Cosmic rays and the search for a Lorentz Invariance Violation

International Nuclear Information System (INIS)

Bietenholz, Wolfgang

2008-11-01

This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors γ ∝ O(10 11 ). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous γ-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic γ-rays. For multi TeV γ-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects next to them - as probable UHECR sources. (orig.)

Cosmic rays and the search for a Lorentz Invariance Violation

Energy Technology Data Exchange (ETDEWEB)

Bietenholz, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2008-11-15

This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma} {proportional_to} O(10{sup 11}). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi TeV {gamma}-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects

Tests of local Lorentz invariance violation of gravity in the standard model extension with pulsars.

Science.gov (United States)

Shao, Lijing

2014-03-21

The standard model extension is an effective field theory introducing all possible Lorentz-violating (LV) operators to the standard model and general relativity (GR). In the pure-gravity sector of minimal standard model extension, nine coefficients describe dominant observable deviations from GR. We systematically implemented 27 tests from 13 pulsar systems to tightly constrain eight linear combinations of these coefficients with extensive Monte Carlo simulations. It constitutes the first detailed and systematic test of the pure-gravity sector of minimal standard model extension with the state-of-the-art pulsar observations. No deviation from GR was detected. The limits of LV coefficients are expressed in the canonical Sun-centered celestial-equatorial frame for the convenience of further studies. They are all improved by significant factors of tens to hundreds with existing ones. As a consequence, Einstein's equivalence principle is verified substantially further by pulsar experiments in terms of local Lorentz invariance in gravity.

Unusual high-energy phenomenology of Lorentz-invariant noncommutative field theories

International Nuclear Information System (INIS)

Carone, Christopher D.; Kwee, Herry J.

2006-01-01

It has been suggested that one may construct a Lorentz-invariant noncommutative field theory by extending the coordinate algebra to additional, fictitious coordinates that transform nontrivially under the Lorentz group. Integration over these coordinates in the action produces a four-dimensional effective theory with Lorentz invariance intact. Previous applications of this approach, in particular, to a specific construction of noncommutative QED, have been studied only in a low-momentum approximation. Here we discuss Lorentz-invariant field theories in which the relevant physics can be studied without requiring an expansion in the inverse scale of noncommutativity. Qualitatively, we find that tree-level scattering cross sections are dramatically suppressed as the center-of-mass energy exceeds the scale of noncommutativity, that cross sections that are isotropic in the commutative limit can develop a pronounced angular dependence, and that nonrelativistic potentials (for example, the Coloumb potential) become nonsingular at the origin. We consider a number of processes in noncommutative QED that may be studied at a future linear collider. We also give an example of scattering via a four-fermion operator in which the noncommutative modifications of the interaction can unitarize the tree-level amplitude, without requiring any other new physics in the ultraviolet

Lorentz and CPT invariances and the Einstein-Podolsky-Rosen correlations

International Nuclear Information System (INIS)

Beauregard, O.C. de

1984-01-01

This paper shows that there is no conflict between Einstein-Podolsky-Rosen (EPR) correlation and the new 1925 - 55 ''microrelativity principle'' stating the Lorentz and CPT invariance of physical law at the microlevel. The CPT invariance concept is a perfectly legal heir of the 1876 Loschmidt T-invariance concept. Therefore, the EPR-paradox can be understood as synthetizing two earlier ''paradoxes'': the wavelike probability calculus, and the T- or CPT-symmetry of elementary physical processes. The CPT-invariance can be summarized as the basic requirement of second quantization, that particle emission and antiparticle absorption are mathematically equivalent. The phenomenology displays causality as arrowless at the microlevel. The relativistic S-matrix scheme displays the CPT invariance of causality concept at the microlevel. In order to strengthen the point that the Lorentz and CPT invariant schemes of relativistic quantum mechanics do contain the full formalization of the EPR correlation, the covariant calculations pertaining to the subject are presented. The formalization of the EPR correlation and its interpretation are contained in the existing relativistic quantum mechanics. (Kato, T.)

Late-time acceleration and phantom divide line crossing with non-minimal coupling and Lorentz-invariance violation

International Nuclear Information System (INIS)

Nozari, Kourosh; Sadatian, S.D.

2008-01-01

We consider two alternative dark-energy models: a Lorentz-invariance preserving model with a non-minimally coupled scalar field and a Lorentz-invariance violating model with a minimally coupled scalar field. We study accelerated expansion and the dynamics of the equation of state parameter in these scenarios. While a minimally coupled scalar field does not have the capability to be a successful dark-energy candidate with line crossing of the cosmological constant, a non-minimally coupled scalar field in the presence of Lorentz invariance or a minimally coupled scalar field with Lorentz-invariance violation have this capability. In the latter case, accelerated expansion and phantom divide line crossing are the results of the interactive nature of this Lorentz-violating scenario. (orig.)

A precision test of Lorentz invariance using room-temperature high-finesse optical resonators

International Nuclear Information System (INIS)

Eisele, Christian

2009-01-01

An apparatus for a test of a basic postulate of the theory of Special Relativity, the isotropy of the speed of light, has been developed. Deviations from the isotropy imply a violation of Lorentz invariance, a symmetry assumed by all established theories of the fundamental forces. Such a signal may provide a glimpse on physics beyond our current theories of the fundamental forces, the General Theory of Relativity and the Standard Modell of particle physics. Since long theoreticians try to unify General Relativity and the Standard Modell within one theory, a grand unified theory (GUT). So far they did not succeed, although promising candidate theories have been developed, e.g. string theories or loop quantum gravity. However, there are hints that Lorentz invariance might not be an exact symmetry of nature, but that deviations are to be expected. This is a strong motivation for tests of Lorentz invariance with increased sensitivity as the one presented within this thesis. We employ, for the first time for a test of the isotropy of the speed of light, monolithic optical resonators fabricated from a glass ceramic with ultra low expansion coefficient (ULE). By means of a monolithic Nd:YAG-laser (λ = 1064 nm) we measure the difference between the resonance frequencies of two orthogonally oriented resonators. The low thermal expansion coefficient reduces the influence of thermal fluctuations on the resonance frequencies, which are a function of the mirror spacing and the speed of light inside the resonators only. The complete optical setup has been put on top of active vibration isolation supports, which strongly damp mechanical vibrations. This improves the short-time stability of the resonators resonance frequencies. This technique is used for the first time in a Speed of Light Isotropy Test (SLIT) experiment. Furthermore, a system for the stabilization of the tilt of the optics breadboard is implemented, based on electromagnetic actuators. This stabilization is

A precision test of Lorentz invariance using room-temperature high-finesse optical resonators

Energy Technology Data Exchange (ETDEWEB)

Eisele, Christian

2009-10-28

An apparatus for a test of a basic postulate of the theory of Special Relativity, the isotropy of the speed of light, has been developed. Deviations from the isotropy imply a violation of Lorentz invariance, a symmetry assumed by all established theories of the fundamental forces. Such a signal may provide a glimpse on physics beyond our current theories of the fundamental forces, the General Theory of Relativity and the Standard Modell of particle physics. Since long theoreticians try to unify General Relativity and the Standard Modell within one theory, a grand unified theory (GUT). So far they did not succeed, although promising candidate theories have been developed, e.g. string theories or loop quantum gravity. However, there are hints that Lorentz invariance might not be an exact symmetry of nature, but that deviations are to be expected. This is a strong motivation for tests of Lorentz invariance with increased sensitivity as the one presented within this thesis. We employ, for the first time for a test of the isotropy of the speed of light, monolithic optical resonators fabricated from a glass ceramic with ultra low expansion coefficient (ULE). By means of a monolithic Nd:YAG-laser ({lambda} = 1064 nm) we measure the difference between the resonance frequencies of two orthogonally oriented resonators. The low thermal expansion coefficient reduces the influence of thermal fluctuations on the resonance frequencies, which are a function of the mirror spacing and the speed of light inside the resonators only. The complete optical setup has been put on top of active vibration isolation supports, which strongly damp mechanical vibrations. This improves the short-time stability of the resonators resonance frequencies. This technique is used for the first time in a Speed of Light Isotropy Test (SLIT) experiment. Furthermore, a system for the stabilization of the tilt of the optics breadboard is implemented, based on electromagnetic actuators. This stabilization is

Constraints on violation of Lorentz invariance from atmospheric showers initiated by multi-TeV photons

Energy Technology Data Exchange (ETDEWEB)

Rubtsov, Grigory; Satunin, Petr; Sibiryakov, Sergey, E-mail: grisha@ms2.inr.ac.ru, E-mail: satunin@ms2.inr.ac.ru, E-mail: Sergey.Sibiryakov@cern.ch [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation)

2017-05-01

Parameterizing hypothetical violation of Lorentz invariance at high energies using the framework of effective quantum field theory, we discuss its effect on the formation of atmospheric showers by very-high-energy gamma rays. In the scenario where Lorentz invariance violation leads to a decrease of the photon velocity with energy the formation of the showers is suppressed compared to the Lorentz invariant case. Absence of such suppression in the high-energy part of spectrum of the Crab nebula measured independently by HEGRA and H.E.S.S. collaborations is used to set lower bounds on the energy scale of Lorentz invariance violation. These bounds are competitive with the strongest existing constraints obtained from timing of variable astrophysical sources and the absorption of TeV photons on the extragalactic background light. They will be further improved by the next generation of multi-TeV gamma-ray observatories.

Lorentz invariance violation and electromagnetic field in an intrinsically anisotropic spacetime

Energy Technology Data Exchange (ETDEWEB)

Chang, Zhe [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Chinese Academy of Sciences, Theoretical Physics Center for Science Facilities, Beijing (China); Wang, Sai [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

2012-09-15

Recently, Kostelecky [V.A. Kostelecky, Phys. Lett. B 701, 137 (2011)] proposed that the spontaneous Lorentz invariance violation (sLIV) is related to Finsler geometry. Finsler spacetime is intrinsically anisotropic and naturally induces Lorentz invariance violation (LIV). In this paper, the electromagnetic field is investigated in locally Minkowski spacetime. The Lagrangian is presented explicitly for the electromagnetic field. It is compatible with the one in the standard model extension (SME). We show the Lorentz-violating Maxwell equations as well as the electromagnetic wave equation. The formal plane wave solution is obtained for the electromagnetic wave. The speed of light may depend on the direction of light and the lightcone may be enlarged or narrowed. The LIV effects could be viewed as influence from an anisotropic media on the electromagnetic wave. In addition, birefringence of light will not emerge at the leading order in this model. A constraint on the spacetime anisotropy is obtained from observations on gamma-ray bursts (GRBs). (orig.)

Testing Lorentz Invariance Emergence in the Ising Model using Monte Carlo simulations

CERN Document Server

Dias Astros, Maria Isabel

2017-01-01

In the context of the Lorentz invariance as an emergent phenomenon at low energy scales to study quantum gravity a system composed by two 3D interacting Ising models (one with an anisotropy in one direction) was proposed. Two Monte Carlo simulations were run: one for the 2D Ising model and one for the target model. In both cases the observables (energy, magnetization, heat capacity and magnetic susceptibility) were computed for different lattice sizes and a Binder cumulant introduced in order to estimate the critical temperature of the systems. Moreover, the correlation function was calculated for the 2D Ising model.

Lorentz and Poincaré invariance 100 years of relativity

CERN Document Server

Hsu Jong Ping

2001-01-01

This collection of papers provides a broad view of the development of Lorentz and Poincaré invariance and spacetime symmetry throughout the past 100 years. The issues explored in these papers include: (1) formulations of relativity theories in which the speed of light is not a universal constant but which are consistent with the four-dimensional symmetry of the Lorentz and Poincaré groups and with experimental results, (2) analyses and discussions by Reichenbach concerning the concepts of simultaneity and physical time from a philosophical point of view, and (3) results achieved by the union o

Testing the Equivalence Principle and Lorentz Invariance with PeV Neutrinos from Blazar Flares.

Science.gov (United States)

Wang, Zi-Yi; Liu, Ruo-Yu; Wang, Xiang-Yu

2016-04-15

It was recently proposed that a giant flare of the blazar PKS B1424-418 at redshift z=1.522 is in association with a PeV-energy neutrino event detected by IceCube. Based on this association we here suggest that the flight time difference between the PeV neutrino and gamma-ray photons from blazar flares can be used to constrain the violations of equivalence principle and the Lorentz invariance for neutrinos. From the calculated Shapiro delay due to clusters or superclusters in the nearby universe, we find that violation of the equivalence principle for neutrinos and photons is constrained to an accuracy of at least 10^{-5}, which is 2 orders of magnitude tighter than the constraint placed by MeV neutrinos from supernova 1987A. Lorentz invariance violation (LIV) arises in various quantum-gravity theories, which predicts an energy-dependent velocity of propagation in vacuum for particles. We find that the association of the PeV neutrino with the gamma-ray outburst set limits on the energy scale of possible LIV to >0.01E_{pl} for linear LIV models and >6×10^{-8}E_{pl} for quadratic order LIV models, where E_{pl} is the Planck energy scale. These are the most stringent constraints on neutrino LIV for subluminal neutrinos.

Consistency relation for the Lorentz invariant single-field inflation

International Nuclear Information System (INIS)

Huang, Qing-Guo

2010-01-01

In this paper we compute the sizes of equilateral and orthogonal shape bispectrum for the general Lorentz invariant single-field inflation. The stability of field theory implies a non-negative square of sound speed which leads to a consistency relation between the sizes of orthogonal and equilateral shape bispectrum, namely f NL orth. ≤ −0.054f NL equil. . In particular, for the single-field Dirac-Born-Infeld (DBI) inflation, the consistency relation becomes f NL orth. = 0.070f NL equil. ≤ 0. These consistency relations are also valid in the mixed scenario where the quantum fluctuations of some other light scalar fields contribute to a part of total curvature perturbation on the super-horizon scale and may generate a local form bispectrum. A distinguishing prediction of the mixed scenario is τ NL loc. > ((6/5)f NL loc. ) 2 . Comparing these consistency relations to WMAP 7yr data, there is still a big room for the Lorentz invariant inflation, but DBI inflation has been disfavored at more than 68% CL

ICECUBE NEUTRINOS AND LORENTZ INVARIANCE VIOLATION

Energy Technology Data Exchange (ETDEWEB)

Amelino-Camelia, Giovanni [Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sez. Roma1, P.le A. Moro 2, I-00185 Roma (Italy); Guetta, D. [Osservatorio astronomico di Roma, v. Frascati 33, I-00040 Monte Porzio Catone (Italy); Piran, Tsvi [The Racah Institute for Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2015-06-20

The IceCube neutrino telescope has found so far no evidence of gamma-ray burst (GRB) neutrinos. We here notice that these results assume the same travel times from source to telescope for neutrinos and photons, an assumption that is challenged by some much-studied pictures of spacetime quantization. We briefly review previous results suggesting that limits on quantum-spacetime effects obtained for photons might not be applicable to neutrinos, and we then observe that the outcome of GRB-neutrino searches could depend strongly on whether one allows for neutrinos to be affected by the minute effects of Lorentz invariance violation (LIV) predicted by some relevant quantum-spacetime models. We discuss some relevant issues using as an illustrative example three neutrinos that were detected by IceCube in good spatial coincidence with GRBs, but hours before the corresponding gamma rays. In general, this could happen if the earlier arrival reflects quantum-spacetime-induced LIV, but, as we stress, some consistency criteria must be enforced in order to properly test such a hypothesis. Our analysis sets the stage for future GRB-neutrino searches that could systematically test the possibility of quantum-spacetime-induced LIV.

The Apparent Lack of Lorentz Invariance in Zero-Point Fields with Truncated Spectra

Directory of Open Access Journals (Sweden)

Daywitt W. C.

2009-01-01

Full Text Available The integrals that describe the expectation values of the zero-point quantum-field-theoretic vacuum state are semi-infinite, as are the integrals for the stochastic electrodynamic vacuum. The unbounded upper limit to these integrals leads in turn to infinite energy densities and renormalization masses. A number of models have been put forward to truncate the integrals so that these densities and masses are finite. Unfortunately the truncation apparently destroys the Lorentz invariance of the integrals. This note argues that the integrals are naturally truncated by the graininess of the negative-energy Planck vacuum state from which the zero-point vacuum arises, and are thus automatically Lorentz invariant.

Lorentz invariance violation in modified gravity

International Nuclear Information System (INIS)

Brax, Philippe

2012-01-01

We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. Phenomenologically, these models are tightly restricted by the amount of Cerenkov radiation emitted by the superluminal particles, a constraint which is only satisfied by chameleons. Measuring the speed of neutrinos emitted radially from the surface of the earth and observed on the other side of the earth would probe the scalar field profile of modified gravity models in dense environments. We argue that the test of the equivalence principle provided by the Lunar ranging experiment implies that a deviation from the speed of light, for natural values of the coupling scale between the scalar field and fermions, would be below detectable levels, unless gravity is modified by camouflaged chameleons where the field normalisation is environmentally dependent.

Lorentz invariance violation in modified gravity

Energy Technology Data Exchange (ETDEWEB)

Brax, Philippe, E-mail: philippe.brax@cea.fr [Institut de Physique Theorique, CEA, IPhT, CNRS, URA 2306, F-91191Gif/Yvette Cedex (France)

2012-06-06

We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. Phenomenologically, these models are tightly restricted by the amount of Cerenkov radiation emitted by the superluminal particles, a constraint which is only satisfied by chameleons. Measuring the speed of neutrinos emitted radially from the surface of the earth and observed on the other side of the earth would probe the scalar field profile of modified gravity models in dense environments. We argue that the test of the equivalence principle provided by the Lunar ranging experiment implies that a deviation from the speed of light, for natural values of the coupling scale between the scalar field and fermions, would be below detectable levels, unless gravity is modified by camouflaged chameleons where the field normalisation is environmentally dependent.

Search for Violations of Lorentz Invariance and CPT Symmetry in B_{(s)}^{0} Mixing.

Science.gov (United States)

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Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hongming, L; Hulsbergen, W; Humair, T; Hushchyn, M; Hussain, N; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kecke, M; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, B; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusardi, N; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Manning, P; Mapelli, A; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; 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Pappenheimer, C; Parker, W; Parkes, C; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Romanovsky, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Saitta, B; 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Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhong, L; Zhukov, V; Zucchelli, S

2016-06-17

Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{μ} with precisions of O(10^{-15}) and O(10^{-14})  GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic.

Search for violations of Lorentz invariance and $CPT$ symmetry in $B^0_{(s)}$ mixing

CERN Document Server

Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; 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Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Stefkova, Slavomira; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szumlak, Tomasz; T'Jampens, Stephane; Tayduganov, Andrey; Tekampe, Tobias; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Tournefier, Edwige; Tourneur, Stephane; Trabelsi, Karim; Traill, Murdo; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; 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Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zheng, Yangheng; Zhokhov, Anatoly; Zhong, Liang; Zhukov, Valery; Zucchelli, Stefano

2016-06-15

Violations of $ CPT$ symmetry and Lorentz invariance are searched for by studying interference effects in $ B^0$ mixing and in $ B^0_s$ mixing. Samples of $ B^0\\to J/\\psi K^0_{\\mathrm{S}}$ and $ B^0_s\\to J/\\psi K^+ K^-$ decays are recorded by the LHCb detector in proton--proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and $ CPT$ symmetry. Results are expressed in terms of the Standard Model Extension parameter $\\Delta a_{\\mu}$ with precisions of $ \\mathcal{O}(10^{-15})$ and $ \\mathcal{O}(10^{-14})$ GeV for the $ B^0$ and $ B^0_s$ systems, respectively. With no assumption on Lorentz (non-)invariance, the $ CPT$-violating parameter $z$ in the $ B^0_s$ system is measured for the first time and found to be $ \\mathcal{R}e(z) = -0.022 \\pm 0.033 \\pm 0.005$ and $ \\mathcal{I}m(z) = 0.004 \\pm 0.011\\pm 0.002$, where the first uncertainti...

First test of Lorentz violation with a reactor-based antineutrino experiment

International Nuclear Information System (INIS)

Abe, Y.; Ishitsuka, M.; Konno, T.; Kuze, M.; Aberle, C.; Buck, C.; Hartmann, F.X.; Haser, J.; Kaether, F.; Lindner, M.; Reinhold, B.; Schwetz, T.; Wagner, S.; Watanabe, H.; Anjos, J.C. dos; Gama, R.; Lima, H.P.-Jr.; Pepe, I.M.; Bergevin, M.; Felde, J.; Maesano, C.N.; Bernstein, A.; Bowden, N.S.; Dazeley, S.; Erickson, A.; Keefer, G.; Bezerra, T.J.C.; Furuta, H.; Suekane, F.; Bezrukhov, L.; Lubsandorzhiev, B.K.; Yanovitch, E.; Blucher, E.; Conover, E.; Crum, K.; Strait, M.; Worcester, M.; Busenitz, J.; Goon, J.TM.; Habib, S.; Ostrovskiy, I.; Reichenbacher, J.; Stancu, I.; Sun, Y.; Cabrera, A.; Franco, D.; Kryn, D.; Obolensky, M.; Roncin, R.; Tonazzo, A.; Caden, E.; Damon, E.; Lane, C.E.; Maricic, J.; Miletic, T.; Milincic, R.; Perasso, S.; Smith, E.; Camilleri, L.; Carr, R.; Franke, A.J.; Shaevitz, M.H.; Toups, M.; Cerrada, M.; Crespo-Anadon, J.I.; Gil-Botella, I.; Lopez-Castano, J.M.; Novella, P.; Palomares, C.; Santorelli, R.; Chang, P.J.; Horton-Smith, G.A.; McKee, D.; Shrestha, D.; Chimenti, P.; Classen, T.; Collin, A.P.; Cucoanes, A.; Durand, V.; Fechner, M.; Fischer, V.; Hayakawa, T.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Mention, G.; Mueller, Th.A.; Perrin, P.; Sida, J.L.; Sinev, V.; Veyssiere, C.

2012-01-01

We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor. (authors)

Lorentz Invariance Violation and Modified Hawking Fermions Tunneling Radiation

Directory of Open Access Journals (Sweden)

Shu-Zheng Yang

2016-01-01

Full Text Available Recently the modified Dirac equation with Lorentz invariance violation has been proposed, which would be helpful to resolve some issues in quantum gravity theory and high energy physics. In this paper, the modified Dirac equation has been generalized in curved spacetime, and then fermion tunneling of black holes is researched under this correctional Dirac field theory. We also use semiclassical approximation method to get correctional Hamilton-Jacobi equation, so that the correctional Hawking temperature and correctional black hole’s entropy are derived.

Lorentz invariance and the zero-point stress-energy tensor

OpenAIRE

Visser, Matt

2016-01-01

Some 65 years ago (1951) Wolfgang Pauli noted that the net zero-point energy density could be set to zero by a carefully fine-tuned cancellation between bosons and fermions. In the current article I will argue in a slightly different direction: The zero-point energy density is only one component of the zero-point stress energy tensor, and it is this tensor quantity that is in many ways the more fundamental object of interest. I shall demonstrate that Lorentz invariance of the zero-point stres...

Minkowski spacetime and Lorentz invariance: The cart and the horse or two sides of a single coin?

Science.gov (United States)

Acuña, Pablo

2016-08-01

Michel Janssen and Harvey Brown have driven a prominent recent debate concerning the direction of an alleged arrow of explanation between Minkowski spacetime and Lorentz invariance of dynamical laws in special relativity. In this article, I critically assess this controversy with the aim of clarifying the explanatory foundations of the theory. First, I show that two assumptions shared by the parties-that the dispute is independent of issues concerning spacetime ontology, and that there is an urgent need for a constructive interpretation of special relativity-are problematic and negatively affect the debate. Second, I argue that the whole discussion relies on a misleading conception of the link between Minkowski spacetime structure and Lorentz invariance, a misconception that in turn sheds more shadows than light on our understanding of the explanatory nature and power of Einstein's theory. I state that the arrow connecting Lorentz invariance and Minkowski spacetime is not explanatory and unidirectional, but analytic and bidirectional, and that this analytic arrow grounds the chronogeometric explanations of physical phenomena that special relativity offers.

Testing CPT invariance with neutrinos

International Nuclear Information System (INIS)

Ohlsson, Tommy

2003-01-01

We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model, but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, which could be induced by physics beyond the Standard Model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences. In a typical neutrino factory setup simulation, we find, for example, that vertical bar m 3 - m-bar 3 vertical bar $1.9 · 10 -4 eV and vertical bar ≡ 23 - ≡-bar 23 vertical bar < or approx. 2 deg

Searching the laws of thermodynamics in the Lorentz-invariant thermal energy propagation equation

International Nuclear Information System (INIS)

Szőllősi, Tibor; Márkus, Ferenc

2015-01-01

Highlights: • We study the laws of thermodynamics in a Lorentz-invariant Lagrangian model. • We calculate the canonical momenta and tensor. • We give the correspondents of the laws of thermodynamics in the model. • The developed theory is considered to be coherent with the laws of thermodynamics. - Abstract: In earlier works it has been shown that the Lorentz-invariant description of thermal energy transfer can be deduced from a Lagrangian description, by which the definition of a dynamic temperature is involved at the same time. It is also proved that this formulation includes the classical Fourier heat propagation as a natural limit. However, the relation of the elaborated theory to the basic laws of thermodynamics remained open. This connection is studied in details in the present paper. It is posted that though strictly speaking the model is meaningless in equilibrium and corresponds only to the non-equilibrium parts of the temperature, it respects the laws of thermodynamics and provides a way to transfer some form of them into the validity-area of the model

Tests of CPT invariance at neutrino factories

International Nuclear Information System (INIS)

Bilenky, Samoil M.; Freund, Martin; Lindner, Manfred; Ohlsson, Tommy; Winter, Walter

2002-01-01

We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, such as could be induced by physics beyond the standard model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences; we found, for example, that the sensitivity |m 3 -m(bar sign) 3 |(less-or-similar sign)1.9x10 -4 eV could be achieved

Lorentz invariance violation and charge (non)conservation: A general theoretical frame for extensions of the Maxwell equations

International Nuclear Information System (INIS)

Laemmerzahl, Claus; Macias, Alfredo; Mueller, Holger

2005-01-01

All quantum gravity approaches lead to small modifications in the standard laws of physics which in most cases lead to violations of Lorentz invariance. One particular example is the extended standard model (SME). Here, a general phenomenological approach for extensions of the Maxwell equations is presented which turns out to be more general than the SME and which covers charge nonconservation (CNC), too. The new Lorentz invariance violating terms cannot be probed by optical experiments but need, instead, the exploration of the electromagnetic field created by a point charge or a magnetic dipole. Some scalar tensor theories and higher dimensional brane theories predict CNC in four dimensions and some models violating special relativity have been shown to be connected with CNC. Its relation to the Einstein Equivalence Principle has been discussed. Because of this upcoming interest, the experimental status of electric charge conservation is reviewed. Up to now there seem to exist no unique tests of charge conservation. CNC is related to the precession of polarization, to a modification of the 1/r-Coulomb potential, and to a time dependence of the fine structure constant. This gives the opportunity to describe a dedicated search for CNC

String Quantum Gravity, Lorentz-Invariance Violation and Gamma-Ray Astronomy

CERN Document Server

Mavromatos, Nick E

2010-01-01

In the first part of the review, I discuss ways of obtaining Lorentz-Invariance-Violating (LIV) space-time foam in the modern context of string theory, involving brane world scenarios. The foamy structures are provided by lower-dimensional background brane defects in a D3-brane Universe, whose density is a free parameter to be constrained phenomenologically. Such constraining can be provided by high energy gamma-ray photon tests, including ultra-high energy/infrared photon-photon scattering. In the second part, I analyze the currently available data from MAGIC and FERMI Telescopes on delayed cosmic photon arrivals in this context. It is understood of course that conventional Astrophysics source effects, which currently are far from being understood, might be the dominant reason for the observed delayed arrivals. I also discuss how the stringent constraints from studies of synchrotron-radiation from distant Nebulae, absence of cosmic birefringence and non observation of ultra-high-energy cosmic photons can be ...

Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

Energy Technology Data Exchange (ETDEWEB)

Dai, Wei-Ming; Cai, Rong-Gen [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Guo, Zong-Kuan [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Astronomy and Space Science, Beijing (China); Zhang, Yuan-Zhong [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)

2017-06-15

We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

International Nuclear Information System (INIS)

Dai, Wei-Ming; Cai, Rong-Gen; Guo, Zong-Kuan; Zhang, Yuan-Zhong

2017-01-01

We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

Science.gov (United States)

Dai, Wei-Ming; Guo, Zong-Kuan; Cai, Rong-Gen; Zhang, Yuan-Zhong

2017-06-01

We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density.

Noncommutative gauge theory without Lorentz violation

International Nuclear Information System (INIS)

Carlson, Carl E.; Carone, Christopher D.; Zobin, Nahum

2002-01-01

The most popular noncommutative field theories are characterized by a matrix parameter θ μν that violates Lorentz invariance. We consider the simplest algebra in which the θ parameter is promoted to an operator and Lorentz invariance is preserved. This algebra arises through the contraction of a larger one for which explicit representations are already known. We formulate a star product and construct the gauge-invariant Lagrangian for Lorentz-conserving noncommutative QED. Three-photon vertices are absent in the theory, while a four-photon coupling exists and leads to a distinctive phenomenology

Search for Violations of Lorentz Invariance and CPT Symmetry in B-(s)(0) Mixing

NARCIS (Netherlands)

Aaij, R.; Beteta, C. Abellan; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Onderwater, C. J. G.; Pellegrino, A.; Tolk, S.

2016-01-01

Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B-0 mixing and in B-s(0) mixing. Samples of B-0 -> J/psi K-S(0) and B-0(s) -> J/psi K+K- decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8

Gauge-invariant Yang-Mills fields and the role of Lorentz gauge condition

International Nuclear Information System (INIS)

Skachkov, N.B.; Shevchenko, O.Yu.

1985-01-01

A new class of gauge-invariant (G.I.) fields is constructed. The inversion formulae that express these fields through the G.I. strength tensor are obtained. It is shown that for the G.I. fields the Lorentz gauge condition appears as the secondary constraint. These fields coincide with the usual ones in some definite gauges. The Dyson-Schwinger equations for the G.I. spinor propagator are derived. It is found that in QED this propagator has a simple pole singularity (p-m) -1 in the infrared limit

Violations of Lorentz invariance in the neutrino sector after OPERA

Energy Technology Data Exchange (ETDEWEB)

Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liberati, Stefano [Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste (Italy); INFN, Sezione de Trieste (Italy); Mattingly, David M. [New Hampshire Univ., Durham (United States). Dept. of Physics

2011-10-15

The OPERA collaboration has recently reported that neutrinos travel faster than light. We review the theoretical situation of constraints on violations of Lorentz invariance, focusing in particular on the compatibility between the OPERA results with both previous constraints and recently obtained ones. We generalize to higher order operators the recent constraint provided by the absence of neutrino energy loss, via electron-positron pair production at OPERA energies, and show that no modi ed in vacuo dispersion relation within an effective field theory context is compatible with OPERA results. We conclude that the OPERA result is incompatible with current observations, at least without resorting to models beyond effective field theory, possibly with local environmental effects. (orig.)

Violations of Lorentz invariance in the neutrino sector after OPERA

International Nuclear Information System (INIS)

Maccione, Luca; Liberati, Stefano; Mattingly, David M.

2011-10-01

The OPERA collaboration has recently reported that neutrinos travel faster than light. We review the theoretical situation of constraints on violations of Lorentz invariance, focusing in particular on the compatibility between the OPERA results with both previous constraints and recently obtained ones. We generalize to higher order operators the recent constraint provided by the absence of neutrino energy loss, via electron-positron pair production at OPERA energies, and show that no modi ed in vacuo dispersion relation within an effective field theory context is compatible with OPERA results. We conclude that the OPERA result is incompatible with current observations, at least without resorting to models beyond effective field theory, possibly with local environmental effects. (orig.)

Lorentz violations and Euclidean signature metrics

International Nuclear Information System (INIS)

Barbero G, J. Fernando; Villasenor, Eduardo J.S.

2003-01-01

We show that the families of effective actions considered by Jacobson et al. to study Lorentz invariance violations contain a class of models that represent pure general relativity with a Euclidean signature. We also point out that some members of this family of actions preserve Lorentz invariance in a generalized sense

Lorentz-Symmetry Test at Planck-Scale Suppression With a Spin-Polarized 133Cs Cold Atom Clock.

Science.gov (United States)

Pihan-Le Bars, H; Guerlin, C; Lasseri, R-D; Ebran, J-P; Bailey, Q G; Bize, S; Khan, E; Wolf, P

2018-06-01

We present the results of a local Lorentz invariance (LLI) test performed with the 133 Cs cold atom clock FO2, hosted at SYRTE. Such a test, relating the frequency shift between 133 Cs hyperfine Zeeman substates with the Lorentz violating coefficients of the standard model extension (SME), has already been realized by Wolf et al. and led to state-of-the-art constraints on several SME proton coefficients. In this second analysis, we used an improved model, based on a second-order Lorentz transformation and a self-consistent relativistic mean field nuclear model, which enables us to extend the scope of the analysis from purely proton to both proton and neutron coefficients. We have also become sensitive to the isotropic coefficient , another SME coefficient that was not constrained by Wolf et al. The resulting limits on SME coefficients improve by up to 13 orders of magnitude the present maximal sensitivities for laboratory tests and reach the generally expected suppression scales at which signatures of Lorentz violation could appear.

Constrained gauge fields from spontaneous Lorentz violation

DEFF Research Database (Denmark)

Chkareuli, J. L.; Froggatt, C. D.; Jejelava, J. G.

2008-01-01

Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type AµAµ=M2 (M is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant...... theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory...... couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical Lorentz violation due to the simultaneously generated gauge invariance. Udgivelsesdato: June 11...

A unifying framework for ghost-free Lorentz-invariant Lagrangian field theories

Science.gov (United States)

Li, Wenliang

2018-04-01

We propose a framework for Lorentz-invariant Lagrangian field theories where Ostrogradsky's scalar ghosts could be absent. A key ingredient is the generalized Kronecker delta. The general Lagrangians are reformulated in the language of differential forms. The absence of higher order equations of motion for the scalar modes stems from the basic fact that every exact form is closed. The well-established Lagrangian theories for spin-0, spin-1, p-form, spin-2 fields have natural formulations in this framework. We also propose novel building blocks for Lagrangian field theories. Some of them are novel nonlinear derivative terms for spin-2 fields. It is nontrivial that Ostrogradsky's scalar ghosts are absent in these fully nonlinear theories.

Quantum-gravity phenomenology, Lorentz symmetry, and the SME

International Nuclear Information System (INIS)

Lehnert, Ralf

2007-01-01

Violations of spacetime symmetries have recently been identified as promising signatures for physics underlying the Standard Model. The present talk gives an overview over various topics in this field: The motivations for spacetime-symmetry research, including some mechanisms for Lorentz breaking, are reviewed. An effective field theory called the Standard-Model Extension (SME) for the description of the resulting low-energy effects is introduced, and some experimental tests of Lorentz and CPT invariance are discussed

Lorentz Invariance Violation effects on UHECR propagation: A geometrized approach

Science.gov (United States)

Torri, Marco Danilo Claudio; Bertini, Stefano; Giammarchi, Marco; Miramonti, Lino

2018-06-01

We explore the possibility to geometrize the interaction of massive fermions with the quantum structure of space-time, trying to create a theoretical background, in order to explain what some recent experimental results seem to implicate on the propagation of Ultra High Energy Cosmic Rays (UHECR). We will investigate part of the phenomenological implications of this approach on the predicted effect of the UHECR suppression, in fact recent evidences seem to involve the modification of the GZK cut-off phenomenon. The search for an effective theory, which can explain this physical effect, is based on Lorentz Invariance Violation (LIV), which is introduced via Modified Dispersion Relations (MDRs). Furthermore we illustrate that this perspective implies a more general geometry of space-time than the usual Riemannian one, indicating, for example, the opportunity to resort to Finsler theory.

Lorentz violation. Motivation and new constraints

Energy Technology Data Exchange (ETDEWEB)

Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2009-09-15

We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

Lorentz violation. Motivation and new constraints

International Nuclear Information System (INIS)

Liberati, S.; Maccione, L.

2009-09-01

We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

On the Lorentz invariance of bit-string geometry

International Nuclear Information System (INIS)

Noyes, H.P.

1995-09-01

We construct the class of integer-sided triangles and tetrahedra that respectively correspond to two or three discriminately independent bit-strings. In order to specify integer coordinates in this space, we take one vertex of a regular tetrahedron whose common edge length is an even integer as the origin of a line of integer length to the open-quotes pointclose quotes and three integer distances to this open-quotes pointclose quotes from the three remaining vertices of the reference tetrahedron. This - usually chiral - integer coordinate description of bit-string geometry is possible because three discriminately independent bit-strings generate four more; the Hamming measures of these seven strings always allow this geometrical interpretation. On another occasion we intend to prove the rotational invariance of this coordinate description. By identifying the corners of these figures with the positions of recording counters whose clocks are synchronized using the Einstein convention, we define velocities in this space. This suggests that it may be possible to define boosts and discrete Lorentz transformations in a space of integer coordinates. We relate this description to our previous work on measurement accuracy and the discrete ordered calculus of Etter and Kauffman (DOC)

Lorentz covariant tempered distributions in two-dimensional space-time

International Nuclear Information System (INIS)

Zinov'ev, Yu.M.

1989-01-01

The problem of describing Lorentz covariant distributions without any spectral condition has hitherto remained unsolved even for two-dimensional space-time. Attempts to solve this problem have already been made. Zharinov obtained an integral representation for the Laplace transform of Lorentz invariant distributions with support in the product of two-dimensional future light cones. However, this integral representation does not make it possible to obtain a complete description of the corresponding Lorentz invariant distributions. In this paper the author gives a complete description of Lorentz covariant distributions for two-dimensional space-time. No spectral conditions is assumed

Lorentz violation naturalness revisited

Energy Technology Data Exchange (ETDEWEB)

Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)

2016-06-08

We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

Lorentz covariant canonical symplectic algorithms for dynamics of charged particles

Science.gov (United States)

Wang, Yulei; Liu, Jian; Qin, Hong

2016-12-01

In this paper, the Lorentz covariance of algorithms is introduced. Under Lorentz transformation, both the form and performance of a Lorentz covariant algorithm are invariant. To acquire the advantages of symplectic algorithms and Lorentz covariance, a general procedure for constructing Lorentz covariant canonical symplectic algorithms (LCCSAs) is provided, based on which an explicit LCCSA for dynamics of relativistic charged particles is built. LCCSA possesses Lorentz invariance as well as long-term numerical accuracy and stability, due to the preservation of a discrete symplectic structure and the Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which are difficult to handle in traditional construction procedures of symplectic algorithms, LCCSA provides a perfect explicit canonical symplectic solution by implementing the discretization in 4-spacetime. We also show that LCCSA has built-in energy-based adaptive time steps, which can optimize the computation performance when the Lorentz factor varies.

Modelling Planck-scale Lorentz violation via analogue models

International Nuclear Information System (INIS)

Weinfurtner, Silke; Liberati, Stefano; Visser, Matt

2006-01-01

Astrophysical tests of Planck-suppressed Lorentz violations had been extensively studied in recent years and very stringent constraints have been obtained within the framework of effective field theory. There are however still some unresolved theoretical issues, in particular regarding the so called 'naturalness problem' - which arises when postulating that Planck suppressed Lorentz violations arise only from operators with mass dimension greater than four in the Lagrangian. In the work presented here we shall try to address this problem by looking at a condensed-matter analogue of the Lorentz violations considered in quantum gravity phenomenology. specifically, we investigate the class of two-component BECs subject to laserinduced transitions between the two components, and we show that this model is an example for Lorentz invariance violation due to ultraviolet physics. We shall show that such a model can be considered to be an explicit example high-energy Lorentz violations where the 'naturalness problem' does not arise

Constrained Gauge Fields from Spontaneous Lorentz Violation

CERN Document Server

Chkareuli, J L; Jejelava, J G; Nielsen, H B

2008-01-01

Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type $A_{\\mu}^{2}=M^{2}$ ($M$ is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory proves to be QED with a massless vector Goldstone boson naturally associated with the photon, while the non-Abelian symmetry case results in a conventional Yang-Mills theory. These theories, both Abelian and non-Abelian, look essentially nonlinear and contain particular Lorentz (and $CPT$) violating couplings when expressed in terms of the pure Goldstone vector modes. However, they do not lead to physical ...

Searching for Lorentz violation

International Nuclear Information System (INIS)

Allen, Roland E.; Yokoo, Seiichirou

2004-01-01

Astrophysical, terrestrial, and space-based searches for Lorentz violation are very briefly reviewed. Such searches are motivated by the fact that all superunified theories (and other theories that attempt to include quantum gravity) have some potential for observable violations of Lorentz invariance. Another motivation is the exquisite sensitivity of certain well-designed experiments and observations to particular forms of Lorentz violation. We also review some new predictions of a specific Lorentz-violating theory: If a fundamental energy m-bar c2 in this theory lies below the usual GZK cutoff E GZK , the cutoff is shifted to infinite energy; i.e., it no longer exists. On the other hand, if m-bar c2 lies above E GZK , there is a high-energy branch of the fermion dispersion relation which provides an alternative mechanism for super-GZK cosmic-ray protons

Search for Violation of CPT and Lorentz Invariance in $B^0_s$ Meson Oscillations using the D0 Detector

Energy Technology Data Exchange (ETDEWEB)

Van Kooten, R. [Indiana U.

