert) scalar in the presence of a shock wave is thus investigated using high-resolution numerical simulations. The starting point of the analysis relies on the transport equations of the variance of the mixture fraction, i.e., a fuel inlet tracer that quantifies the mixing between fuel and oxidizer. The influence of the shock wave is investigated for three distinct values of the shock Mach number M, and the obtained results are compared to reference solutions featuring no shock wave. The computed solutions show that the shock wave significantly modifies the scalar field topology. The larger the value of M, the stronger is the amplification of the alignment of the scalar gradient with the most compressive principal direction of the strain-rate tensor, which signifies the enhancement of scalar mixing with the shock Mach number.
Energy Technology Data Exchange (ETDEWEB)
Li, Hui-Ling, E-mail: LHL51759@126.com [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 (China); College of Physics Science and Technology, Shenyang Normal University, Shenyang 110034 (China); Yang, Shu-Zheng, E-mail: szyangcwnu@126.com [Institute of Theoretical Physics, China West Normal University, Nanchong 637002 (China); Zu, Xiao-Tao, E-mail: xtzu@uestc.edu.cn [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 (China)
2017-01-10
In the framework of holography, we survey the phase structure for a higher dimensional hairy black hole including the effects of the scalar field hair. It is worth emphasizing that, not only black hole entropy, but also entanglement entropy and two point correlation function exhibit the Van der Waals-like phase transition in a fixed scalar charge ensemble. Furthermore, by making use of numerical computation, we show that the Maxwell's equal area law is valid for the first order phase transition. In addition, we also discuss how the hair parameter affects the black hole's phase transition.
Longitudinal W boson scattering in a light scalar top scenario
Ishiwata, Koji; Yonekura, Yuki
2017-07-01
Scalar tops in the supersymmetric model affect the potential of the standard model-like Higgs at the quantum level. In light of the equivalence theorem, the deviation of the potential from the standard model can be traced by longitudinal gauge bosons. In this work, high-energy longitudinal W boson scattering is studied in a TeV-scale scalar top scenario. O (1 - 10 %) deviation from the standard model prediction in the differential cross section is found, depending on whether the observed Higgs mass is explained only by scalar tops or by additional contributions at a higher scale.
Scalar-Tensor Black Holes Embedded in an Expanding Universe
Tretyakova, Daria; Latosh, Boris
2018-02-01
In this review we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on a black hole, embedded in an expanding universe, describing both cosmological and astrophysical scales. We show that in scalar-tensor gravity it is quite common that the local geometry is isolated from the cosmological expansion, so that it does not backreact on the black hole metric. We try to extract common features of scalar-tensor black holes in an expanding universe and point out the gaps that must be filled.
Scalar-Tensor Black Holes Embedded in an Expanding Universe
Directory of Open Access Journals (Sweden)
Daria Tretyakova
2018-02-01
Full Text Available In this review, we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on black holes, embedded in an expanding universe, describing both cosmological and astrophysical scales. We show that in scalar-tensor gravity it is quite common that the local geometry is isolated from the cosmological expansion, so that it does not backreact on the black hole metric. We try to extract common features of scalar-tensor black holes in an expanding universe and point out the issues that are not fully investigated.
Charged scalar perturbations around Garfinkle–Horowitz–Strominger black holes
Directory of Open Access Journals (Sweden)
Cheng-Yong Zhang
2015-10-01
Full Text Available We examine the stability of the Garfinkle–Horowitz–Strominger (GHS black hole under charged scalar perturbations. Employing the appropriate numerical methods, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the results obtained in the de Sitter and anti-de Sitter black holes. Furthermore, we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.
Scalarization of neutron stars with realistic equations of state
Altaha Motahar, Zahra; Blázquez-Salcedo, Jose Luis; Kleihaus, Burkhard; Kunz, Jutta
2017-09-01
We consider the effect of scalarization on static and slowly rotating neutron stars for a wide variety of realistic equations of state, including pure nuclear matter, nuclear matter with hyperons, hybrid nuclear and quark matter, and pure quark matter. We analyze the onset of scalarization, presenting a universal relation for the critical coupling parameter versus compactness. We find that the onset and the magnitude of the scalarization are strongly correlated with the value of the gravitational potential (the metric component gt t) at the center of the star. We also consider the moment-of-inertia-compactness relations and confirm universality for the nuclear matter, hyperon and hybrid equations of state.