2017-01-01

A search is presented for CPT-violating effects in the mixing of $B^0_s$ mesons using the D0 detector at the Fermilab Tevatron Collider. The CPT-violating asymmetry in the decay $B^0_s \\rightarrow \\mu^{\\pm} D_s^{\\mp} X$ as a function of sidereal phase is measured. No evidence for CPT-violating effects is observed and limits are placed on CPT- and Lorentz-invariance violating coupling coefficients.

Lorentz invariance from classical particle paths in quantum field theory of electric and magnetic charge

International Nuclear Information System (INIS)

Brandt, R.A.; Neri, F.; Zwanziger, D.

1979-01-01

We establish the Lorentz invariance of the quantum field theory of electric and magnetic charge. This is a priori implausible because the theory is the second-quantized version of a classical field theory which is inconsistent if the minimally coupled charged fields are smooth functions. For our proof we express the generating functional for the gauge-invariant Green's functions of quantum electrodynamics: with or without magnetic charge: as a path integral over the trajectories of classical charged point particles. The electric-electric and electric-magnetic interactions contribute factors exp(JDJ) and exp(JD'K), where J and K are the electric and magnetic currents of classical point particles and D is the usual photon propagator. The propagator D' involves the Dirac string but exp(JD'K) depends on it only through a topological integer linking string and classical particle trajectories. The charge quantization condition e/sub i/g/sub j/ - g/sub i/e/sub j/ = integer then suffices to make the gauge-invariant Green's functions string independent. By implication our formulation shows that if the Green's functions of quantum electrodynamics are expressed as usual as functional integrals over classical charged fields, the smooth field configurations have measure zero and all the support of the Feynman measure lies on the trajectories of classical point particles

Searches for Lorentz Violation in Top-Quark Production and Decay at Hadron Colliders

Energy Technology Data Exchange (ETDEWEB)

Whittington, Denver Wade [Indiana Univ., Bloomington, IN (United States)

2012-07-01

We present a first-of-its-kind confirmation that the most massive known elementary particle obeys the special theory of relativity. Lorentz symmetry is a fundamental aspect of special relativity which posits that the laws of physics are invariant regardless of the orientation and velocity of the reference frame in which they are measured. Because this symmetry is a fundamental tenet of physics, it is important to test its validity in all processes. We quantify violation of this symmetry using the Standard-Model Extension framework, which predicts the effects that Lorentz violation would have on elementary particles and their interactions. The top quark is the most massive known elementary particle and has remained inaccessible to tests of Lorentz invariance until now. This model predicts a dependence of the production cross section for top and antitop quark pairs on sidereal time as the orientation of the experiment in which these events are produced changes with the rotation of the Earth. Using data collected with the DØ detector at the Fermilab Tevatron Collider, we search for violation of Lorentz invariance in events involving the production of a $t\\bar{t}$ pair. Within the experimental precision, we find no evidence for such a violation and set upper limits on parameters describing its possible strength within the Standard-Model Extension. We also investigate the prospects for extending this analysis using the ATLAS detector at the Large Hadron Collider which, because of the higher rate of $t\\bar{t}$ events at that experiment, has the potential to improve the limits presented here.

Lorentz Covariance of Langevin Equation

International Nuclear Information System (INIS)

Koide, T.; Denicol, G.S.; Kodama, T.

2008-01-01

Relativistic covariance of a Langevin type equation is discussed. The requirement of Lorentz invariance generates an entanglement between the force and noise terms so that the noise itself should not be a covariant quantity. (author)

CPT and Lorentz violation as signatures for Planck-scale physics

International Nuclear Information System (INIS)

Lehnert, Ralf

2009-01-01

In recent years, the breakdown of spacetime symmetries has been identified as a promising research field in the context of Planck-scale phenomenology. For example, various theoretical approaches to the quantum-gravity problem are known to accommodate minute violations of CPT invariance. This talk covers various topics within this research area. In particular, some mechanisms for spacetime-symmetry breaking as well as the Standard-Model Extension (SME) test framework will be reviewed; the connection between CPT and Lorentz invariance in quantum field theory will be exposed; and the a few experimental CPT tests with emphasis on matter-antimatter comparisons will be discussed.

Lorentz and CPT violation in the Standard-Model Extension

Energy Technology Data Exchange (ETDEWEB)

Lehnert, Ralf, E-mail: ralehner@indiana.edu [Indiana University Center for Spacetime Symmetries (United States)

2013-03-15

Lorentz and CPT invariance are among the symmetries that can be investigated with ultrahigh precision in subatomic physics. Being spacetime symmetries, Lorentz and CPT invariance can be violated by minuscule amounts in many theoretical approaches to underlying physics that involve novel spacetime concepts, such as quantized versions of gravity. Regardless of the underlying mechanism, the low-energy effects of such violations are expected to be governed by effective field theory. This talk provides a survey of this idea and includes an overview of experimental efforts in the field.

Search for Violation of $CPT$ and Lorentz invariance in ${B_s^0}$ meson oscillations

CERN Document Server

Abazov, Victor Mukhamedovich; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Agnew, James P; Alexeev, Guennadi D; Alkhazov, Georgiy D; Alton, Andrew K; Askew, Andrew Warren; Atkins, Scott; Augsten, Kamil; Avila, Carlos A; Badaud, Frederique; Bagby, Linda F; Baldin, Boris; Bandurin, Dmitry V; Banerjee, Sunanda; Barberis, Emanuela; Baringer, Philip S; Bartlett, JFrederick; Bassler, Ursula Rita; Bazterra, Victor; Bean, Alice L; Begalli, Marcia; Bellantoni, Leo; Beri, Suman B; Bernardi, Gregorio; Bernhard, Ralf Patrick; Bertram, Iain A; Besancon, Marc; Beuselinck, Raymond; Bhat, Pushpalatha C; Bhatia, Sudeep; Bhatnagar, Vipin; Blazey, Gerald Charles; Blessing, Susan K; Bloom, Kenneth A; Boehnlein, Amber S; Boline, Daniel Dooley; Boos, Edward E; Borissov, Guennadi; Borysova, Maryna; Brandt, Andrew; Brandt, Oleg; Brock, Raymond L; Bross, Alan D; Brown, Duncan Paul; Bu, Xue-Bing; Buehler, Marc; Buescher, Volker; Bunichev, Viacheslav Yevgenyevich; Burdin, Sergey; Buszello, Claus Peter; Camacho-Perez, Enrique; Casey, Brendan Cameron Kieran; Castilla-Valdez, Heriberto; Caughron, Seth Aaron; Chakrabarti, Subhendu; Chan, Kwok Ming Leo; Chandra, Avdhesh; Chapon, Emilien; Chen, Guo; Cho, Sung-Woong; Choi, Suyong; Choudhary, Brajesh C; Cihangir, Selcuk; Claes, Daniel R; Clutter, Justace Randall; Cooke, Michael P; Cooper, William Edward; Corcoran, Marjorie D; Couderc, Fabrice; Cousinou, Marie-Claude; Cuth, Jakub; Cutts, David; Das, Amitabha; Davies, Gavin John; de Jong, Sijbrand Jan; De La Cruz-Burelo, Eduard; Deliot, Frederic; Demina, Regina; Denisov, Dmitri S; Denisov, Sergei P; Desai, Satish Vijay; Deterre, Cecile; DeVaughan, Kayle Otis; Diehl, HThomas; Diesburg, Michael; Ding, Pengfei; Dominguez, DAaron M; Dubey, Abhinav Kumar; Dudko, Lev V; Duperrin, Arnaud; Dutt, Suneel; Eads, Michael T; Edmunds, Daniel L; Ellison, John A; Elvira, VDaniel; Enari, Yuji; Evans, Harold G; Evdokimov, Anatoly V; Evdokimov, Valeri N; Faure, Alexandre; Feng, Lei; Ferbel, Thomas; Fiedler, Frank; Filthaut, Frank; Fisher, Wade Cameron; Fisk, HEugene; Fortner, Michael R; Fox, Harald; Fuess, Stuart C; Garbincius, Peter H; Garcia-Bellido, Aran; Garcia-Gonzalez, Jose Andres; Gavrilov, Vladimir B; Geng, Weigang; Gerber, Cecilia Elena; Gershtein, Yuri S; Ginther, George E; Gogota, Olga; Golovanov, Georgy Anatolievich; Grannis, Paul D; Greder, Sebastien; Greenlee, Herbert B; Grenier, Gerald Jean; Gris, Phillipe Luc; Grivaz, Jean-Francois; Grohsjean, Alexander; Gruenendahl, Stefan; Gruenewald, Martin Werner; Guillemin, Thibault; Gutierrez, Gaston R; Gutierrez, Phillip; Haley, Joseph Glenn Biddle; Han, Liang; Harder, Kristian; Harel, Amnon; Hauptman, John Michael; Hays, Jonathan M; Head, Tim; Hebbeker, Thomas; Hedin, David R; Hegab, Hatim; Heinson, Ann; Heintz, Ulrich; Hensel, Carsten; Heredia-De La Cruz, Ivan; Herner, Kenneth Richard; Hesketh, Gavin G; Hildreth, Michael D; Hirosky, Robert James; Hoang, Trang; Hobbs, John D; Hoeneisen, Bruce; Hogan, Julie; Hohlfeld, Mark; Holzbauer, Jenny Lyn; Howley, Ian James; Hubacek, Zdenek; Hynek, Vlastislav; Iashvili, Ia; Ilchenko, Yuriy; Illingworth, Robert A; Ito, Albert S; Jabeen, Shabnam; Jaffre, Michel J; Jayasinghe, Ayesh; Jeong, Min-Soo; Jesik, Richard L; Jiang, Peng; Johns, Kenneth Arthur; Johnson, Emily; Johnson, Marvin E; Jonckheere, Alan M; Jonsson, Per Martin; Joshi, Jyoti; Jung, Andreas Werner; Juste, Aurelio; Kajfasz, Eric; Karmanov, Dmitriy Y; Katsanos, Ioannis; Kaur, Manbir; Kehoe, Robert Leo Patrick; Kermiche, Smain; Khalatyan, Norayr; Khanov, Alexander; Kharchilava, Avto; Kharzheev, Yuri N; Kiselevich, Ivan Lvovich; Kohli, Jatinder M; Kozelov, Alexander V; Kraus, James Alexander; Kumar, Ashish; Kupco, Alexander; Kurca, Tibor; Kuzmin, Valentin Alexandrovich; Lammers, Sabine Wedam; Lebrun, Patrice; Lee, Hyeon-Seung; Lee, Seh-Wook; Lee, William M; Lei, Xiaowen; Lellouch, Jeremie; Li, Dikai; Li, Hengne; Li, Liang; Li, Qi-Zhong; Lim, Jeong Ku; Lincoln, Donald W; Linnemann, James Thomas; Lipaev, Vladimir V; Lipton, Ronald J; Liu, Huanzhao; Liu, Yanwen; Lobodenko, Alexandre; Lokajicek, Milos; Lopes de Sa, Rafael; Luna-Garcia, Rene; Lyon, Adam Leonard; Maciel, Arthur KA; Madar, Romain; Magana-Villalba, Ricardo; Malik, Sudhir; Malyshev, Vladimir L; Mansour, Jason; Martinez-Ortega, Jorge; McCarthy, Robert L; Mcgivern, Carrie Lynne; Meijer, Melvin M; Melnitchouk, Alexander S; Menezes, Diego D; Mercadante, Pedro Galli; Merkin, Mikhail M; Meyer, Arnd; Meyer, Jorg Manfred; Miconi, Florian; Mondal, Naba K; Mulhearn, Michael James; Nagy, Elemer; Narain, Meenakshi; Nayyar, Ruchika; Neal, Homer A; Negret, Juan Pablo; Neustroev, Petr V; Nguyen, Huong Thi; Nunnemann, Thomas P; Hernandez Orduna, Jose de Jesus; Osman, Nicolas Ahmed; Osta, Jyotsna; Pal, Arnab; Parashar, Neeti; Parihar, Vivek; Park, Sung Keun; Partridge, Richard A; Parua, Nirmalya; Patwa, Abid; Penning, Bjoern; Perfilov, Maxim Anatolyevich; Peters, Reinhild Yvonne Fatima; Petridis, Konstantinos; Petrillo, Gianluca; Petroff, Pierre; Pleier, Marc-Andre; Podstavkov, Vladimir M; Popov, Alexey V; Prewitt, Michelle; Price, Darren; Prokopenko, Nikolay N; Qian, Jianming; Quadt, Arnulf; Quinn, Gene Breese; Ratoff, Peter N; Razumov, Ivan A; Ripp-Baudot, Isabelle; Rizatdinova, Flera; Rominsky, Mandy Kathleen; Ross, Anthony; Royon, Christophe; Rubinov, Paul Michael; Ruchti, Randal C; Sajot, Gerard; Sanchez-Hernandez, Alberto; Sanders, Michiel P; Santos, Angelo Souza; Savage, David G; Savitskyi, Mykola; Sawyer, HLee; Scanlon, Timothy P; Schamberger, RDean; Scheglov, Yury A; Schellman, Heidi M; Schott, Matthias; Schwanenberger, Christian; Schwienhorst, Reinhard H; Sekaric, Jadranka; Severini, Horst; Shabalina, Elizaveta K; Shary, Viacheslav V; Shaw, Savanna; Shchukin, Andrey A; Simak, Vladislav J; Skubic, Patrick Louis; Slattery, Paul F; Smirnov, Dmitri V; Snow, Gregory R; Snow, Joel Mark; Snyder, Scott Stuart; Soldner-Rembold, Stefan; Sonnenschein, Lars; Soustruznik, Karel; Stark, Jan; Stoyanova, Dina A; Strauss, Michael G; Suter, Louise; Svoisky, Peter V; Titov, Maxim; Tokmenin, Valeriy V; Tsai, Yun-Tse; Tsybychev, Dmitri; Tuchming, Boris; Tully, Christopher George T; Uvarov, Lev; Uvarov, Sergey L; Uzunyan, Sergey A; Van Kooten, Richard J; van Leeuwen, Willem M; Varelas, Nikos; Varnes, Erich W; Vasilyev, Igor A; Verkheev, Alexander Yurievich; Vertogradov, Leonid S; Verzocchi, Marco; Vesterinen, Mika; Vilanova, Didier; Vokac, Petr; Wahl, Horst D; Wang, Michael HLS; Warchol, Jadwiga; Watts, Gordon Thomas; Wayne, Mitchell R; Weichert, Jonas; Welty-Rieger, Leah Christine; Williams, Mark Richard James; Wilson, Graham Wallace; Wobisch, Markus; Wood, Darien Robert; Wyatt, Terence R; Xie, Yunhe; Yamada, Ryuji; Yang, Siqi; Yasuda, Takahiro; Yatsunenko, Yuriy A; Ye, Wanyu; Ye, Zhenyu; Yin, Hang; Yip, Kin; Youn, Sungwoo; Yu, Jiaming; Zennamo, Joseph; Zhao, Tianqi Gilbert; Zhou, Bing; Zhu, Junjie; Zielinski, Marek; Zieminska, Daria; Zivkovic, Lidija

2015-10-14

We present the first search for CPT-violating effects in the mixing of ${B_s^0}$ mesons using the full Run II data set with an integrated luminosity of 10.4 fb$^{-1}$ of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay $B_s^0 \\to \\mu^\\pm D_s^\\pm$ as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95\\% confidence intervals of $\\Delta a_{\\perp} < 1.2 \\times 10^{-12}$ GeV and $(-0.8 < \\Delta a_T - 0.396 \\Delta a_Z < 3.9) \\times 10^{-13}$ GeV.

Electromagnetic pion production in manifestly Lorentz invariant baryonic chiral perturbation theory; Elektromagnetische Pionproduktion in manifest Lorentz-invarianter baryonischer chiraler Stoerungstheorie

Energy Technology Data Exchange (ETDEWEB)

Lehnhart, B.C.

2007-05-15

This thesis is concerned with electromagnetic pion production within manifestly Lorentz-invariant chiral perturbation theory using the assumption of isospin symmetry. In a one-loop calculation up to the chiral order O(q{sup 4}), 105 Feynman diagrams contribute, consisting of 20 tree graphs and 85 loop diagrams. The tree graphs are classified as 16 pole diagrams and 4 contact graphs. Of the 85 loop diagrams, 50 diagrams are of order three and 35 diagrams are of fourth order. To calculate the pion production amplitude algorithms are developed on the basis of the Mathematica package FeynCalc. The one-photon-exchange approximation allows one to parametrise the pion production amplitude as the product of the polarisation vector of the (virtual) photon and the matrix element of the transition current. The polarisation vector is related to the leptonic vertex and the photon propagator and is well-known from QED. The dependence of the amplitude on the strong interaction is contained in the matrix element of the transition current, and we use chiral perturbation theory to describe this matrix element. The transition current can be expressed in terms of six gauge invariant amplitudes, each of which can again be decomposed into three isospin amplitudes. Linear combinations of these amplitudes allow us to describe the physical amplitudes. The one-loop integrals appearing within this calculation are determined numerically by the program LoopTools. In the case of tensorial integrals it is required to perform the method of Passarino and Veltman first. Furthermore, we apply the reformulated infrared regularisation which ensures that the results fulfill the chiral power counting. For this purpose algorithms are developed which determine the subtraction terms automatically. The obtained isospin amplitudes are integrated in the program MAID. As tests the s-wave multipoles E{sub 0+} and L{sub 0+} (using results up to chiral order O(q{sup 3})) are calculated in the threshold region

Anomalous Lorentz and CPT violation

Science.gov (United States)

Klinkhamer, F. R.

2018-01-01

If there exists Lorentz and CPT violation in nature, then it is crucial to discover and understand the underlying mechanism. In this contribution, we discuss one such mechanism which relies on four-dimensional chiral gauge theories defined over a spacetime manifold with topology ℛ3 × S 1 and periodic spin structure for the compact dimension. It can be shown that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. For arbitrary Abelian U(1) gauge fields with trivial holonomies in the compact direction, this anomalous Lorentz and CPT violation has recently been established perturbatively with a Pauli-Villars-type regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.

A new perspective on relativistic transformation: formulation of the differential Lorentz transformation based on first principles

International Nuclear Information System (INIS)

Huang, Young-Sea

2010-01-01

The differential Lorentz transformation is formulated solely from the principle of relativity and the invariance of the speed of light. The differential Lorentz transformation transforms physical quantities, instead of space-time coordinates, to keep laws of nature form-invariant among inertial frames. The new relativistic transformation fulfills the principle of relativity, whereas the usual Lorentz transformation of space-time coordinates does not. Furthermore, the new relativistic transformation is compatible with quantum mechanics. The formulation herein provides theoretical foundations for the differential Lorentz transformation as the fundamental relativistic transformation.

Lorentz-violating alternative to the Higgs mechanism?

International Nuclear Information System (INIS)

Alexandre, Jean; Mavromatos, Nick E.

2011-01-01

We consider a four-dimensional field-theory model with two massless fermions, coupled to an Abelian vector field without flavor mixing, and to another Abelian vector field with flavor mixing. Both Abelian vectors have a Lorentz-violating kinetic term, introducing a Lorentz-violation mass scale M, from which fermions and the flavor-mixing vector get their dynamical masses, whereas the vector coupled without flavor mixing remains massless. When the two coupling constants have similar values in order of magnitude, a mass hierarchy pattern emerges, in which one fermion is very light compared to the other, while the vector mass is of the order of the heavy fermion mass. The work presented here may be considered as a Lorentz-symmetry-violating alternative to the Higgs mechanism, in the sense that no scalar particle (fundamental or composite) is necessary for the generation of the vector-meson mass. However, the model is not realistic given that, as a result of Lorentz violation, the maximal (light-cone) speed seen by the fermions is smaller than that of the massless gauge boson (which equals the speed of light in vacuo) by an amount which is unacceptably large to be compatible with the current tests of Lorentz invariance, unless the gauge couplings assume unnaturally small values. Possible ways out of this phenomenological drawback are briefly discussed, postponing a detailed construction of more realistic models for future work.

Generalizations of teleparallel gravity and local Lorentz symmetry

International Nuclear Information System (INIS)

Sotiriou, Thomas P.; Barrow, John D.; Li Baojiu

2011-01-01

We analyze the relation between teleparallelism and local Lorentz invariance. We show that generic modifications of the teleparallel equivalent to general relativity will not respect local Lorentz symmetry. We clarify the reasons for this and explain why the situation is different in general relativity. We give a prescription for constructing teleparallel equivalents for known theories. We also explicitly consider a recently proposed class of generalized teleparallel theories, called f(T) theories of gravity, and show why restoring local Lorentz symmetry in such theories cannot lead to sensible dynamics, even if one gives up teleparallelism.

Spacetime-varying couplings and Lorentz violation

International Nuclear Information System (INIS)

Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

2003-01-01

Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

Lorentz violation and generalized uncertainty principle

Science.gov (United States)

Lambiase, Gaetano; Scardigli, Fabio

2018-04-01

Investigations on possible violation of Lorentz invariance have been widely pursued in the last decades, both from theoretical and experimental sides. A comprehensive framework to formulate the problem is the standard model extension (SME) proposed by A. Kostelecky, where violation of Lorentz invariance is encoded into specific coefficients. Here we present a procedure to link the deformation parameter β of the generalized uncertainty principle to the SME coefficients of the gravity sector. The idea is to compute the Hawking temperature of a black hole in two different ways. The first way involves the deformation parameter β , and therefore we get a deformed Hawking temperature containing the parameter β . The second way involves a deformed Schwarzschild metric containing the Lorentz violating terms s¯μ ν of the gravity sector of the SME. The comparison between the two different techniques yields a relation between β and s¯μ ν. In this way bounds on β transferred from s¯μ ν are improved by many orders of magnitude when compared with those derived in other gravitational frameworks. Also the opposite possibility of bounds transferred from β to s¯μ ν is briefly discussed.

Vortices in superconductors from Lorentz violation

International Nuclear Information System (INIS)

Belich, H.; Orlando, M.T.D.; Costa-Soares, T.; Helayel-Neto, J.A.

2004-01-01

We start from a Lorentz non-invariant Abelian-Higgs model in 1+3 dimensions, and carry out its dimensional reduction to D = 1 + 2. The planar model resulting thereof is composed by a Maxwell-Chern-Simons-Proca gauge sector, a massive scalar sector, and a mixing term (involving the fixed background, v μ ) that realizes Lorentz violation for the reduced model. Vortex type solutions of the planar model are investigated in a superconducting environment . Our vortex solutions are electrically charged and exhibit a screened electric field. (author)

An application of Lorentz-invariance violation in black hole thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Li, Guo-Ping; Zu, Xiao-Tao [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Pu, Jin [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); China West Normal University, College of Physics and Space Science, Nanchong (China); Jiang, Qing-Quan [China West Normal University, College of Physics and Space Science, Nanchong (China)

2017-10-15

In this paper, we have applied the Lorentz-invariance violation (LIV) class of dispersion relations (DRs) with the dimensionless parameter n = 2 and the ''sign of LIV'' η{sub +} = 1, to a phenomenological study of the effect of quantum gravity in a strong gravitational field. Specifically, we have studied the effect of the LIV-DR induced quantum gravity on the Schwarzschild black hole thermodynamics. The result shows that the effect of the LIV-DR induced quantum gravity speeds up the black hole evaporation, and its corresponding black hole entropy undergoes a leading logarithmic correction to the ''reduced Bekenstein-Hawking entropy'', and the ill-defined situations (i.e. the singularity problem and the critical problem) are naturally bypassed when the LIV-DR effect is present. Also, to put our results in a proper perspective, we have compared results with the earlier findings by another quantum-gravity candidate, i.e. the generalized uncertainty principle (GUP). Finally, we conclude from the inert remnants at the final stage of the black hole evaporation that, the GUP as a candidate for describing quantum gravity can always do as well as the LIV-DR by adjusting the model-dependent parameters, but in the same model-dependent parameters the LIV-DR acts as a more suitable candidate. (orig.)

New bounds on isotropic Lorentz violation

International Nuclear Information System (INIS)

Carone, Christopher D.; Sher, Marc; Vanderhaeghen, Marc

2006-01-01

Violations of Lorentz invariance that appear via operators of dimension four or less are completely parametrized in the Standard Model Extension (SME). In the pure photonic sector of the SME, there are 19 dimensionless, Lorentz-violating parameters. Eighteen of these have experimental upper bounds ranging between 10 -11 and 10 -32 ; the remaining parameter, k-tilde tr , is isotropic and has a much weaker bound of order 10 -4 . In this Brief Report, we point out that k-tilde tr gives a significant contribution to the anomalous magnetic moment of the electron and find a new upper bound of order 10 -8 . With reasonable assumptions, we further show that this bound may be improved to 10 -14 by considering the renormalization of other Lorentz-violating parameters that are more tightly constrained. Using similar renormalization arguments, we also estimate bounds on Lorentz-violating parameters in the pure gluonic sector of QCD

Statistical mechanics and Lorentz violation

International Nuclear Information System (INIS)

Colladay, Don; McDonald, Patrick

2004-01-01

The theory of statistical mechanics is studied in the presence of Lorentz-violating background fields. The analysis is performed using the Standard-Model Extension (SME) together with a Jaynesian formulation of statistical inference. Conventional laws of thermodynamics are obtained in the presence of a perturbed hamiltonian that contains the Lorentz-violating terms. As an example, properties of the nonrelativistic ideal gas are calculated in detail. To lowest order in Lorentz violation, the scalar thermodynamic variables are only corrected by a rotationally invariant combination of parameters that mimics a (frame dependent) effective mass. Spin-couplings can induce a temperature-independent polarization in the classical gas that is not present in the conventional case. Precision measurements in the residual expectation values of the magnetic moment of Fermi gases in the limit of high temperature may provide interesting limits on these parameters

Lorentz invariance violation and chemical composition of ultra high energy cosmic rays

Energy Technology Data Exchange (ETDEWEB)

Saveliev, Andrey; Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group

2010-12-15

Motivated by experimental indications of a significant presence of heavy nuclei in the cosmic ray flux at ultra high energies (>or similar 10{sup 19} eV), we consider the effects of Planck scale suppressed Lorentz Invariance Violation (LIV) on the propagation of cosmic ray nuclei. In particular we focus on LIV effects on the photodisintegration of nuclei onto the background radiation fields. After a general discussion of the behavior of the relevant quantities, we apply our formalism to a simplified model where the LIV parameters of the various nuclei are assumed to kinematically result from a single LIV parameter for the constituent nucleons, {eta}, and we derive constraints on {eta}. Assuming a nucleus of a particular species to be actually present at 10{sup 20} eV the following constraints can be placed: -3 x 10{sup -2}

Conditions for Lorentz-invariant superluminal information transfer without signaling

Science.gov (United States)

Grössing, G.; Fussy, S.; Mesa Pascasio, J.; Schwabl, H.

2016-03-01

We understand emergent quantum mechanics in the sense that quantum mechanics describes processes of physical emergence relating an assumed sub-quantum physics to macroscopic boundary conditions. The latter can be shown to entail top-down causation, in addition to usual bottom-up scenarios. With this example it is demonstrated that definitions of “realism” in the literature are simply too restrictive. A prevailing manner to define realism in quantum mechanics is in terms of pre-determination independent of the measurement. With our counter-example, which actually is ubiquitous in emergent, or self-organizing, systems, we argue for realism without pre-determination. We refer to earlier results of our group showing how the guiding equation of the de Broglie-Bohm interpretation can be derived from a theory with classical ingredients only. Essentially, this corresponds to a “quantum mechanics without wave functions” in ordinary 3-space, albeit with nonlocal correlations. This, then, leads to the central question of how to deal with the nonlocality problem in a relativistic setting. We here show that a basic argument discussing the allegedly paradox time ordering of events in EPR-type two-particle experiments falls short of taking into account the contextuality of the experimental setup. Consequently, we then discuss under which circumstances (i.e. physical premises) superluminal information transfer (but not signaling) may be compatible with a Lorentz-invariant theory. Finally, we argue that the impossibility of superluminal signaling - despite the presence of superluminal information transfer - is not the result of some sort of conspiracy (á la “Nature likes to hide”), but the consequence of the impossibility to exactly reproduce in repeated experimental runs a state's preparation, or of the no-cloning theorem, respectively.

Conditions for Lorentz-invariant superluminal information transfer without signaling

International Nuclear Information System (INIS)

Grössing, G; Fussy, S; Pascasio, J Mesa; Schwabl, H

2016-01-01

We understand emergent quantum mechanics in the sense that quantum mechanics describes processes of physical emergence relating an assumed sub-quantum physics to macroscopic boundary conditions. The latter can be shown to entail top-down causation, in addition to usual bottom-up scenarios. With this example it is demonstrated that definitions of “realism” in the literature are simply too restrictive. A prevailing manner to define realism in quantum mechanics is in terms of pre-determination independent of the measurement. With our counter-example, which actually is ubiquitous in emergent, or self-organizing, systems, we argue for realism without pre-determination. We refer to earlier results of our group showing how the guiding equation of the de Broglie-Bohm interpretation can be derived from a theory with classical ingredients only. Essentially, this corresponds to a “quantum mechanics without wave functions” in ordinary 3-space, albeit with nonlocal correlations. This, then, leads to the central question of how to deal with the nonlocality problem in a relativistic setting. We here show that a basic argument discussing the allegedly paradox time ordering of events in EPR-type two-particle experiments falls short of taking into account the contextuality of the experimental setup. Consequently, we then discuss under which circumstances (i.e. physical premises) superluminal information transfer (but not signaling) may be compatible with a Lorentz-invariant theory. Finally, we argue that the impossibility of superluminal signaling - despite the presence of superluminal information transfer - is not the result of some sort of conspiracy (á la “Nature likes to hide”), but the consequence of the impossibility to exactly reproduce in repeated experimental runs a state's preparation, or of the no-cloning theorem, respectively. (paper)

The energy-momentum spectrum in local field theories with broken Lorentz-symmetry

International Nuclear Information System (INIS)

Borchers, H.J.; Buchholz, D.

1984-05-01

Assuming locality of the observables and positivity of the energy it is shown that the joint spectrum of the energy-momentum operators has a Lorentz-invariant lower boundary in all superselection sectors. This result is of interest if the Lorentz-symmetry is (spontaneously) broken, such as in the charged sectors of quantum electrodynamics. (orig.)

Cosmological constraints on Lorentz violating dark energy

CERN Document Server

Audren, B; Lesgourgues, J; Sibiryakov, S

2013-01-01

The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the case for the cosmological constant problem. Indeed, it has been shown that breaking Lorentz invariance provides Lagrangians that can drive the current acceleration of the universe without experiencing large corrections from ultraviolet physics. In this work, we focus on the simplest model of this type, called ThetaCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from LambdaCDM. The differences appear at the level of perturbations. We show that in ThetaCDM, the spectrum of CMB anisotropies and matter fluctuations may be affected by a rescaling of the gravitational constant in the Poisson equation, by the presence of extra contributions to the anisotropic stress, and finally by the existence of ...

Lorentz invariance violation and simultaneous emission of electromagnetic and gravitational waves

Directory of Open Access Journals (Sweden)

E. Passos

2017-09-01

Full Text Available In this work, we compute some phenomenological bounds for the electromagnetic and massive gravitational high-derivative extensions supposing that it is possible to have an astrophysical process that generates simultaneously gravitational and electromagnetic waves. We present Lorentz invariance violating (LIV higher-order derivative models, following the Myers–Pospelov approach, to electrodynamics and massive gravitational waves. We compute the corrected equation of motion of these models, their dispersion relations and the velocities. The LIV parameters for the gravitational and electromagnetic sectors, ξg and ξγ, respectively, were also obtained for three different approaches: luminal photons, time delay of flight and the difference of graviton and photon velocities. These LIV parameters depend on the mass scales where the LIV-terms become relevant, M for the electromagnetic sector and M1 for the gravitational one. We obtain, using the values for M and M1 found in the literature, that ξg∼10−2, which is expected to be phenomenologically relevant and ξγ∼103, which cannot be suitable for an effective LIV theory. However, we show that ξγ can be interesting in a phenomenological point of view if M≫M1. Finally the relation between the variation of the velocities of the photon and the graviton in relation to the speed of light was calculated and resulted in Δvg/Δvγ≲1.82×10−3.

Lorentz violating p-form gauge theories in superspace

Energy Technology Data Exchange (ETDEWEB)

Upadhyay, Sudhaker [Indian Institute of Technology Kharagpur, Centre for Theoretical Studies, Kharagpur (India); Shah, Mushtaq B.; Ganai, Prince A. [National Institute of Technology, Department of Physics, Srinagar, Kashmir (India)

2017-03-15

Very special relativity (VSR) keeps the main features of special relativity but breaks rotational invariance due to an intrinsic preferred direction. We study the VSR-modified extended BRST and anti-BRST symmetry of the Batalin-Vilkovisky (BV) actions corresponding to the p = 1, 2, 3-form gauge theories. Within the VSR framework, we discuss the extended BRST invariant and extended BRST and anti-BRST invariant superspace formulations for these BV actions. Here we observe that the VSR-modified extended BRST invariant BV actions corresponding to the p = 1, 2, 3-form gauge theories can be written in a manifestly covariant manner in a superspace with one Grassmann coordinate. Moreover, two Grassmann coordinates are required to describe the VSR-modified extended BRST and extended anti-BRST invariant BV actions in a superspace. These results are consistent with the Lorentz-invariant (special relativity) formulation. (orig.)

Spontaneous Lorentz violation and the long-range gravitational preferred-frame effect

International Nuclear Information System (INIS)

Graesser, Michael L.; Jenkins, Alejandro; Wise, Mark B.

2005-01-01

Lorentz-violating operators involving Standard Model fields are tightly constrained by experimental data. However, bounds are more model-independent for Lorentz violation appearing in purely gravitational couplings. The spontaneous breaking of Lorentz invariance by the vacuum expectation value of a vector field selects a universal rest frame. This affects the propagation of the graviton, leading to a modification of Newton's law of gravity. We compute the size of the long-range preferred-frame effect in terms of the coefficients of the two-derivative operators in the low-energy effective theory that involves only the graviton and the Goldstone bosons

Importance of tests for the complete Lorentz structure of the t→W+b vertex at hadron colliders

International Nuclear Information System (INIS)

Nelson, C.A.; Kress, B.T.; Lopes, M.; McCauley, T.P.

1998-01-01

In a separate paper, the most general Lorentz-invariant decay-density matrix for t→W + b→(l + ν)b, or for t→W + b→(j bar d j u )b, is expressed in terms of eight helicity parameters. The parameters can be used to test for a variety of sources of new physics in t→W + b decay. By stage-two spin-correlation techniques, percent level statistical uncertainties are typical for W-polarimetry measurements of these helicity parameters at the Fermilab Tevatron, and several mill level uncertainties are typical for W-polarimetry measurements at the CERN LHC. Λ b polarimetry could be used to measure the relative phase of the b L and b R amplitudes. copyright 1998 The American Physical Society

Spontaneous Lorentz breaking at high energies

International Nuclear Information System (INIS)

Cheng, H.-C.; Luty, Markus A.; Mukohyama, Shinji; Thaler, Jesse

2006-01-01

Theories that spontaneously break Lorentz invariance also violate diffeomorphism symmetries, implying the existence of extra degrees of freedom and modifications of gravity. In the minimal model ('ghost condensation') with only a single extra degree of freedom at low energies, the scale of Lorentz violation cannot be larger than about M ∼ 100GeV due to an infrared instability in the gravity sector. We show that Lorentz symmetry can be broken at much higher scales in a non-minimal theory with additional degrees of freedom, in particular if Lorentz symmetry is broken by the vacuum expectation value of a vector field. This theory can be constructed by gauging ghost condensation, giving a systematic effective field theory description that allows us to estimate the size of all physical effects. We show that nonlinear effects become important for gravitational fields with strength Φ 1/2 ∼> g, where g is the gauge coupling, and we argue that the nonlinear dynamics is free from singularities. We then analyze the phenomenology of the model, including nonlinear dynamics and velocity-dependent effects. The strongest bounds on the gravitational sector come from either black hole accretion or direction-dependent gravitational forces, and imply that the scale of spontaneous Lorentz breaking is M ∼ 12 GeV, g 2 10 15 GeV). If the Lorentz breaking sector couples directly to matter, there is a spin-dependent inverse-square law force, which has a different angular dependence from the force mediated by the ghost condensate, providing a distinctive signature for this class of models

Unified derivation of the Galileo and the Lorentz transformations

International Nuclear Information System (INIS)

Sardelis, D.A.

1982-01-01

By using the principle of relativity together with the general assumptions of space-time homogeneity and space isotropy underlying the principle of inertia, a most general transformation is constructed connecting any two inertial frames. The Galileo and the Lorentz transformations are then deduced by constraining these general inertial transformations through the corresponding two physical principles: the (classical) principle of acceleration invariance and the (relativistic) principle that all interactions propagate with the same finite and invariant speed. (author)

Effects of Lorentz violation through the γe → Wνe process in the Standard Model extension

International Nuclear Information System (INIS)

Aranda, J I; Ramírez-Zavaleta, F; Tututi, E S; Rosete, D A; Tlachino, F J; Toscano, J J

2014-01-01

Physics beyond the Fermi scale could show up through deviations of the gauge couplings predicted by the electroweak Yang–Mills sector. This possibility is explored in the context of the International Linear Collider through the helicity amplitudes for the γe → Wν e reaction to which the trilinear WWγ coupling contributes. The new physics effects on this vertex are parametrized in a model-independent fashion through an effective electroweak Yang–Mills sector, which is constructed by considering two essentially different sources of new physics. In one scenario, Lorentz violation will be considered exclusively as the source of new physics effects. This type of new physics is considered in an extension of the Standard Model (SM) that is known as the SM extension (SME), which is an effective field theory that contemplates CPT and Lorentz violation in a model-independent fashion. Any source of new physics that respects the Lorentz symmetry will be considered within the general context of the well-known conventional effective SM (CESM) extension. Both the SME and CESM descriptions include gauge invariant operators of dimension higher than 4, which, in general, transform as Lorentz tensors of rank higher than zero. In the former theory, observer Lorentz invariants are constructed by contracting these operators with constant Lorentz tensors, whereas in the latter the corresponding Lorentz invariant interactions are obtained contracting such operators with products of the metric tensor. In this work, we focus on a dimension 6 Lorentz 2-tensor, O αβ , which arises from an effective SU(2) L Yang–Mills sector. Contributions to the WWγ coupling arising from dimension 4 operators are ignored since they are strongly constrained. When these operators are contracted with a constant antisymmetric background tensor, b αβ , the corresponding observer invariant belongs to the SME, whereas if they are contracted with the metric tensor, g αβ , an effective interaction in

Charged Lifshitz black hole and probed Lorentz-violation fermions from holography

Energy Technology Data Exchange (ETDEWEB)

Luo, Cheng-Jian, E-mail: rocengeng@hotmail.com [Department of Physics, Nanchang University, Nanchang, 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China); Kuang, Xiao-Mei, E-mail: xmeikuang@gmail.com [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Shu, Fu-Wen, E-mail: shufuwen@ncu.edu.cn [Department of Physics, Nanchang University, Nanchang, 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China)

2017-06-10

We analytically obtain a new charged Lifshitz solution by adding a non-relativistic Maxwell field in Hořava–Lifshitz gravity. The black hole exhibits an anisotropic scaling between space and time (Lifshitz scaling) in the UV limit, while in the IR limit, the Lorentz invariance is approximately recovered. We introduce the probed Lorentz-violation fermions into the background and holographically investigate the spectral properties of the dual fermionic operator. The Lorentz-violation of the fermions will enhance the peak and correspond larger fermi momentum, which compensates the non-relativistic bulk effect of the dynamical exponent (z). For a fixed z, when the Lorentz-violation of fermions increases to a critical value, the behavior of the low energy excitation goes from a non-Fermi liquid type to a Fermi liquid type, which implies a kind of phase transition.

Prospects for testing Lorentz and CPT symmetry with antiprotons

Science.gov (United States)

Vargas, Arnaldo J.

2018-03-01

A brief overview of the prospects of testing Lorentz and CPT symmetry with antimatter experiments is presented. The models discussed are applicable to atomic spectroscopy experiments, Penning-trap experiments and gravitational tests. Comments about the sensitivity of the most recent antimatter experiments to the models reviewed here are included. This article is part of the Theo Murphy meeting issue `Antiproton physics in the ELENA era'.

Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

International Nuclear Information System (INIS)

Belich, H. Jr.; Helayel Neto, J.A.; Ferreira, M.M. Jr.; Maranhao Univ., Sao Luiz, MA; Orlando, M.T.D.; Espirito Santo Univ., Vitoria, ES

2003-01-01

Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, ν μ . In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of ν μ . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

Lorentz invariance and the rotor Doppler shift experiments

International Nuclear Information System (INIS)

Rodrigues Junior, W.A.; Tiomno, J.

1984-01-01

It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

Lorentz invariance and the rotor Doppler shift experiments

International Nuclear Information System (INIS)

Rodrigues Junior, W.A.; Tiomno, J.

1984-01-01

It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT. Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

Prospects for testing Lorentz and CPT symmetry with antiprotons.

Science.gov (United States)

Vargas, Arnaldo J

2018-03-28

A brief overview of the prospects of testing Lorentz and CPT symmetry with antimatter experiments is presented. The models discussed are applicable to atomic spectroscopy experiments, Penning-trap experiments and gravitational tests. Comments about the sensitivity of the most recent antimatter experiments to the models reviewed here are included.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'. © 2018 The Author(s).

Tests of Lorentz violation in νμ→νe oscillations

International Nuclear Information System (INIS)

Auerbach, L.B.; Burman, R.L.; Donahue, J.B.; Garvey, G.T.; Louis, W.C.; Mills, G.B.; Sandberg, V.D.; White, D.H.; Caldwell, D.O.; Yellin, S.; Church, E.D.; McIlhany, K.L.; Strossman, W.H.; Cochran, A.K.; Fazely, A.R.; Gunasingha, R.; Imlay, R.L.; Metcalf, W.J.; Sung, M.; Katori, T.

2005-01-01

A recently developed standard-model extension (SME) formalism for neutrino oscillations that includes Lorentz and CPT violation is used to analyze the sidereal time variation of the neutrino event excess measured by the liquid scintillator neutrino detector (LSND) experiment. The LSND experiment, performed at Los Alamos National Laboratory, observed an excess, consistent with neutrino oscillations, of ν e in a beam of ν μ . It is determined that the LSND oscillation signal is consistent with no sidereal variation. However, there are several combinations of SME coefficients that describe the LSND data; both with and without sidereal variations. The scale of Lorentz and CPT violation extracted from the LSND data is of order 10 -19 GeV for the SME coefficients a L and Exc L . This solution for Lorentz and CPT violating neutrino oscillations may be tested by other short baseline neutrino oscillation experiments, such as the MiniBooNE experiment

A Study of Gaugeon Formalism for QED in Lorentz Violating Background

Science.gov (United States)

Shah, Mushtaq B.; Ganai, Prince A.

2018-02-01

At the energy regimes close to Planck scales, the usual structure of Lorentz symmetry fails to address certain fundamental issues and eventually breaks down, thus paving the way for an alternative road map. It is thus argued that some subgroup of proper Lorentz group could stand consistent and might possibly help us to circumvent this problem. It is this subgroup that goes by the name of Very Special Relativity (VSR). Apart from violating rotational symmetry, VSR is believed to preserve the very tenets of special relativity. The gaugeon formalism due to type-I Yokoyama and type-II Izawa are found to be invariant under BRST symmetry. In this paper, we analyze the scope of this invariance in the scheme of VSR. Furthermore, we will obtain VSR modified Lagrangian density using path integral derivation. We will explore the consistency of VSR with regard to these theories.

Lorentz Violation in Warped Extra Dimensions

International Nuclear Information System (INIS)

Rizzo, Thomas G.

2011-01-01

Higher dimensional theories which address some of the problematic issues of the Standard Model(SM) naturally involve some form of D = 4 + n-dimensional Lorentz invariance violation (LIV). In such models the fundamental physics which leads to, e.g., field localization, orbifolding, the existence of brane terms and the compactification process all can introduce LIV in the higher dimensional theory while still preserving 4-d Lorentz invariance. In this paper, attempting to capture some of this physics, we extend our previous analysis of LIV in 5-d UED-type models to those with 5- d warped extra dimensions. To be specific, we employ the 5-d analog of the SM Extension of Kostelecky et al. which incorporates a complete set of operators arising from spontaneous LIV. We show that while the response of the bulk scalar, fermion and gauge fields to the addition of LIV operators in warped models is qualitatively similar to what happens in the flat 5-d UED case, the gravity sector of these models reacts very differently than in flat space. Specifically, we show that LIV in this warped case leads to a non-zero bulk mass for the 5-d graviton and so the would-be zero mode, which we identify as the usual 4-d graviton, must necessarily become massive. The origin of this mass term is the simultaneous existence of the constant non-zero AdS 5 curvature and the loss of general co-ordinate invariance via LIV in the 5-d theory. Thus warped 5-d models with LIV in the gravity sector are not phenomenologically viable.

Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation

Energy Technology Data Exchange (ETDEWEB)

Mattingly, David M. [New Hamshire Univ., Durham, NH (United States); Maccione, Luca [DESY Hamburg (Germany). Theory Group; Galaverni, Matteo [INAF-IASF Bologna (Italy); Liberati, Stefano [INFN, Trieste (Italy); SISSA, Trieste (Italy); Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

2009-11-15

We study, within an effective field theory framework, O(E{sup 2}/M{sup 2}{sub Pl}) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter {eta}{sub {nu}}. We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10{sup 19} eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10{sup 17} eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as {eta}{sub {nu}}

Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation

International Nuclear Information System (INIS)

Mattingly, David M.; Maccione, Luca; Galaverni, Matteo; Liberati, Stefano; Sigl, Günter

2010-01-01

We study, within an effective field theory framework, O(E 2 M Pl 2 ) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter η ν . We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10 19 eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10 17 eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as η ν ∼ −4 on the neutrino LV parameter, depending on how LV is distributed among neutrino mass states. Constraints on η ν < 0 can in principle be obtained with this strategy, but they require a more detailed modeling of how LV affects the neutrino sector

Dimensional reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons model

Energy Technology Data Exchange (ETDEWEB)

Belich, H. Jr.; Helayel Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas; Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mails: belich@cbpf.br; helayel@cbpf.br; Ferreira, M.M. Jr. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Maranhao Univ., Sao Luiz, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br; Orlando, M.T.D. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Fisica e Quimica; E-mail: orlando@cce.ufes.br

2003-01-01

Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional to D = 1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, {nu}{sup {mu}}. In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of {nu}{sup {mu}} . Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitary of the gauge sector is assured without any restriction , while the scalar sector is unitary only in the space-like case. (author)

A note on Lorentz transformation and pseudo-rapidity distributions

International Nuclear Information System (INIS)

Hama, Y.

1980-07-01

It is shown that although rapidity and pseudo-rapidity are almost equivalent variables, their difference may in pratice become quite remarkable. Non Lorentz invariance of pseudo-rapidity distributions may cause appearance of strange effects at first sight, such as deformation of a perfectly symmetric particle distribution into an asymmetric one when going to another frame. (Author) [pt

Conformal invariance of extended spinning particle mechanics

International Nuclear Information System (INIS)

Siegel, W.

1988-01-01

Recently a mechanics action has been considered with extended, local, one-dimensional supersymmetry. The authors show this action is conformally invariant in arbitrary spacetime dimensions, and derive the corresponding quantum mechanical restriction on the Lorentz representations it describes

New test of Lorentz symmetry using ultrahigh-energy cosmic rays

Science.gov (United States)

Anchordoqui, Luis A.; Soriano, Jorge F.

2018-02-01

We propose an innovative test of Lorentz symmetry by observing pairs of simultaneous parallel extensive air showers produced by the fragments of ultrahigh-energy cosmic ray nuclei which disintegrated in collisions with solar photons. We show that the search for a cross-correlation of showers in arrival time and direction becomes background free for an angular scale ≲3 ° and a time window O (10 s ) . We also show that if the solar photo-disintegration probability of helium is O (10-5.5) then the hunt for spatiotemporal coincident showers could be within range of existing cosmic ray facilities, such as the Pierre Auger Observatory. We demonstrate that the actual observation of a few events can be used to constrain Lorentz violating dispersion relations of the nucleon.

Intrinsic Regularization in a Lorentz invariant non-orthogonal Euclidean Space

OpenAIRE

Tornow, Carmen

2006-01-01

It is shown that the Lorentz transformations can be derived for a non-orthogonal Euclidean space. In this geometry one finds the same relations of special relativity as the ones known from the orthogonal Minkowski space. In order to illustrate the advantage of a non-orthogonal Euclidean metric the two-point Green’s function at x = 0 for a self-interacting scalar field is calculated. In contrast to the Minkowski space the one loop mass correction derived from this function gives a convergent r...

Constraining Anisotropic Lorentz Violation via the Spectral-lag Transition of GRB 160625B

Energy Technology Data Exchange (ETDEWEB)

Wei, Jun-Jie; Wu, Xue-Feng; Shao, Lang [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bin-Bin [Instituto de Astrofísica de Andalucá (IAA-CSIC), P.O. Box 03004, E-18080 Granada (Spain); Mészáros, Peter [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Kostelecký, V. Alan, E-mail: xfwu@pmo.ac.cn, E-mail: kostelec@indiana.edu [Physics Department, Indiana University, Bloomington, IN 47405 (United States)

2017-06-20

Violations of Lorentz invariance can lead to an energy-dependent vacuum dispersion of light, which results in arrival-time differences of photons with different energies arising from a given transient source. In this work, direction-dependent dispersion constraints are obtained on nonbirefringent Lorentz-violating effects using the observed spectral lags of the gamma-ray burst GRB 160625B. This burst has unusually large high-energy photon statistics, so we can obtain constraints from the true spectral time lags of bunches of high-energy photons rather than from the rough time lag of a single highest-energy photon. Also, GRB 160625B is the only burst to date having a well-defined transition from positive lags to negative lags, providing a unique opportunity to distinguish Lorentz-violating effects from any source-intrinsic time lag in the emission of photons of different energy bands. Our results place comparatively robust two-sided constraints on a variety of isotropic and anisotropic coefficients for Lorentz violation, including the first bounds on Lorentz-violating effects from operators of mass dimension 10 in the photon sector.

Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

Energy Technology Data Exchange (ETDEWEB)

Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T. [Universidade Federal de Lavras, Departamento de Fisica, Caixa Postal 3037, Lavras, Minas Gerais (Brazil); Scarpelli, A.P.B. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Sao Paulo (Brazil)

2017-02-15

S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)

Tree-level equivalence between a Lorentz-violating extension of QED and its dual model in electron-electron scattering

International Nuclear Information System (INIS)

Toniolo, Giuliano R.; Fargnoli, H.G.; Brito, L.C.T.; Scarpelli, A.P.B.

2017-01-01

S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter. (orig.)

Testing local Lorentz and position invariance and variation of fundamental constants by searching the derivative of the comparison frequency between a cryogenic sapphire oscillator and hydrogen maser

International Nuclear Information System (INIS)

Tobar, Michael Edmund; Wolf, Peter; Bize, Sebastien; Santarelli, Giorgio; Flambaum, Victor

2010-01-01

The cryogenic sapphire oscillator at the Paris Observatory has been continuously compared to various hydrogen masers since 2001. The early data sets were used to test local Lorentz invariance in the Robertson-Mansouri-Sexl (RMS) framework by searching for sidereal modulations with respect to the cosmic microwave background, and represent the best Kennedy-Thorndike experiment to date. In this work, we present continuous operation over a period of greater than six years from September 2002 to December 2008 and present a more precise way to analyze the data by searching the time derivative of the comparison frequency. Because of the long-term operation we are able to search both sidereal and annual modulations. The results give P KT =β RMS -α RMS -1=-1.7(4.0)x10 -8 for the sidereal and -23(10)x10 -8 for the annual term, with a weighted mean of -4.8(3.7)x10 -8 , a factor of 8 better than previous. Also, we analyze the data with respect to a change in gravitational potential for both diurnal and annual variations. The result gives β H-Maser -β CSO =-2.7(1.4)x10 -4 for the annual and -6.9(4.0)x10 -4 for the diurnal terms, with a weighted mean of -3.2(1.3)x10 -4 . This result is 2 orders of magnitude better than other tests that use electromagnetic resonators. With respect to fundamental constants a limit can be provided on the variation with ambient gravitational potential and boost of a combination of the fine structure constant (α), the normalized quark mass (m q ), and the electron to proton mass ratio (m e /m p ), setting the first limit on boost dependence of order 10 -10 .

Hadronic Lorentz violation in chiral perturbation theory including the coupling to external fields

Science.gov (United States)

Kamand, Rasha; Altschul, Brett; Schindler, Matthias R.

2018-05-01

If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a 2-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons—such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories—can only reliably constrain certain particular combinations of quark coefficients.

Neutrality of the lorentz transformations in SRT

International Nuclear Information System (INIS)

Hamdan, N.; Baza, S.

2005-01-01

The special theory of Relativity (SRT), gives us two results, the dilation of time and the contraction of the Length, which have been refuted by many scientists. The solution to these kinematical effects has driven researchers to develop new methods. One of these methods is using the physical law equations and apply the principle of relativity to them. With this approach, we reformulated the SRT in a simple manner which has dynamical applications without using the Lorentz transformations (LT) and its kinematical effects. We obtained the results which require the invariant of Maxwell's field equations under the LT in a way different to that of Einsterin. In the present paper, we get the LT from the Lorentz force. In contrast to Einstein's LT with its kinematical effects, the LT produced in this paper is simply a neutral transformation. Containing no physical significance, i.e. LT and its kinematical effects do not explain any physical phenomenon. (author)

Cosmological constraints on Lorentz violating dark energy

Energy Technology Data Exchange (ETDEWEB)

Audren, B.; Lesgourgues, J. [FSB/ITP/LPPC, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Blas, D. [Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Sibiryakov, S., E-mail: Benjamin.Audren@epfl.ch, E-mail: Diego.Blas@cern.ch, E-mail: Julien.Lesgourgues@cern.ch, E-mail: Sergey.Sibiryakov@cern.ch [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect, 7a, 117312 Moscow (Russian Federation)

2013-08-01

The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the case for the cosmological constant problem. Indeed, it has been shown that breaking Lorentz invariance provides Lagrangians that can drive the current acceleration of the universe without experiencing large corrections from ultraviolet physics. In this work, we focus on the simplest model of this type, called ΘCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from ΛCDM. The differences appear at the level of perturbations. We show that in ΘCDM, the spectrum of CMB anisotropies and matter fluctuations may be affected by a rescaling of the gravitational constant in the Poisson equation, by the presence of extra contributions to the anisotropic stress, and finally by the existence of extra clustering degrees of freedom. To explore these modifications accurately, we modify the Boltzmann code class. We then use the parameter inference code Monte Python to confront ΘCDM with data from WMAP-7, SPT and WiggleZ. We obtain strong bounds on the parameters accounting for deviations from ΛCDM. In particular, we find that the discrepancy between the gravitational constants appearing in the Poisson and Friedmann equations is constrained at the level of 1.8%.

Exact Lorentz-violating all-loop ultraviolet divergences in scalar field theories

Energy Technology Data Exchange (ETDEWEB)

Carvalho, P.R.S. [Universidade Federal do Piaui, Departamento de Fisica, Teresina, PI (Brazil); Sena-Junior, M.I. [Universidade de Pernambuco, Escola Politecnica de Pernambuco, Recife, PE (Brazil); Universidade Federal de Alagoas, Instituto de Fisica, Maceio, AL (Brazil)

2017-11-15

In this work we evaluate analytically the ultraviolet divergences of Lorentz-violating massive O(N) λφ{sup 4} scalar field theories, which are exact in the Lorentz-violating mechanism, firstly explicitly at next-to-leading order and latter at any loop level through an induction procedure based on a theorem following from the exact approach, for computing the corresponding critical exponents. For attaining that goal, we employ three different and independent field-theoretic renormalization group methods. The results found for the critical exponents show that they are identical in the three distinct methods and equal to their Lorentz-invariant counterparts. Furthermore, we show that the results obtained here, based on the single concept of loop order of the referred terms of the corresponding β-function and anomalous dimensions, reduce to the ones obtained through the earlier non-exact approach based on a joint redefinition of the field and coupling constant of the theory, in the appropriate limit. (orig.)

Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories

Energy Technology Data Exchange (ETDEWEB)

Belich, H [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil); Dias, G S; Leal, F J.L. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Durand, L G; Helayel-Neto, Jose Abdalla; Spalenza, W [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes (GFT-JLL), Petropolis, RJ (Brazil)

2011-07-01

Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)

Imprints of supersymmetry in the Lorentz-symmetry breaking of Gauge Theories

International Nuclear Information System (INIS)

Belich, H.; Dias, G.S.; Leal, F.J.L.; Durand, L.G.; Helayel-Neto, Jose Abdalla; Spalenza, W.

2011-01-01

Full text: The breaking of Lorentz symmetry that may take place at very high energies opens up a venue for the discussion of the interplay between the violations of supersymmetry and relativistic symmetry. Recently, there have appeared in the literature models which propose a residual (non-relativistic) supersymmetry after Lorentz symmetry has been broken in a Horava gravity scenario. We here propose an N=1-supersymmetric Abelian gauge model which realises the breaking of Lorentz invariance by means of a CPT-even term. Our attempt assumes the point of view that supersymmetry and Lorentz symmetry are broken down at the same scale. If this is the case, the fermionic sector of the supermultiplets that accomplish the breaking of the symmetries into consideration may give rise to condensates that play an important role in the photon and photino dispersion relations. Contemporarily, they may also point to a more fundamental origin for the (bosonic) tensors usually associated to the backgrounds that parametrize Lorentz-symmetry breaking. We also highlight that, by studying the the violation of Lorentz symmetry in connection with supersymmetry, we find out that the Myers-Pospelov Electrodynamics, proposed on the basis of an analysis of the set of dimension-five operators, naturally appears in the bosonic sector of our model. Also, as a result of the interconnection between the supersymmetry and Lorentz-symmetry breakings, the photino-photino and photon-photino mixings that correspond to the supersymmetric completion of the Myers-Pospelov purely photonic terms come out. Finally, we present some comments on the possible modifications the supersymmetric fermions may introduce in the dispersion relations for particles at (high) energies close to the scale where supersymmetry and Lorentz symmetry are broken. (author)

Strong equivalence, Lorentz and CPT violation, anti-hydrogen spectroscopy and gamma-ray burst polarimetry

International Nuclear Information System (INIS)

Shore, Graham M.

2005-01-01

The strong equivalence principle, local Lorentz invariance and CPT symmetry are fundamental ingredients of the quantum field theories used to describe elementary particle physics. Nevertheless, each may be violated by simple modifications to the dynamics while apparently preserving the essential fundamental structure of quantum field theory itself. In this paper, we analyse the construction of strong equivalence, Lorentz and CPT violating Lagrangians for QED and review and propose some experimental tests in the fields of astrophysical polarimetry and precision atomic spectroscopy. In particular, modifications of the Maxwell action predict a birefringent rotation of the direction of linearly polarised radiation from synchrotron emission which may be studied using radio galaxies or, potentially, gamma-ray bursts. In the Dirac sector, changes in atomic energy levels are predicted which may be probed in precision spectroscopy of hydrogen and anti-hydrogen atoms, notably in the Doppler-free, two-photon 1s-2s and 2s-nd (n∼10) transitions

Invariant length scale in relativistic kinematics: lessons from Dirichlet branes

International Nuclear Information System (INIS)

Schuller, Frederic P.; Pfeiffer, Hendryk

2004-01-01

Dirac-Born-Infeld theory is shown to possess a hidden invariance associated with its maximal electric field strength. The local Lorentz symmetry O(1,n) on a Dirichlet-n-brane is thereby enhanced to an O(1,n)xO(1,n) gauge group, encoding both an invariant velocity and acceleration (or length) scale. The presence of this enlarged gauge group predicts consequences for the kinematics of observers on Dirichlet branes, with admissible accelerations being bounded from above. An important lesson is that the introduction of a fundamental length scale into relativistic kinematics does not enforce a deformation of Lorentz boosts, as one might assume naively. The exhibited structures further show that Moffat's non-symmetric gravitational theory qualifies as a candidate for a consistent Born-Infeld type gravity with regulated solutions

Constraints on Lorentz Invariance Violation from Fermi -Large Area Telescope Observations of Gamma-Ray Bursts

Science.gov (United States)

Vasileiou, V.; Jacholkowska, A.; Piron, F.; Bolmont, J.; Courturier, C.; Granot, J.; Stecker, Floyd William; Cohen-Tanugi, J.; Longo, F.

2013-01-01

We analyze the MeV/GeV emission from four bright Gamma-Ray Bursts (GRBs) observed by the Fermi-Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some Quantum Gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the "QG energy scale" (the energy scale that LIV-inducing QG effects become important, E(sub QG)) and the coefficients of the Standard Model Extension. For the subluminal case (where high energy photons propagate more slowly than lower energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% CL) are obtained from GRB 090510 and are E(sub QG,1) > 7.6 times the Planck energy (E(sub Pl)) and E(sub QG,2) > 1.3×10(exp 11) GeV for linear and quadratic leading order LIV-induced vacuum dispersion, respectively. These limits improve the latest constraints by Fermi and H.E.S.S. by a factor of approx. 2. Our results disfavor any class of models requiring E(sub QG,1) < or approx. E(sub Pl)

Lorentz covariance ‘almost’ implies electromagnetism and more

International Nuclear Information System (INIS)

Sobouti, Y

2015-01-01

Beginning from two simple assumptions, (i) the speed of light is a universal constant, or its equivalent, the spacetime intervals are Lorentz invariant, and (ii) there are mutually interacting particles, with a covariant ‘source-field’ equation, one arrives at a class of field equations of which the standard electromagnetism (EM) and electrodynamics are special cases. The formalism, depending on how one formulates the source-field equation, allows one to speculate magnetic monopoles, massive photons, nonlinear EMs, and more. (paper)

Erratum (astro-ph/0510172) Robust Limits on Lorentz Violation from Gamma-Ray Bursts

CERN Document Server

AUTHOR|(CDS)2108556; Nanopoulos, D V; Sakharov, Alexander S; Sarkisyan-Grinbaum, E

2008-01-01

We correct the fitting formula used in refs. [1,2] to obtain a robust limit on a violation of Lorentz invariance that depends linearly on the photon energy. The correction leads to a slight increase of the limit on the scale of the violation, to M > 1.4 x 10^{16} GeV.

Constraining Lorentz Violation in Electroweak Physics

Science.gov (United States)

Lehnert, Ralf

2018-01-01

For practical reasons, the majority of past Lorentz tests has involved stable or quasistable particles, such as photons, neutrinos, electrons, protons, and neutrons. Similar efforts in the electroweak sector have only recently taken shape. Within this context, Lorentz-violation searches in the Standard-Model Extension’s Z-Boson sector will be discussed. It is argued that existing precision data on polarized electron-electron scattering can be employed to extract the first conservative two-sided limits on Lorentz breakdown in this sector at the level of 10-7.

Universal dynamics of spontaneous Lorentz violation and a new spin-dependent inverse-square law force

International Nuclear Information System (INIS)

Arkani-Hamed, Nima; Cheng, Hsin-Chia; Luty, Markus; Thaler, Jesse

2005-01-01

We study the universal low-energy dynamics associated with the spontaneous breaking of Lorentz invariance down to spatial rotations. The effective lagrangian for the associated Goldstone field can be uniquely determined by the non-linear realization of a broken time diffeomorphism symmetry, up to some overall mass scales. It has previously been shown that this symmetry breaking pattern gives rise to a Higgs phase of gravity, in which gravity is modified in the infrared. In this paper, we study the effects of direct couplings between the Goldstone boson and standard model fermions, which necessarily accompany Lorentz-violating terms in the theory. The leading interaction is the coupling to the axial vector current, which reduces to spin in the non-relativistic limit. A spin moving relative to the 'ether' rest frame will emit Goldstone Cerenkov radiation. The Goldstone also induces a long-range inverse-square law force between spin sources with a striking angular dependence, reflecting the underlying Goldstone shockwaves and providing a smoking gun for this theory. We discuss the regime of validity of the effective theory describing these phenomena, and the possibility of probing Lorentz violations through Goldstone boson signals in a way that is complementary to direct tests in some regions of parameter space

Revisiting measurement invariance in intelligence testing in aging research: Evidence for almost complete metric invariance across age groups.

Science.gov (United States)

Sprague, Briana N; Hyun, Jinshil; Molenaar, Peter C M

2017-01-01

Invariance of intelligence across age is often assumed but infrequently explicitly tested. Horn and McArdle (1992) tested measurement invariance of intelligence, providing adequate model fit but might not consider all relevant aspects such as sub-test differences. The goal of the current paper is to explore age-related invariance of the WAIS-R using an alternative model that allows direct tests of age on WAIS-R subtests. Cross-sectional data on 940 participants aged 16-75 from the WAIS-R normative values were used. Subtests examined were information, comprehension, similarities, vocabulary, picture completion, block design, picture arrangement, and object assembly. The two intelligence factors considered were fluid and crystallized intelligence. Self-reported ages were divided into young (16-22, n = 300), adult (29-39, n = 275), middle (40-60, n = 205), and older (61-75, n = 160) adult groups. Results suggested partial metric invariance holds. Although most of the subtests reflected fluid and crystalized intelligence similarly across different ages, invariance did not hold for block design on fluid intelligence and picture arrangement on crystallized intelligence for older adults. Additionally, there was evidence of a correlated residual between information and vocabulary for the young adults only. This partial metric invariance model yielded acceptable model fit compared to previously-proposed invariance models of Horn and McArdle (1992). Almost complete metric invariance holds for a two-factor model of intelligence. Most of the subtests were invariant across age groups, suggesting little evidence for age-related bias in the WAIS-R. However, we did find unique relationships between two subtests and intelligence. Future studies should examine age-related differences in subtests when testing measurement invariance in intelligence.

Test of Lorentz symmetry with a 3He/129Xe clock-comparison experiment

International Nuclear Information System (INIS)

Gemmel, Claudia

2011-01-01

The minimal Standard Model Extension (SME) of Kostelecky and coworkers, which parametrizes the general treatment of CPT- and Lorentz invariance violation, predicts sidereal modulations of atomic transition frequencies as the Earth rotates relative to a Lorentz-violating background field. One method to search for these modulations is the so-called clock-comparison experiment, where the frequencies of co-located clocks are compared as they rotate with respect to the fixed stars. In this work an experiment is presented where polarized 3 He and 129 Xe gas samples in a glass cell serve as clocks, whose nuclear spin precession frequencies are detected with the help of highly sensitive SQUID sensors inside a magnetically shielded room. The unique feature of this experiment is the fact that the spins are precessing freely, with transverse relaxation times T * 2 of up to 4.4 h for 129 Xe and 14.1 h for 3 He. To be sensitive to Lorentz-violating effects, the influence of external magnetic fields is canceled via the weighted 3 He/ 129 Xe phase difference, ΔΦ=Φ he -(γ he )/(γ xe ) Φ xe . The Lorentz-violating SME parameters for the neutron, b n X and b n Y , are determined out of a χ 2 fit on the phase difference data of 7 spin precession measurements of 12 to 16 hours length. The piecewise defined fit model contains a sine and a cosine term to describe the sidereal modulation, as well as 7 offset terms, 7 linear terms and 7 . 2 exponential terms decreasing with T * 2,he and T * 2,xe , which are assigned to the respective measurement. The linear term in the weighted phase difference mainly arises from deviations of the gyromagnetic ratios from their literature values due to chemical shifts, while the exponential terms reflect the phase shifts resulting from demagnetization fields in the non-ideally spherical sample cell. The result of the χ 2 fit constrains the parameter b n perpendicular to =√((b n X ) 2 +(b n Y ) 2 ) to be -32 GeV at the 95% confidence level. This

Radiative proton-deuteron capture in a gauge invariant relativistic model

NARCIS (Netherlands)

Korchin, AY; Van Neck, D; Scholten, O; Waroquier, M

A relativistic model is developed for the description of the process p+dHe-3+gamma*. It is based on the impulse approximation, but is explicitly gauge invariant and Lorentz covariant. The model is applied to radiative proton-deuteron capture and electrodisintegration of He-3 nt intermediate

Limit Laws and Recurrence for the Planar Lorentz Process with Infinite Horizon

CERN Document Server

Szász, D

2006-01-01

As Bleher observed the free flight vector of the planar, infinite horizon, periodic Lorentz process $\\{S_n | n=0, 1, 2, \\dots \\}$ belongs to the non-standard domain of attraction of the Gaussian law --- actually with the $\\sqrt{n \\log n}$ scaling. Our first aim is to establish his conjecture that, indeed, $\\frac{S_n}{\\sqrt{n \\log n}}$ converges in distribution to the Gaussian law (a Global Limit Theorem). Here the recent method of B\\'alint and Gou\\"ezel, \\cite{BG} helped us to essentially simplify the ideas of our earlier sketchy proof. Moreover, we can also derive a.) the local version of the Global Limit Theorem, b.) the recurrence of the planar, infinite horizon, periodic Lorentz process, and finally c.) the ergodicity of its infinite invariant measure.

Search for violation of Lorentz invariance in top quark pair production and decay

Czech Academy of Sciences Publication Activity Database

Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

2012-01-01

Roč. 108, č. 26 (2012), "261603-1"-"261603-7" ISSN 0031-9007 R&D Projects: GA MŠk LA08047; GA MŠk(CZ) LG12006 Institutional research plan: CEZ:AV0Z10100502 Keywords : D0 * violation Lorentz * pair productionl * decay * Batavia TEVATRON, Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 7.943, year: 2012 http://prl.aps.org/abstract/PRL/v108/i26/e261603

Concerning the equivalence of Lorentz's and Einstein's theories

International Nuclear Information System (INIS)

Clube, S.V.M.

1978-01-01

A clear distinction is drawn between derivations of the Lorentz transformations by Lorentz and Einstein. The choice as to which derivation is correct is still open to experimental test. Possible reasons are given for preferring the Lorentz derivation in terms of a material aether, and the role of covariance in physical theory is considered to be heuristic rather than fundamental. The existence of a material aether also permits one to question the fundamental role of fields in modern theory

Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses

International Nuclear Information System (INIS)

Aguilar-Arevalo, A.A.; Anderson, C.E.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J.M.; Cox, D.C.; Curioni, A.; Dharmapalan, R.; Djurcic, Z.; Finley, D.A.; Fleming, B.T.; Ford, R.; Garcia, F.G.; Garvey, G.T.; Grange, J.; Green, C.

2013-01-01

The sidereal time dependence of MiniBooNE ν e and ν ¯ e appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov–Smirnov (K–S) test shows both the ν e and ν ¯ e appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the ν e appearance data prefer a sidereal time-independent solution, and the ν ¯ e appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10 −20 GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for ν μ →ν e and ν ¯ μ →ν ¯ e oscillations. The fit values and limits of combinations of SME coefficients are provided.

A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization

Science.gov (United States)

Stecker, Floyd W.

2011-01-01

Constraints on possible Lorentz invariance violation (UV) to first order in E/M(sub Plank) for photons in the framework of effective field theory (EFT) are discussed, taking cosmological factors into account. Then. using the reported detection of polarized soft gamma-ray emission from the gamma-ray burst GRB041219a that is indicative' of an absence of vacuum birefringence, together with a very recent improved method for estimating the redshift of the burst, we derive constraints on the dimension 5 Lorentz violating modification to the Lagrangian of an effective local QFT for QED. Our new constraints are more than five orders of magnitude better than recent constraints from observations of the Crab Nebula.. We obtain the upper limit on the Lorentz violating dimension 5 EFT parameter absolute value of zeta of 2.4 x 10(exp -15), corresponding to a constraint on the dimension 5 standard model extension parameter. Kappa (sup 5) (sub (v)oo) much less than 4.2 X 10(exp -3)4 / GeV.

A heuristic derivation of Minkowski distance and Lorentz transformation

International Nuclear Information System (INIS)

Hassani, Sadri

2008-01-01

Students learn new abstract concepts best when these concepts are connected through a well-designed analogy, to familiar ideas. Since the concept of the relativistic spacetime distance is highly abstract, it would be desirable to connect it to the familiar Euclidean distance, but present the latter in such a way that it makes a transparent contact with the former. Starting with some intuitive and 'obvious' assumptions concerning distance in one dimension, we 'derive' the two-dimensional Euclidean distance between two points in terms of their coordinates. Then, assuming the invariance of this distance, we deduce the (familiar) two-dimensional orthogonal coordinate transformation. We present the derivation in such a way that the transition to spacetime becomes 'self-evident.' Thus, following exactly the same procedure, we derive the Minkowskian distance and the corresponding transformation that respects the invariance of that distance, i.e., the Lorentz transformation

On physical complementarity of Galileo and Lorentz groups in the electrodynamics of isotropic inertial moving media

International Nuclear Information System (INIS)

Barykin, V.N.

1989-01-01

A physical interpretation of the early detected ambiguity of the electrodynamic material equations of isotropic, inertially moving media which mathematically manifests itself through complementarity of the equations invariant under the Galileo group in some cases and in other ones - under the Lorentz group that can be experimentally discovered in the aberration phenomenon and Doppler effect

Essay on gravitation: The cosmological constant problem in brane-worlds and gravitational Lorentz violations

International Nuclear Information System (INIS)

Csaki, Csaba; Erlich, Joshua; Grojean, Christophe

2001-01-01

Brane worlds are theories with extra spatial dimensions in which ordinary matter is localized on a (3+1) dimensional submanifold. Such theories could have interesting consequences for particle physics and gravitational physics. In this essay we concentrate on the cosmological constant (CC) problem in the context of brane worlds. We show how extra-dimensional scenarios may violate Lorentz invariance in the gravity sector of the effective 4D theory, while particle physics remains unaffected. In such theories the usual no-go theorems for adjustment of the CC do not apply, and we indicate a possible explanation of the smallness of the CC. Lorentz violating effects would manifest themselves in gravitational waves travelling with a speed different from light, which can be searched for in gravitational wave experiments

Reconcile Planck-scale discreteness and the Lorentz-Fitzgerald contraction

International Nuclear Information System (INIS)

Rovelli, Carlo; Speziale, Simone

2003-01-01

A Planck-scale minimal observable length appears in many approaches to quantum gravity. It is sometimes argued that this minimal length might conflict with Lorentz invariance, because a boosted observer can see the minimal length further Lorentz contracted. We show that this is not the case within loop quantum gravity. In loop quantum gravity the minimal length (more precisely, minimal area) does not appear as a fixed property of geometry, but rather as the minimal (nonzero) eigenvalue of a quantum observable. The boosted observer can see the same observable spectrum, with the same minimal area. What changes continuously in the boost transformation is not the value of the minimal length: it is the probability distribution of seeing one or the other of the discrete eigenvalues of the area. We discuss several difficulties associated with boosts and area measurement in quantum gravity. We compute the transformation of the area operator under a local boost, propose an explicit expression for the generator of local boosts, and give the conditions under which its action is unitary

Test of Lorentz and CPT violation with short baseline neutrino oscillation excesses

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Arevalo, A.A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, D.F. 04510 (Mexico); Anderson, C.E. [Yale University, New Haven, CT 06520 (United States); Bazarko, A.O. [Princeton University, Princeton, NJ 08544 (United States); Brice, S.J.; Brown, B.C. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Bugel, L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cao, J. [University of Michigan, Ann Arbor, MI 48109 (United States); Coney, L. [Columbia University, New York, NY 10027 (United States); Conrad, J.M. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cox, D.C. [Indiana University, Bloomington, IN 47405 (United States); Curioni, A. [Yale University, New Haven, CT 06520 (United States); Dharmapalan, R. [University of Alabama, Tuscaloosa, AL 35487 (United States); Djurcic, Z. [Argonne National Laboratory, Argonne, IL 60439 (United States); Finley, D.A. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Fleming, B.T. [Yale University, New Haven, CT 06520 (United States); Ford, R.; Garcia, F.G. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Garvey, G.T. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Grange, J. [University of Florida, Gainesville, FL 32611 (United States); Green, C. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); and others

2013-01-29

The sidereal time dependence of MiniBooNE {nu}{sub e} and {nu}{sup Macron }{sub e} appearance data is analyzed to search for evidence of Lorentz and CPT violation. An unbinned Kolmogorov-Smirnov (K-S) test shows both the {nu}{sub e} and {nu}{sup Macron }{sub e} appearance data are compatible with the null sidereal variation hypothesis to more than 5%. Using an unbinned likelihood fit with a Lorentz-violating oscillation model derived from the Standard Model Extension (SME) to describe any excess events over background, we find that the {nu}{sub e} appearance data prefer a sidereal time-independent solution, and the {nu}{sup Macron }{sub e} appearance data slightly prefer a sidereal time-dependent solution. Limits of order 10{sup -20} GeV are placed on combinations of SME coefficients. These limits give the best limits on certain SME coefficients for {nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sup Macron }{sub {mu}}{yields}{nu}{sup Macron }{sub e} oscillations. The fit values and limits of combinations of SME coefficients are provided.

A test of conformal invariance: Correlation functions on a disk

International Nuclear Information System (INIS)

Badke, R.; Rittenberg, V.; Ruegg, H.

1985-06-01

Using conformal invariance one can derive the correlation functions of a disk from those in the half-plane. The correlation function in the half-plane is determined by the 'small' conformal invariance up to an unknown function of one variable. By measuring through the Monte Carlo method the correlation function for two different configurations, the unknown function can be eliminated and one obtains a test of conformal invariance. It is shown that the Ising and the three state Potts model pass the test for very small lattices. (orig.)

Covariant Renormalizable Modified and Massive Gravity Theories on (Non) Commutative Tangent Lorentz Bundles

CERN Document Server

Vacaru, Sergiu I

2014-01-01

The fundamental field equations in modified gravity (including general relativity; massive and bimetric theories; Ho\\vrava-Lifshits, HL; Einstein--Finsler gravity extensions etc) posses an important decoupling property with respect to nonholonomic frames with 2 (or 3) +2+2+... spacetime decompositions. This allows us to construct exact solutions with generic off--diagonal metrics depending on all spacetime coordinates via generating and integration functions containing (un-) broken symmetry parameters. Such nonholonomic configurations/ models have a nice ultraviolet behavior and seem to be ghost free and (super) renormalizable in a sense of covariant and/or massive modifications of HL gravity. The apparent noncommutativity and breaking of Lorentz invariance by quantum effects can be encoded into fibers of noncommutative tangent Lorentz bundles for corresponding "partner" anisotropically induced theories. We show how the constructions can be extended to include conjectured covariant reonormalizable models with...

Experimental Studies on the Lorentz Symmetry in Post-Newtonian Gravity with Pulsars

Directory of Open Access Journals (Sweden)

Lijing Shao

2016-12-01

Full Text Available Local Lorentz invariance (LLI is one of the most important fundamental symmetries in modern physics. While the possibility of LLI violation (LLIv was studied extensively in flat spacetime, its counterpart in gravitational interaction also deserves significant examination from experiments. In this contribution, I review several recent studies of LLI in post-Newtonian gravity, using powerful tools of pulsar timing. It shows that precision pulsar timing experiments hold a unique position to probe LLIv in post-Newtonian gravity.

Planck-scale deformation of Lorentz symmetry as a solution to the UHECR and the TeV-$\\gamma$ paradoxes

CERN Document Server

Amelino-Camelia, G; Amelino-Camelia, Giovanni; Piran, Tsvi

2001-01-01

One of the most puzzling current experimental physics paradoxes is the arrival on Earth of Ultra High Energy Cosmic Rays with energies above the GZK threshold. The recent observation of 20TeV photons from Mk 501 is another somewhat similar paradox. Several models have been proposed for the UHECR paradox. No solution has yet been proposed for the TeV-$\\gamma$ paradox. Remarkably, the drastic assumption of a violation of ordinary Lorentz invariance would resolve both paradoxes. We present a formalism for the description of the type of Lorentz-invariance deformation (LID) that could be induced by non-trivial short-distance structure of space-time, and we show that this formalism is well suited for comparison of experimental data with LID predictions. We use the UHECR and TeV-$\\gamma$ data, as well as bounds on time-of-flight differences between photons of different energies, to constrain the LID parameter space. A model with only two parameters, an energy scale and a dimensionless parameter characterizing the fu...

Brane Lorentz symmetry from Lorentz breaking in the bulk

Energy Technology Data Exchange (ETDEWEB)

Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisbon (Portugal); Carvalho, C [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisbon (Portugal)

2007-05-15

We propose the mechanism of spontaneous symmetry breaking of a bulk vector field as a way to generate the selection of bulk dimensions invisible to the standard model confined to the brane. By assigning a nonvanishing vacuum value to the vector field, a direction is singled out in the bulk vacuum, thus breaking the bulk Lorentz symmetry. We present the condition for induced Lorentz symmetry on the brane, as phenomenologically required.

Uniformly bounded representations of the Lorentz groups

International Nuclear Information System (INIS)

Brega, A.O.