On the transverse Scalar Curvature of a Compact Sasaki Manifold
Directory of Open Access Journals (Sweden)
He Weiyong
2014-09-01
Full Text Available We show that the standard picture regarding the notion of stability of constant scalar curvature metrics in Kähler geometry described by S.K. Donaldson [10, 11], which involves the geometry of infinitedimensional groups and spaces, can be applied to the constant scalar curvature metrics in Sasaki geometry with only few modification. We prove that the space of Sasaki metrics is an infinite dimensional symmetric space and that the transverse scalar curvature of a Sasaki metric is a moment map of the strict contactomophism group
Uncovering the relation of a di-photon scalar resonance to the Higgs boson
Carmona, Adrian
2017-05-26
We consider the associated production of a scalar resonance, decaying to a pair of photons, with the standard model Higgs boson. We demonstrate via a realistic phenomenological analysis that couplings of such a resonance to the Higgs boson can be constrained in a meaningful way in future runs of the LHC, providing insights on its origin and its relation to the electroweak symmetry breaking sector. Moreover, the final state can provide a direct way to determine whether the new resonance is produced predominantly in gluon fusion or quark-anti-quark annihilation. The analysis focusses on a resonance with a mass of 750 GeV, coming from a scalar field with vanishing vacuum expectation value. It can however be straightforwardly generalised to other scenarios.
Energy Technology Data Exchange (ETDEWEB)
Marzola, Luca; Racioppi, Antonio; Vaskonen, Ville [National Institute of Chemical Physics and Biophysics, Tallinn (Estonia)
2017-07-15
Thermal corrections in classically conformal models typically induce a strong first-order electroweak phase transition, thereby resulting in a stochastic gravitational background that could be detectable at gravitational wave observatories. After reviewing the basics of classically conformal scenarios, in this paper we investigate the phase transition dynamics in a thermal environment and the related gravitational wave phenomenology within the framework of scalar conformal extensions of the Standard Model. We find that minimal extensions involving only one additional scalar field struggle to reproduce the correct phase transition dynamics once thermal corrections are accounted for. Next-to-minimal models, instead, yield the desired electroweak symmetry breaking and typically result in a very strong gravitational wave signal. (orig.)
Asselmeyer-Maluga, Torsten
2016-01-01
In this book, leading theorists present new contributions and reviews addressing longstanding challenges and ongoing progress in spacetime physics. In the anniversary year of Einstein's General Theory of Relativity, developed 100 years ago, this collection reflects the subsequent and continuing fruitful development of spacetime theories. The volume is published in honour of Carl Brans on the occasion of his 80th birthday. Carl H. Brans, who also contributes personally, is a creative and independent researcher and one of the founders of the scalar-tensor theory, also known as Jordan-Brans-Dicke theory. In the present book, much space is devoted to scalar-tensor theories. Since the beginning of the 1990s, Brans has worked on new models of spacetime, collectively known as exotic smoothness, a field largely established by him. In this Festschrift, one finds an outstanding and unique collection of articles about exotic smoothness. Also featured are Bell's inequality and Mach's principle. Personal memories and hist...
Integrable Scalar Cosmologies I. Foundations and links with String Theory
Fré, P.; Sagnotti, A.; Sorin, A. S.
2013-12-01
We build a number of integrable one-scalar spatially flat cosmologies, which play a natural role in inflationary scenarios, examine their behavior in several cases and draw from them some general lessons on this type of systems, whose potentials involve combinations of exponential functions, and on similar non-integrable ones. These include the impossibility for the scalar to emerge from the initial singularity descending along asymptotically exponential potentials with logarithmic slopes exceeding a critical value (“climbing phenomenon”) and the inevitable collapse in a Big Crunch whenever the scalar tries to settle at negative extrema of the potential. We also elaborate on the links between these types of potentials and “brane supersymmetry breaking”, a mechanism that ties together string scale and scale of supersymmetry breaking in a class of orientifold models. Our Universe is highly isotropic and homogeneous at large scales, while its current state of acceleration is well accounted for by a small positive cosmological constant; Our Universe is spatially flat, which brings to the forefront metrics of the form ds2=e dt2-a2(t) dxṡdx. Special “gauge functions” B(t) can result in simpler expressions for the scale factor a(t), which becomes a quantity of utmost interest for Theoretical Physics; Vacuum energy accounts for about 70% of the present contents of the Universe, dark matter of unknown origin for another 24%, so that only 6% is left for conventional baryonic matter in the form of luminous stars and galaxies. The climbing phenomenon, whereby the scalar field cannot emerge from the initial singularity climbing down potentials that are asymptotically exponential with logarithmic slopes exceeding a critical value. Or, if you will, the impossibility for scalar fields to overcome, in a contracting phase, the attractive force of such potential ends. The physical meaning of this phenomenon was first elucidated in [18] in the simple exponential
Transverse relaxation of scalar-coupled protons.
Segawa, Takuya F; Baishya, Bikash; Bodenhausen, Geoffrey
2010-10-25
In a preliminary communication (B. Baishya, T. F. Segawa, G. Bodenhausen, J. Am. Chem. Soc. 2009, 131, 17538-17539), we recently demonstrated that it is possible to obtain clean echo decays of protons in biomolecules despite the presence of homonuclear scalar couplings. These unmodulated decays allow one to determine apparent transverse relaxation rates R(2) (app) of individual protons. Herein, we report the observation of R(2) (app) for three methyl protons, four amide H(N) protons, and all 11 backbone H(α) protons in cyclosporin A. If the proton resonances overlap, their R(2) (app) rates can be measured by transferring their magnetization to neighboring (13)C nuclei, which are less prone to overlap. The R(2) (app) rates of protons attached to (13)C are faster than those attached to (12)C because of (13)C-(1)H dipolar interactions. The differences of these rates allow the determination of local correlation functions. Backbone H(N) and H(α) protons that have fast decay rates R(2) (app) also feature fast longitudinal relaxation rates R(1) and intense NOESY cross peaks that are typical of crowded environments. Variations of R(2) (app) rates of backbone H(α) protons in similar amino acids reflect differences in local environments.
Searches for high mass BSM scalars
Nam, Kyungwook
2017-01-01
Searches for BSM particles using the 126 GeV Higgs boson have been carried out with the CMS detector at LHC, based on pp collision data collected at centre-of-mass energies of 7, 8, and 13 TeV. The talk presents the latest results and gives a brief review of earlier results. A search for heavy resonances decaying to Zgamma is presented. This search is based on the data collected with the CMS detector at 13 TeV. The search strategy is to look for an excess above the non-resonant Standard Model background in the Zgamma invariant mass spectrum. The background is extracted directly from data and compared with the signal expected to be produced by hypothetical scalar resonances. While the HH production within the Standard Model is very small and essentially out of the experimental reach within the LHC Run II, several theories foresee an enhancement that can be already probed with the available data. The latest searches for resonant and non-resonant Higgs pair production, made using 13 TeV pp collisions data recor...
On the Scalar Manifold of Exceptional Supergravity
Cacciatori, Sergio L; Marrani, Alessio
2012-01-01
We construct two parametrizations of the non compact exceptional Lie group G=E7(-25), based on a fibration which has the maximal compact subgroup K=(E6 x U(1))/Z_3 as a fiber. It is well known that G plays an important role in the N=2 d=4 magic exceptional supergravity, where it describes the U-duality of the theory and where the symmetric space M=G/K gives the vector multiplets' scalar manifold. First, by making use of the exponential map, we compute a realization of G/K, that is based on the E6 invariant d-tensor, and hence exhibits the maximal possible manifest [(E6 x U(1))/Z_3]-covariance. This provides a basis for the corresponding supergravity theory, which is the analogue of the Calabi-Vesentini coordinates. Then we study the Iwasawa decomposition. Its main feature is that it is SO(8)-covariant and therefore it highlights the role of triality. Along the way we analyze the relevant chain of maximal embeddings which leads to SO(8). It is worth noticing that being based on the properties of a "mixed" Freu...