1982-01-01

For the Lorentz group G = SO/sub e/(n + 1, 1)(ngreater than or equal to 2) the author constructs a family of uniformly bounded representations by means of analytically continuing a certain normalization of the unitary principal series. The method the author uses relies on an analysis of various operators under a Mellin transform and extends earlier work of E.N. Wilson. In a series of papers Kunze and Stein initiated the theory of uniformly bounded representations of semisimple Lie groups; the starting point is the unitary principal series T(sigma,s) obtained in a certain subgroup M of G and a purely imaginary number s. From there Kunze and Stein constructed families of representations R(sigma,s) depending analytically on a parameter s in a domain D of C containing the imaginary axis which are unitarily equilvalent to T(sigma,s) for s contained in the set of imaginary numbers and whose operator norms are uniformly bounded for each s in D. In the case of the Lorentz groups SO/sub e/(n + 1, 1)(ngreater than or equal to2) and the trivial representation 1 of M, E.N. Wilson obtained such a family R(1,s) for the domain D = [s contained in the set of C: absolute value Re(s) Vertical Bar2]. For this domain D and for any representation sigma of M the author provides a family R(sigma,s) of uniformly bounded representations analytically continuing T(sigma,s), thereby generalizing Wilson's work. The author has also investigated certain symmetry properties of the representations R(sigma,s) under the action of the Weyl group. The trivial representation is Weyl group invariant and the family R(1,s) obtained by Wilson satisfies R(1,s) = R(1,-s) reflecting this. Obtained was the analogous result R(sigma,s) = R(sigma,-s) for some well known representations sigma that are Weyl group invariant. This involves the explicit computation of certain constants arising in the Fourier transforms of intertwining operators

A modified Lorentz theory as a test theory of special relativity

Science.gov (United States)

Chang, T.; Torr, D. G.; Gagnon, D. R.

1988-01-01

Attention has been given recently to a modified Lorentz theory (MLT) that is based on the generalized Galilean transformation. Some explicit formulas within the framework of MLT, dealing with the one-way velocity of light, slow-clock transport, and the Doppler effect are derived. A number of typical experiments are analyzed on this basis. Results indicate that the empirical equivalence between MLT and special relativity is still maintained to second order terms. The results of previous works that predict that the MLT might be distinguished from special relativity at the third order by Doppler centrifuge tests capable of a fractional frequency detection threshold of 10 to the -15th are confirmed.

Threshold analyses and Lorentz violation

International Nuclear Information System (INIS)

Lehnert, Ralf

2003-01-01

In the context of threshold investigations of Lorentz violation, we discuss the fundamental principle of coordinate independence, the role of an effective dynamical framework, and the conditions of positivity and causality. Our analysis excludes a variety of previously considered Lorentz-breaking parameters and opens an avenue for viable dispersion-relation investigations of Lorentz violation

Test of Lorentz symmetry with a {sup 3}He/{sup 129}Xe clock-comparison experiment

Energy Technology Data Exchange (ETDEWEB)

Gemmel, Claudia

2011-01-28

The minimal Standard Model Extension (SME) of Kostelecky and coworkers, which parametrizes the general treatment of CPT- and Lorentz invariance violation, predicts sidereal modulations of atomic transition frequencies as the Earth rotates relative to a Lorentz-violating background field. One method to search for these modulations is the so-called clock-comparison experiment, where the frequencies of co-located clocks are compared as they rotate with respect to the fixed stars. In this work an experiment is presented where polarized {sup 3}He and {sup 129}Xe gas samples in a glass cell serve as clocks, whose nuclear spin precession frequencies are detected with the help of highly sensitive SQUID sensors inside a magnetically shielded room. The unique feature of this experiment is the fact that the spins are precessing freely, with transverse relaxation times T{sup *}{sub 2} of up to 4.4 h for {sup 129}Xe and 14.1 h for {sup 3}He. To be sensitive to Lorentz-violating effects, the influence of external magnetic fields is canceled via the weighted {sup 3}He/{sup 129}Xe phase difference, {delta}{phi}={phi}{sub he}-({gamma}{sub he})/({gamma}{sub xe}) {phi}{sub xe}. The Lorentz-violating SME parameters for the neutron, b{sup n}{sub X} and b{sup n}{sub Y}, are determined out of a {chi}{sup 2} fit on the phase difference data of 7 spin precession measurements of 12 to 16 hours length. The piecewise defined fit model contains a sine and a cosine term to describe the sidereal modulation, as well as 7 offset terms, 7 linear terms and 7 . 2 exponential terms decreasing with T{sup *}{sub 2,he} and T{sup *}{sub 2,xe}, which are assigned to the respective measurement. The linear term in the weighted phase difference mainly arises from deviations of the gyromagnetic ratios from their literature values due to chemical shifts, while the exponential terms reflect the phase shifts resulting from demagnetization fields in the non-ideally spherical sample cell. The result of the {chi

Einstein causal quantum fields on lattices with discrete Lorentz invariance

International Nuclear Information System (INIS)

Baumgaertel, H.

1986-01-01

Results on rigorous construction of quantum fields on the hypercubic lattice Z 4 considered as a lattice in the Minkowski space R 4 are presented. Two associated fields are constructed: The first one having on the lattice points of Z 4 is causal and Poincare invariant in the discrete sense. The second one is an interpolating field over R 4 which is pointlike, translationally covariant and spectral in such a manner that the 'real' lattices field is the restriction of the interpolating field to Z 4 . Furthermore, results on a rigorous perturbation theory of such fields are mentioned

Strong binary pulsar constraints on Lorentz violation in gravity.

Science.gov (United States)

Yagi, Kent; Blas, Diego; Yunes, Nicolás; Barausse, Enrico

2014-04-25

Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of general relativity. One of these is Lorentz symmetry, which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

Strong Binary Pulsar Constraints on Lorentz Violation in Gravity

CERN Document Server

Yagi, Kent; Yunes, Nicolas; Barausse, Enrico

2014-01-01

Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of General Relativity. One of these is Lorentz symmetry which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

Sixth Meeting on CPT and Lorentz Symmetry

CERN Document Server

CPT and Lorentz Symmetry

2014-01-01

This book contains the Proceedings of the Sixth Meeting on CPT and Lorentz Symmetry, held at Indiana University in Bloomington on June 17–21, 2013. The Meeting focused on tests of these fundamental symmetries and on related theoretical issues, including scenarios for possible violations. Topics covered at the meeting include searches for CPT and Lorentz violations involving: accelerator and collider experiments; atomic, nuclear, and particle decays; birefringence, dispersion, and anisotropy in cosmological sources; clock-comparison measurements; electromagnetic resonant cavities and lasers; tests of the equivalence principle; gauge and Higgs particles; high-energy astrophysical observations; laboratory tests of gravity; matter interferometry; neutrino oscillations and propagation; oscillations and decays of neutral mesons; particle–antiparticle comparisons; post-newtonian gravity in the solar system and beyond; second- and third-generation particles; space-based missions; spectroscopy of hydrogen and ant...

Physics of the Lorentz Group

Science.gov (United States)

Başkal, Sibel

2015-11-01

This book explains the Lorentz mathematical group in a language familiar to physicists. While the three-dimensional rotation group is one of the standard mathematical tools in physics, the Lorentz group of the four-dimensional Minkowski space is still very strange to most present-day physicists. It plays an essential role in understanding particles moving at close to light speed and is becoming the essential language for quantum optics, classical optics, and information science. The book is based on papers and books published by the authors on the representations of the Lorentz group based on harmonic oscillators and their applications to high-energy physics and to Wigner functions applicable to quantum optics. It also covers the two-by-two representations of the Lorentz group applicable to ray optics, including cavity, multilayer and lens optics, as well as representations of the Lorentz group applicable to Stokes parameters and the Poincaré sphere on polarization optics.

Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

International Nuclear Information System (INIS)

Babusci, D.; Balwierz-Pytko, I.; Bencivenni, G.; Bloise, C.; Bossi, F.; Branchini, P.; Budano, A.; Caldeira Balkeståhl, L.; Capon, G.; Ceradini, F.; Ciambrone, P.; Curciarello, F.; Czerwiński, E.; Danè, E.; De Leo, V.; De Lucia, E.; De Robertis, G.; De Santis, A.; De Simone, P.

2014-01-01

Neutral kaon pairs produced in ϕ decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process ϕ→K S K L →π + π − π + π − based on 1.7 fb −1 of data collected by the KLOE experiment at the Frascati ϕ-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters Δa μ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Δa 0 =(−6.0±7.7 stat ±3.1 syst )×10 −18 GeV, Δa X =(0.9±1.5 stat ±0.6 syst )×10 −18 GeV, Δa Y =(−2.0±1.5 stat ±0.5 syst )×10 −18 GeV, Δa Z =(3.1±1.7 stat ±0.5 syst )×10 −18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension.

Tests of Lorentz and CPT violation with MiniBooNE neutrino oscillation excesses

International Nuclear Information System (INIS)

Katori, Teppei

2014-01-01

Lorentz and CPT symmetry violaton is a predicted phenomenon of Planck–scale physics. Various types of data are analyzed to search for Lorentz violation under the Standard–Model Extension (SME) framework, including neutrino oscillation data. MiniBooNE is a short–baseline neutrino oscillation experiment at Fermilab. The measured excesses from MiniBooNE cannot be reconciled within the neutrino Standard Model (vSM); thus it might be a signal of new physics, such as Lorentz violation. We have analyzed the sidereal time dependence of MiniBooNE data for signals of the possible sidereal time dependence of the ocillation signals. we find that the v e appearance data prefer a sidereal time–independent solution, and the v-bar e appearance data slightly prefer a sidereal time–dependent solution, however, the statistical significance is not high to claim the discovery. Limits of order 10 −20 GeV are placed on combinations of SME coefficients

Three questions on Lorentz violation

Energy Technology Data Exchange (ETDEWEB)

Iorio, Alfredo [Institute of Particle and Nuclear Physics, Charles University of Prague - V Holesovickach 2, 180 00 Prague 8 (Czech Republic); Department of Physics ' E. R. Caianiello' , University of Salerno and I.N.F.N. Naples, Gruppo Collegato di Salerno - Via Allende, 84081 Baronissi (Italy)

2007-05-15

We review the basics of the two most widely used approaches to Lorentz violation - the Standard Model Extension and Noncommutative Field Theory - and discuss in some detail the example of the modified spectrum of the synchrotron radiation. Motivated by touching upon such a fundamental issue as Lorentz symmetry, we ask three questions: What is behind the search for Lorentz violation? Is String Theory a physical theory? Is there an alternative to Supersymmetry?.

Concerning tests of time-reversal invariance via the polarization-analyzing power equality

International Nuclear Information System (INIS)

Conzett, H.E.

1982-01-01

Previous tests of time-reversal invariance via comparisons of polarizations and analyzing powers in nuclear scattering have been examined. It is found that all of these comparisons fail as adequate tests of time-reversal invariance either because of a lack of experimental precision or the lack of sensitivity to any time-reversal symmetry violation

Test of charge conjugation invariance

International Nuclear Information System (INIS)

Nefkens, B.M.K.; Prakhov, S.; Gaardestig, A.; Clajus, M.; Marusic, A.; McDonald, S.; Phaisangittisakul, N.; Price, J.W.; Starostin, A.; Tippens, W.B.; Allgower, C.E.; Spinka, H.; Bekrenev, V.; Koulbardis, A.; Kozlenko, N.; Kruglov, S.; Lopatin, I.; Briscoe, W.J.; Shafi, A.; Comfort, J.R.

2005-01-01

We report on the first determination of upper limits on the branching ratio (BR) of η decay to π 0 π 0 γ and to π 0 π 0 π 0 γ. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(η→π 0 π 0 γ) -4 at the 90% confidence level, in support of C invariance of isoscalar electromagnetic interactions of the light quarks. We have also measured BR(η→π 0 π 0 π 0 γ) -5 at the 90% confidence level, in support of C invariance of isovector electromagnetic interactions

k-essence explains a Lorentz violation experiment

International Nuclear Information System (INIS)

Li Miao; Pang Yi; Wang Yi

2009-01-01

Recently, a state of the art experiment shows evidence for Lorentz violation in the gravitational sector. To explain this experiment, we investigate a spontaneous Lorentz violation scenario with a generalized scalar field. We find that when the scalar field is nonminimally coupled to gravity, the Lorentz violation induces a deformation in the Newtonian potential along the direction of Lorentz violation.

Testing strong factorial invariance using three-level structural equation modeling

Directory of Open Access Journals (Sweden)

Suzanne eJak

2014-07-01

Full Text Available Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias across groups. Although this approach is possible in principle, it is hardly practical when the number of groups is large or when the group size is relatively small. Jak, Oort and Dolan (2013 showed how strong factorial invariance across large numbers of groups can be tested in a multilevel structural equation modeling framework, by treating group as a random instead of a fixed variable. In the present study, this model is extended for use with three-level data. The proposed method is illustrated with an investigation of strong factorial invariance across 156 school classes and 50 schools in a Dutch dyscalculia test, using three-level structural equation modeling.

Prospects for Lorentz and CPT tests with hydrogen and antihydrogen

CERN Document Server

Becker, Tobias Frederic

2017-01-01

As a summer student for 13 weeks in the ASACUSA-CUSP collaboration, under the supervision of Chloé Malbrunot, my project consisted in a first part on the theoretical treatment of Lorentz and CPT violation in hydrogen & antihydrogen in the framework of the Standard Model Extension SME and in second part on experimental measurements on a hydrogen beam.

A Test for Cluster Bias: Detecting Violations of Measurement Invariance across Clusters in Multilevel Data

Science.gov (United States)

Jak, Suzanne; Oort, Frans J.; Dolan, Conor V.

2013-01-01

We present a test for cluster bias, which can be used to detect violations of measurement invariance across clusters in 2-level data. We show how measurement invariance assumptions across clusters imply measurement invariance across levels in a 2-level factor model. Cluster bias is investigated by testing whether the within-level factor loadings…

Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

Energy Technology Data Exchange (ETDEWEB)

Babusci, D. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Balwierz-Pytko, I. [Institute of Physics, Jagiellonian University, Cracow (Poland); Bencivenni, G.; Bloise, C.; Bossi, F. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Budano, A. [Dipartimento di Matematica e Fisica dell' Università “Roma Tre”, Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Caldeira Balkeståhl, L. [Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Capon, G. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Ceradini, F. [Dipartimento di Matematica e Fisica dell' Università “Roma Tre”, Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ciambrone, P. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Curciarello, F. [Dipartimento di Fisica e Scienze della Terra dell' Università di Messina, Messina (Italy); INFN Sezione di Catania, Catania (Italy); Czerwiński, E. [Institute of Physics, Jagiellonian University, Cracow (Poland); Danè, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Leo, V. [Dipartimento di Fisica e Scienze della Terra dell' Università di Messina, Messina (Italy); INFN Sezione di Catania, Catania (Italy); De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Robertis, G. [INFN Sezione di Bari, Bari (Italy); De Santis, A., E-mail: antonio.desantis@roma1.infn.it [Dipartimento di Fisica dell' Università “Sapienza”, Roma (Italy); INFN Sezione di Roma, Roma (Italy); De Simone, P. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); and others

2014-03-07

Neutral kaon pairs produced in ϕ decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process ϕ→K{sub S}K{sub L}→π{sup +}π{sup −}π{sup +}π{sup −} based on 1.7 fb{sup −1} of data collected by the KLOE experiment at the Frascati ϕ-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters Δa{sub μ} for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Δa{sub 0}=(−6.0±7.7{sub stat}±3.1{sub syst})×10{sup −18} GeV, Δa{sub X}=(0.9±1.5{sub stat}±0.6{sub syst})×10{sup −18} GeV, Δa{sub Y}=(−2.0±1.5{sub stat}±0.5{sub syst})×10{sup −18} GeV, Δa{sub Z}=(3.1±1.7{sub stat}±0.5{sub syst})×10{sup −18} GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension.

Lorentz- and CPT-symmetry studies in subatomic physics

Energy Technology Data Exchange (ETDEWEB)

Lehnert, Ralf, E-mail: ralehner@indiana.edu [Leibniz Universität Hannover (Germany)

2016-12-15

Subatomic systems provide an exquisite test bench for spacetime symmetries. This work motivates such measurements, reviews the effective field theory test framework for the description of Lorentz and CPT violation, and employs this framework to study the phenomenology of spacetime-symmetry breaking in various subatomic systems.

Structural aspects of Lorentz-violating quantum field theory

Science.gov (United States)

Cambiaso, M.; Lehnert, R.; Potting, R.

2018-01-01

In the last couple of decades the Standard Model Extension has emerged as a fruitful framework to analyze the empirical and theoretical extent of the validity of cornerstones of modern particle physics, namely, of Special Relativity and of the discrete symmetries C, P and T (or some combinations of these). The Standard Model Extension allows to contrast high-precision experimental tests with posited alterations representing minute Lorentz and/or CPT violations. To date no violation of these symmetry principles has been observed in experiments, mostly prompted by the Standard-Model Extension. From the latter, bounds on the extent of departures from Lorentz and CPT symmetries can be obtained with ever increasing accuracy. These analyses have been mostly focused on tree-level processes. In this presentation I would like to comment on structural aspects of perturbative Lorentz violating quantum field theory. I will show that some insight coming from radiative corrections demands a careful reassessment of perturbation theory. Specifically I will argue that both the standard renormalization procedure as well as the Lehmann-Symanzik-Zimmermann reduction formalism need to be adapted given that the asymptotic single-particle states can receive quantum corrections from Lorentz-violating operators that are not present in the original Lagrangian.

The Impact of Partial Measurement Invariance on Testing Moderation for Single and Multi-Level Data.

Science.gov (United States)

Hsiao, Yu-Yu; Lai, Mark H C

2018-01-01

Moderation effect is a commonly used concept in the field of social and behavioral science. Several studies regarding the implication of moderation effects have been done; however, little is known about how partial measurement invariance influences the properties of tests for moderation effects when categorical moderators were used. Additionally, whether the impact is the same across single and multilevel data is still unknown. Hence, the purpose of the present study is twofold: (a) To investigate the performance of the moderation test in single-level studies when measurement invariance does not hold; (b) To examine whether unique features of multilevel data, such as intraclass correlation (ICC) and number of clusters, influence the effect of measurement non-invariance on the performance of tests for moderation. Simulation results indicated that falsely assuming measurement invariance lead to biased estimates, inflated Type I error rates, and more gain or more loss in power (depends on simulation conditions) for the test of moderation effects. Such patterns were more salient as sample size and the number of non-invariant items increase for both single- and multi-level data. With multilevel data, the cluster size seemed to have a larger impact than the number of clusters when falsely assuming measurement invariance in the moderation estimation. ICC was trivially related to the moderation estimates. Overall, when testing moderation effects with categorical moderators, employing a model that accounts for the measurement (non)invariance structure of the predictor and/or the outcome is recommended.

A q-deformed Lorentz algebra

International Nuclear Information System (INIS)

Schmidke, W.B.; Wess, J.; Muenchen Univ.; Zumino, B.; Lawrence Berkeley Lab., CA

1991-01-01

We derive a q-deformed version of the Lorentz algebra by deformating the algebra SL(2, C). The method is based on linear representations of the algebra on the complex quantum spinor space. We find that the generators usually identified with SL q (2, C) generate SU q (2) only. Four additional generators are added which generate Lorentz boosts. The full algebra of all seven generators and their coproduct is presented. We show that in the limit q→1 the generators are those of the classical Lorentz algebra plus an additional U(1). Thus we have a deformation of SL(2, C)xU(1). (orig.)

A test for ordinal measurement invariance

NARCIS (Netherlands)

Ligtvoet, R.; Millsap, R.E.; Bolt, D.M.; van der Ark, L.A.; Wang, W.-C.

2015-01-01

One problem with the analysis of measurement invariance is the reliance of the analysis on having a parametric model that accurately describes the data. In this paper an ordinal version of the property of measurement invariance is proposed, which relies only on nonparametric restrictions. This

On the invariance of world time reference system

International Nuclear Information System (INIS)

Asanov, G.S.

1978-01-01

A universal reference system is studied. It is shown that time differentiation acquires an invariant meaning in the covariant theory of a curved space-time. All the principal covariant equations of the Einstein gravitational field theory can be interpreted successively relative to a universal reference system, whose base congruence is the S-congruence. The Lorentz calibration conditions determine the base tetrades of the universal reference system with an accuracy to rigid spatial rotations with constant coefficients. The use of rigid tetrades eliminates the ambiguity in the interpretation of the value of the energy momentum of a gravitational field

In-depth Study on Cylinder Wake Controlled by Lorentz Force

International Nuclear Information System (INIS)

Zhang Hui; Fan Bao-Chun; Chen Zhi-Hua

2011-01-01

The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed. The effects of Lorentz force are found to be composed of two parts, one is its direct action on the cylinder (the wall Lorentz force) and the other is applied to the fluid (called the field Lorentz force) near the cylinder surface. Our results show that the wall Lorentz force can generate thrust and reduce the drag; the field Lorentz force increases the drag. However, the cylinder drag is dominated by the wall Lorentz force. In addition, the field Lorentz force above the upper surface decreases the lift, while the upper wall Lorentz force increases it. The total lift is dominated by the upper wall Lorentz force. (fundamental areas of phenomenology(including applications))

Scale invariant for one-sided multivariate likelihood ratio tests

Directory of Open Access Journals (Sweden)

Samruam Chongcharoen

2010-07-01

Full Text Available Suppose 1 2 , ,..., n X X X is a random sample from Np ( ,V distribution. Consider 0 1 2 : ... 0 p H      and1 : 0 for 1, 2,..., i H   i  p , let 1 0 H  H denote the hypothesis that 1 H holds but 0 H does not, and let ~ 0 H denote thehypothesis that 0 H does not hold. Because the likelihood ratio test (LRT of 0 H versus 1 0 H  H is complicated, severalad hoc tests have been proposed. Tang, Gnecco and Geller (1989 proposed an approximate LRT, Follmann (1996 suggestedrejecting 0 H if the usual test of 0 H versus ~ 0 H rejects 0 H with significance level 2 and a weighted sum of the samplemeans is positive, and Chongcharoen, Singh and Wright (2002 modified Follmann’s test to include information about thecorrelation structure in the sum of the sample means. Chongcharoen and Wright (2007, 2006 give versions of the Tang-Gnecco-Geller tests and Follmann-type tests, respectively, with invariance properties. With LRT’s scale invariant desiredproperty, we investigate its powers by using Monte Carlo techniques and compare them with the tests which we recommendin Chongcharoen and Wright (2007, 2006.

Detecting Lorentz Violations with Gravitational Waves From Black Hole Binaries

Science.gov (United States)

Sotiriou, Thomas P.

2018-01-01

Gravitational wave observations have been used to test Lorentz symmetry by looking for dispersive effects that are caused by higher order corrections to the dispersion relation. In this Letter I argue on general grounds that, when such corrections are present, there will also be a scalar excitation. Hence, a smoking-gun observation of Lorentz symmetry breaking would be the direct detection of scalar waves that travel at a speed other than the speed of the standard gravitational wave polarizations or the speed of light. Interestingly, in known Lorentz-breaking gravity theories the difference between the speeds of scalar and tensor waves is virtually unconstrained, whereas the difference between the latter and the speed of light is already severely constrained by the coincident detection of gravitational waves and gamma rays from a binary neutron star merger.

Transport properties of stochastic Lorentz models

NARCIS (Netherlands)

Beijeren, H. van

Diffusion processes are considered for one-dimensional stochastic Lorentz models, consisting of randomly distributed fixed scatterers and one moving light particle. In waiting time Lorentz models the light particle makes instantaneous jumps between scatterers after a stochastically distributed

The Impact of Partial Measurement Invariance on Testing Moderation for Single and Multi-Level Data

Directory of Open Access Journals (Sweden)

Yu-Yu Hsiao

2018-05-01

Full Text Available Moderation effect is a commonly used concept in the field of social and behavioral science. Several studies regarding the implication of moderation effects have been done; however, little is known about how partial measurement invariance influences the properties of tests for moderation effects when categorical moderators were used. Additionally, whether the impact is the same across single and multilevel data is still unknown. Hence, the purpose of the present study is twofold: (a To investigate the performance of the moderation test in single-level studies when measurement invariance does not hold; (b To examine whether unique features of multilevel data, such as intraclass correlation (ICC and number of clusters, influence the effect of measurement non-invariance on the performance of tests for moderation. Simulation results indicated that falsely assuming measurement invariance lead to biased estimates, inflated Type I error rates, and more gain or more loss in power (depends on simulation conditions for the test of moderation effects. Such patterns were more salient as sample size and the number of non-invariant items increase for both single- and multi-level data. With multilevel data, the cluster size seemed to have a larger impact than the number of clusters when falsely assuming measurement invariance in the moderation estimation. ICC was trivially related to the moderation estimates. Overall, when testing moderation effects with categorical moderators, employing a model that accounts for the measurement (noninvariance structure of the predictor and/or the outcome is recommended.

Lorentz violation, gravitoelectromagnetic field and Bhabha scattering

Science.gov (United States)

Santos, A. F.; Khanna, Faqir C.

2018-01-01

Lorentz symmetry is a fundamental symmetry in the Standard Model (SM) and in General Relativity (GR). This symmetry holds true for all models at low energies. However, at energies near the Planck scale, it is conjectured that there may be a very small violation of Lorentz symmetry. The Standard Model Extension (SME) is a quantum field theory that includes a systematic description of Lorentz symmetry violations in all sectors of particle physics and gravity. In this paper, SME is considered to study the physical process of Bhabha Scattering in the Gravitoelectromagnetism (GEM) theory. GEM is an important formalism that is valid in a suitable approximation of general relativity. A new nonminimal coupling term that violates Lorentz symmetry is used in this paper. Differential cross-section for gravitational Bhabha scattering is calculated. The Lorentz violation contributions to this GEM scattering cross-section are small and are similar in magnitude to the case of the electromagnetic field.

An Affine Invariant Bivariate Version of the Sign Test.

Science.gov (United States)

1987-06-01

words: affine invariance, bivariate quantile, bivariate symmetry, model,. generalized median, influence function , permutation test, normal efficiency...calculate a bivariate version of the influence function , and the resulting form is bounded, as is the case for the univartate sign test, and shows the...terms of a blvariate analogue of IHmpel’s (1974) influence function . The latter, though usually defined as a von-Mises derivative of certain

Lorentz violations in multifractal spacetimes

Energy Technology Data Exchange (ETDEWEB)

Calcagni, Gianluca [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)

2017-05-15

Using the recent observation of gravitational waves (GW) produced by a black-hole merger, we place a lower bound on the energy above which a multifractal spacetime would display an anomalous geometry and, in particular, violations of Lorentz invariance. In the so-called multifractional theory with q-derivatives, we show that the deformation of dispersion relations is much stronger than in generic quantum-gravity approaches (including loop quantum gravity) and, contrary to the latter, present observations on GWs can place very strong bounds on the characteristic scales at which spacetime deviates from standard Minkowski. The energy at which multifractal effects should become apparent is E{sub *} > 10{sup 14} GeV (thus improving previous bounds by 12 orders of magnitude) when the exponents in the measure are fixed to their central value 1 / 2. We also estimate, for the first time, the effect of logarithmic oscillations in the measure (corresponding to a discrete spacetime structure) and find that they do not change much the bounds obtained in their absence, unless the amplitude of the oscillations is fine tuned. This feature, unavailable in known quantum-gravity scenarios, may help the theory to avoid being ruled out by gamma-ray burst (GRB) observations, for which E{sub *} > 10{sup 17} GeV or greater. (orig.)

Violation of CPT invariance in the early universe and leptogenesis/baryogenesis

CERN Document Server

Mavromatos, Nick E

2013-01-01

In this talk, I review some plausible scenarios entailing violation of CPT symmetry in the early Universe, due to space-time backgrounds which do not respect some of the assumptions for the validity of the CPT theorem (here considered will be Lorentz invariance and/or Unitarity). The key point in all these models is that the background induces different populations of fermions as compared to antifermions, and hence CPT Violation (CPTV), already in thermal equilibrium. Such populations may freeze out at various conditions depending on the details of the underlying microscopic model, thereby leading to leptogenesis and baryogenesis. Among the considered scenarios is a stringy one, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. We also discuss briefly (Lorentz Violating) CPTV models that go beyond the local effective lagrangian framework, such as a stochastic Finsler metric and D-par...

BPS Lorentz-violating vortex solutions

International Nuclear Information System (INIS)

Casana, Rodolfo; Ferreira Junior, Manoel M.; Hora, E. da

2011-01-01

In this work, we deal with the construction of static Bogomol'nyi-Prasad-Sommerfield (BPS) rotationally symmetric configurations on the dimensional CPT-even Lorentz-breaking photonic sector of the Standard Model Extension (SME). The main objective of this presentation is to show the possibility of obtaining such BPS solutions, even in the presence of a Lorentz-violating background. A secondary objective is to analyze the effects of this background on such topologically non-trivial BPS configurations. In order to obtain these results, we deal with some specific components of Lorentz-violating field, handling with the static Euler-Lagrange equation of motion to gauge field, from which we fix temporal gauge (absence of electric field) as a proper gauge choice. Also, considering this equation, we consistently determine an interesting configuration (discarding non-interesting ones) to the Lorentz-breaking sector. Using this configuration and the standard rotationally symmetric vortex Ansatz (which describes the behaviors of Higgs and gauge fields via two profile functions, g(r) and a(r), respectively), we construct a rotationally symmetric expression to the energy density of the system. To obtain BPS solutions, we rewrite this expression in order to have static vortex solutions satisfying a set of first order differential equations (BPS ones). The existence of such solutions is strongly constrained by a relation between some parameters of the model, including the Lorentz-breaking one. Naturally, we show that the total energy of these BPS solutions is proportional to their magnetic flux, which is quantized according to their winding number. Using suitable boundary conditions (near the origin and asymptotically), we numerically integrate the BPS equations (by means of the shooting method). By this way, we obtain solutions for some physical quantities (Higgs field, magnetic field and energy density) for several values of the Lorentz-violating parameters. From these

The Formalization of Fairness: Issues in Testing for Measurement Invariance Using Subtest Scores

Science.gov (United States)

Molenaar, Dylan; Borsboom, Denny

2013-01-01

Measurement invariance is an important prerequisite for the adequate comparison of group differences in test scores. In psychology, measurement invariance is typically investigated by means of linear factor analyses of subtest scores. These subtest scores typically result from summing the item scores. In this paper, we discuss 4 possible problems…

Power properties of invariant tests for spatial autocorrelation in linear regression

NARCIS (Netherlands)

Martellosio, F.

2006-01-01

Many popular tests for residual spatial autocorrelation in the context of the linear regression model belong to the class of invariant tests. This paper derives a number of exact properties of the power function of such tests. In particular, we extend the work of Krämer (2005, Journal of Statistical

Yang-Mills theory on a momentum lattice: Gauge invariance, chiral invariance, and no fermion doubling

International Nuclear Information System (INIS)

Berube, D.; Kroeger, H.; Lafrance, R.; Marleau, L.

1991-01-01

We discuss properties of a noncompact formulation of gauge theories with fermions on a momentum (k) lattice. (a) This formulation is suitable to build in Fourier acceleration in a direct way. (b) The numerical effort to compute the action (by fast Fourier transform) goes essentially like logV with the lattice volume V. (c) For the Yang-Mills theory we find that the action conserves gauge symmetry and chiral symmetry in a weak sense: On a finite lattice the action is invariant under infinitesimal transformations with compact support. Under finite transformations these symmetries are approximately conserved and they are restored on an infinite lattice and in the continuum limit. Moreover, these symmetries also hold on a finite lattice under finite transformations, if the classical fields, instead of being c-number valued, take values from a finite Galois field. (d) There is no fermion doubling. (e) For the φ 4 model we investigate the transition towards the continuum limit in lattice perturbation theory up to second order. We compute the two- and four-point functions and find local and Lorentz-invariant results. (f) In QED we compute a one-loop vacuum polarization and find in the continuum limit the standard result. (g) As a numerical application, we compute the propagator left-angle φ(k)φ(k')right-angle in the φ 4 model, investigate Euclidean invariance, and extract m R as well as Z R . Moreover we compute left-angle F μν (k)F μν (k')right-angle in the SU(2) model

Testing Non-commutative QED, Constructing Non-commutative MHD

OpenAIRE

Guralnik, Z.; Jackiw, R.; Pi, S. Y.; Polychronakos, A. P.

2001-01-01

The effect of non-commutativity on electromagnetic waves violates Lorentz invariance: in the presence of a background magnetic induction field b, the velocity for propagation transverse to b differs from c, while propagation along b is unchanged. In principle, this allows a test by the Michelson-Morley interference method. We also study non-commutativity in another context, by constructing the theory describing a charged fluid in a strong magnetic field, which forces the fluid particles into ...

Testing Measurement Invariance Using MIMIC: Likelihood Ratio Test with a Critical Value Adjustment

Science.gov (United States)

Kim, Eun Sook; Yoon, Myeongsun; Lee, Taehun

2012-01-01

Multiple-indicators multiple-causes (MIMIC) modeling is often used to test a latent group mean difference while assuming the equivalence of factor loadings and intercepts over groups. However, this study demonstrated that MIMIC was insensitive to the presence of factor loading noninvariance, which implies that factor loading invariance should be…

Effective potential in Lorentz-breaking field theory models

Energy Technology Data Exchange (ETDEWEB)

Baeta Scarpelli, A.P. [Centro Federal de Educacao Tecnologica, Nova Gameleira Belo Horizonte, MG (Brazil); Setor Tecnico-Cientifico, Departamento de Policia Federal, Belo Horizonte, MG (Brazil); Brito, L.C.T. [Universidade Federal de Lavras, Departamento de Fisica, Lavras, MG (Brazil); Felipe, J.C.C. [Universidade Federal de Lavras, Departamento de Fisica, Lavras, MG (Brazil); Universidade Federal dos Vales do Jequitinhonha e Mucuri, Instituto de Engenharia, Ciencia e Tecnologia, Veredas, Janauba, MG (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil)

2017-12-15

We calculate explicitly the one-loop effective potential in different Lorentz-breaking field theory models. First, we consider a Yukawa-like theory and some examples of Lorentz-violating extensions of scalar QED. We observe, for the extended QED models, that the resulting effective potential converges to the known result in the limit in which Lorentz symmetry is restored. Besides, the one-loop corrections to the effective potential in all the cases we study depend on the background tensors responsible for the Lorentz-symmetry violation. This has consequences for physical quantities like, for example, in the induced mass due to the Coleman-Weinberg mechanism. (orig.)

Effective potential in Lorentz-breaking field theory models

International Nuclear Information System (INIS)

Baeta Scarpelli, A.P.; Brito, L.C.T.; Felipe, J.C.C.; Nascimento, J.R.; Petrov, A.Yu.

2017-01-01

We calculate explicitly the one-loop effective potential in different Lorentz-breaking field theory models. First, we consider a Yukawa-like theory and some examples of Lorentz-violating extensions of scalar QED. We observe, for the extended QED models, that the resulting effective potential converges to the known result in the limit in which Lorentz symmetry is restored. Besides, the one-loop corrections to the effective potential in all the cases we study depend on the background tensors responsible for the Lorentz-symmetry violation. This has consequences for physical quantities like, for example, in the induced mass due to the Coleman-Weinberg mechanism. (orig.)

Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

International Nuclear Information System (INIS)

Membiela, Federico Agustin; Bellini, Mauricio

2010-01-01

Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

Energy Technology Data Exchange (ETDEWEB)

Membiela, Federico Agustin, E-mail: membiela@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Fisica de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

2010-02-22

Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

Semiclassical gravitoelectromagnetic inflation in a Lorentz gauge: Seminal inflaton fluctuations and electromagnetic fields from a 5D vacuum state

Science.gov (United States)

Membiela, Federico Agustín; Bellini, Mauricio

2010-02-01

Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. The difference with other previous works is that in this one we use a Lorentz gauge. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of magnetic field modes during the early inflationary epoch of the universe on cosmological scales.

Precision tests of CPT invariance with single trapped antiprotons

Energy Technology Data Exchange (ETDEWEB)

Ulmer, Stefan [RIKEN, Ulmer Initiative Research Unit, Wako, Saitama (Japan); Collaboration: BASE-Collaboration

2015-07-01

The reason for the striking imbalance of matter and antimatter in our Universe has yet to be understood. This is the motivation and inspiration to conduct high precision experiments comparing the fundamental properties of matter and antimatter equivalents at lowest energies and with greatest precision. According to theory, the most sensitive tests of CPT invariance are measurements of antihydrogen ground-state hyperfine splitting as well as comparisons of proton and antiproton magnetic moments. Within the BASE collaboration we target the latter. By using a double Penning trap we performed very recently the first direct high precision measurement of the proton magnetic moment. The achieved fractional precision of 3.3 ppb improves the currently accepted literature value by a factor of 2.5. Application of the method to a single trapped antiproton will improve precision of the particles magnetic moment by more than a factor of 1000, thus providing one of the most stringent tests of CPT invariance. In my talk I report on the status and future perspectives of our efforts.

Consistent Lorentz violation in flat and curved space

International Nuclear Information System (INIS)

Dvali, Gia; Pujolas, Oriol; Redi, Michele

2007-01-01

Motivated by the severity of the bounds on Lorentz violation in the presence of ordinary gravity, we study frameworks in which Lorentz violation does not affect the spacetime geometry. We show that there are at least two inequivalent classes of spontaneous Lorentz breaking that even in the presence of gravity result in Minkowski space. The first one generically corresponds to the condensation of tensor fields with tachyonic mass, which in turn is related to ghost condensation. In the second class, realized by the Dvali-Gabadadze-Porrati model or theories of massive gravitons, spontaneous Lorentz breaking is induced by the expectation value of sources. The generalization to de Sitter space is also discussed

A more general model for testing measurement invariance and differential item functioning.

Science.gov (United States)

Bauer, Daniel J

2017-09-01

The evaluation of measurement invariance is an important step in establishing the validity and comparability of measurements across individuals. Most commonly, measurement invariance has been examined using 1 of 2 primary latent variable modeling approaches: the multiple groups model or the multiple-indicator multiple-cause (MIMIC) model. Both approaches offer opportunities to detect differential item functioning within multi-item scales, and thereby to test measurement invariance, but both approaches also have significant limitations. The multiple groups model allows 1 to examine the invariance of all model parameters but only across levels of a single categorical individual difference variable (e.g., ethnicity). In contrast, the MIMIC model permits both categorical and continuous individual difference variables (e.g., sex and age) but permits only a subset of the model parameters to vary as a function of these characteristics. The current article argues that moderated nonlinear factor analysis (MNLFA) constitutes an alternative, more flexible model for evaluating measurement invariance and differential item functioning. We show that the MNLFA subsumes and combines the strengths of the multiple group and MIMIC models, allowing for a full and simultaneous assessment of measurement invariance and differential item functioning across multiple categorical and/or continuous individual difference variables. The relationships between the MNLFA model and the multiple groups and MIMIC models are shown mathematically and via an empirical demonstration. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Constraints on spacetime anisotropy and Lorentz violation from the GRAAL experiment

Energy Technology Data Exchange (ETDEWEB)

Chang, Zhe [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Chinese Academy of Sciences, Theoretical Physics Center for Science Facilities, Beijing (China); Wang, Sai [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

2013-02-15

The GRAAL experiment could constrain the variations of the speed of light. The anisotropy of the speed of light may imply that the spacetime is anisotropic. Finsler geometry is a reasonable candidate to deal with the spacetime anisotropy. In this paper, the Lorentz invariance violation (LIV) of the photon sector is investigated in the locally Minkowski spacetime. The locally Minkowski spacetime is a class of flat Finsler spacetime and refers a metric with the anisotropic departure from the Minkowski one. The LIV matrices used to fit the experimental data are represented in terms of these metric deviations. The GRAAL experiment constrains the spacetime anisotropy to be less than 10{sup -14}. In addition, we find that the simplest Finslerian photon sector could be viewed as a geometric representation of the photon sector in the minimal standard model extension (SME). (orig.)

Lorentz violation and black-hole thermodynamics

International Nuclear Information System (INIS)

Betschart, G.; Kant, E.; Klinkhamer, F.R.

2009-01-01

We consider nonstandard photons from nonbirefringent modified Maxwell theory and discuss their propagation in a fixed Schwarzschild spacetime background. This particular modification of Maxwell theory is Lorentz-violating and allows for maximal photon velocities differing from the causal speed c of the asymptotic background spacetime. In the limit of geometrical optics, light rays from modified Maxwell theory are found to propagate along null geodesics in an effective metric. We observe that not every Lorentz-violating theory with multiple maximal velocities different from the causal speed c modifies the notion of the event horizon, contrary to naive expectations. This result implies that not every Lorentz-violating theory with multiple maximal velocities necessarily leads to a contradiction with the generalized second law of thermodynamics.

A Measurement of the muon neutrino charged current quasielastic interaction and a test of Lorentz violation with the MiniBooNE experiment

Energy Technology Data Exchange (ETDEWEB)

Katori, Teppei [Indiana Univ., Bloomington, IN (United States)

2008-12-01

The Mini-Booster neutrino experiment (MiniBooNE) at Fermi National Accelerator Laboratory (Fermilab) is designed to search for v_μ → v_e appearance neutrino oscillations. Muon neutrino charged-current quasi-elastic (CCQE) interactions (v_μ + n → μ + p) make up roughly 40% of our data sample, and it is used to constrain the background and cross sections for the oscillation analysis. Using high-statistics MiniBooNE CCQE data, the muon-neutrino CCQE cross section is measured. The nuclear model is tuned precisely using the MiniBooNE data. The measured total cross section is σ = (1.058 ± 0.003 (stat) ± 0.111 (syst)) x 10^-38 cm² at the MiniBooNE muon neutrino beam energy (700-800 MeV). v_e appearance candidate data is also used to search for Lorentz violation. Lorentz symmetry is one of the most fundamental symmetries in modern physics. Neutrino oscillations offer a new method to test it. We found that the MiniBooNE result is not well-described using Lorentz violation, however further investigation is required for a more conclusive result.

Breaking Lorentz reciprocity to overcome the time-bandwidth limit in physics and engineering

Science.gov (United States)

Tsakmakidis, K. L.; Shen, L.; Schulz, S. A.; Zheng, X.; Upham, J.; Deng, X.; Altug, H.; Vakakis, A. F.; Boyd, R. W.

2017-06-01

A century-old tenet in physics and engineering asserts that any type of system, having bandwidth Δω, can interact with a wave over only a constrained time period Δt inversely proportional to the bandwidth (Δt·Δω ~ 2π). This law severely limits the generic capabilities of all types of resonant and wave-guiding systems in photonics, cavity quantum electrodynamics and optomechanics, acoustics, continuum mechanics, and atomic and optical physics but is thought to be completely fundamental, arising from basic Fourier reciprocity. We propose that this “fundamental” limit can be overcome in systems where Lorentz reciprocity is broken. As a system becomes more asymmetric in its transport properties, the degree to which the limit can be surpassed becomes greater. By way of example, we theoretically demonstrate how, in an astutely designed magnetized semiconductor heterostructure, the above limit can be exceeded by orders of magnitude by using realistic material parameters. Our findings revise prevailing paradigms for linear, time-invariant resonant systems, challenging the doctrine that high-quality resonances must invariably be narrowband and providing the possibility of developing devices with unprecedentedly high time-bandwidth performance.

Traveling solitons in Lorentz and CPT breaking systems

International Nuclear Information System (INIS)

Souza Dutra, A. de; Correa, R. A. C.

2011-01-01

In this work we present a class of traveling solitons in Lorentz and CPT breaking systems. In the case of Lorentz violating scenarios, as far as we know, only static solitonic configurations were analyzed up to now in the literature. Here it is shown that it is possible to construct some traveling solitons which cannot be mapped into static configurations by means of Lorentz boosts due to explicit breaking. In fact, the traveling solutions cannot be reached from the static ones by using something similar to a Lorentz boost in those cases. Furthermore, in the model studied, a complete set of exact solutions is obtained. The solutions present a critical behavior controlled by the choice of an arbitrary integration constant.

A Lorentz-Violating Alternative to Higgs Mechanism?

CERN Document Server

Alexandre, Jean

2011-01-01

We consider a four-dimensional field-theory model with two massless fermions, coupled to an Abelian vector field without flavour mixing, and to another Abelian vector field with flavour mixing. Both Abelian vectors have a Lorentz-violating kinetic term, introducing a Lorentz-violation mass scale $M$, from which fermions and the flavour-mixing vector get their dynamical masses, whereas the vector coupled without flavour mixing remains massless. When the two coupling constants have similar values in order of magnitude, a mass hierarchy pattern emerges, in which one fermion is very light compared to the other, whilst the vector mass is larger than the mass of the heavy fermion. The work presented here may be considered as a Lorentz-symmetry-Violating alternative to the Higgs mechanism, in the sense that no scalar particle (fundamental or composite) is necessary for the generation of the vector-meson mass. However, the model is not realistic given that, as a result of Lorentz Violation, the maximal (light-cone) s...

Lorentz Violation, Möller Scattering, and Finite Temperature

Directory of Open Access Journals (Sweden)

Alesandro F. Santos

2018-01-01

Full Text Available Lorentz and CPT symmetries may be violated in new physics that emerges at very high energy scale, that is, at the Planck scale. The differential cross section of the Möller scattering due to Lorentz violation at finite temperature is calculated. Lorentz-violating effects emerge from an interaction vertex due to a CPT-odd nonminimal coupling in the covariant derivative. The finite temperature effects are determined using the Thermo Field Dynamics (TFD formalism.

Lorentz violation, gravitoelectromagnetism and Bhabha scattering at finite temperature

Science.gov (United States)

Santos, A. F.; Khanna, Faqir C.

2018-04-01

Gravitoelectromagnetism (GEM) is an approach for the gravitation field that is described using the formulation and terminology similar to that of electromagnetism. The Lorentz violation is considered in the formulation of GEM that is covariant in its form. In practice, such a small violation of the Lorentz symmetry may be expected in a unified theory at very high energy. In this paper, a non-minimal coupling term, which exhibits Lorentz violation, is added as a new term in the covariant form. The differential cross-section for Bhabha scattering in the GEM framework at finite temperature is calculated that includes Lorentz violation. The Thermo Field Dynamics (TFD) formalism is used to calculate the total differential cross-section at finite temperature. The contribution due to Lorentz violation is isolated from the total cross-section. It is found to be small in magnitude.

On the ether-like Lorentz-breaking actions

International Nuclear Information System (INIS)

Petrov, A.Yu; Nascimento, J.R.; Gomes, M.; Silva, A. J. da

2011-01-01

We demonstrate the generation of the CPT-even, ether-like Lorentz-breaking actions for the scalar and electro-magnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in three, four and five space-time dimensions. Besides, we show that the ether-like terms for the spinor field also can be generated as a consequence of the same couplings. The key result which will be presented here is the finiteness of the ether-like term for the electromagnetic field not only in three and five space-time dimensions where it is natural due to known effects of the dimensional regularization but also in four space-time dimensions. Moreover, we present the calculation of the last result within different calculational schemes and conclude that the result for the four-dimensional ether-like term for the electromagnetic field essentially depending on the calculation scheme, similarly to the result for the Carroll-Field-Jackiw (CFJ) term which probably signalizes a possibility for arising of a new anomaly. Also we discuss the dispersion relations in the theories with ether-like Lorentz-breaking terms which allows to discuss the consistency of the Lorentz-breaking modified theories for different (space-like or time-like) Lorentz-breaking vectors and find the tree-level effective (Breit) potential for fermion scattering and the one-loop effective potential corresponding to the action of the scalar field. (author)

Breaking diffeomorphism invariance and tests for the emergence of gravity

International Nuclear Information System (INIS)

Anber, Mohamed M.; Aydemir, Ufuk; Donoghue, John F.

2010-01-01

If general relativity is an emergent phenomenon, there may be small violations of diffeomorphism invariance. We propose a phenomenology of perturbatively small violations of general relativity by the inclusion of terms which break general covariance. These can be tested by matching to the parameterized post-Newtonian formalism. The most sensitive tests involve pulsar timing and provide an extremely strong bound, with a dimensionless constraint of order 10 -20 relative to gravitational strength.

Lorentz-violating electrodynamics and the cosmic microwave background.

Science.gov (United States)

Kostelecký, V Alan; Mewes, Matthew

2007-07-06

Possible Lorentz-violating effects in the cosmic microwave background are studied. We provide a systematic classification of renormalizable and nonrenormalizable operators for Lorentz violation in electrodynamics and use polarimetric observations to search for the associated violations.

Adaptive compensation of Lorentz force detuning in superconducting RF cavities

Energy Technology Data Exchange (ETDEWEB)

Pischalnikov, Yuriy [Fermilab; Schappert, Warren [Fermilab

2011-11-01

The Lorentz force can dynamically detune pulsed Superconducting RF cavities and considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate. Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

Black holes in Lorentz-violating gravity theories

International Nuclear Information System (INIS)

Barausse, Enrico; Sotiriou, Thomas P

2013-01-01

Lorentz symmetry and the notion of light cones play a central role in the definition of horizons and the existence of black holes. Current observations provide strong indications that astrophysical black holes do exist in Nature. Here we explore what happens to the notion of a black hole in gravity theories where local Lorentz symmetry is violated, and discuss the relevant astrophysical implications. Einstein-aether theory and Hořava gravity are used as the theoretical background for addressing this question. We review earlier results about static, spherically symmetric black holes, which demonstrate that in Lorentz-violating theories there can be a new type of horizon and, hence, a new notion of black hole. We also present both known and new results on slowly rotating black holes in these theories, which provide insights on how generic these new horizons are. Finally, we discuss the differences between black holes in Lorentz-violating theories and in General Relativity, and assess to what extent they can be probed with present and future observations. (paper)

Coupled inflaton and electromagnetic fields from Gravitoelectromagnetic Inflation with Lorentz and Feynman gauges

International Nuclear Information System (INIS)

Membiela, Federico Agustín; Bellini, Mauricio

2010-01-01

Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases

Coupled inflaton and electromagnetic fields from Gravitoelectromagnetic Inflation with Lorentz and Feynman gauges

Energy Technology Data Exchange (ETDEWEB)

Membiela, Federico Agustín; Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar, E-mail: membiela@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina)

2010-10-01

Using a semiclassical approach to Gravitoelectromagnetic Inflation (GEMI), we study the origin and evolution of seminal inflaton and electromagnetic fields in the early inflationary universe from a 5D vacuum state. We use simultaneously the Lorentz and Feynman gauges. Our formalism is naturally not conformal invariant on the effective 4D de Sitter metric, which make possible the super adiabatic amplification of electric and magnetic field modes during the early inflationary epoch of the universe on cosmological scales. This is the first time that solutions for the electric field fluctuations are investigated in a systematic way as embeddings for inflationary models in 4D. An important and new result here obtained is that the spectrum of the electric field fluctuations depend with the scale, such that the spectral index increases quadratically as the scale decreases.

Factor structure and invariance test of the alcohol use disorder identification test (AUDIT): Comparison and further validation in a U.S. and Philippines college student sample.

Science.gov (United States)

Tuliao, Antover P; Landoy, Bernice Vania N; McChargue, Dennis E

2016-01-01

The Alcohol Use Disorder Identification Test's factor structure varies depending on population and culture. Because of this inconsistency, this article examined the factor structure of the test and conducted a factorial invariance test between a U.S. and a Philippines college sample. Confirmatory factor analyses indicated that a three-factor solution outperforms the one- and two-factor solution in both samples. Factorial invariance analyses further supports the confirmatory findings by showing that factor loadings were generally invariant across groups; however, item intercepts show non-invariance. Country differences between factors show that Filipino consumption factor mean scores were significantly lower than their U.S. counterparts.

Neutral meson tests of time-reversal symmetry invariance

OpenAIRE

Bevan, Adrian; Inguglia, Gianluca; Zoccali, Michele

2013-01-01

The laws of quantum physics can be studied under the mathematical operation T that inverts the direction of time. Strong and electromagnetic forces are known to be invariant under temporal inversion, however the weak force is not. The BaBar experiment recently exploited the quantum-correlated production of pairs of B0 mesons to show that T is a broken symmetry. Here we show that it is possible to perform a wide range of tests of quark flavour changing processes under T in order to validate th...

The Lorentz Theory of Electrons and Einstein's Theory of Relativity

Science.gov (United States)

Goldberg, Stanley

1969-01-01

Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…

Two-dimensional Lorentz-Weyl anomaly and gravitational Chern-Simons theory

International Nuclear Information System (INIS)

Chamseddine, A.H.; Froehlich, J.

1992-01-01

Two-dimensional chiral fermions and bosons, more generally conformal blocks of two-dimensional conformal field theories, exhibit Weyl-, Lorentz- and mixed Lorentz-Weyl anomalies. A novel way of computing these anomalies for a system of chiral bosons of arbitrary conformal spin j is sketched. It is shown that the Lorentz- and mixed Lorentz-Weyl anomalies of these theories can be cancelled by the anomalies of a three-dimensional classical Chern-Simons action for the spin connection, expressed in terms of the dreibein field. Some tentative applications of this result to string theory are indicated. (orig.)

Hendrik Antoon Lorentz: his role in physics and society

Science.gov (United States)

Berends, Frits

2009-04-01

Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

Hendrik Antoon Lorentz: his role in physics and society

Energy Technology Data Exchange (ETDEWEB)

Berends, Frits [Emeritus Theoretical Physics, Leiden University (Netherlands)

2009-04-22

Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

Hendrik Antoon Lorentz: his role in physics and society

International Nuclear Information System (INIS)

Berends, Frits

2009-01-01

Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.

The Lorentz-Dirac equation in light of quantum theory

International Nuclear Information System (INIS)

Nikishov, A.I.

1996-01-01

To high accuracy, an electron in ultrarelativistic motion 'sees' an external field in its rest frame as a crossed field (E=H, E·H=0). In this case, quantum expressions allow the introduction of a local intensity of the radiation, which determines the radiative term of the force of radiative reaction. For γ=(1-v2)-1/2>> 1 this term is much larger than the mass term, i.e., the term with xd3do. Under these conditions, the reduced Lorentz-Dirac equation, which is obtained from the full Lorentz-Dirac equation by eliminating the terms xd3do and xe on the right side using the equation of motion without taking into account the force of radiative reaction, is equivalent to good accuracy to the original Lorentz-Dirac equation. Exact solutions to the reduced Lorentz-Dirac equation are obtained for a constant field and the field of a plane wave. For γ∼1 a local expression for the radiative term cannot be obtained quantitatively from the quantum expressions. In this case the mass (Lorentz-Dirac) terms in the original and reduced Lorentz-Dirac equations are not small compared to the radiative term. The predictions of these equations, which depend appreciably on the mass terms, are therefore less reliable

Rotation associated with product of two Lorentz transformations

International Nuclear Information System (INIS)

Van Wyk, C.B.

1984-01-01

In the usual presentation of the Lorentz transformation there is an almost complete absence of the use of products of these transformations. One of the reasons for this appears to be the large amount of calculation involved when multi-plying the 4X4 matrices of the vector representation of the Lorentz transformation. In the article this problem is partly cleared up by using the coordinate free two-component spinor representation of rotations and Lorentz transformations. It is also shown that the theory derived in the article can be applied to Thomas precission in a very simple and direct way

Self-duality in generalized Lorentz superspaces

International Nuclear Information System (INIS)

Devchand, C.; Nuyts, J.

1996-12-01

We extend the notion of self-duality to spaces built from a set of representations of the Lorentz group with bosonic or fermionic behaviour, not having the traditional spin-one upper-bound of super Minkowski space. The generalized derivative vector fields on such superspace are assumed to form a superalgebra. Introducing corresponding gauge potentials and hence covariant derivatives and curvatures, we define generalized self-duality as the Lorentz covariant vanishing of certain irreducible parts of the curvatures. (author). 4 refs

Studies on representation of the Lorentz group and gauge theory

International Nuclear Information System (INIS)

Hanitriarivo, R.

2002-01-01

This work is focused on studies about the representation of the Lorentz group and gauge theory. The mathematical tools required for the different studies are presented, as well as for the representation of the Lorentz group and for the gauge theory. Representation of the Lorentz group gives the possible types of fields and wave functions that describe particles: fermions are described by spinors and bosons are described by scalar or vector. Each of these entities (spinors, scalars, vectors) are characterized by their behavior under the action of Lorentz transformations.Gauge theory is used to describe the interactions between particles. [fr

QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

Energy Technology Data Exchange (ETDEWEB)

Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Scarpelli, A.P. Baeta [Departamento de Policia Federal (DPF), Sao Paulo, SP (Brazil). Setor Tecnico-Cientifico

2011-07-01

In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

International Nuclear Information System (INIS)

Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C.; Scarpelli, A.P. Baeta

2011-01-01

In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

Test of feasibility of a novel high precision test of time reversal invariance

International Nuclear Information System (INIS)

Samuel, Deepak

2007-01-01

The first results of a feasibility test of a novel high precision test of time reversal invariance are reported. The Time Reversal Invariance test at COSY (TRIC) was planned to measure the time reversal violating observable A y,xz with an accuracy of 10 -6 in proton-deuteron (p-d) scattering. A novel technique for measuring total cross sections is introduced and the achievable precision of this measuring technique is tested. The correlation coefficient A y,y in p-d scattering fakes a time-reversal violating effect. This work reports the feasibility test of the novel method in the measurement of A y,y in p-p scattering. The first step in the experimental design was the development of a hard real-time data acquisition system. To meet stringent latency requirements, the capabilities of Windows XP had to be augmented with a real-time subsystem. The remote control feature of the data acquisition enables users to operate it from any place via an internet connection. The data acquisition proved its reliability in several beam times without any failures. The analysis of the data showed the presence of 1/f noise which substantially limits the quality of our measurements. The origin of 1/f noise was traced and found to be the Barkhausen noise from the ferrite core of the beam current transformer (BCT). A global weighted fitting technique based on a modified Wiener-Khinchin method was developed and used to suppress the influence of 1/f noise, which increased the error bar of the results by a factor 3. This is the only deviation from our expectations. The results are presented and discussed. (orig.)

Test of feasibility of a novel high precision test of time reversal invariance

Energy Technology Data Exchange (ETDEWEB)

Samuel, Deepak

2007-07-01

The first results of a feasibility test of a novel high precision test of time reversal invariance are reported. The Time Reversal Invariance test at COSY (TRIC) was planned to measure the time reversal violating observable A{sub y,xz} with an accuracy of 10{sup -6} in proton-deuteron (p-d) scattering. A novel technique for measuring total cross sections is introduced and the achievable precision of this measuring technique is tested. The correlation coefficient A{sub y,y} in p-d scattering fakes a time-reversal violating effect. This work reports the feasibility test of the novel method in the measurement of A{sub y,y} in p-p scattering. The first step in the experimental design was the development of a hard real-time data acquisition system. To meet stringent latency requirements, the capabilities of Windows XP had to be augmented with a real-time subsystem. The remote control feature of the data acquisition enables users to operate it from any place via an internet connection. The data acquisition proved its reliability in several beam times without any failures. The analysis of the data showed the presence of 1/f noise which substantially limits the quality of our measurements. The origin of 1/f noise was traced and found to be the Barkhausen noise from the ferrite core of the beam current transformer (BCT). A global weighted fitting technique based on a modified Wiener-Khinchin method was developed and used to suppress the influence of 1/f noise, which increased the error bar of the results by a factor 3. This is the only deviation from our expectations. The results are presented and discussed. (orig.)

Evaluating Forecasts, Narratives and Policy Using a Test of Invariance

Directory of Open Access Journals (Sweden)

Jennifer L. Castle

2017-09-01

Full Text Available Economic policy agencies produce forecasts with accompanying narratives, and base policy changes on the resulting anticipated developments in the target variables. Systematic forecast failure, defined as large, persistent deviations of the outturns from the numerical forecasts, can make the associated narrative false, which would in turn question the validity of the entailed policy implementation. We establish when systematic forecast failure entails failure of the accompanying narrative, which we call forediction failure, and when that in turn implies policy invalidity. Most policy regime changes involve location shifts, which can induce forediction failure unless the policy variable is super exogenous in the policy model. We propose a step-indicator saturation test to check in advance for invariance to policy changes. Systematic forecast failure, or a lack of invariance, previously justified by narratives reveals such stories to be economic fiction.

Introduction to Ives' 'Derivation of the Lorentz transformations'

International Nuclear Information System (INIS)

Ruderfer, M.

1979-01-01

Lorentz ether theory is elevated on a par with special relativity by Ives' derivation of the Lorentz transformations. The two theories combined then demand the physical existence of a relativistic ether. This is supported by the still unfolding hierarchy of matter. Cogent implications for physical theory follow. (Auth.)

Collected charge and Lorentz angle measurement on non-irradiated ATLAS silicon micro-strip sensors for the HL-LHC

Energy Technology Data Exchange (ETDEWEB)

Yildirim, Eda

2017-02-15

In this thesis, the collected charge and the Lorentz angle on non-irradiated and the irradiated miniature of the current test silicon micro-strip sensors (ATLAS12) of the future ATLAS inner tracker are measured. The samples are irradiated up to 5 x 10{sup 15} 1 MeV n{sub eq}/cm{sup 2} and some of them also measured after short-term annealing (80 min at 60 C). The measurements are performed at the DESY II test beam, which provides the advantage of tracking to suppress noise hits. The collected charge is measured at various bias voltages for each sample. The results are compared with the measurements performed using a Sr{sup 90} radioactive source. It is shown that the measurements with beam and radioactive source are consistent with each other, and the advantage of tracking at the beam measurements provides the measurement of collected charge on highly irradiated sensors at lower bias voltages. The Lorentz angle is measured for each sample at different magnetic field strengths between 0 T and 1 T, the results are extrapolated to 2 T, which is the magnetic field in the inner tracker of the ATLAS detector. Most of the measurements are performed at -500 V bias voltage, which is the planned operation bias voltage of the future strip tracker. Some samples are also measured at different bias voltages to observe the effect of bias voltage on the Lorentz angle. The signal reconstruction of the strip sensors are performed using the lowest possible signal-to-noise thresholds. For non-irradiated samples, the measured Lorentz angle agrees with the prediction of the BFK model. On the irradiated samples, the results suggest that the Lorentz angle decreases with increasing bias voltage due to the increasing electric field in the sensor. The Lorentz angle decreases with increasing irradiation level; however, if the sample is under-depleted, the effect of electric field dominates and the Lorentz angle increases. Once the irradiation level becomes too high, hence the collected charge

Vortex deformation and reduction of the Lorentz force

International Nuclear Information System (INIS)

Vuorio, M.

1977-01-01

A vortex of an extreme II-type superconductor is considered in the presence of a transport current. The equivalence of Magnus and Lorentz forces in a static vortex is discussed and the effect of vortex deformation is included in calculating corrections to the conventional expression of the Lorentz force. (author)

Lorentz Transformation from Symmetry of Reference Principle

International Nuclear Information System (INIS)

Petre, M.; Dima, M.; Dima, A.; Petre, C.; Precup, I.

2010-01-01

The Lorentz Transformation is traditionally derived requiring the Principle of Relativity and light-speed universality. While the latter can be relaxed, the Principle of Relativity is seen as core to the transformation. The present letter relaxes both statements to the weaker, Symmetry of Reference Principle. Thus the resulting Lorentz transformation and its consequences (time dilatation, length contraction) are, in turn, effects of how we manage space and time.

Status of time reversal invariance

International Nuclear Information System (INIS)

Henley, E.M.

1989-01-01

Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed. 30 refs., 2 figs., 1 tab

Lorentz-invariant Bell's inequality

International Nuclear Information System (INIS)

Kim, Won Tae; Son, Edwin J.

2005-01-01

We study Bell's inequality in relation to the Einstein-Podolsky-Rosen paradox in the relativistic regime. For this purpose, a relativistically covariant analysis is used in the calculation of the Bell's inequality, which results in the maximally violated Bell's inequality in any reference frame

Testing the time-invariance of fundamental constants using microwave spectroscopy on cold diatomic radicals

NARCIS (Netherlands)

Bethlem, H.L.; Ubachs, W.M.G.

2009-01-01

The recently demonstrated methods to cool and manipulate neutral molecules offer new possibilities for precision tests of fundamental physics theories. We here discuss the possibility of testing the time-invariance of fundamental constants using near degeneracies between rotational levels in the

Atom-Interferometry Tests of the Isotropy of Post-Newtonian Gravity

International Nuclear Information System (INIS)

Mueller, Holger; Chiow, Sheng-wey; Herrmann, Sven; Chu, Steven; Chung, Keng-Yeow

2008-01-01

We present a test of the local Lorentz invariance of post-Newtonian gravity by monitoring Earth's gravity with a Mach-Zehnder atom interferometer that features a resolution of up to 8x10 -9 g/√(Hz), the highest reported thus far. Expressed within the standard model extension (SME) or Nordtvedt's anisotropic universe model, the analysis limits four coefficients describing anisotropic gravity at the ppb level and three others, for the first time, at the 10 ppm level. Using the SME we explicitly demonstrate how the experiment actually compares the isotropy of gravity and electromagnetism

Einstein-Yang-Mills-Lorentz black holes

Energy Technology Data Exchange (ETDEWEB)

Cembranos, Jose A.R.; Gigante Valcarcel, Jorge [Universidad Complutense de Madrid, Departamento de Fisica Teorica I, Madrid (Spain)

2017-12-15

Different black hole solutions of the coupled Einstein-Yang-Mills equations have been well known for a long time. They have attracted much attention from mathematicians and physicists since their discovery. In this work, we analyze black holes associated with the gauge Lorentz group. In particular, we study solutions which identify the gauge connection with the spin connection. This ansatz allows one to find exact solutions to the complete system of equations. By using this procedure, we show the equivalence between the Yang-Mills-Lorentz model in curved space-time and a particular set of extended gravitational theories. (orig.)

Investigations on the Effects of Vortex-Induced Vibration with Different Distributions of Lorentz Forces

Directory of Open Access Journals (Sweden)

Hui Zhang

2017-01-01

Full Text Available The control of vortex-induced vibration (VIV in shear flow with different distributions of Lorentz force is numerically investigated based on the stream function–vorticity equations in the exponential-polar coordinates exerted on moving cylinder for Re = 150. The cylinder motion equation coupled with the fluid, including the mathematical expressions of the lift force coefficient C l , is derived. The initial and boundary conditions as well as the hydrodynamic forces on the surface of cylinder are also formulated. The Lorentz force applied to suppress the VIV has no relationship with the flow field, and involves two categories, i.e., the field Lorentz force and the wall Lorentz force. With the application of symmetrical Lorentz forces, the symmetric field Lorentz force can amplify the drag, suppress the flow separation, decrease the lift fluctuation, and then suppress the VIV while the wall Lorentz force decreases the drag only. With the application of asymmetrical Lorentz forces, besides the above-mentioned effects, the field Lorentz force can increase additional lift induced by shear flow, whereas the wall Lorentz force can counteract the additional lift, which is dominated on the total effect.

Noninvariance of Space and Time Scale Ranges under a Lorentz Transformation and the Implications for the Numerical Study of Relativistic Systems

International Nuclear Information System (INIS)

Vay, J.-L.; Vay, J.-L.

2007-01-01

We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under the Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived for example cases: free electron laser, laser-plasma accelerator, and particle beam interacting with electron clouds. Implications for experimental, theoretical and numerical studies are discussed. The most immediate relevance is the reduction by orders of magnitude in computer simulation run times for such systems

Testing measurement invariance of the Learning Programme Management and Evaluation scale across academic achievement

Directory of Open Access Journals (Sweden)

Maelekanyo C. Mulaudzi

2016-10-01

Full Text Available Orientation: Measurement invariance is one of the most precarious aspects of the scale development process without which the interpretation of research findings on population subgroups may be ambiguous and even invalid. Besides tests for validity and reliability, measurement invariance represents the hallmark for psychometric compliance of a new measuring instrument and provides the basis for inference of research findings across a range of relevant population sub-groups. Research purpose: This study tested the measurement invariance of a Learning Programme Management and Evaluation (LPME scale across levels of academic achievement. Motivation for the study: It is important for any researcher involved in new scale development to ensure that the measurement instrument and its underlying constructs have proper structural alignment and that they both have the same level of meaning and significance across comparable heterogeneous groups. Research design, approach and method: A quantitative, non-experimental, cross-sectional survey design was used, and data were obtained from 369 participants who were selected from three public sector organisations using a probabilistic simple random sampling technique. The Statistical Package for Social Sciences and Analysis of Moment Structures software (versions 21.0.0 were used to analyse the data. Main findings: The findings show that all the four invariance models tested have achieved acceptable goodness-of-fit indices. Furthermore, the findings show that the factorial structure of the LPME scale and the meaning of its underlying constructs are invariant across different levels of academic achievement for human resource development (HRD practitioners and learners or apprentices involved in occupational learning programmes. Practical implications: The findings of this study suggest practical implications for HRD scholars as they are enabled to make informed decisional balance comparisons involving educational

Test of time-reversal invariance at COSY (TRIC)

Energy Technology Data Exchange (ETDEWEB)

Eversheim, D., E-mail: evershei@hiskp.uni-bonn.de; Valdau, Yu. [University Bonn, Helmholtz Institut fuer Strahlen- und Kernphysik (Germany); Lorentz, B. [Forschungszentrum Juelich, Institut fuer Kernphysik (Germany)

2013-03-15

At the Cooler Synchrotron COSY a novel (P-even, T-odd) null test of time-reversal invariance to an accuracy of 10{sup - 6} is planned as an internal target transmission experiment. The parity conserving time-reversal violating observable is the total cross-section asymmetry A{sub y,xz}. This quantity is measured using a polarized proton beam with an energy of 135 MeV and an internal tensor polarized deuteron target from the PAX atomic beam source. The reaction rate will be measured by means of an integrating beam current transformer. Thus, in this experiment the cooler synchroton ring serves as ideal forward spectrometer, as a detector, and an accelerator.

Anomalous Lorentz and CPT violation from a local Chern-Simons-like term in the effective gauge-field action

Science.gov (United States)

Ghosh, K. J. B.; Klinkhamer, F. R.

2018-01-01

We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3 ×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U (1) gauge fields Aμ (x) which depend on all four spacetime coordinates (including the coordinate x4 ∈S1 of the compact dimension) and have vanishing components A4 (x) (implying trivial holonomies in the 4-direction). Our calculation shows that the effective gauge-field action contains a local Chern-Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli-Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg-Wilson fermions.

Measurement of the Lorentz-FitzGerald body contraction

Science.gov (United States)

Rafelski, Johann

2018-02-01

A complete foundational discussion of acceleration in the context of Special Relativity (SR) is presented. Acceleration allows the measurement of a Lorentz-FitzGerald body contraction created. It is argued that in the back scattering of a probing laser beam from a relativistic flying electron cloud mirror generated by an ultra-intense laser pulse, a first measurement of a Lorentz-FitzGerald body contraction is feasible.

Finally! A valid test of configural invariance using permutation in multigroup CFA

NARCIS (Netherlands)

Jorgensen, T.D.; Kite, B.A.; Chen, P.-Y.; Short, S.D.; van der Ark, L.A.; Wiberg, M.; Culpepper, S.A.; Douglas, J.A.; Wang, W.-C.

2017-01-01

In multigroup factor analysis, configural measurement invariance is accepted as tenable when researchers either (a) fail to reject the null hypothesis of exact fit using a χ2 test or (b) conclude that a model fits approximately well enough, according to one or more alternative fit indices (AFIs).

Unified cosmic history in modified gravity: From F(R) theory to Lorentz non-invariant models

Science.gov (United States)

Nojiri, Shin'Ichi; Odintsov, Sergei D.

2011-08-01

The classical generalization of general relativity is considered as the gravitational alternative for a unified description of the early-time inflation with late-time cosmic acceleration. The structure and cosmological properties of a number of modified theories, including traditional F(R) and Hořava-Lifshitz F(R) gravity, scalar-tensor theory, string-inspired and Gauss-Bonnet theory, non-local gravity, non-minimally coupled models, and power-counting renormalizable covariant gravity are discussed. Different representations of and relations between such theories are investigated. It is shown that some versions of the above theories may be consistent with local tests and may provide a qualitatively reasonable unified description of inflation with the dark energy epoch. The cosmological reconstruction of different modified gravities is provided in great detail. It is demonstrated that eventually any given universe evolution may be reconstructed for the theories under consideration, and the explicit reconstruction is applied to an accelerating spatially flat Friedmann-Robertson-Walker (FRW) universe. Special attention is paid to Lagrange multiplier constrained and conventional F(R) gravities, for latter F(R) theory, the effective ΛCDM era and phantom divide crossing acceleration are obtained. The occurrences of the Big Rip and other finite-time future singularities in modified gravity are reviewed along with their solutions via the addition of higher-derivative gravitational invariants.

Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

International Nuclear Information System (INIS)

Grasland-Mongrain, Pol; Destrempes, François; Cloutier, Guy; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril

2015-01-01

Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging. (paper)

Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography

Science.gov (United States)

Grasland-Mongrain, Pol; Destrempes, François; Mari, Jean-Martial; Souchon, Rémi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril; Cloutier, Guy

2015-05-01

Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an ‘acousto-electrical speckle’ in the Lorentz force electrical impedance tomography with spatial characteristics driven by the acoustic parameters but due to electrical impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging.

Propagation of partially coherent Lorentz-Gauss vortex beam through oceanic turbulence.

Science.gov (United States)

Liu, Dajun; Yin, Hongming; Wang, Guiqiu; Wang, Yaochuan

2017-11-01

The partially coherent Lorentz-Gauss vortex beam generated by a Schell-model source has been introduced. Based on the extended Huygens-Fresnel principle, the cross-spectral density function of a partially coherent Lorentz-Gauss vortex beam propagating in oceanic turbulence is derived. The influences of coherence length, topological charge M, and oceanic turbulence on the spreading properties and position of the coherence vortex for a partially coherent Lorentz-Gauss vortex beam are analyzed in detail. The results show that a partially coherent Lorentz-Gauss vortex beam propagating in stronger oceanic turbulence will evolve into a Gaussian-like beam more rapidly as the propagation distance increases, and the number of coherent vortices will change.

Experimental evaluation of the ‘transport-of-intensity’ equation for magnetic phase reconstruction in Lorentz transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Kohn, Amit, E-mail: akohn@post.tau.ac.il [Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv (Israel); Habibi, Avihay; Mayo, Martin [Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva (Israel)

2016-01-15

The ‘transport-of-intensity’ equation (TIE) is a general phase reconstruction methodology that can be applied to Lorentz transmission electron microscopy (TEM) through the use of Fresnel-contrast (defocused) images. We present an experimental study to test the application of the TIE for quantitative magnetic mapping in Lorentz TEM without aberration correction by examining sub-micrometer sized Ni{sub 80}Fe{sub 20} (Permalloy) elements. For a JEOL JEM 2100F adapted for Lorentz microscopy, we find that quantitative magnetic phase reconstructions are possible for defoci distances ranging between approximately 200 μm and 800 μm. The lower limit originates from competing sources of image intensity variations in Fresnel-contrast images, namely structural defects and diffraction contrast. The upper defocus limit is due to a numerical error in the estimation of the intensity derivative based on three images. For magnetic domains, we show quantitative reconstructions of the product of the magnetic induction vector and thickness in element sizes down to approximately 100 nm in lateral size and 5 nm thick resulting in a minimal detection of 5 T nm. Three types of magnetic structures are tested in terms of phase reconstruction: vortex cores, domain walls, and element edges. We quantify vortex core structures at a diameter of 12 nm while the structures of domain walls and element edges are characterized qualitatively. Finally, we show by image simulations that the conclusions of this experimental study are relevant to other Lorentz TEM in which spherical aberration and defocus are dominant aberrations. - Highlights: • Testing TIE for quantitative magnetic phase reconstruction in Lorentz TEM. • Quantitative magnetic phase reconstructions for defoci distances in 200–800 μm range. • Minimal detection of the product of the magnetic induction and thickness is 5 T nm. • Quantitative phase reconstruction for vortex core structures at 12 nm diameter. • Observations

Lorentz violation and black-hole thermodynamics: Compton scattering process

International Nuclear Information System (INIS)

Kant, E.; Klinkhamer, F.R.; Schreck, M.

2009-01-01

A Lorentz-noninvariant modification of quantum electrodynamics (QED) is considered, which has photons described by the nonbirefringent sector of modified Maxwell theory and electrons described by the standard Dirac theory. These photons and electrons are taken to propagate and interact in a Schwarzschild spacetime background. For appropriate Lorentz-violating parameters, the photons have an effective horizon lying outside the Schwarzschild horizon. A particular type of Compton scattering event, taking place between these two horizons (in the photonic ergoregion) and ultimately decreasing the mass of the black hole, is found to have a nonzero probability. These events perhaps allow for a violation of the generalized second law of thermodynamics in the Lorentz-noninvariant theory considered.

Convexity and concavity constants in Lorentz and Marcinkiewicz spaces

Science.gov (United States)

Kaminska, Anna; Parrish, Anca M.

2008-07-01

We provide here the formulas for the q-convexity and q-concavity constants for function and sequence Lorentz spaces associated to either decreasing or increasing weights. It yields also the formula for the q-convexity constants in function and sequence Marcinkiewicz spaces. In this paper we extent and enhance the results from [G.J.O. Jameson, The q-concavity constants of Lorentz sequence spaces and related inequalities, Math. Z. 227 (1998) 129-142] and [A. Kaminska, A.M. Parrish, The q-concavity and q-convexity constants in Lorentz spaces, in: Banach Spaces and Their Applications in Analysis, Conference in Honor of Nigel Kalton, May 2006, Walter de Gruyter, Berlin, 2007, pp. 357-373].

Propagation of a radial phased-locked Lorentz beam array in turbulent atmosphere.

Science.gov (United States)

Zhou, Guoquan

2011-11-21

A radial phased-locked (PL) Lorentz beam array provides an appropriate theoretical model to describe a coherent diode laser array, which is an efficient radiation source for high-power beaming use. The propagation of a radial PL Lorentz beam array in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and some mathematical techniques, analytical formulae for the average intensity and the effective beam size of a radial PL Lorentz beam array are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a radial PL Lorentz beam array in turbulent atmosphere are numerically calculated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a radial PL Lorentz beam array in turbulent atmosphere are discussed in detail. © 2011 Optical Society of America

Factoring the dispersion relation in the presence of Lorentz violation

International Nuclear Information System (INIS)

Colladay, Don; McDonald, Patrick; Mullins, David

2010-01-01

We produce an explicit formula for the dispersion relation for the Dirac equation in the standard model extension in the presence of Lorentz violation. Our expression is obtained using novel techniques which exploit the algebra of quaternions. The dispersion relation is found to conveniently factor in two special cases that each involve a mutually exclusive set of nonvanishing Lorentz-violating parameters. This suggests that a useful approach to studies of Lorentz-violating models is to split the parameter space into two separate pieces, each of which yields a simple, tractable dispersion relation that can be used for analysis.

Lorentz Violation of the Photon Sector in Field Theory Models

Directory of Open Access Journals (Sweden)

Lingli Zhou

2014-01-01

Full Text Available We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME and the standard model supplement (SMS. From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients (kAFα of the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrix Δαβ of free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients (kFαβμν, which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints (2σ on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.

The BTZ black hole as a Lorentz-flat geometry

Energy Technology Data Exchange (ETDEWEB)

Alvarez, Pedro D., E-mail: alvarez@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford (United Kingdom); Pais, Pablo, E-mail: pais@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Rodríguez, Eduardo, E-mail: eduarodriguezsal@unal.edu.co [Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Concepción (Chile); Salgado-Rebolledo, Patricio, E-mail: pasalgado@udec.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Zanelli, Jorge, E-mail: z@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile)

2014-11-10

It is shown that 2+1 dimensional anti-de Sitter spacetimes are Lorentz-flat. This means, in particular, that any simply-connected patch of the BTZ black hole solution can be endowed with a Lorentz connection that is locally pure gauge. The result can be naturally extended to a wider class of black hole geometries and point particles in three-dimensional spacetime.

Lorentz-violating theories in the standard model extension

Energy Technology Data Exchange (ETDEWEB)

Ferreira Junior, Manoel Messias [Universidade Federal do Maranhao (UFMA), Sao Luis, MA (Brazil)

2012-07-01

Full text: Lorentz-violating theories have been an issue of permanent interest in the latest years. Many of these investigations are developed under the theoretical framework of the Standard Model Extension (SME), a broad extension of the minimal Standard Model embracing Lorentz-violating (LV) terms, generated as vacuum expectation values of tensor quantities, in all sectors of interaction. In this talk, we comment on some general properties of the SME, concerning mainly the gauge and fermion sectors, focusing in new phenomena induced by Lorentz violation. The LV terms are usually separated in accordance with the behavior under discrete symmetries, being classified as CPT-odd or CPT-even, parity-even or parity-odd. We follow this classification scheme discussing some features and new properties of the CPT-even and CPT-odd parts of the gauge and fermion sectors. We finalize presenting some upper bounds imposed on the corresponding LV coefficients. (author)

Anomalous Lorentz and CPT violation from a local Chern–Simons-like term in the effective gauge-field action

Directory of Open Access Journals (Sweden)

K.J.B. Ghosh

2018-01-01

Full Text Available We consider four-dimensional chiral gauge theories defined over a spacetime manifold with topology R3×S1 and periodic boundary conditions over the compact dimension. The effective gauge-field action is calculated for Abelian U(1 gauge fields Aμ(x which depend on all four spacetime coordinates (including the coordinate x4∈S1 of the compact dimension and have vanishing components A4(x (implying trivial holonomies in the 4-direction. Our calculation shows that the effective gauge-field action contains a local Chern–Simons-like term which violates Lorentz and CPT invariance. This result is established perturbatively with a generalized Pauli–Villars regularization and nonperturbatively with a lattice regularization based on Ginsparg–Wilson fermions.

Lorentz force actuation of a heated atomic force microscope cantilever.

Science.gov (United States)

Lee, Byeonghee; Prater, Craig B; King, William P

2012-02-10

We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 °C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift.

The Lorentz integral transform and its inversion

International Nuclear Information System (INIS)

Barnea, N.; Efros, V.D.; Leidemann, W.; Orlandini, G.