Scalar quark searches in $e^+ e^-$ collisions at $\\sqrt{s}$ = 181-184 GeV
Barate, R; Décamp, D; Ghez, P; Goy, C; Jézéquel, S; Lees, J P; Lucotte, A; Martin, F; Merle, E; Minard, M N; Nief, J Y; Pietrzyk, B; Alemany, R; Boix, G; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Graugès-Pous, E; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Morawitz, P; Park, I C; Pascual, A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Becker, U; Bright-Thomas, P G; Casper, David William; Cattaneo, M; Ciulli, V; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Gianotti, F; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Lehraus, Ivan; Maley, P; Mato, P; Minten, Adolf G; Moneta, L; Qi, N; Pacheco, A; Ranjard, F; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Vreeswijk, M; Wachsmuth, H W; Ajaltouni, Ziad J; Badaud, F; Chazelle, G; Deschamps, O; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Vayaki, Anna; Blondel, A; Brient, J C; Machefert, F P; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Videau, H L; Focardi, E; Parrini, G; Zachariadou, K; Cavanaugh, R J; Corden, M; Georgiopoulos, C H; Hühn, T; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Cerutti, F; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Chalmers, M; Curtis, L; Halley, A W; Lynch, J G; Negus, P; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Ward, J J; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Marinelli, N; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Robertson, N A; Williams, M I; Giehl, I; Hoffmann, C; Jakobs, K; Kleinknecht, K; Kröcker, M; Nürnberger, H A; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Ziegler, T; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Ealet, A; Fouchez, D; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Tilquin, A; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Büscher, V; Cowan, G D; Dietl, H; Ganis, G; Lütjens, G; Mannert, C; Männer, W; Moser, H G; Schael, S; Settles, Ronald; Seywerd, H C J; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kado, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Serin, L; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Bettarini, S; Boccali, T; Bozzi, C; Calderini, G; Dell'Orso, R; Fantechi, R; Ferrante, I; Giassi, A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Sguazzoni, G; Tenchini, Roberto; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Coles, J; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Fabbro, B; Faïf, G; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Przysiezniak, H; Rander, J; Renardy, J F; Rosowsky, A; Roussarie, A; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Kim, H Y; Konstantinidis, N P; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Foss, J; Grupen, Claus; Smolik, L; Stephan, F; Giannini, G; Gobbo, B; Musolino, G; Pütz, J; Rothberg, J E; Wasserbaech, S R; Williams, R W; Armstrong, S R; Betteridge, A P; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Zobernig, G
1998-01-01
Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57~$\\mathrm{pb}^{-1}$ taken at $\\rts$ = 181--184~GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels $\\stop \\rightarrow \\mathrm{c}\
Scalar mesons and the search for the 0{sup ++} Glueball
Energy Technology Data Exchange (ETDEWEB)
Ulrike Thoma
2002-10-01
The possibility that gluonic excitations of hadronic matter or of the QCD vacuum may exist is perhaps one of the most fascinating topics in hadron spectroscopy. Glueballs are predicted by many models; in particular present-day lattice gauge calculations require their existence. All these models agree that the lightest glueball should have scalar quantum numbers and a mass around 1.6 GeV, which corresponds to the mass region where the scalar qq[bar]-mesons are expected. Therefore mixing effects can complicate the search for the glueball. Experiments indeed show an overpopulation of states, for which many different interpretations exist. This reflects the complexity of the situation. New data from various experiments on scalar states give hints toward an interpretation of the scalar states. But, still many questions remain.
Scalar mesons and the search for the 0{sup ++} glueball
Energy Technology Data Exchange (ETDEWEB)
Thoma, U. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2003-11-01
The possibility that gluonic excitations of hadronic matter or of the QCD vacuum may exist is perhaps one of the most fascinating topics in hadron spectroscopy. Glueballs are predicted by many models; in particular, present-day lattice gauge calculations require their existence. All these models agree that the lightest glueball should have scalar quantum numbers and a mass around 1.6GeV, which corresponds to the mass region where the scalar q anti q-mesons are expected. Therefore, mixing effects can complicate the search for the glueball. Experiments indeed show an overpopulation of states, for which many different interpretations exist. This reflects the complexity of the situation. New data from various experiments on scalar states give hints toward an interpretation of the scalar states. But still many questions remain. (orig.)