2010-01-01

The Lorentz integral transform method is briefly reviewed. The issue of the inversion of the transform, and in particular its ill-posedness, is addressed. It is pointed out that the mathematical term ill-posed is misleading and merely due to a historical misconception. In this connection standard regularization procedures for the solution of the integral transform problem are presented. In particular a recent one is considered in detail and critical comments on it are provided. In addition a general remark concerning the concept of the Lorentz integral transform as a method with a controlled resolution is made. (author)

Anomalous current in periodic Lorentz gases with infinite horizon

Energy Technology Data Exchange (ETDEWEB)

Dolgopyat, Dmitrii I [University of Maryland, College Park (United States); Chernov, Nikolai I [University of Alabama at Birmingham, Birmingham, Alabama (United States)

2009-08-31

Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

Anomalous current in periodic Lorentz gases with infinite horizon

International Nuclear Information System (INIS)

Dolgopyat, Dmitrii I; Chernov, Nikolai I

2009-01-01

Electric current is studied in a two-dimensional periodic Lorentz gas in the presence of a weak homogeneous electric field. When the horizon is finite, that is, free flights between collisions are bounded, the resulting current J is proportional to the voltage difference E, that is, J=1/2 D*E+o(||E||), where D* is the diffusion matrix of a Lorentz particle moving freely without an electric field (see a mathematical proof). This formula agrees with Ohm's classical law and the Einstein relation. Here the more difficult model with an infinite horizon is investigated. It is found that infinite corridors between scatterers allow the particles (electrons) to move faster, resulting in an abnormal current (causing 'superconductivity'). More precisely, the current is now given by J=1/2 DE| log||E|| | + O(||E||), where D is the 'superdiffusion' matrix of a Lorentz particle moving freely without an electric field. This means that Ohm's law fails in this regime, but the Einstein relation (suitably interpreted) still holds. New results are also obtained for the infinite-horizon Lorentz gas without external fields, complementing recent studies by Szasz and Varju. Bibliography: 31 titles.

Synthesizing Modular Invariants for Synchronous Code

Directory of Open Access Journals (Sweden)

Pierre-Loic Garoche

2014-12-01

Full Text Available In this paper, we explore different techniques to synthesize modular invariants for synchronous code encoded as Horn clauses. Modular invariants are a set of formulas that characterizes the validity of predicates. They are very useful for different aspects of analysis, synthesis, testing and program transformation. We describe two techniques to generate modular invariants for code written in the synchronous dataflow language Lustre. The first technique directly encodes the synchronous code in a modular fashion. While in the second technique, we synthesize modular invariants starting from a monolithic invariant. Both techniques, take advantage of analysis techniques based on property-directed reachability. We also describe a technique to minimize the synthesized invariants.

Testing Measurement Invariance of the Students' Affective Characteristics Model across Gender Sub-Groups

Science.gov (United States)

Demir, Ergül

2017-01-01

In this study, the aim was to construct a significant structural measurement model comparing students' affective characteristics with their mathematic achievement. According to this model, the aim was to test the measurement invariances between gender sub-groups hierarchically. This study was conducted as basic and descriptive research. Secondary…

Diffusion limit of Lévy-Lorentz gas is Brownian motion

Science.gov (United States)

Magdziarz, Marcin; Szczotka, Wladyslaw

2018-07-01

In this paper we analyze asymptotic behaviour of a stochastic process called Lévy-Lorentz gas. This process is aspecial kind of continuous-time random walk in which walker moves in the fixed environment composed of scattering points. Upon each collision the walker performs a flight to the nearest scattering point. This type of dynamics is observed in Lévy glasses or long quenched polymers. We show that the diffusion limit of Lévy-Lorentz gas with finite mean distance between scattering centers is the standard Brownian motion. Thus, for long times the behaviour of the Lévy-Lorentz gas is close to the diffusive regime.

Comment on 'Lorentz transformations with arbitrary line of motion'

International Nuclear Information System (INIS)

Tjiang, Paulus C; Sutanto, Sylvia H

2007-01-01

A short comment regarding the derivation of Lorentz transformation proposed by Iyer and Prabhu (2007 Eur. J. Phys. 11 183-90) is given. It is shown that the proposed derivation is similar to that appearing in the standard textbooks of classical mechanics, electrodynamics and the theory of relativity. In fact, those textbooks also provide an elegant form of the Lorentz matrix for the (3+1)-dimensional case, which Iyer and Prabhu claim to be difficult to attain because of its algebraic complexity. We also provide the derivation of the (3+1)-dimensional version of the Lorentz matrix using a method analogous to that proposed by Iyer and Prabhu, and show that the result is completely equivalent to the (3+1)-dimensional version appearing in the textbooks. (letters and comments)

Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

International Nuclear Information System (INIS)

Abdel-Aziz, Yehia A.; Shoaib, Muhammad

2014-01-01

The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ 0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated. (research papers)

Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques

Science.gov (United States)

Abdel-Aziz, Yehia A.; Shoaib, Muhammad

2014-07-01

The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained. The numerical results show that the charge q and radius ρ0 of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated.

Tests of CPT invariance for neutral flavored meson-antimeson mixing

CERN Document Server

Dass, G V

2002-01-01

We focus on two aspects of CPT invariance in neutral meson-antimeson (M sup 0 anti M sup 0) mixing: (1) tests of CPT invariance, using only the property of ''lack of vacuum regeneration'', which occurs as a part of the well-known Lee-Oehme-Yang (LOY) theory; (2) methods for extracting the CPT-violating mixing parameter theta through explicit calculations by fully using the LOY-type theory. In the latter context, we demonstrate the importance of the C-even vertical stroke M sup 0 anti M sup 0 right angle state. In particular, by measuring the time dependence of opposite-sign dilepton events arising from decays of the C-even and C-odd vertical stroke M sup 0 anti M sup 0 right angle states, theta may be disentangled from the parameters lambda sub + and anti lambda sub - characterizing violations of the DELTA F = DELTA Q rule. Furthermore, these two parameters may also be determined. The same is true if one uses like-sign dilepton events arising from only the C-even vertical stroke M sup 0 anti M sup 0 right ang...

Feedback-Driven Dynamic Invariant Discovery

Science.gov (United States)

Zhang, Lingming; Yang, Guowei; Rungta, Neha S.; Person, Suzette; Khurshid, Sarfraz

2014-01-01

Program invariants can help software developers identify program properties that must be preserved as the software evolves, however, formulating correct invariants can be challenging. In this work, we introduce iDiscovery, a technique which leverages symbolic execution to improve the quality of dynamically discovered invariants computed by Daikon. Candidate invariants generated by Daikon are synthesized into assertions and instrumented onto the program. The instrumented code is executed symbolically to generate new test cases that are fed back to Daikon to help further re ne the set of candidate invariants. This feedback loop is executed until a x-point is reached. To mitigate the cost of symbolic execution, we present optimizations to prune the symbolic state space and to reduce the complexity of the generated path conditions. We also leverage recent advances in constraint solution reuse techniques to avoid computing results for the same constraints across iterations. Experimental results show that iDiscovery converges to a set of higher quality invariants compared to the initial set of candidate invariants in a small number of iterations.

Studying Lorentz-violating electromagnetic waves in confined media

International Nuclear Information System (INIS)

Viana, Davidson R.; Gomes, Andre H.; Fonseca, Jakson M.; Moura-Melo, Winder A.

2009-01-01

Full text. Planck energy scale is still far beyond current possibilities. A question of interest is whether the Lorentz symmetry remains valid at these extremely high energies, whose answer certainly would be useful whenever building grand unified theories, in which general relativity is consistently accommodated. Here, we study a reminiscent of this possible symmetry violation, incorporated in the body of the so-called Standard Model Extension (SME). More precisely, we deal with the pure (Abelian) gauge sector, so that we have a modified classical electromagnetism in (3+1) dimensions, whose Lagrangian include a term proportional to a (constant) background tensor that breaks the Lorentz symmetry, but respecting CPT. Our attention is devoted to the wave-like solutions constrained to propagate inside confined media, like waveguides and resonant cavities. Our preliminary findings indicate that Lorentz-breaking implies in modifications of the standard results which are proportional to the (very small) violating parameters, but could be largely enhanced by diminishing the size of the confined media. Under study is the case of a toroidal cavity where the electromagnetic field should respect the additional requirement of being single-valued in the (toroidal) angular variable. Perhaps, such an extra feature combined with the usual boundary conditions could lead us to large effects of this violation, somewhat similar to those predicted for CPT- and Lorentz-odd electromagnetic waves constrained to propagate along a hollow conductor waveguide. (author)

Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

Energy Technology Data Exchange (ETDEWEB)

Baeta Scarpelli, A.P. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Rua Hugo D' Antola, 95, Lapa, Sao Paulo (Brazil); Mariz, T. [Universidade Federal de Alagoas, Instituto de Fisica, Maceio, Alagoas (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, Paraiba (Brazil)

2013-08-15

In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

International Nuclear Information System (INIS)

Baeta Scarpelli, A.P.; Mariz, T.; Nascimento, J.R.; Petrov, A.Yu.

2013-01-01

In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

Regularization of the quantum field theory of charges and monopoles

International Nuclear Information System (INIS)

Panagiotakopoulos, C.

1981-09-01

A gauge invariant regularization procedure for quantum field theories of electric and magnetic charges based on Zwanziger's local formulation is proposed. The bare regularized full Green's functions of gauge invariant operators are shown to be Lorentz invariant. This would have as a consequence the Lorentz invariance of the finite Green's functions that might result after any reasonable subtraction if such a subtraction can be found. (author)

Non-Abelian Gauge Theory in the Lorentz Violating Background

Science.gov (United States)

Ganai, Prince A.; Shah, Mushtaq B.; Syed, Masood; Ahmad, Owais

2018-03-01

In this paper, we will discuss a simple non-Abelian gauge theory in the broken Lorentz spacetime background. We will study the partial breaking of Lorentz symmetry down to its sub-group. We will use the formalism of very special relativity for analysing this non-Abelian gauge theory. Moreover, we will discuss the quantisation of this theory using the BRST symmetry. Also, we will analyse this theory in the maximal Abelian gauge.

Testing the Invariance of the National Health and Nutrition Examination Survey's Sexual Behavior Questionnaire Across Gender, Ethnicity/Race, and Generation.

Science.gov (United States)

Zhou, Anne Q; Hsueh, Loretta; Roesch, Scott C; Vaughn, Allison A; Sotelo, Frank L; Lindsay, Suzanne; Klonoff, Elizabeth A

2016-02-01

Federal and state policies are based on data from surveys that examine sexual-related cognitions and behaviors through self-reports of attitudes and actions. No study has yet examined their factorial invariance--specifically, whether the relationship between items assessing sexual behavior and their underlying construct differ depending on gender, ethnicity/race, or age. This study examined the factor structure of four items from the sexual behavior questionnaire part of the National Health and Nutrition Examination Survey (NHANES). As NHANES provided different versions of the survey per gender, invariance was tested across gender to determine whether subsequent tests across ethnicity/race and generation could be done across gender. Items were not invariant across gender groups so data files for women and men were not collapsed. Across ethnicity/race for both genders, and across generation for women, items were configurally invariant, and exhibited metric invariance across Latino/Latina and Black participants for both genders. Across generation for men, the configural invariance model could not be identified so the baseline models were examined. The four item one factor model fit well for the Millennial and GenerationX groups but was a poor fit for the baby boomer and silent generation groups, suggesting that gender moderated the invariance across generation. Thus, comparisons between ethnic/racial and generational groups should not be made between the genders or even within gender. Findings highlight the need for programs and interventions that promote a more inclusive definition of "having had sex."

Scheme dependence of quantum gravity on de Sitter background

Energy Technology Data Exchange (ETDEWEB)

Kitamoto, Hiroyuki, E-mail: kitamoto@post.kek.jp [KEK Theory Center, Tsukuba, Ibaraki 305-0801 (Japan); Kitazawa, Yoshihisa, E-mail: kitazawa@post.kek.jp [KEK Theory Center, Tsukuba, Ibaraki 305-0801 (Japan); The Graduate University for Advanced Studies (Sokendai), Department of Particle and Nuclear Physics, Tsukuba, Ibaraki 305-0801 (Japan)

2013-08-11

We extend our investigation of the IR effects on the local dynamics of matter fields in quantum gravity. Specifically we clarify how the IR effects depend on the change of the quantization scheme: different parametrization of the metric and the matter field redefinition. Conformal invariance implies effective Lorentz invariance of the matter system in de Sitter space. An arbitrary choice of the parametrization of the metric and the matter field redefinition does not preserve the effective Lorentz invariance of the local dynamics. As for the effect of different parametrization of the metric alone, the effective Lorentz symmetry breaking term can be eliminated by shifting the background metric. In contrast, we cannot compensate the matter field redefinition dependence by such a way. The effective Lorentz invariance can be retained only when we adopt the specific matter field redefinitions where all dimensionless couplings become scale invariant at the classical level. This scheme is also singled out by unitarity as the kinetic terms are canonically normalized.

Dynamics and control of Lorentz-augmented spacecraft relative motion

CERN Document Server

Yan, Ye; Yang, Yueneng

2017-01-01

This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

Science.gov (United States)

Borges, L. H. C.; Barone, F. A.

2016-02-01

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

Energy Technology Data Exchange (ETDEWEB)

Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)

2016-02-15

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

Traces of Lorentz symmetry breaking in a hydrogen atom at ground state

International Nuclear Information System (INIS)

Borges, L.H.C.; Barone, F.A.

2016-01-01

Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)

Testing Special Relativity at High Energies with Astrophysical Sources

Science.gov (United States)

Stecker, F. W.

2007-01-01

Since the group of Lorentz boosts is unbounded, there is a question as to whether Lorentz invariance (LI) holds to infinitely short distances. However, special and general relativity may break down at the Planck scale. Various quantum gravity scenarios such as loop quantum gravity, as well as some forms of string theory and extra dimension models may imply Lorentz violation (LV) at ultrahigh energies. The Gamma-Ray Large Area Space Telescope (GLAST), to be launched in mid-December, will measure the spectra of distant extragalactic sources of high energy gamma-rays, particularly active galactic nuclei and gamma-ray bursts. GLAST can look for energy-dependent gamma-ray propagation effects from such sources as a signal of Lorentz invariance violation. These sources may also exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions with low energy photons having a flux level as determined by various astronomical observations. With LV the threshold for such interactions can be significantly raised, changing the predicted absorption turnover in the observed spectrum of the sources. Stecker and Glashow have shown that the existence such absorption features in the spectra of extragalactic sources puts constraints on LV. Such constraints have important implications for some quantum gravity and large extra dimension models. Future spaceborne detectors dedicated to measuring gamma-ray polarization can look for birefringence effects as a possible signal of loop quantum gravity. A very small LV may also result in the modification or elimination of the GZK effect, thus modifying the spectrum of ultrahigh energy cosmic rays. This possibility can be explored with ground-based arrays such as Auger or with a space based detector system such as the proposed OWL satellite mission.

On a possible origin of modular invariance

International Nuclear Information System (INIS)

Tahir Shah, K.

1991-06-01

We propose an information theoretic model of the space-time pre-geometry where the pre-geometry is considered as a ''coded state of matter and space-time'', distinctly different from the classical space-time or any known state of matter. Assuming that physical processes at Planck's dimensions are stochastic Markov processes and using information theoretic and algebro-geometric coding techniques, we show that modular invariance is a natural consequence of: 1. Shannon's channel capacity theorem. 2. Nature selects and uses only those error-correcting codes to transfer information between space-time entities which allow the value of propagation rate R reaching its critical value R C , the channel capacity. Next, using the strong converse theorem we show that a phase-transition occurs at (R C -R) 0. Furthermore, it is known that some symmetrically packed optimal codes lead to E 8 lattice while others to a 26-dimensional Lorentz lattice used in string theories. This suggests a precise connection between our model and string theories. (author). 26 refs

A limit on the variation of the speed of light arising from quantum gravity effects.

Science.gov (United States)

Abdo, A A; Ackermann, M; Ajello, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Bloom, E D; Bonamente, E; Bonnell, J; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Briggs, M S; Brigida, M; Bruel, P; Burgess, J M; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Chaplin, V; Charles, E; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Connaughton, V; Conrad, J; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Dingus, B L; do Couto E Silva, E; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Finke, J; Fishman, G; Focke, W B; Foschini, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Gibby, L; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Granot, J; Greiner, J; Grenier, I A; Grondin, M-H; Grove, J E; Grupe, D; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hoversten, E A; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Kippen, R M; Knödlseder, J; Kocevski, D; Kouveliotou, C; Kuehn, F; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Mazziotta, M N; McBreen, S; McEnery, J E; McGlynn, S; Mészáros, P; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paciesas, W S; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Petrosian, V; Piron, F; Porter, T A; Preece, R; Rainò, S; Ramirez-Ruiz, E; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Stecker, F W; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Toma, K; Torres, D F; Tosti, G; Troja, E; Uchiyama, Y; Uehara, T; Usher, T L; van der Horst, A J; Vasileiou, V; Vilchez, N; Vitale, V; von Kienlin, A; Waite, A P; Wang, P; Wilson-Hodge, C; Winer, B L; Wood, K S; Wu, X F; Yamazaki, R; Ylinen, T; Ziegler, M

2009-11-19

A cornerstone of Einstein's special relativity is Lorentz invariance-the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck) approximately 1.62 x 10(-33) cm or E(Planck) = M(Planck)c(2) approximately 1.22 x 10(19) GeV), at which quantum effects are expected to strongly affect the nature of space-time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in gamma-ray burst (GRB) light-curves. Here we report the detection of emission up to approximately 31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space-time on a very small scale linearly alters the speed of light.

PSI collapse and relativistic covariance

International Nuclear Information System (INIS)

Costa de Beauregard, Olivier

1980-01-01

We call macrorelativistic a theory invariant under the orthochronous Lorentz group and obeying the 'factlike' principle of retarded causality, and microrelativistic a theory invariant under the full Lorentz group and CPT symmetric. The Einstein correlations either direct (non-separability of measurements issuing from a common preparation) or reversed (non-separability of preparations producing a common measurement) are incompatible with the macro-, but compatible with the microrelativity. We assume that fundamental physics is fully Lorentz and CPT invariant (the transition to macrophysics introducing a 'factlike asymmetry) and consequently define the collapse-and-retrocollapse concept [fr

Vacuum solutions of a gravity model with vector-induced spontaneous Lorentz symmetry breaking

International Nuclear Information System (INIS)

Bertolami, O.; Paramos, J.

2005-01-01

We study the vacuum solutions of a gravity model where Lorentz symmetry is spontaneously broken once a vector field acquires a vacuum expectation value. Results are presented for the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB. The purely radial LSB result corresponds to new black hole solutions. When possible, parametrized post-Newtonian parameters are computed and observational boundaries used to constrain the Lorentz symmetry breaking scale

Special Relativity in Week One: 3) Introducing the Lorentz Contraction

Science.gov (United States)

Huggins, Elisha

2011-05-01

This is the third of four articles on teaching special relativity in the first week of an introductory physics course.1,2 With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie "Time Dilation, an Experiment with Mu-Mesons" by David Frisch and James Smith.3,4 The movie demonstrates that time dilation and the Lorentz contraction are essentially two sides of the same coin. Here we take the muon's point of view for a more intuitive understanding of the Lorentz contraction, and use the results of the movie to provide an insight into the way we interpret experimental results involving special relativity.

Remote sub-wavelength focusing of ultrasonically activated Lorentz current

Science.gov (United States)

Rekhi, Angad S.; Arbabian, Amin

2017-04-01

We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.

Test of time-reversal invariance at COSY

Energy Technology Data Exchange (ETDEWEB)

Valdau, Yury [Helmholtz Institut fuer Strahlen- und Kernphysik, Bonn Univ. (Germany); National Research Center ' ' Kurchatov Institute' ' Petersburg Nuclear Physics Institute B.P. Konstantinov, Gatchina (Russian Federation); Eversheim, Dieter [Helmholtz Institut fuer Strahlen- und Kernphysik, Bonn Univ. (Germany); Lorentz, Bernd [Forschungszentrum Juelich, Institute fuer Kernphysik (Germany)

2016-07-01

The experiment to test the Time Reversal Invariance at Cosy (TRIC) is under the preparation by the PAX collaboration. It is planned to improve present limit on the T-odd P-even interaction by at least one order of magnitude using a unique genuine null observable available in double polarized proton-deuteron scattering. The TRIC experiment is planned as a transmission experiment using a tensor polarized deuterium target placed at the internal target place of the Cooler-Synchrotron COSY-Juelich. Total double polarized cross section will be measured observing a beam current change due to the interaction of a polarized proton beam with an internal tensor polarized deuterium target from the PAX atomic beam source. Hence, in this experiment COSY will be used as an accelerator, detector and ideal zero degree spectrometer. In addition to the high intensity polarized proton beam and high density polarized deuterium target, a new high precision beam current measurement system will be prepared for the TRIC experiment. In this report status of all the activities of PAX collaboration towards realization of the TRIC experiment will be presented.

A new General Lorentz Transformation model

International Nuclear Information System (INIS)

Novakovic, Branko; Novakovic, Alen; Novakovic, Dario

2000-01-01

A new general structure of Lorentz Transformations, in the form of General Lorentz Transformation model (GLT-model), has been derived. This structure includes both Lorentz-Einstein and Galilean Transformations as its particular (special) realizations. Since the free parameters of GLT-model have been identified in a gravitational field, GLT-model can be employed both in Special and General Relativity. Consequently, the possibilities of an unification of Einstein's Special and General Theories of Relativity, as well as an unification of electromagnetic and gravitational fields are opened. If GLT-model is correct then there exist four new observation phenomena (a length and time neutrality, and a length dilation and a time contraction). Besides, the well-known phenomena (a length contraction, and a time dilation) are also the constituents of GLT-model. It means that there is a symmetry in GLT-model, where the center of this symmetry is represented by a length and a time neutrality. A time and a length neutrality in a gravitational field can be realized if the velocity of a moving system is equal to the free fall velocity. A time and a length neutrality include an observation of a particle mass neutrality. A special consideration has been devoted to a correlation between GLT-model and a limitation on particle velocities in order to investigate the possibility of a travel time reduction. It is found out that an observation of a particle speed faster then c=299 792 458 m/s, is possible in a gravitational field, if certain conditions are fulfilled

Invariance Signatures: Characterizing contours by their departures from invariance

OpenAIRE

Squire, David; Caelli, Terry M.

1997-01-01

In this paper, a new invariant feature of two-dimensional contours is reported: the Invariance Signature. The Invariance Signature is a measure of the degree to which a contour is invariant under a variety of transformations, derived from the theory of Lie transformation groups. It is shown that the Invariance Signature is itself invariant under shift, rotation and scaling of the contour. Since it is derived from local properties of the contour, it is well-suited to a neural network implement...

A measurement of Lorentz Angle of radiation-hard Pixel Sensors

CERN Document Server

Aleppo, M

2001-01-01

Silicon pixel detectors developed to meet LHC requirements were tested in a beam at CERN in the framework of the ATLAS collaboration. The experimental behaviour of irradiated and not-irradiated sensors in a magnetic field is discussed. The measurement of the Lorentz angle for these sensors at different operating conditions is presented. A simple model of the charge drift in silicon before and after irradiation is presented. The good agreement between the model predictions and the experimental results is shown.

CPT symmetry tests with cold anti {rho} and antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Yamazaki, Yasunori [RIKEN, Atomic Physics Laboratory, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Ulmer, Stefan [RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan)

2013-07-15

Precision comparisons of the properties of particles and their corresponding antiparticles are highly relevant because the Standard Model of elementary particle physics, a local, Lorentz-invariant field theory, is necessarily symmetric with respect to the combined CPT operation. This symmetry defines exact equality between the fundamental properties of particles and their anti-images. Any measured and confirmed violation constitutes a significant challenge to the Standard Model. Recent results of different CPT-tests are summarized, with emphasis to the high-precision measurement of the magnetic moment of the proton and the antiproton, as well as the precision investigation of antihydrogen ground state hyperfine splitting. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

On the duality in CPT-even Lorentz-breaking theories

Energy Technology Data Exchange (ETDEWEB)

Scarpelli, A.P.B. [Departamento de Policia Federal, Sao Paulo (Brazil); Ribeiro, R.F.; Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica (Brazil)

2015-07-15

We generalize the duality between self-dual and Maxwell-Chern-Simons theories for the case of a CPT-even Lorentz-breaking extension of these theories. The duality is shown using the gauge embedding procedure, both in free and coupled cases, and with the master action approach. The physical spectra of both Lorentz-breaking theories are studied. The massive poles are shown to coincide and to respect the requirements for unitarity and causality at tree level. The extra massless poles which are present in the dualized model are shown to be nondynamical. (orig.)

On the duality in CPT-even Lorentz-breaking theories

International Nuclear Information System (INIS)

Scarpelli, A.P.B.; Ribeiro, R.F.; Nascimento, J.R.; Petrov, A.Yu.

2015-01-01

We generalize the duality between self-dual and Maxwell-Chern-Simons theories for the case of a CPT-even Lorentz-breaking extension of these theories. The duality is shown using the gauge embedding procedure, both in free and coupled cases, and with the master action approach. The physical spectra of both Lorentz-breaking theories are studied. The massive poles are shown to coincide and to respect the requirements for unitarity and causality at tree level. The extra massless poles which are present in the dualized model are shown to be nondynamical. (orig.)

Conserved Noether Currents, Utiyama's Theory of Invariant Variation, and Velocity Dependence in Local Gauge Invariance

Science.gov (United States)

Darvas, Gyrgy

2009-01-01

The paper discusses the mathematical consequences of the application of derived variables in gauge fields. Physics is aware of several phenomena, which depend first of all on velocities (like e.g., the force caused by charges moving in a magnetic field, or the Lorentz transformation). Applying the property of the second Noether theorem, that allowed generalised variables, this paper extends the article by Al-Kuwari and Taha (1991) with a new conclusion. They concluded that there are no extra conserved currents associated with local gauge invariance. We show, that in a more general case, there are further conserved Noether currents. In its method the paper reconstructs the clue introduced by Utiyama (1956, 1959) and followed by Al-Kuwari and Taha (1991) in the presence of a gauge field that depends on the co-ordinates of the velocity space. In this course we apply certain (but not full) analogies with Mills (1989). We show, that handling the space-time coordinates as implicit variables in the gauge field, reproduces the same results that have been derived in the configuration space (i.e., we do not lose information), while the proposed new treatment gives additional information extending those. The result is an extra conserved Noether current.

The Scientific Correspondence of H A Lorentz

CERN Document Server

Kox, AJ

2008-01-01

Presents a selection of more than 400 letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death.

Testing Measurement Invariance across Groups of Children with and without Attention-Deficit/ Hyperactivity Disorder: Applications for Word Recognition and Spelling Tasks.

Science.gov (United States)

Lúcio, Patrícia S; Salum, Giovanni; Swardfager, Walter; Mari, Jair de Jesus; Pan, Pedro M; Bressan, Rodrigo A; Gadelha, Ary; Rohde, Luis A; Cogo-Moreira, Hugo

2017-01-01

Although studies have consistently demonstrated that children with attention-deficit/hyperactivity disorder (ADHD) perform significantly lower than controls on word recognition and spelling tests, such studies rely on the assumption that those groups are comparable in these measures. This study investigates comparability of word recognition and spelling tests based on diagnostic status for ADHD through measurement invariance methods. The participants ( n = 1,935; 47% female; 11% ADHD) were children aged 6-15 with normal IQ (≥70). Measurement invariance was investigated through Confirmatory Factor Analysis and Multiple Indicators Multiple Causes models. Measurement invariance was attested in both methods, demonstrating the direct comparability of the groups. Children with ADHD were 0.51 SD lower in word recognition and 0.33 SD lower in spelling tests than controls. Results suggest that differences in performance on word recognition and spelling tests are related to true mean differences based on ADHD diagnostic status. Implications for clinical practice and research are discussed.

Quantum tests for the linearity and permutation invariance of Boolean functions

Energy Technology Data Exchange (ETDEWEB)

Hillery, Mark [Department of Physics, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10021 (United States); Andersson, Erika [SUPA, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

2011-12-15

The goal in function property testing is to determine whether a black-box Boolean function has a certain property or is {epsilon}-far from having that property. The performance of the algorithm is judged by how many calls need to be made to the black box in order to determine, with high probability, which of the two alternatives is the case. Here we present two quantum algorithms, the first to determine whether the function is linear and the second to determine whether it is symmetric (invariant under permutations of the arguments). Both require order {epsilon}{sup -2/3} calls to the oracle, which is better than known classical algorithms. In addition, in the case of linearity testing, if the function is linear, the quantum algorithm identifies which linear function it is. The linearity test combines the Bernstein-Vazirani algorithm and amplitude amplification, while the test to determine whether a function is symmetric uses projective measurements and amplitude amplification.

Characterisation of Embeddings in Lorentz Spaces

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Johansson, M.; Okpoti, C.A.; Persson, L. E.

2007-01-01

Roč. 76, č. 1 (2007), s. 69-92 ISSN 0004-9727 R&D Projects: GA ČR GA201/05/2033 Institutional research plan: CEZ:AV0Z10190503 Keywords : non-increasing rearrangement * Lorentz spaces * weights Subject RIV: BA - General Mathematics Impact factor: 0.297, year: 2007

A CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation

Energy Technology Data Exchange (ETDEWEB)

Ferreira Junior, Manoel; Casana, M.R.; Santos, Frederico E.P. dos; Silva, E.O. [UFMA, Sao Luis (Brazil); Passos, E. [UFCG, Campina Grande, PB (Brazil)

2013-07-01

Full text: The Standard Model Extension (SME) has been the usual framework for investigating signals of Lorentz violation in physical systems. It is the natural framework for studying properties of physical systems with Lorentz-violation since it includes Lorentz-violating terms in all sectors of the minimal standard model. The Lorentz-violating (LV) terms are generated as vacuum expectation values of tensors defined in a high energy scale. This framework has inspired a great deal of investigation in recent years. Such works encompass several distinct aspects involving fermion systems and radiative corrections, CPT- probing experiments, the electromagnetic CPT- and Lorentz-odd term, the 19 electromagnetic CPT-even coefficients. Recently, some studies involving higher dimensional operators have also been reported with great interest, including nonminimal interactions. These many contributions have elucidated the effects induced by Lorentz violation and served to set up stringent upper bounds on the LV coefficients. In the present work, we propose a new CPT-even, dimension-five, nonminimal coupling linking the fermionic and gauge fields in the context of the Dirac equation, involving the CPT-even tensor of the gauge term of the SME. By considering the nonrelativistic limit of the modified Dirac equation, we explicitly evaluate the new contributions to the nonrelativistic Hamiltonian. These new terms imply a direct correction on the anomalous magnetic moment, a kind of electrical Zeeman-like effect on the atomic spectrum, and a Rashba-like coupling term. These effects are then used to impose upper bounds on the magnitude of the non minimally coupled LV coefficients at the level of 1 part in 10{sub 16}. (author)

A CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation

International Nuclear Information System (INIS)

Ferreira Junior, Manoel; Casana, M.R.; Santos, Frederico E.P. dos; Silva, E.O.; Passos, E.

2013-01-01

Full text: The Standard Model Extension (SME) has been the usual framework for investigating signals of Lorentz violation in physical systems. It is the natural framework for studying properties of physical systems with Lorentz-violation since it includes Lorentz-violating terms in all sectors of the minimal standard model. The Lorentz-violating (LV) terms are generated as vacuum expectation values of tensors defined in a high energy scale. This framework has inspired a great deal of investigation in recent years. Such works encompass several distinct aspects involving fermion systems and radiative corrections, CPT- probing experiments, the electromagnetic CPT- and Lorentz-odd term, the 19 electromagnetic CPT-even coefficients. Recently, some studies involving higher dimensional operators have also been reported with great interest, including nonminimal interactions. These many contributions have elucidated the effects induced by Lorentz violation and served to set up stringent upper bounds on the LV coefficients. In the present work, we propose a new CPT-even, dimension-five, nonminimal coupling linking the fermionic and gauge fields in the context of the Dirac equation, involving the CPT-even tensor of the gauge term of the SME. By considering the nonrelativistic limit of the modified Dirac equation, we explicitly evaluate the new contributions to the nonrelativistic Hamiltonian. These new terms imply a direct correction on the anomalous magnetic moment, a kind of electrical Zeeman-like effect on the atomic spectrum, and a Rashba-like coupling term. These effects are then used to impose upper bounds on the magnitude of the non minimally coupled LV coefficients at the level of 1 part in 10 16 . (author)

Lorentz and CPT violation in QED revisited: A missing analysis

Energy Technology Data Exchange (ETDEWEB)

Del Cima, Oswaldo M., E-mail: wadodelcima@if.uff.b [Universidade Federal Fluminense (UFF), Polo Universitario de Rio das Ostras, Rua Recife s/n, 28890-000, Rio das Ostras, RJ (Brazil); Fonseca, Jakson M., E-mail: jakson.fonseca@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Franco, Daniel H.T., E-mail: daniel.franco@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Piguet, Olivier, E-mail: opiguet@pq.cnpq.b [Universidade Federal do Espirito Santo (UFES), Departamento de Fisica, Campus Universitario de Goiabeiras, 29060-900, Vitoria, ES (Brazil)

2010-05-03

We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

Lorentz and CPT violation in QED revisited: A missing analysis

International Nuclear Information System (INIS)

Del Cima, Oswaldo M.; Fonseca, Jakson M.; Franco, Daniel H.T.; Piguet, Olivier

2010-01-01

We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

Comment on self-inverse form of the Lorentz transformation

International Nuclear Information System (INIS)

Cook, R.J.

1979-01-01

It has been shown that the kinematic relations between two iertial reference frames in relative motion can be made symmetric by an appropriate orientation of the coordinate axes of the two frames. It follows from this symmetry and the principle of relativity that the transformation matrix, A, from one frame to the other, and its inverse, A -1 , are equal. This result, along with a limiting-velocity postulate, was used in a derivation of the Lorentz transformation. The present note points out that only two transformation laws are compatible with the symmetry condition A = A -1 . One of these is the Lorentz transformation and the other violates causality. Thus, if the limiting-velocity postulate is replaced by the requirement that causality be satisfied in all inertial frames, one arrives at a derivation of the Lorentz transformation based entirely on concepts which were known and widely accepted long before the advent of special relativity: the homogeneity and isotropy of space in all inertial frames, the principle of relativity, and the principle of causality

Invariant differential operators for non-compact Lie groups: an introduction

International Nuclear Information System (INIS)

Dobrev, V.K.

2015-01-01

In the present paper we review the progress of the project of classification and construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we called earlier 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduced recently the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. In the present paper we consider in detail the orthogonal algebras so(p,q) all of which are parabolically related to the conformal algebra so(n,2) with p+q=n+2, the parabolic subalgebras including the Lorentz subalgebra so(n-1,1) and its analogs so(p-1,q-1)

Collective variables method in relativistic theory

International Nuclear Information System (INIS)

Shurgaya, A.V.

1983-01-01

Classical theory of N-component field is considered. The method of collective variables accurately accounting for conservation laws proceeding from invariance theory under homogeneous Lorentz group is developed within the frames of generalized hamiltonian dynamics. Hyperboloids are invariant surfaces Under the homogeneous Lorentz group. Proceeding from this, field transformation is introduced, and the surface is parametrized so that generators of the homogeneous Lorentz group do not include components dependent on interaction and their effect on the field function is reduced to geometrical. The interaction is completely included in the expression for the energy-momentum vector of the system which is a dynamical value. Gauge is chosen where parameters of four-dimensional translations and their canonically-conjugated pulses are non-physical and thus phase space is determined by parameters of the homogeneous Lorentz group, field function and their canonically-conjugated pulses. So it is managed to accurately account for conservation laws proceeding from the requirement of lorentz-invariance

Classroom Experiment to Verify the Lorentz Force

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 3. Classroom Experiment to Verify the Lorentz Force. Somnath Basu Anindita Bose Sumit Kumar Sinha Pankaj Vishe S Chatterjee. Classroom Volume 8 Issue 3 March 2003 pp 81-86 ...

Average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence

Science.gov (United States)

Liu, Dajun; Wang, Guiqiu; Wang, Yaochuan

2018-01-01

Based on the Huygens-Fresnel integral and the relationship of Lorentz distribution and Hermite-Gauss function, the average intensity and coherence properties of a partially coherent Lorentz-Gauss beam propagating through oceanic turbulence have been investigated by using numerical examples. The influences of beam parameters and oceanic turbulence on the propagation properties are also discussed in details. It is shown that the partially coherent Lorentz-Gauss beam with smaller coherence length will spread faster in oceanic turbulence, and the stronger oceanic turbulence will accelerate the spreading of partially coherent Lorentz-Gauss beam in oceanic turbulence.

The CTA Sensitivity to Lorentz-Violating Effects on the Gamma-Ray Horizon

CERN Document Server

Fairbairn, Malcolm; Ellis, John; Hinton, Jim; White, Richard

2014-01-01

The arrival of TeV-energy photons from distant galaxies is expected to be affected by their QED interaction with intergalactic radiation fields through electron-positron pair production. In theories where high-energy photons violate Lorentz symmetry, the kinematics of the process $\\gamma + \\gamma\\rightarrow e^+ + e^-$ is altered and the cross-section suppressed. Consequently, one would expect more of the highest-energy photons to arrive if QED is modified by Lorentz violation than if it is not. We estimate the sensitivity of Cherenkov Telescope Array (CTA) to changes in the $\\gamma$-ray horizon of the Universe due to Lorentz violation, and find that it should be competitive with other leading constraints.

Maxwell-Chern-Simons vortices in a CPT-odd Lorentz-violating Higgs electrodynamics

International Nuclear Information System (INIS)

Casana, R.; Ferreira, M.M.; Hora, E. da; Neves, A.B.F.

2014-01-01

We study BPS vortices in a CPT-odd and Lorentz-violating Maxwell-Chern-Simons-Higgs (MCSH) electrodynamics attained from the dimensional reduction of the Carroll-Field-Jackiw-Higgs model. The Lorentz-violating parameter induces a pronounced behavior at origin (for the magnetic/electric fields and energy density) which is absent in the MCSH vortices. For some combination of the Lorentz-violating coefficients there always exists a sufficiently large winding number n 0 such that for all vertical stroke n vertical stroke ≥ vertical stroke n 0 vertical stroke the magnetic field flips sign, yielding two well-defined regions with opposite magnetic flux. However, the total magnetic flux remains quantized and proportional to the winding number. (orig.)

Linear negative magnetoresistance in two-dimensional Lorentz gases

Science.gov (United States)

Schluck, J.; Hund, M.; Heckenthaler, T.; Heinzel, T.; Siboni, N. H.; Horbach, J.; Pierz, K.; Schumacher, H. W.; Kazazis, D.; Gennser, U.; Mailly, D.

2018-03-01

Two-dimensional Lorentz gases formed by obstacles in the shape of circles, squares, and retroreflectors are reported to show a pronounced linear negative magnetoresistance at small magnetic fields. For circular obstacles at low number densities, our results agree with the predictions of a model based on classical retroreflection. In extension to the existing theoretical models, we find that the normalized magnetoresistance slope depends on the obstacle shape and increases as the number density of the obstacles is increased. The peaks are furthermore suppressed by in-plane magnetic fields as well as by elevated temperatures. These results suggest that classical retroreflection can form a significant contribution to the magnetoresistivity of two-dimensional Lorentz gases, while contributions from weak localization cannot be excluded, in particular for large obstacle densities.

Vacuum Cherenkov radiation for Lorentz-violating fermions

Science.gov (United States)

Schreck, M.

2017-11-01

The current work focuses on the process of vacuum Cherenkov radiation for Lorentz-violating fermions that are described by the minimal standard-model extension (SME). To date, most considerations of this important hypothetical process have been restricted to Lorentz-violating photons, as the necessary theoretical tools for the SME fermion sector have not been available. With their development in a very recent paper, we are now in a position to compute the decay rates based on a modified Dirac theory. Two realizations of the Cherenkov process are studied. In the first scenario, the spin projection of the incoming fermion is assumed to be conserved, and in the second, the spin projection is allowed to flip. The first type of process is shown to be still forbidden for the dimensionful a and b coefficients where there are strong indications that it is energetically disallowed for the H coefficients, as well. However, it is rendered possible for the dimensionless c , d , e , f , and g coefficients. For large initial fermion energies, the decay rates for the c and d coefficients were found to grow linearly with momentum and to be linearly suppressed by the smallness of the Lorentz-violating coefficient where for the e , f , and g coefficients this suppression is even quadratic. The decay rates vanish in the vicinity of the threshold, as expected. The decay including a fermion spin-flip plays a role for the spin-nondegenerate operators and it was found to occur for the dimensionful b and H coefficients as well as for the dimensionless d and g . The characteristics of this process differ much from the properties of the spin-conserving one, e.g., there is no threshold. Based on experimental data of ultra-high-energy cosmic rays, new constraints on Lorentz violation in the quark sector are obtained from the thresholds. However, it does not seem to be possible to derive bounds from the spin-flip decays. This work reveals the usefulness of the quantum field theoretic methods

Quantizations of D = 3 Lorentz symmetry

Energy Technology Data Exchange (ETDEWEB)

Lukierski, J. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Tolstoy, V.N. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation)

2017-04-15

Using the isomorphism o(3; C) ≅ sl(2; C) we develop a new simple algebraic technique for complete classification of quantum deformations (the classical r-matrices) for real forms o(3) and o(2,1) of the complex Lie algebra o(3; C) in terms of real forms of sl(2; C): su(2), su(1,1) and sl(2; R). We prove that the D = 3 Lorentz symmetry o(2,1) ≅ su(1,1) ≅ sl(2; R) has three different Hopf-algebraic quantum deformations, which are expressed in the simplest way by two standard su(1,1) and sl(2; R) q-analogs and by simple Jordanian sl(2; R) twist deformation. These quantizations are presented in terms of the quantum Cartan-Weyl generators for the quantized algebras su(1,1) and sl(2; R) as well as in terms of quantum Cartesian generators for the quantized algebra o(2,1). Finally, some applications of the deformed D = 3 Lorentz symmetry are mentioned. (orig.)

Entropic information for travelling solitons in Lorentz and CPT breaking systems

International Nuclear Information System (INIS)

Correa, R.A.C.; Rocha, Roldão da; Souza Dutra, A. de

2015-01-01

In this work we group four research topics apparently disconnected, namely solitons, Lorentz symmetry breaking, supersymmetry, and entropy. Following a recent work (Gleiser and Stamatopoulos, 2012), we show that it is possible to construct in the context of travelling wave solutions a configurational entropy measure in functional space, from the field configurations. Thus, we investigate the existence and properties of travelling solitons in Lorentz and CPT breaking scenarios for a class of models with two interacting scalar fields. Here, we obtain a complete set of exact solutions for the model studied which display both double and single-kink configurations. In fact, such models are very important in applications that include Bloch branes, Skyrmions, Yang–Mills, Q-balls, oscillons and various superstring-motivated theories. We find that the so-called Configurational Entropy (CE) for travelling solitons shows that the best value of parameter responsible to break the Lorentz symmetry is one where the energy density is distributed equally around the origin. In this way, the information-theoretical measure of travelling solitons in Lorentz symmetry violation scenarios opens a new window to probe situations where the parameters responsible for breaking the symmetries are arbitrary. In this case, the CE selects the best value of the parameter in the model

Testing measurement invariance of the Depression, Anxiety, and Stress Scales (DASS-21) across four countries.

Science.gov (United States)

Scholten, Saskia; Velten, Julia; Bieda, Angela; Zhang, Xiao Chi; Margraf, Jürgen

2017-11-01

The rising burden of mental and behavioral disorders has become a global challenge (Murray et al., 2012). Measurement invariant clinical instruments are necessary for the assessment of relevant symptoms across countries. The present study tested the measurement invariance of the 21-item version of the Depression, Anxiety, and Stress Scales (DASS; Lovibond & Lovibond, 1995b) in Poland, Russia, the United Kingdom (U.K.), and the United States of America (U.S.). Telephone interviews were conducted with population-based samples (nPL = 1003, nRU = 3020, nU.K. = 1002, nU.S. = 1002). The DASS-21 shows threshold measurement invariance. Comparisons of latent means did not indicate differences between U.K. and U.S. However, Polish and Russian samples reported more depressive symptoms compared with U.K. and U.S. samples; the Russian sample had the highest levels of anxiety symptoms and the Polish sample demonstrated the highest stress levels. The DASS-21 can be recommended to meaningfully compare the relationships between variables across groups and to compare latent means in Polish-, Russian-, and English-speaking populations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

LORENTZ PHASE IMAGING AND IN-SITU LORENTZ MICROSCOPY OF PATTERNED CO-ARRAYS

International Nuclear Information System (INIS)

VOLKOV, V.V.; ZHU, Y.

2003-01-01

Understanding magnetic structures and properties of patterned and ordinary magnetic films at nanometer length-scale is the area of immense technological and fundamental scientific importance. The key feature to such success is the ability to achieve visual quantitative information on domain configurations with a maximum ''magnetic'' resolution. Several methods have been developed to meet these demands (Kerr and Faraday effects, differential phase contrast microscopy, magnetic force microscopy, SEMPA etc.). In particular, the modern off-axis electron holography allows retrieval of the electron-wave phase shifts down to 2π/N (with typical N = 10-20, approaching in the limit N ∼ 100) in TEM equipped with field emission gun, which is already successfully employed for studies of magnetic materials at nanometer scale. However, it remains technically demanding, sensitive to noise and needs highly coherent electron sources. As possible alternative we developed a new method of Lorentz phase microscopy [1,2] based on the Fourier solution [3] of magnetic transport-of-intensity (MTIE) equation. This approach has certain advantages, since it is less sensitive to noise and does not need high coherence of the source required by the holography. In addition, it can be realized in any TEM without basic hardware changes. Our approach considers the electron-wave refraction in magnetic materials (magnetic refraction) and became possible due to general progress in understanding of noninterferometric phase retrieval [4-6] dealing with optical refraction. This approach can also be treated as further development of Fresnel microscopy, used so far for imaging of in-situ magnetization process in magnetic materials studied by TEM. Figs. 1-3 show some examples of what kind information can be retrieved from the conventional Fresnel images using the new approach. Most of these results can be compared with electron-holographic data. Using this approach we can shed more light on fine details of

Synchronizing and controlling hyperchaos in complex Lorentz-Haken systems

International Nuclear Information System (INIS)

Fang Jinqing

1995-03-01

Synchronizing hyperchaos is realized by the drive-response relationship in the complex Lorentz-Haken system and its higher-order cascading systems for the first time. Controlling hyperchaos is achieved by the intermittent proportional feedback to all of the drive (master) system variables. The complex Lorentz-Haken system describes the detuned single-mode laser and is taken as a typical example of hyperchaotic synchronization to clarify our ideas and results. The ideas and concepts could be extended to some nonlinear dynamical systems and have prospects for potential applications, for example. to laser, electronics, plasma, cryptography, communication, chemical and biological systems and so on. (8 figs., 2 tabs.)

Synchronizing and controlling hyperchaos in complex Lorentz-Haken systems

Energy Technology Data Exchange (ETDEWEB)

Jinqing, Fang [Academia Sinica, Beijing, BJ (China). Inst. of Atomic Energy

1995-03-01

Synchronizing hyperchaos is realized by the drive-response relationship in the complex Lorentz-Haken system and its higher-order cascading systems for the first time. Controlling hyperchaos is achieved by the intermittent proportional feedback to all of the drive (master) system variables. The complex Lorentz-Haken system describes the detuned single-mode laser and is taken as a typical example of hyperchaotic synchronization to clarify our ideas and results. The ideas and concepts could be extended to some nonlinear dynamical systems and have prospects for potential applications, for example. to laser, electronics, plasma, cryptography, communication, chemical and biological systems and so on. (8 figs., 2 tabs.).

Invariant subspaces

CERN Document Server

Radjavi, Heydar

2003-01-01

This broad survey spans a wealth of studies on invariant subspaces, focusing on operators on separable Hilbert space. Largely self-contained, it requires only a working knowledge of measure theory, complex analysis, and elementary functional analysis. Subjects include normal operators, analytic functions of operators, shift operators, examples of invariant subspace lattices, compact operators, and the existence of invariant and hyperinvariant subspaces. Additional chapters cover certain results on von Neumann algebras, transitive operator algebras, algebras associated with invariant subspaces,

What’s hampering measurement invariance: Detecting non-invariant items using clusterwise simultaneous component analysis

Directory of Open Access Journals (Sweden)

Kim eDe Roover

2014-06-01

Full Text Available The issue of measurement invariance is ubiquitous in the behavioral sciences nowadays as more and more studies yield multivariate multigroup data. When measurement invariance cannot be established across groups, this is often due to different loadings on only a few items. Within the multigroup CFA framework, methods have been proposed to trace such non-invariant items, but these methods have some disadvantages in that they require researchers to run a multitude of analyses and in that they imply assumptions that are often questionable. In this paper, we propose an alternative strategy which builds on clusterwise simultaneous component analysis (SCA. Clusterwise SCA, being an exploratory technique, assigns the groups under study to a few clusters based on differences and similarities in the covariance matrices, and thus based on the component structure of the items. Non-invariant items can then be traced by comparing the cluster-specific component loadings via congruence coefficients, which is far more parsimonious than comparing the component structure of all separate groups. In this paper we present a heuristic for this procedure. Afterwards, one can return to the multigroup CFA framework and check whether removing the non-invariant items or removing some of the equality restrictions for these items, yields satisfactory invariance test results. An empirical application concerning cross-cultural emotion data is used to demonstrate that this novel approach is useful and can co-exist with the traditional CFA approaches.

Generation of higher derivatives operators and electromagnetic wave propagation in a Lorentz-violation scenario

Energy Technology Data Exchange (ETDEWEB)

Borges, L.H.C., E-mail: luizhenriqueunifei@yahoo.com.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Dias, A.G., E-mail: alex.dias@ufabc.edu.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Ferrari, A.F., E-mail: alysson.ferrari@ufabc.edu.br [Universidade Federal do ABC, Centro de Ciências Naturais e Humanas, Av. dos Estados, 5001, Santo André, SP, 09210-580 (Brazil); Nascimento, J.R., E-mail: jroberto@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, Paraíba, 58051-970 (Brazil); Petrov, A.Yu., E-mail: petrov@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, João Pessoa, Paraíba, 58051-970 (Brazil)

2016-05-10

We study the perturbative generation of higher-derivative Lorentz violating operators as quantum corrections to the photon effective action, originated from a specific Lorentz violation background, which has already been studied in connection with the physics of light pseudoscalars. We calculate the complete one loop effective action of the photon field through the proper-time method, using the zeta function regularization. This result can be used as a starting point to study possible effects of the Lorentz violating background we are considering in photon physics. As an example, we focus on the lowest order corrections and investigate whether they could influence the propagation of electromagnetic waves through the vacuum. We show, however, that no effects of the kind of Lorentz violation we consider can be detected in such a context, so that other aspects of photon physics have to be studied.

Angular momentum conservation law in light-front quantum field theory

Energy Technology Data Exchange (ETDEWEB)

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.; /SLAC /Stanford U.

2017-03-01

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.

Variational Algorithms for Test Particle Trajectories

Science.gov (United States)

Ellison, C. Leland; Finn, John M.; Qin, Hong; Tang, William M.

2015-11-01

The theory of variational integration provides a novel framework for constructing conservative numerical methods for magnetized test particle dynamics. The retention of conservation laws in the numerical time advance captures the correct qualitative behavior of the long time dynamics. For modeling the Lorentz force system, new variational integrators have been developed that are both symplectic and electromagnetically gauge invariant. For guiding center test particle dynamics, discretization of the phase-space action principle yields multistep variational algorithms, in general. Obtaining the desired long-term numerical fidelity requires mitigation of the multistep method's parasitic modes or applying a discretization scheme that possesses a discrete degeneracy to yield a one-step method. Dissipative effects may be modeled using Lagrange-D'Alembert variational principles. Numerical results will be presented using a new numerical platform that interfaces with popular equilibrium codes and utilizes parallel hardware to achieve reduced times to solution. This work was supported by DOE Contract DE-AC02-09CH11466.

Measurement invariance versus selection invariance: Is fair selection possible?

NARCIS (Netherlands)

Borsboom, D.; Romeijn, J.W.; Wicherts, J.M.

2008-01-01

This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement

Measurement invariance versus selection invariance : Is fair selection possible?

NARCIS (Netherlands)

Borsboom, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.

This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement

Lorentz Spengler's descriptions of chitons (Mollusca: Polyplacophora)

NARCIS (Netherlands)

Kaas, P.; Knudsen, J.

1992-01-01

The present paper deals with an important Danish paper on the Polyplacophora, published in 1797 by Lorentz Spengler: Udförlig Beskrivelse over det mangeskallede Konkylie-Slaegt, af Linnaeus kaldet Chiton; med endeel nye Arter og Varieteter. -Skrivter af Naturhistorie-Selskabet, 4e Bind, Ie Hefte,

CPT-symmetry studies with antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Lehnert, Ralf, E-mail: ralehner@indiana.edu [Indiana University Center for Spacetime Symmetries (United States)

2012-05-15

Various approaches to physics beyond the Standard Model can lead to small violations of CPT invariance. Since CPT symmetry can be measured with ultra-high precision, CPT tests offer an interesting phenomenological avenue to search for underlying physics. We discuss this reasoning in more detail, comment on the connection between CPT and Lorentz invariance, and review how CPT breaking would affect the (anti)hydrogen spectrum.

Compare diagnostic tests using transformation-invariant smoothed ROC curves⋆

Science.gov (United States)

Tang, Liansheng; Du, Pang; Wu, Chengqing

2012-01-01

Receiver operating characteristic (ROC) curve, plotting true positive rates against false positive rates as threshold varies, is an important tool for evaluating biomarkers in diagnostic medicine studies. By definition, ROC curve is monotone increasing from 0 to 1 and is invariant to any monotone transformation of test results. And it is often a curve with certain level of smoothness when test results from the diseased and non-diseased subjects follow continuous distributions. Most existing ROC curve estimation methods do not guarantee all of these properties. One of the exceptions is Du and Tang (2009) which applies certain monotone spline regression procedure to empirical ROC estimates. However, their method does not consider the inherent correlations between empirical ROC estimates. This makes the derivation of the asymptotic properties very difficult. In this paper we propose a penalized weighted least square estimation method, which incorporates the covariance between empirical ROC estimates as a weight matrix. The resulting estimator satisfies all the aforementioned properties, and we show that it is also consistent. Then a resampling approach is used to extend our method for comparisons of two or more diagnostic tests. Our simulations show a significantly improved performance over the existing method, especially for steep ROC curves. We then apply the proposed method to a cancer diagnostic study that compares several newly developed diagnostic biomarkers to a traditional one. PMID:22639484

New effects in the interaction between electromagnetic sources mediated by nonminimal Lorentz violating interactions

Energy Technology Data Exchange (ETDEWEB)

Borges, L.H.C.; Ferrari, A.F. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [Universidade Federal de Itajuba, IFQ, Itajuba, MG (Brazil)

2016-11-15

This paper is dedicated to the study of interactions between external sources for the electromagnetic field in the presence of Lorentz symmetry breaking. We focus on a higher derivative, Lorentz violating interaction that arises from a specific model that was argued to lead to interesting effects in the low energy phenomenology of light pseudoscalars interacting with photons. The kind of higher derivative Lorentz violating interaction we discuss are called nonminimal. They are usually expected to be relevant only at very high energies, but we argue they might also induce relevant effects in low energy phenomena. Indeed, we show that the Lorentz violating background considered by us leads to several phenomena that have no counterpart in Maxwell theory, such as nontrivial torques on isolated electric dipoles, as well as nontrivial forces and torques between line currents and point like charges, as well as among Dirac strings and other electromagnetic sources. (orig.)

Testing measurement invariance of composites using partial least squares

NARCIS (Netherlands)

Henseler, Jörg; Ringle, Christian M.; Sarstedt, Marko

2016-01-01

Purpose Research on international marketing usually involves comparing different groups of respondents. When using structural equation modeling (SEM), group comparisons can be misleading unless researchers establish the invariance of their measures. While methods have been proposed to analyze

Fluctuation induced critical behavior at nonzero temperature and chemical potential

International Nuclear Information System (INIS)

Splittorff, K.; Lenaghan, J.T.; Wirstam, J.

2003-01-01

We discuss phase transitions in relativistic systems as a function of both the chemical potential and temperature. The presence of a chemical potential explicitly breaks Lorentz invariance and may additionally break other internal symmetries. This introduces new subtleties in the determination of the critical properties. We discuss separately three characteristic effects of a nonzero chemical potential. First, we consider only the explicit breaking of Lorentz invariance using a scalar field theory with a global U(1) symmetry. Second, we study the explicit breaking of an internal symmetry in addition to Lorentz invariance using two-color QCD at nonzero baryonic chemical potential. Finally, we consider the spontaneous breaking of a symmetry using three-color QCD at nonzero baryonic and isospin chemical potential. For each case, we derive the appropriate three-dimensional effective theory at criticality and study the effect of the chemical potential on the fixed point structure of the β functions. We find that the order of the phase transition is not affected by the explicit breaking of Lorentz invariance but is sensitive to the breaking of additional symmetries by the chemical potential

Space-like surfaces with free boundary in the Lorentz-Minkowski space

International Nuclear Information System (INIS)

López, R; Pyo, J

2012-01-01

We investigate a variational problem in the Lorentz-Minkowski space L 3 whose critical points are space-like surfaces with a constant mean curvature and making a constant contact angle with a given support surface along its common boundary. We show that if the support surface is a pseudosphere, then the surface is a planar disc or a hyperbolic cap. We also study the problem of space-like hypersurfaces with free boundary in the higher dimensional Lorentz-Minkowski space L n+1 . (paper)

Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation

OpenAIRE

Bertolami, O.; Rosa, J. G.

2004-01-01

We study the recently proposed Lorentz-violating dispersion relation for fermions and show that it leads to two distinct cubic operators in the momentum. We compute the leading order terms that modify the non-relativistic equations of motion and use experimental results for the hyperfine transition in the ground state of the ${}^9\\textrm Be^+$ ion to bound the values of the Lorentz-violating parameters $\\eta_1$ and $\\eta_2$ for neutrons. The resulting bounds depend on the value of the Lorenz-...

Transport coefficients in Lorentz plasmas with the power-law kappa-distribution

International Nuclear Information System (INIS)

Jiulin, Du

2013-01-01

Transport coefficients in Lorentz plasma with the power-law κ-distribution are studied by means of using the transport equation and macroscopic laws of Lorentz plasma without magnetic field. Expressions of electric conductivity, thermoelectric coefficient, and thermal conductivity for the power-law κ-distribution are accurately derived. It is shown that these transport coefficients are significantly modified by the κ-parameter, and in the limit of the parameter κ→∞ they are reduced to the standard forms for a Maxwellian distribution

Validity of the Internet Addiction Test for Adolescents and Older Children (IAT-A): Tests of Measurement Invariance and Latent Mean Differences

Science.gov (United States)

Teo, Timothy; Kam, Chester

2014-01-01

Following the call to ensure the validity of instruments used to assess users' level of Internet usage, this study examined the factor structure of the Internet Addiction Test-Adolescence version (IAT-A) when applied to a sample of young children in a multicultural society and assessed whether the items in the IAT-A were invariant by gender and,…

The flight of the bumblebee: solutions from a vector-induced spontaneous Lorentz symmetry breaking model

International Nuclear Information System (INIS)

Bertolami, Orfeu; Paramos, Jorge

2006-01-01

The vacuum solutions arising from a spontaneous breaking of Lorentz symmetry due to the acquisition of a vacuum expectation value by a vector field are derived. These include the purely radial Lorentz symmetry breaking (LSB), radial/temporal LSB and axial/temporal LSB scenarios. It is found that the purely radial LSB case gives rise to new black hole solutions. Whenever possible. Parametrized Post-Newtonian (PPN) parameters are computed and compared to observational bounds, in order to constrain the Lorentz symmetry breaking scale

Generalized Lorentz-Dirac Equation for a Strongly Coupled Gauge Theory

Science.gov (United States)

Chernicoff, Mariano; García, J. Antonio; Güijosa, Alberto

2009-06-01

We derive a semiclassical equation of motion for a “composite” quark in strongly coupled large-Nc N=4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

Generalized Lorentz-Dirac Equation for a Strongly Coupled Gauge Theory

International Nuclear Information System (INIS)

Chernicoff, Mariano; Garcia, J. Antonio; Gueijosa, Alberto

2009-01-01

We derive a semiclassical equation of motion for a 'composite' quark in strongly coupled large-N c N=4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

Trouble with the Lorentz law of force: incompatibility with special relativity and momentum conservation.

Science.gov (United States)

Mansuripur, Masud

2012-05-11

The Lorentz law of force is the fifth pillar of classical electrodynamics, the other four being Maxwell's macroscopic equations. The Lorentz law is the universal expression of the force exerted by electromagnetic fields on a volume containing a distribution of electrical charges and currents. If electric and magnetic dipoles also happen to be present in a material medium, they are traditionally treated by expressing the corresponding polarization and magnetization distributions in terms of bound-charge and bound-current densities, which are subsequently added to free-charge and free-current densities, respectively. In this way, Maxwell's macroscopic equations are reduced to his microscopic equations, and the Lorentz law is expected to provide a precise expression of the electromagnetic force density on material bodies at all points in space and time. This Letter presents incontrovertible theoretical evidence of the incompatibility of the Lorentz law with the fundamental tenets of special relativity. We argue that the Lorentz law must be abandoned in favor of a more general expression of the electromagnetic force density, such as the one discovered by Einstein and Laub in 1908. Not only is the Einstein-Laub formula consistent with special relativity, it also solves the long-standing problem of "hidden momentum" in classical electrodynamics.

Emergence of nonwhite noise in Langevin dynamics with magnetic Lorentz force

Science.gov (United States)

Chun, Hyun-Myung; Durang, Xavier; Noh, Jae Dong

2018-03-01

We investigate the low mass limit of Langevin dynamics for a charged Brownian particle driven by a magnetic Lorentz force. In the low mass limit, velocity variables relaxing quickly are coarse-grained out to yield effective dynamics for position variables. Without the Lorentz force, the low mass limit is equivalent to the high friction limit. Both cases share the same Langevin equation that is obtained by setting the mass to zero. The equivalence breaks down in the presence of the Lorentz force. The low mass limit cannot be achieved by setting the mass to zero. The limit is also distinct from the large friction limit. We derive the effective equations of motion in the low mass limit. The resulting stochastic differential equation involves a nonwhite noise whose correlation matrix has antisymmetric components. We demonstrate the importance of the nonwhite noise by investigating the heat dissipation by a driven Brownian particle, where the emergent nonwhite noise has a physically measurable effect.

A small mass tachyon theory

International Nuclear Information System (INIS)

Hohly, R.W.

1992-01-01

Tachyons of very small mass, m, have been assumed to satisfy a Proca-like equation, approximately but not exactly, so that the Lorentz gauge condition can be retained as in the photon case. THe tachyon fields therefore have four non-zero conjugate momenta, making invariance manifest. On introducing particle operators, two consistent, theories are found, a particle theory and a 'non-particle' theory, depending on which version of the Reinterpretation Principle one applies. The particle theory is relativistically invariant, gauge invariant, and also causal in the naive sense. While the vacuum is not invariant, using RIP, the fields and Fock space of physical tachyon states is invariant. The Lorentz gauge is satisfied by restricting states to those meeting a Gupta-Bleuler condition. Physical states can further be modified to travel symmetrically in time, and thus, will not violate causality. Under this restriction, a time symmetric tachyon sent backwards in time by Lorentz transformation becomes a tachyon going forward in time, but in the opposite direction

Physical properties of scalar and spinor field states with the Rindler-Milne (hyperbolic) symmetry

International Nuclear Information System (INIS)

Ritus, V.I.

2001-01-01

It is shown that right and left combinations of the positive- and negative-frequency hyperbolically symmetric solutions of the Klein-Fock-Gordon equation possess an everywhere timelike current density vector with a definite Lorentz-invariant sing of the charge density, and similar combinations of solutions to the Dirac equation possess the energy-momentum tensor with everywhere real eigenvalues and a definite Lorentz-invariant sing of the energy density. These right and left modes, just as their ±-frequency components, are eigenfunctions of the Lorentz generator [ru

Chronoprojective invariance of the five-dimensional Schroedinger formalism

International Nuclear Information System (INIS)

Perrin, M.; Burdet, G.; Duval, C.

1984-10-01

Invariance properties of the five-dimensional Schroedinger formalism describing a quantum test particle in the Newton-Cartan theory of gravitation are studied. The geometry which underlies these invariance properties is presented as a reduction of the 0(5,2) conformal geometry various applications are given

Testing the Structural Invariance of the Africultural Coping Systems Inventory Across Three Samples of African Descent Populations

Science.gov (United States)

Utsey, Shawn O.; Brown, Christa; Bolden, Mark A.

2004-01-01

Confirmatory factor analysis was used to test the factorial invariance of the Africultural Coping Systems Inventory's (ACSI) measurement model and underlying factor structure across three independent and ethnically distinct samples of African descent populations. Results indicated that factor pattern coefficients of the ACSI's underlying…

Meson-baryon scattering in manifestly Lorentz invariant chiral perturbation theory

International Nuclear Information System (INIS)

Mai, Maxim; Bruns, Peter C.; Kubis, Bastian; Meissner, Ulf-G.

2011-01-01

We analyze meson-baryon scattering lengths in the framework of covariant baryon chiral perturbation theory at leading one-loop order. We compute the complete set of matching relations between the dimension-two low-energy constants in the two- and three-flavor formulations of the theory. We derive new two-flavor low-energy theorems for pion-hyperon scattering that can be tested in lattice simulations.

QCD's Partner Needed for Mass Spectra and Parton Structure Functions

International Nuclear Information System (INIS)

Kim, Y.S.

2009-01-01

as in the case of the hydrogen atom, bound-state wave functions are needed to generate hadronic spectra. For this purpose, in 1971, Feynman and his students wrote down a Lorentz-invariant harmonic oscillator equation. This differential equation has one set of solutions satisfying the Lorentz-covariant boundary condition. This covariant set generates Lorentz-invariant mass spectra with their degeneracies. Furthermore, the Lorentz-covariant wave functions allow us to calculate the valence parton distribution by Lorentz-boosting the quark-model wave function from the hadronic rest frame. However, this boosted wave function does not give an accurate parton distribution. The wave function needs QCD corrections to make a contact with the real world. Likewise, QCD needs the wave function as a starting point for calculating the parton structure function. (author)

A Novel Approach for Automatic Control of Piezoelectric Elements Used for Lorentz Force Detuning Compensation

CERN Document Server

Przygoda, K; Napieralski, A; Grecki, M

2010-01-01

Abstract: Linear accelerators such as Free Electron Lasers (FELs) use superconducting (SC) resonant cavities to accelerate electron beam to high energies. TESLA type resonators are extremely sensitive to detuning induced by mechanical deformations – Lorentz force detuning (LFD), mainly due to the extremely high quality factor (Q) of the 1.3 GHz resonance mode, in the range of 1e6. The resulting modulation of a resonance frequency of the cavity makes power consumption and stability performances of the Low-Latency Radio Frequency (LLRF) control more critical. In order to minimize the RF control efforts and desired stabilities, the fast piezoelectric actuators with digital control systems are commonly used. The paper presents a novel approach for automatic control of piezoelectric actuators used for compensation of Lorentz force detuning, the practical application and carried out tests in accelerating module ACC6 in Free-Electron Laser in Hamburg (FLASH).

Adiabatic invariants of the extended KdV equation

Energy Technology Data Exchange (ETDEWEB)

Karczewska, Anna [Faculty of Mathematics, Computer Science and Econometrics, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Rozmej, Piotr, E-mail: p.rozmej@if.uz.zgora.pl [Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Infeld, Eryk [National Centre for Nuclear Research, Hoża 69, 00-681 Warszawa (Poland); Rowlands, George [Department of Physics, University of Warwick, Coventry, CV4 7A (United Kingdom)

2017-01-30

When the Euler equations for shallow water are taken to the next order, beyond KdV, momentum and energy are no longer exact invariants. (The only one is mass.) However, adiabatic invariants (AI) can be found. When the KdV expansion parameters are zero, exact invariants are recovered. Existence of adiabatic invariants results from general theory of near-identity transformations (NIT) which allow us to transform higher order nonintegrable equations to asymptotically equivalent (when small parameters tend to zero) integrable form. Here we present a direct method of calculations of adiabatic invariants. It does not need a transformation to a moving reference frame nor performing a near-identity transformation. Numerical tests show that deviations of AI from constant values are indeed small. - Highlights: • We suggest a new and simple method for calculating adiabatic invariants of second order wave equations. • It is easy to use and we hope that it will be useful if published. • Interesting numerics included.

Properties of TEM standing waves with E||B

Science.gov (United States)

Zaghloul, H.; Buckmaster, H. A.

This paper summarizes the known properties of E∥B TEM standing waves and shows that for such waves (i) E and B cannot be linearly polarized, (ii) E ≠ αB where α is a constant (iii) it is impossible to find a Lorentz frame where E>B, (iv) direction of the propagation vector cannot be inferred from the fields at one point of the space, (v) their behaviour under Lorentz, parity, time-reversal and gauge transformations is proper, (vi) both Lorentz invariants E2 - B2 and E·B are nonzero, (vii) the magnetic helicity may be nonzero, (viii) the magnetic field may be force-free, and (ix) kμFμv ≠ 0. It also shows how electromagnetic waves can be classified using Lorentz invariants. Cet article résume les qualités connues des ondes stationnaires E∥B TEM et montre que pour des ondes parallèles (i) E et B ne peuvent pas être polarisées linéairement, (ii) E ≠ αB où a est une constante, (iii) il est impossible de trouver une construction de Lorentz où E>B, (iv) la direction de propagation d'un vecteur ne peut pas être déduite des opérations à un point d'intervalle, (v) leur conduite sous Lorentz, parité, temps inverse et transformations de jauge est propre, (vi) les deux invariants de Lorentz E2 - B2 et E·B sont non nulles (vii) l'hélice magnétique peut être non nulle (viii) l'opération magnétique peut être de force libre et (ix) KμFμ v ≠ 0. Ceci montre aussi comment les ondes électromagnétiques peuvent être classifiées, en employant les invariants de Lorentz.

Einstein's theory recovered

International Nuclear Information System (INIS)

Sebestyen, A.

1980-11-01

It is shown that a consequent treatment of local Lorentz invariance and of the group of translations as a gauge symmetry group necessarily leads to theories in which torsion has no place. It is also shown that the requirement of symmetry under Lorentz gauge tranformations leads to the emergence of the conventional √-gR additive term, responsible for the effects of gravitation, in the Lagrangian. It is thus proved that Einstein's general relativity is a unique consequence of the requirements of invariance under translations and Lorentz transformations. (author)

Lorentz covariant theory of gravitation

International Nuclear Information System (INIS)

Fagundes, H.V.

1974-12-01

An alternative method for the calculation of second order effects, like the secular shift of Mercury's perihelium is developed. This method uses the basic ideas of thirring combined with the more mathematical approach of Feyman. In the case of a static source, the treatment used is greatly simplified. Besides, Einstein-Infeld-Hoffmann's Lagrangian for a system of two particles and spin-orbit and spin-spin interactions of two particles with classical spin, ie, internal angular momentum in Moller's sense, are obtained from the Lorentz covariant theory

Computational invariant theory

CERN Document Server

Derksen, Harm

2015-01-01

This book is about the computational aspects of invariant theory. Of central interest is the question how the invariant ring of a given group action can be calculated. Algorithms for this purpose form the main pillars around which the book is built. There are two introductory chapters, one on Gröbner basis methods and one on the basic concepts of invariant theory, which prepare the ground for the algorithms. Then algorithms for computing invariants of finite and reductive groups are discussed. Particular emphasis lies on interrelations between structural properties of invariant rings and computational methods. Finally, the book contains a chapter on applications of invariant theory, covering fields as disparate as graph theory, coding theory, dynamical systems, and computer vision. The book is intended for postgraduate students as well as researchers in geometry, computer algebra, and, of course, invariant theory. The text is enriched with numerous explicit examples which illustrate the theory and should be ...

Dynamics on Lorentz manifolds

CERN Document Server

Adams, Scot

2001-01-01

Within the general framework of the dynamics of "large" groups on geometric spaces, the focus is on the types of groups that can act in complicated ways on Lorentz manifolds, and on the structure of the resulting manifolds and actions. This particular area of dynamics is an active one, and not all the results are in their final form. However, at this point, a great deal can be said about the particular Lie groups that come up in this context. It is impressive that, even assuming very weak recurrence of the action, the list of possible groups is quite restricted. For the most complicated of the

Testing Quantum Gravity Induced Nonlocality via Optomechanical Quantum Oscillators.

Science.gov (United States)

Belenchia, Alessio; Benincasa, Dionigi M T; Liberati, Stefano; Marin, Francesco; Marino, Francesco; Ortolan, Antonello

2016-04-22

Several quantum gravity scenarios lead to physics below the Planck scale characterized by nonlocal, Lorentz invariant equations of motion. We show that such nonlocal effective field theories lead to a modified Schrödinger evolution in the nonrelativistic limit. In particular, the nonlocal evolution of optomechanical quantum oscillators is characterized by a spontaneous periodic squeezing that cannot be generated by environmental effects. We discuss constraints on the nonlocality obtained by past experiments, and show how future experiments (already under construction) will either see such effects or otherwise cast severe bounds on the nonlocality scale (well beyond the current limits set by the Large Hadron Collider). This paves the way for table top, high precision experiments on massive quantum objects as a promising new avenue for testing some quantum gravity phenomenology.

Quantum theory of string in the four-dimensional space-time

International Nuclear Information System (INIS)

Pron'ko, G.P.

1986-01-01

The Lorentz invariant quantum theory of string is constructed in four-dimensional space-time. Unlike the traditional approach whose result was breaking of Lorentz invariance, our method is based on the usage of other variables for description of string configurations. The method of an auxiliary spectral problem for periodic potentials is the main tool in construction of these new variables

Invariant submanifold flows

Energy Technology Data Exchange (ETDEWEB)

Olver, Peter J [School of Mathematics, University of Minnesota, Minneapolis, MN 55455 (United States)], E-mail: olver@math.umn.edu

2008-08-29

Given a Lie group acting on a manifold, our aim is to analyze the evolution of differential invariants under invariant submanifold flows. The constructions are based on the equivariant method of moving frames and the induced invariant variational bicomplex. Applications to integrable soliton dynamics, and to the evolution of differential invariant signatures, used in equivalence problems and object recognition and symmetry detection in images, are discussed.

Bumpy black holes from spontaneous Lorentz violation

International Nuclear Information System (INIS)

Dubovsky, Sergei; Tinyakov, Peter; Zaldarriaga, Matias

2007-01-01

We consider black holes in Lorentz violating theories of massive gravity. We argue that in these theories black hole solutions are no longer universal and exhibit a large number of hairs. If they exist, these hairs probe the singularity inside the black hole providing a window into quantum gravity. The existence of these hairs can be tested by future gravitational wave observatories. We generically expect that the effects we discuss will be larger for the more massive black holes. In the simplest models the strength of the hairs is controlled by the same parameter that sets the mass of the graviton (tensor modes). Then the upper limit on this mass coming from the inferred gravitational radiation emitted by binary pulsars implies that hairs are likely to be suppressed for almost the entire mass range of the super-massive black holes in the centers of galaxies

Absence of the Gribov ambiguity in a quadratic gauge

International Nuclear Information System (INIS)

Raval, Haresh

2016-01-01

The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S 3 , when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

Absence of the Gribov ambiguity in a quadratic gauge

Energy Technology Data Exchange (ETDEWEB)

Raval, Haresh [Indian Institute of Technology, Bombay, Department of Physics, Mumbai (India)

2016-05-15

The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S{sup 3}, when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

The four point correlations of all primary operators of the d=2 conformally invariant SU(2) sigma-model with Wess-Zumino term

International Nuclear Information System (INIS)

Christe, P.; Flume, R.

1986-05-01

We derive a contour integral representation for the four point correlations of all primary operators in the conformally invariant two-dimensional SU(2) sigma-model with Wess-Zumino term. The four point functions are identical in structure with those found in some special degenerate operator algebras with central Virasoro charge smaller than one. Using methods of Dotsenko and Fateev we evaluate for irrational values of the central SU(2) Kac-Moody charge the expansion coefficients of the algebra of Lorentz scalar operators. The conformal bootstrap provides in this case a unique determination. All SU(2) representations are non-trivially realised in the operator algebra. (orig.)

How (not) to teach Lorentz covariance of the Dirac equation

International Nuclear Information System (INIS)

Nikolić, Hrvoje

2014-01-01

In the textbook proofs of the Lorentz covariance of the Dirac equation, one treats the wave function as a spinor and gamma matrices as scalars, leading to a quite complicated formalism with several pedagogic drawbacks. As an alternative, I propose to teach the Dirac equation and its Lorentz covariance by using a much simpler, but physically equivalent formalism, in which these drawbacks do not appear. In this alternative formalism, the wave function transforms as a scalar and gamma matrices as components of a vector, such that the standard physically relevant bilinear combinations do not change their transformation properties. The alternative formalism allows also a natural construction of some additional non-standard bilinear combinations with well-defined transformation properties. (paper)

The original Ampere force and Biot-Savart and Lorentz forces

International Nuclear Information System (INIS)

Pappas, P.T.

1983-01-01

The purpose of this paper is to present the results of a very simple experiment, which favours the original Ampere force and unambiguously disproves the Biot-Savart force of relativity, or its approximation in a covariant relativistic form, namely the Lorentz force. This experiment with its extra degree of freedom has the advantage over the many other similar ones, including Ampere's original experiment, which have been performed in the past and recently by Graneau, of giving results which are both qualitative and quantitative, as well as unambiguous. Due to the strong association of the Biot-Savart and Lorentz force to relativistic theories, the experiment can be also considered as limiting the generality of these theories

Nonparaxial propagation of Lorentz-Gauss beams in uniaxial crystal orthogonal to the optical axis.

Science.gov (United States)

Wang, Xun; Liu, Zhirong; Zhao, Daomu

2014-04-01

Analytical expressions for the three components of nonparaxial propagation of a polarized Lorentz-Gauss beam in uniaxial crystal orthogonal to the optical axis are derived and used to investigate its propagation properties in uniaxial crystal. The influences of the initial beam parameters and the parameters of the uniaxial crystal on the evolution of the beam-intensity distribution in the uniaxial crystal are examined in detail. Results show that the statistical properties of a nonparaxial Lorentz-Gauss beam in a uniaxial crystal orthogonal to the optical axis are closely determined by the initial beam's parameters and the parameters of the crystal: the beam waist sizes-w(0), w(0x), and w(0y)-not only affect the size and shape of the beam profile in uniaxial crystal but also determine the nonparaxial effect of a Lorentz-Gauss beam; the beam profile of a Lorentz-Gauss beam in uniaxial crystal is elongated in the x or y direction, which is determined by the ratio of the extraordinary refractive index to the ordinary refractive index; with increasing deviation of the ratio from unity, the extension of the beam profile augments. The results indicate that uniaxial crystal provides an effective and convenient method for modulating the Lorentz-Gauss beams. Our results may be valuable in some fields, such as optical trapping and nonlinear optics, where a light beam with a special profile and polarization is required.

Electromagnetic reactions of few-body systems with the Lorentz integral transform method

International Nuclear Information System (INIS)

Leidemann, W.

2007-01-01

Various electromagnetic few-body break-up reactions into the many-body continuum are calculated microscopically with the Lorentz integral transform (LIT) method. For three- and four-body nuclei the nuclear Hamiltonian includes two- and three-nucleon forces, while semirealistic interactions are used in case of six- and seven-body systems. Comparisons with experimental data are discussed. In addition various interesting aspects of the 4 He photodisintegration are studied: investigation of a tetrahedrical symmetry of 4 He and a test of non-local nuclear force models via the induced two-body currents

Compatibility of the Ampere and Lorentz force laws with the virtual-work concept

International Nuclear Information System (INIS)

Graneau, P.

1983-01-01

Whenever the reaction forces between parts of an electric circuit have to be calculated, as in the design of railguns, a choice has to be made between three available formulae which have evolved during the past 160 years. The first was Ampere's force law for the mechanical interaction between two current elements. Neumann then derived the virtual-work formula from what may be called the Ampere-Neumann electrodynamics. The last to be introduced was the Lorentz force law. This paper investigates whether both the Amperian and the Lorentzian forces are compatible with the virtual-work concept. The conclusion is that only Ampere's formula agrees in all cases with the virtual-work idea, but in special circumstances the Lorentz law will give the same result. After demonstrating how Ampere's law can be derived from the virtual-work formula, it is shown that for two closed circuits the relativistic component of the Lorentz force vanishes under the double integral around the two circuits. The remaining nonvanishing term is also present in the Ampere electrodynamics. This is not the case when considering the reaction forces between two parts of an isolated circuit. The Lorentz force is then, in general, not compatible with the virtual-work concept unless the circuit possesses a high degree of symmetry

Application of the Lorentz-transform technique to meson photoproduction

International Nuclear Information System (INIS)

Reiss, C.; Leidemann, W.; Orlandini, G.; Tomusiak, E.L.

2003-01-01

We show that the Lorentz integral transform (LIT) technique which has been successfully applied to photoreactions in light nuclei can also be applied to photoreactions involving particle production. A simple model where results are easily calculable in the traditional fashion is used to test the technique. Specifically, we compute inclusive π + photoproduction from deuterium for photon energies less than 200 MeV using a Yamaguchi model for the NN interaction. It is demonstrated that, although the response functions for inclusive meson production do not have favourable asymptotic behavior, one can nonetheless extract them by inversion of the transform. The implication is that one can treat realistic problems of photo-meson production, including all final-state interactions, by means of the LIT technique. (orig.)

Computer calculation of Witten's 3-manifold invariant

International Nuclear Information System (INIS)

Freed, D.S.; Gompf, R.E.

1991-01-01

Witten's 2+1 dimensional Chern-Simons theory is exactly solvable. We compute the partition function, a topological invariant of 3-manifolds, on generalized Seifert spaces. Thus we test the path integral using the theory of 3-manifolds. In particular, we compare the exact solution with the asymptotic formula predicted by perturbation theory. We conclude that this path integral works as advertised and gives an effective topological invariant. (orig.)

Measurement invariance within and between individuals: a distinct problem in testing the equivalence of intra- and inter-individual model structures.

Science.gov (United States)

Adolf, Janne; Schuurman, Noémi K; Borkenau, Peter; Borsboom, Denny; Dolan, Conor V

2014-01-01

We address the question of equivalence between modeling results obtained on intra-individual and inter-individual levels of psychometric analysis. Our focus is on the concept of measurement invariance and the role it may play in this context. We discuss this in general against the background of the latent variable paradigm, complemented by an operational demonstration in terms of a linear state-space model, i.e., a time series model with latent variables. Implemented in a multiple-occasion and multiple-subject setting, the model simultaneously accounts for intra-individual and inter-individual differences. We consider the conditions-in terms of invariance constraints-under which modeling results are generalizable (a) over time within subjects, (b) over subjects within occasions, and (c) over time and subjects simultaneously thus implying an equivalence-relationship between both dimensions. Since we distinguish the measurement model from the structural model governing relations between the latent variables of interest, we decompose the invariance constraints into those that involve structural parameters and those that involve measurement parameters and relate to measurement invariance. Within the resulting taxonomy of models, we show that, under the condition of measurement invariance over time and subjects, there exists a form of structural equivalence between levels of analysis that is distinct from full structural equivalence, i.e., ergodicity. We demonstrate how measurement invariance between and within subjects can be tested in the context of high-frequency repeated measures in personality research. Finally, we relate problems of measurement variance to problems of non-ergodicity as currently discussed and approached in the literature.

Restricted gravity: Abelian projection of Einstein's theory

International Nuclear Information System (INIS)

Cho, Y.M.

2013-01-01

Treating Einstein's theory as a gauge theory of Lorentz group, we decompose the gravitational connection Γμ into the restricted connection made of the potential of the maximal Abelian subgroup H of Lorentz group G and the valence connection made of G/H part of the potential which transforms covariantly under Lorentz gauge transformation. With this we show that Einstein's theory can be decomposed into the restricted gravity made of the restricted connection which has the full Lorentz gauge invariance which has the valence connection as gravitational source. The decomposition shows the existence of a restricted theory of gravitation which has the full general invariance but is much simpler than Einstein's theory. Moreover, it tells that the restricted gravity can be written as an Abelian gauge theory,

Constraints on the bulk Lorentz factor of gamma-ray bursts with the detection rate by Fermi LAT

Science.gov (United States)

Chen, Ye; Liu, Ruo-Yu; Wang, Xiang-Yu

2018-05-01

The bulk Lorentz factor(Γ) of the outflow is an essential parameter to understanding the physics of gamma-ray burst (GRB). Informations about the Lorentz factors of some individual GRBs have been obtained from the spectral features of the high-energy gamma-ray emissions (>100 MeV), assuming that the spectral breaks or cutoffs are due to the pair-production attenuation (i.e., γγ → e+e-). In this paper, we attempt to interpret the dependence of the LAT detection rate of GRBs on the number of high-energy gamma-rays, taking into account the attenuation effect. We first simulate a long-GRB sample with Monte Carlo method using the luminosity function, rate distribution with redshift and properties of the GRB spectrum. To characterize the distribution of the Lorentz factors, we assume that the Lorentz factors follow the relation Γ =Γ _0E_iso,52k, where Eiso, 52 is the isotropic photon energy in unit of 1052erg. After taking into account the attenuation effect related with the above Lorentz factor distribution, we are able to reproduce the LAT-detected rate of GRBs as the function of the number of gamma-rays for suitable choice of the values of Γ0 and k. The result suggests that the distribution of the bulk Lorentz factor for the majority of GRBs is in the range of 50 - 250.

Constraint quantization of a worldline system invariant under reciprocal relativity: II

International Nuclear Information System (INIS)

Jarvis, P D; Morgan, S O

2008-01-01

We consider the worldline quantization of a system invariant under the symmetries of reciprocal relativity. Imposition of the first class constraint, the generator of local time reparametrizations, on physical states enforces identification of the worldline cosmological constant with a fixed value of the quadratic Casimir of the quaplectic symmetry group Q(3, 1) ≅ U(3, 1) x H(4), the semi-direct product of the pseudo-unitary group with the Weyl-Heisenberg group. In our previous paper, J. Phys. A: Math. Theor. 40 (2007) 12095, the 'spin' degrees of freedom were handled as covariant oscillators, leading to a unique choice of cosmological constant, required for projecting out negative-norm states from the physical gauge-invariant states. In the present paper, the spin degrees of freedom are treated as standard oscillators with positive norm states (wherein Lorentz boosts are not number-conserving in the auxiliary space; reciprocal transformations are of course not spin-conserving in general). As in the covariant approach, the spectrum of the square of the energy-momentum vector is continuous over the entire real line, and thus includes tachyonic (spacelike) and null branches. Adopting standard frames, the Wigner method on each branch is implemented, to decompose the auxiliary space into unitary irreducible representations of the respective little algebras and additional degeneracy algebras. The physical state space is vastly enriched as compared with the covariant approach, and contains towers of integer spin massive states, as well as unconventional massless representations of continuous spin type, with continuous Euclidean momentum and arbitrary integer helicity

Constraint quantization of a worldline system invariant under reciprocal relativity: II

Energy Technology Data Exchange (ETDEWEB)

Jarvis, P D; Morgan, S O [School of Mathematics and Physics, University of Tasmania, Private Bag 37 Hobart, Tasmania 7001 (Australia)], E-mail: Peter.Jarvis@utas.edu.au, E-mail: Stuart.Morgan@utas.edu.au

2008-11-21

We consider the worldline quantization of a system invariant under the symmetries of reciprocal relativity. Imposition of the first class constraint, the generator of local time reparametrizations, on physical states enforces identification of the worldline cosmological constant with a fixed value of the quadratic Casimir of the quaplectic symmetry group Q(3, 1) {approx_equal} U(3, 1) x H(4), the semi-direct product of the pseudo-unitary group with the Weyl-Heisenberg group. In our previous paper, J. Phys. A: Math. Theor. 40 (2007) 12095, the 'spin' degrees of freedom were handled as covariant oscillators, leading to a unique choice of cosmological constant, required for projecting out negative-norm states from the physical gauge-invariant states. In the present paper, the spin degrees of freedom are treated as standard oscillators with positive norm states (wherein Lorentz boosts are not number-conserving in the auxiliary space; reciprocal transformations are of course not spin-conserving in general). As in the covariant approach, the spectrum of the square of the energy-momentum vector is continuous over the entire real line, and thus includes tachyonic (spacelike) and null branches. Adopting standard frames, the Wigner method on each branch is implemented, to decompose the auxiliary space into unitary irreducible representations of the respective little algebras and additional degeneracy algebras. The physical state space is vastly enriched as compared with the covariant approach, and contains towers of integer spin massive states, as well as unconventional massless representations of continuous spin type, with continuous Euclidean momentum and arbitrary integer helicity.

Testing strong factorial invariance using three-level structural equation modeling

NARCIS (Netherlands)

Jak, Suzanne

Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias) across groups. Although this approach is

Constraints on torsion from the bosonic sector of Lorentz violation and magnetogenesis data

International Nuclear Information System (INIS)

Garcia de Andrade, L.C.

2011-01-01

A. Kostelecky et al. [Phys. Rev. Lett. 100 (2008) 111102], have shown that there is an exceptional sensitivity of spacetime torsion components by coupling it to fermions and constraining it to Lorentz violation. They obtain new constraints on torsion components down to the level of 10 -31 GeV. Yet more recently, L.C. Garcia de Andrade [Phys. Lett. B 468 (2011) 28] has shown that the photon sector of Lorentz violation (LV) Lagrangian leads to linear non-standard Maxwell equations where the magnetic field decays slower giving rise to a seed for galactic dynamos. In this paper bounds are placed on torsion based on the magnetogenesis or the origin of magnetic fields in the universe. On a coherence scale of 10 kpc, galactic magnetic fields of the order of some μG yield a torsion primordial field of the order of K 0 ∼10 -48 GeV. Just to give an idea of how tiny it is we mention that torsion limit in the Early universe yield K 0 ∼10 -31 GeV had been obtained by V. de Sabbata and C. Sivaram. Good limits were also obtained by B.R. Heckel et al. [Phys. Rev. D 78 (2008) 092006]. In our case the advantage from astro-particle physics point of view, is that a very small seed torsion field is enough to seed galactic dynamo. C. Sivaram limit is obtained from a massive photon electrodynamics [L.C. Garcia de Andrade, C. Sivaram, Ap. Space Sci. 209 (1993) 109] where a gauge invariant electrodynamics is used. Dynamo stars data are able to raise this value of torsion up to 10 -34 GeV at magnetar atmosphere. From these estimates one notices that they coincide with the ones obtained by A. Kostelecky et al., the difference being basically in the method. The ones here were obtained from magnetogenesis data while theirs were obtained from the Earth laboratory data from polarised electrons. Besides here one used the torsion derivatives while A. Kostelecky et al. uses the constant axial torsion tensor. Another fundamental distinction is that we use bosonic sector of the Lagrangian while

Dimensionality and measurement invariance in the Satisfaction with Life Scale in Norway.

Science.gov (United States)

Clench-Aas, Jocelyne; Nes, Ragnhild Bang; Dalgard, Odd Steffen; Aarø, Leif Edvard

2011-10-01

Results from previous studies examining the dimensionality and factorial invariance of the Satisfaction with Life Scale (SWLS) are inconsistent and often based on small samples. This study examines the factorial structure and factorial invariance of the SWLS in a Norwegian sample. Confirmatory factor analysis (AMOS) was conducted to explore dimensionality and test for measurement invariance in factor structure, factor loadings, intercepts, and residual variance across gender and four age groups in a large (N = 4,984), nationally representative sample of Norwegian men and women (15-79 years). The data supported a modified unidimensional structure. Factor loadings could be constrained to equality between the sexes, indicating metric invariance between genders. Further testing indicated invariance also at the strong and strict levels, thus allowing analyses involving group means. The SWLS was shown to be sensitive to age, however, at the strong and strict levels of invariance testing. In conclusion, the results in this Norwegian study seem to confirm that a unidimensional structure is acceptable, but that a modified single-factor model with correlations between error terms of items 4 and 5 is preferred. Additionally, comparisons may be made between the genders. Caution must be exerted when comparing age groups.

Test of special relativity theory by means of laser spectroscopy on relativistic {sup 7}Li{sup +} ions in the ESR; Test der Speziellen Relativitaetstheorie mittels Laserspektroskopie an relativistischen {sup 7}Li{sup +}-Ionen am ESR

Energy Technology Data Exchange (ETDEWEB)

Botermann, Benjamin

2012-10-31

The invariance under Lorentz transformation of the laws of physics is a fundamental postulate of modern physics and all theories of the fundamental interactions have been stated in a covariant form. Although the theory of Special Relativity (SR) has been tested and confirmed with high accuracy in a large number of experiments, improved tests are of fundamental interest due to the far-reaching relevance of this postulate. Additionally modern attempts of a unified description of the four fundamental interactions point to possible violations of Lorentz invariance. In this context experiments of the Ives-Stilwell type for a test of time dilation play an important role. High resolution laser spectroscopy is applied on relativistic particle beams to investigate the validity of the relativistic Doppler formula - and therefore of the time dilation factor γ. In the course of this thesis an Ives-Stilwell experiment was performed with {sup 7}Li{sup +} ions at a velocity of 34 % of the speed of light, which were stored at the experimental storage ring (ESR) of the GSI Helmholtzzentrum fuer Schwerionenforschung. The techniques of Λ- as well as saturation spectroscopy were employed on the 1s2s{sup 3}S{sub 1}→1s2p{sup 3}P{sub 2} transition. By a computer based analysis of the fluorescence detection system and utilization of appropriate edge filters the signal to noise ratio was decisively improved and the application of an additional pump laser allowed for the observation of a saturation signal for the first time. The frequency stability of both laser systems was specified by means of a frequency comb to obtain the highest possible accuracy. The data from the beam times were analyzed in the frameworks of the Robertson-Mansouri-Sexl test theory (RMS) and the Standard Model Extension (SME) and the corresponding upper limits of the relevant test parameters of the assigned theories were calculated. The upper limit of the parameter α was improved by a factor of 4 compared to

Translation, Adaptation and Invariance Testing of the Teaching Perspectives Inventory: Comparing Faculty of Malaysia and the United States

Science.gov (United States)

Misieng, Jecky

2013-01-01

As a result of growing attention in cross-cultural research, existing measurement instruments developed in one language are being translated and adapted for use in other languages and cultural contexts. Producing invariant measurement instruments that assess educational and psychological constructs provide a way of testing the cross-cultural…

Invariant and Absolute Invariant Means of Double Sequences

Directory of Open Access Journals (Sweden)

Abdullah Alotaibi

2012-01-01

Full Text Available We examine some properties of the invariant mean, define the concepts of strong σ-convergence and absolute σ-convergence for double sequences, and determine the associated sublinear functionals. We also define the absolute invariant mean through which the space of absolutely σ-convergent double sequences is characterized.

Jet invariant mass in quantum chromodynamics

International Nuclear Information System (INIS)

Clavelli, L.

1979-03-01

We give heuristic argument that a new class of observable related to the invariant mass of jets in e + e - annihilation is infrared finite to all orders of perturbation theory in Quantum Chromodynamics. We calculate the lowest order QCD predictions for the mass distribution as well as for the double differential cross section to produce back to back jets of invariant mass M 1 and M 2 . The resulting cross sections are quite different from that expected in simple hadronic fireball models and should provide experimentally accessible tests of QCD. (orig.) [de

Space-time spaceless-timeless interactions

International Nuclear Information System (INIS)

Corsiglia, L.

1975-01-01

An argument, based on Lorentz invariance for the number of discrete objects and Lorentz non-invariance for continuous physical quantities, is used to arrive at an uncertainty relation involving dipole moment and mass. Applied to a photon, a virtual dipole moment is defined and the photon itself is described as an electromagnetic wave. The small distance singularity in the Coulomb potential is removed by using a complex number for distance. (author)

Quantum mechanics versus relativity: an experimental test of the structure of spacetime

International Nuclear Information System (INIS)

Emelyanov, S A

2012-01-01

We have performed an experimental test under the conditions in which quantum mechanics predicts spatially discontinuous single-particle transport. The transport is beyond the relativistic paradigm of movement in Cartesian space and therefore may well be nonlocal. Our test has demonstrated that such transport does exist. This fact opens the door for a realistic interpretation of quantum mechanics in so far as the requirement of Lorentz invariance appears inapplicable to any version of quantum theory. Moreover, as quantum mechanics proposes a particle dynamics beyond relativity, it automatically requires an adequate ‘quantum’ concept of spacetime, for which the relativistic concept is only a limiting case. The quantum concept allows absolute simultaneity and hence revives the notion of absolute time. It also goes beyond the relativistic curvilinear Cartesian order of space to account for quantum phenomena such as discontinuity and nonlocality in the spirit of Bohm's concept of the implicate order.

Measurement Invariance: A Foundational Principle for Quantitative Theory Building

Science.gov (United States)

Nimon, Kim; Reio, Thomas G., Jr.

2011-01-01

This article describes why measurement invariance is a critical issue to quantitative theory building within the field of human resource development. Readers will learn what measurement invariance is and how to test for its presence using techniques that are accessible to applied researchers. Using data from a LibQUAL+[TM] study of user…

Magnetic monopoles, Galilean invariance, and Maxwell's equations

International Nuclear Information System (INIS)

Crawford, F.S.

1992-01-01

Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ''as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant---i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v much-lt c are considered.) This ends up with Maxwell's equations (Maxwell did not need special relativity, so why should we,) but facing Einstein's paradox, the solution of which is encapsulated in the Einstein velocity-addition formula

Lorentz laser-assisted stripping (Lolas) for H-/H0 injection into proton drivers

International Nuclear Information System (INIS)

Gastaldi, Ugo

2002-01-01

We discuss the main components of schemes for Lorentz laser-assisted stripping (abbreviated Lolas henceforth) proposed for injection into proton driver accumulators: H- → H0 + e- Lorentz stripping, H0→H0(n) laser excitation, H0(n)→p+ + e- Lorentz stripping. We mention results obtained in practice of H- beam transport and storage and of experiments addressing physics of the H- ion, of the H0 atom and of vacuum, which prove the feasibility of each Lolas component. For high enough injection energies, it is feasible to split without losses the H0 beam sent towards the accumulator into a fraction stripped to p+s and stored inside the accumulator and a complementary fraction of H0s delivered to high duty-cycle users. The fraction of stored beam can exceed 50% with one single Fabry-Perot cavity used to enhance the laser power density. Aspects of Lolas integration and optimization are pointed out

On the Lorentz degree of a product of polynomials

KAUST Repository

Ait-Haddou, Rachid

2015-01-01

In this note, we negatively answer two questions of T. Erdélyi (1991, 2010) on possible lower bounds on the Lorentz degree of product of two polynomials. We show that the correctness of one question for degree two polynomials is a direct consequence

The Groenewold-Moyal Plane and its Quantum Physics

International Nuclear Information System (INIS)

Balachandran, A. P.; Padmanabhan, Pramod

2009-01-01

Quantum theories constructed on the noncommutative spacetime called the Groenewold-Moyal(GM) plane exhibit many interesting properties such as causality violation, Lorentz and CPT non-invariance and twisted statistics. Such violations lead to many striking features that may be tested experimentally. Thus these theories predict Pauli-forbidden transitions due to twisted statistics, anisotropies and acausal effects in the cosmic microwave background radiation in correlations of observables and Lorentz and CPT violations in scattering amplitudes. Such features of quantum physics on the GM plane are surveyed in this review.

Mixed Lorentz boosted $Z^{0}'s$

CERN Document Server

Kjaer, N J

2001-01-01

A novel technique is proposed to study systematic errors on jet reconstruction in W physics measurements at LEP2 with high statistical precision. The method is based on the emulation of W pair events using Mixed Lorentz Boosted Z0 events. The scope and merits of the method and its statistical accuracy are discussed in the context of the DELPHI W mass measurement in the fully hadronic channel. The numbers presented are preliminary in the sense that they do not constitute the final DELPHI systematic errors.

Invariant and semi-invariant probabilistic normed spaces

Energy Technology Data Exchange (ETDEWEB)

Ghaemi, M.B. [School of Mathematics Iran, University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)], E-mail: mghaemi@iust.ac.ir; Lafuerza-Guillen, B. [Departamento de Estadistica y Matematica Aplicada, Universidad de Almeria, Almeria E-04120 (Spain)], E-mail: blafuerz@ual.es; Saiedinezhad, S. [School of Mathematics Iran, University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)], E-mail: ssaiedinezhad@yahoo.com

2009-10-15

Probabilistic metric spaces were introduced by Karl Menger. Alsina, Schweizer and Sklar gave a general definition of probabilistic normed space based on the definition of Menger . We introduce the concept of semi-invariance among the PN spaces. In this paper we will find a sufficient condition for some PN spaces to be semi-invariant. We will show that PN spaces are normal spaces. Urysohn's lemma, and Tietze extension theorem for them are proved.

Very special relativity.

Science.gov (United States)

Cohen, Andrew G; Glashow, Sheldon L

2006-07-14

By very special relativity (VSR) we mean descriptions of nature whose space-time symmetries are certain proper subgroups of the Poincaré group. These subgroups contain space-time translations together with at least a two-parameter subgroup of the Lorentz group isomorphic to that generated by K(x) + J(y) and K(y)- J(x). We find that VSR implies special relativity (SR) in the context of local quantum field theory or of conservation. Absent both of these added hypotheses, VSR provides a simulacrum of SR for which most of the consequences of Lorentz invariance remain wholly or essentially intact, and for which many sensitive searches for departures from Lorentz invariance must fail. Several feasible experiments are discussed for which Lorentz-violating effects in VSR may be detectable.

On the harmonic-type and linear-type confinement of a relativistic scalar particle yielded by Lorentz symmetry breaking effects

Energy Technology Data Exchange (ETDEWEB)

Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Belich, H., E-mail: belichjr@gmail.com [Departamento de Física e Química, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29060-900, Vitória, ES (Brazil)

2016-10-15

Based on the Standard Model Extension, we investigate relativistic quantum effects on a scalar particle in backgrounds of the Lorentz symmetry violation defined by a tensor field. We show that harmonic-type and linear-type confining potentials can stem from Lorentz symmetry breaking effects, and thus, relativistic bound state solutions can be achieved. We first analyse a possible scenario of the violation of the Lorentz symmetry that gives rise to a harmonic-type potential. In the following, we analyse another possible scenario of the breaking of the Lorentz symmetry that induces both harmonic-type and linear-type confining potentials. In this second case, we also show that not all values of the parameter associated with the intensity of the electric field are permitted in the search for polynomial solutions to the radial equation, where the possible values of this parameter are determined by the quantum numbers of the system and the parameters associated with the violation of the Lorentz symmetry.

Lorentz angle measurements in irradiated silicon detectors between 77 K and 300 K

International Nuclear Information System (INIS)

Bartsch, V.; Boer, W. de; Bol, J.

2001-01-01

Future experiments are using silicon detectors in a high radiation environment and in high magnetic fields. The radiation tolerance of silicon improves by cooling it to temperatures below 180 K. However, at low temperatures the mobility increases, which leads to larger deflections of the charge carriers by the Lorentz force. We present measurements of the Lorentz angle between 77 K and 300 K before and after irradiation with a primary beam of 21 MeV protons to a flux of 10 13 /cm 2 . (author)

Some impacts of Lorentz violation on cosmology

International Nuclear Information System (INIS)

Arianto; Zen, Freddy P.; Gunara, Bobby E.; Triyanta; Supardi

2007-01-01

The impact of Lorentz violation on the dynamics of a scalar field is investigated. In particular, we study the dynamics of a scalar field in the scalar-vector-tensor theory where the vector field is constrained to be unity and time like. By taking a generic form of the scalar field action, a generalized dynamical equation for the scalar-vector-tensor theory of gravity is obtained to describe the cosmological solutions. We present a class of exact solutions for an ordinary scalar field or phantom field corresponding to a power law coupling vector and the Hubble parameter. As the results, we find a constant equation of state in de Sitter space-time and power law expansion with the quadratic of coupling vector, while a dynamic equation of state is obtained for n > 2. Then, we consider the inflationary scenario based on the Lorentz violating scalar-vector-tensor theory of gravity with general power-law coupling vector and two typical potentials: inverse power-law and power-law potentials. In fact, both the coupling vector and the potential models affect the dynamics of the inflationary solutions. Finally, we use the dynamical system formalism to study the attractor behavior of a cosmological model containing a scalar field endowed with a quadratic coupling vector and a chaotic potential

Measurement Invariance of the "Servant Leadership Questionnaire" across K-12 Principal Gender

Science.gov (United States)

Xu, Lihua; Stewart, Trae; Haber-Curran, Paige

2015-01-01

Measurement invariance of the five-factor "Servant Leadership Questionnaire" between female and male K-12 principals was tested using multi-group confirmatory factor analysis. A sample of 956 principals (56.9% were females and 43.1% were males) was analysed in this study. The hierarchical multi-step measurement invariance test supported…

Rotationally invariant correlation filtering

International Nuclear Information System (INIS)

Schils, G.F.; Sweeney, D.W.

1985-01-01

A method is presented for analyzing and designing optical correlation filters that have tailored rotational invariance properties. The concept of a correlation of an image with a rotation of itself is introduced. A unified theory of rotation-invariant filtering is then formulated. The unified approach describes matched filters (with no rotation invariance) and circular-harmonic filters (with full rotation invariance) as special cases. The continuum of intermediate cases is described in terms of a cyclic convolution operation over angle. The angular filtering approach allows an exact choice for the continuous trade-off between loss of the correlation energy (or specificity regarding the image) and the amount of rotational invariance desired

Properties of invariant modelling and invariant glueing of vector fields

International Nuclear Information System (INIS)

Petukhov, V.R.

1987-01-01

Invariant modelling and invariant glueing of both continuous (rates and accelerations) and descrete vector fields, gradient and divergence cases are considered. The following appendices are discussed: vector fields in crystals, crystal disclinations, topological charges and their fields

Test of special relativity theory by means of laser spectroscopy on relativistic 7Li+ ions in the ESR

International Nuclear Information System (INIS)

Botermann, Benjamin

2012-01-01

The invariance under Lorentz transformation of the laws of physics is a fundamental postulate of modern physics and all theories of the fundamental interactions have been stated in a covariant form. Although the theory of Special Relativity (SR) has been tested and confirmed with high accuracy in a large number of experiments, improved tests are of fundamental interest due to the far-reaching relevance of this postulate. Additionally modern attempts of a unified description of the four fundamental interactions point to possible violations of Lorentz invariance. In this context experiments of the Ives-Stilwell type for a test of time dilation play an important role. High resolution laser spectroscopy is applied on relativistic particle beams to investigate the validity of the relativistic Doppler formula - and therefore of the time dilation factor γ. In the course of this thesis an Ives-Stilwell experiment was performed with 7 Li + ions at a velocity of 34 % of the speed of light, which were stored at the experimental storage ring (ESR) of the GSI Helmholtzzentrum fuer Schwerionenforschung. The techniques of Λ- as well as saturation spectroscopy were employed on the 1s2s 3 S 1 →1s2p 3 P 2 transition. By a computer based analysis of the fluorescence detection system and utilization of appropriate edge filters the signal to noise ratio was decisively improved and the application of an additional pump laser allowed for the observation of a saturation signal for the first time. The frequency stability of both laser systems was specified by means of a frequency comb to obtain the highest possible accuracy. The data from the beam times were analyzed in the frameworks of the Robertson-Mansouri-Sexl test theory (RMS) and the Standard Model Extension (SME) and the corresponding upper limits of the relevant test parameters of the assigned theories were calculated. The upper limit of the parameter α was improved by a factor of 4 compared to earlier measurements performed

The scientific correspondence of H. A. Lorentz: Volume I

NARCIS (Netherlands)

Kox, A.J.

2008-01-01

This book presents a selection of 434 carefully annotated letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death in February 1928. Most of these letters are of a scientific nature, with the

Invariance algorithms for processing NDE signals

Science.gov (United States)

Mandayam, Shreekanth; Udpa, Lalita; Udpa, Satish S.; Lord, William

1996-11-01

Signals that are obtained in a variety of nondestructive evaluation (NDE) processes capture information not only about the characteristics of the flaw, but also reflect variations in the specimen's material properties. Such signal changes may be viewed as anomalies that could obscure defect related information. An example of this situation occurs during in-line inspection of gas transmission pipelines. The magnetic flux leakage (MFL) method is used to conduct noninvasive measurements of the integrity of the pipe-wall. The MFL signals contain information both about the permeability of the pipe-wall and the dimensions of the flaw. Similar operational effects can be found in other NDE processes. This paper presents algorithms to render NDE signals invariant to selected test parameters, while retaining defect related information. Wavelet transform based neural network techniques are employed to develop the invariance algorithms. The invariance transformation is shown to be a necessary pre-processing step for subsequent defect characterization and visualization schemes. Results demonstrating the successful application of the method are presented.

Reply to 'Comment on 'Lorentz contraction and current-carrying wires''

International Nuclear Information System (INIS)

Van Kampen, Paul

2010-01-01

This reply answers the issues raised in the Comment on my paper (van Kampen 2008 Eur. J. Phys. 29 879-83). The error of applying a single Lorentz transformation to a wire segment is discussed in some detail. (letters and comments)

Reynolds averaged turbulence modelling using deep neural networks with embedded invariance

International Nuclear Information System (INIS)

Ling, Julia; Kurzawski, Andrew; Templeton, Jeremy

2016-01-01

There exists significant demand for improved Reynolds-averaged Navier–Stokes (RANS) turbulence models that are informed by and can represent a richer set of turbulence physics. This paper presents a method of using deep neural networks to learn a model for the Reynolds stress anisotropy tensor from high-fidelity simulation data. A novel neural network architecture is proposed which uses a multiplicative layer with an invariant tensor basis to embed Galilean invariance into the predicted anisotropy tensor. It is demonstrated that this neural network architecture provides improved prediction accuracy compared with a generic neural network architecture that does not embed this invariance property. Furthermore, the Reynolds stress anisotropy predictions of this invariant neural network are propagated through to the velocity field for two test cases. For both test cases, significant improvement versus baseline RANS linear eddy viscosity and nonlinear eddy viscosity models is demonstrated.

Remarks on the E-invariant and the Casson invariant

International Nuclear Information System (INIS)

Seade, J.

1991-08-01

In this work a framed manifold means a pair (M,F) consisting of a closed C ∞ , stably parallelizable manifold M, together with a trivialization F of its stable tangent bundle. The purpose of this work is to understand and determine in higher dimensions the invariant h(M,F) appearing in connection with the Adams e-invariants. 28 refs

What Governs Lorentz Factors of Jet Components in Blazars?

Indian Academy of Sciences (India)

We use a sample of radio-loud Active Galactic Nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present ...

Helicity and evanescent waves. [Energy transport velocity, helicity, Lorentz transformation

Energy Technology Data Exchange (ETDEWEB)

Agudin, J L; Platzeck, A M [La Plata Univ. Nacional (Argentina); Albano, J R [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina

1978-02-20

It is shown that the projection of the angular momentum of a circularly polarized electromagnetic evanescent wave along the mean velocity of energy transport (=helicity) can be reverted by a Lorentz transformation, in spite of the fact that this velocity is c.

Generation of geometrical phases and persistent spin currents in 1-dimensional rings by Lorentz-violating terms

Energy Technology Data Exchange (ETDEWEB)

Casana, R.; Ferreira, M.M., E-mail: manojr.ufma@gmail.com; Mouchrek-Santos, V.E.; Silva, Edilberto O.

2015-06-30

We have demonstrated that Lorentz-violating terms stemming from the fermion sector of the SME are able to generate geometrical phases on the wave function of electrons confined in 1-dimensional rings, as well as persistent spin currents, in the total absence of electromagnetic fields. We have explicitly evaluated the eigenenergies and eigenspinors of the electrons modified by the Lorentz-violating terms, using them to calculate the dynamic and the Aharonov–Anandan phases in the sequel. The total phase presents a pattern very similar to the Aharonov–Casher phase accumulated by electrons in rings under the action of the Rashba interaction. Finally, the persistent spin current were carried out and used to impose upper bounds on the Lorentz-violating parameters.

Invariants of generalized Lie algebras

International Nuclear Information System (INIS)

Agrawala, V.K.

1981-01-01

Invariants and invariant multilinear forms are defined for generalized Lie algebras with arbitrary grading and commutation factor. Explicit constructions of invariants and vector operators are given by contracting invariant forms with basic elements of the generalized Lie algebra. The use of the matrix of a linear map between graded vector spaces is emphasized. With the help of this matrix, the concept of graded trace of a linear operator is introduced, which is a rich source of multilinear forms of degree zero. To illustrate the use of invariants, a characteristic identity similar to that of Green is derived and a few Racah coefficients are evaluated in terms of invariants

Phenomenologically viable Lorentz-violating quantum gravity.

Science.gov (United States)

Sotiriou, Thomas P; Visser, Matt; Weinfurtner, Silke

2009-06-26

Horava's "Lifschitz point gravity" has many desirable features, but in its original incarnation one is forced to accept a nonzero cosmological constant of the wrong sign to be compatible with observation. We develop an extension of Horava's model that abandons "detailed balance" and regains parity invariance, and in 3+1 dimensions exhibit all five marginal (renormalizable) and four relevant (super-renormalizable) operators, as determined by power counting. We also consider the classical limit of this theory, evaluate the Hamiltonian and supermomentum constraints, and extract the classical equations of motion in a form similar to the Arnowitt-Deser-Misner formulation of general relativity. This puts the model in a framework amenable to developing detailed precision tests.

Non-abelian gauge invariant classical Lagrangian formalism for point electric and magnetic charge

International Nuclear Information System (INIS)

Brandt, R.A.; Neri, F.

1978-01-01

The classical electrodynamics of electrically charged point particles has been generalized to include non-Abelian gauge groups and to include magnetically charged point particles. In this paper these two distinct generalizations are unified into a non-Abelian gauge theory of electric and magnetic charge. Just as the electrically charged particles constitute the generalized source of the gauge fields, the magnetically charged particles constitute the generalized source of the dual fields. The resultant equations of motion are invariant to the original 'electric' non-Abelian gauge group, but, because of the absence of a corresponding 'magnetic' gauge group, there is no 'duality' symmetry between electric and magnetic quantities. However, for a class of solutions to these equations, which includes all known point electric and magnetic monopole constructions, there is shown to exist an equivalent description based on a magnetic, rather than electric, gauge group. The gauge potentials in general are singular on strings extending from the particle position to infinity, but it is shown that the observables are without string singularities, and that the theory is Lorentz invariant, provided a charge quantization condition is satisfied. This condition, deduced from a stability analysis, is necessary for the consistency of the classical non-Abelian theory, in contrast to the Abelian case, where such a condition is necessary only for the consistency of the quantum theory. It is also shown that in the classical theory the strings cannot be removed by gauge transformations, as they sometimes can be in the quantum theory. (Auth.)

On density of the Vassiliev invariants

DEFF Research Database (Denmark)

Røgen, Peter

1999-01-01

The main result is that the Vassiliev invariants are dense in the set of numeric knot invariants if and only if they separate knots.Keywords: Knots, Vassiliev invariants, separation, density, torus knots......The main result is that the Vassiliev invariants are dense in the set of numeric knot invariants if and only if they separate knots.Keywords: Knots, Vassiliev invariants, separation, density, torus knots...

Test of parity and time reversal invariance with low energy polarized neutrons

International Nuclear Information System (INIS)

Masaike, Akira

1996-01-01

Measurements of helicity asymmetries in slow neutron reactions on nuclei have been performed by transmission and capture γ-ray detection. Large enhancements of parity-violation effects have been observed on p-wave resonances of various medium and heavy nuclei. The weak matrix elements in hadron reactions have been deduced from these experimental results. Neutron spin precession near the p-wave resonance has been measured. In recent years violation of time reversal invariance is being searched for in the neutron reactions in which large enhancements of the parity violation effects have been observed. The measurement of the term σ n ·(k n x I) in a neutron reaction using polarized neutrons and a polarized target is an example of the test of T-violation. Polarizations of the neutron and lanthanum nucleus for these experiments are also presented. (author)

Lorentz-violating vortex solutions in the CPT-even electrodynamics of the Standard Model Extension

International Nuclear Information System (INIS)

Casana, Rodolfo; Ferreira Junior, Manoel M.; Hora, E. da

2011-01-01

Full text: In this work, we investigate the formation of static rotationally symmetric solutions on the (1+3) dimensional CPT-even and Lorentz-violating photonic sector of the Standard Model Extension (SME). The main goal of this work is to show the possibility of obtaining these solutions, even in the presence of Lorentz-breaking fields. A secondary goal is to examine the effects of these fields on topologically non-trivial configurations. In order to obtain these results, we focus on specific components of Lorentz-violating background, dealing with static Euler-Lagrange equations, from which we fix temporal gauge (absence of electric field) as a proper gauge choice. We assume the usual rotationally symmetric Ansatz, inserting it in the Euler-Lagrange equations previously obtained. This Ansatz describes the Higgs and gauge fields via profile functions g(r) and a(r), respectively. From this Ansatz, we construct suitable boundary conditions near the origin. Also, we write the energy density in terms of these two profile functions, obtaining from it asymptotic boundary conditions. This set of conditions is used to numerically solve the Euler-Lagrange equations (by means of the shooting method). Finally, we plot solutions for some physical quantities (Higgs field, magnetic field and energy density) for several values of the Lorentz-violating parameters. From these plots, we discuss the influence of these coefficients on the topologically non-trivial rotationally symmetric configurations, focusing on the profiles of both magnetic field and energy density. (author)

On the Lorentz degree of a product of polynomials

KAUST Repository

Ait-Haddou, Rachid

2015-01-01

In this note, we negatively answer two questions of T. Erdélyi (1991, 2010) on possible lower bounds on the Lorentz degree of product of two polynomials. We show that the correctness of one question for degree two polynomials is a direct consequence of a result of Barnard et al. (1991) on polynomials with nonnegative coefficients.

Embeddings of Lorentz-type spaces involving weighted integral means

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Křepela, M.; Pick, L.; Soudský, F.

2017-01-01

Roč. 273, č. 9 (2017), s. 2939-2980 ISSN 0022-1236 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : classical Lorentz spaces * embeddings * iterated operators Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.254, year: 2016 http://www.sciencedirect.com/science/article/pii/S0022123617302252

Relativistic Anandan quantum phase and the Aharonov–Casher effect under Lorentz symmetry breaking effects in the cosmic string spacetime

Energy Technology Data Exchange (ETDEWEB)

Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Furtado, C., E-mail: furtado@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Belich, H., E-mail: belichjr@gmail.com [Departamento de Física e Química, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29060-900, Vitória, ES (Brazil)

2016-09-15

From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the violation of the Lorentz symmetry and write an effective metric for the cosmic string spacetime. Then, we investigate the arising of an analogue of the Anandan quantum phase for a relativistic Dirac neutral particle with a permanent magnetic dipole moment in the cosmic string spacetime under Lorentz symmetry breaking effects. Besides, we analyse the influence of the effects of the Lorentz symmetry violation and the topology of the defect on the Aharonov–Casher geometric quantum phase in the nonrelativistic limit.

Cohomological invariants in Galois cohomology

CERN Document Server

Garibaldi, Skip; Serre, Jean Pierre

2003-01-01

This volume is concerned with algebraic invariants, such as the Stiefel-Whitney classes of quadratic forms (with values in Galois cohomology mod 2) and the trace form of �tale algebras (with values in the Witt ring). The invariants are analogues for Galois cohomology of the characteristic classes of topology. Historically, one of the first examples of cohomological invariants of the type considered here was the Hasse-Witt invariant of quadratic forms. The first part classifies such invariants in several cases. A principal tool is the notion of versal torsor, which is an analogue of the universal bundle in topology. The second part gives Rost's determination of the invariants of G-torsors with values in H^3(\\mathbb{Q}/\\mathbb{Z}(2)), when G is a semisimple, simply connected, linear group. This part gives detailed proofs of the existence and basic properties of the Rost invariant. This is the first time that most of this material appears in print.

Some Exact Solutions of Boundary Layer Flows along a Vertical Plate with Buoyancy Forces Combined with Lorentz Forces under Uniform Suction

Directory of Open Access Journals (Sweden)

Asterios Pantokratoras

2008-01-01

Full Text Available Exact analytical solutions of boundary layer flows along a vertical porous plate with uniform suction are derived and presented in this paper. The solutions concern the Blasius, Sakiadis, and Blasius-Sakiadis flows with buoyancy forces combined with either MHD Lorentz or EMHD Lorentz forces. In addition, some exact solutions are presented specifically for water in the temperature range of 0∘C≤≤8∘C, where water density is nearly parabolic. Except for their use as benchmarking means for testing the numerical solution of the Navier-Stokes equations, the presented exact solutions with EMHD forces have use in flow separation control in aeronautics and hydronautics, whereas the MHD results have applications in process metallurgy and fusion technology. These analytical solutions are valid for flows with strong suction.

Cosmological disformal invariance

Energy Technology Data Exchange (ETDEWEB)

Domènech, Guillem; Sasaki, Misao [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Naruko, Atsushi, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2015-10-01

The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whether it is true for disformal transformations is still an open question. In this paper, it is shown that a pure disformal transformation without any conformal factor is equivalent to rescaling the time coordinate. Since this rescaling applies equally to all the physical quantities, physics must be invariant under a disformal transformation, that is, neither causal structure, propagation speed nor any other property of the fields are affected by a disformal transformation itself. This fact is presented at the action level for gravitational and matter fields and it is illustrated with some examples of observable quantities. We also find the physical invariance for cosmological perturbations at linear and high orders in perturbation, extending previous studies. Finally, a comparison with Horndeski and beyond Horndeski theories under a disformal transformation is made.

Donaldson invariants in algebraic geometry

International Nuclear Information System (INIS)

Goettsche, L.

2000-01-01

In these lectures I want to give an introduction to the relation of Donaldson invariants with algebraic geometry: Donaldson invariants are differentiable invariants of smooth compact 4-manifolds X, defined via moduli spaces of anti-self-dual connections. If X is an algebraic surface, then these moduli spaces can for a suitable choice of the metric be identified with moduli spaces of stable vector bundles on X. This can be used to compute Donaldson invariants via methods of algebraic geometry and has led to a lot of activity on moduli spaces of vector bundles and coherent sheaves on algebraic surfaces. We will first recall the definition of the Donaldson invariants via gauge theory. Then we will show the relation between moduli spaces of anti-self-dual connections and moduli spaces of vector bundles on algebraic surfaces, and how this makes it possible to compute Donaldson invariants via algebraic geometry methods. Finally we concentrate on the case that the number b + of positive eigenvalues of the intersection form on the second homology of the 4-manifold is 1. In this case the Donaldson invariants depend on the metric (or in the algebraic geometric case on the polarization) via a system of walls and chambers. We will study the change of the invariants under wall-crossing, and use this in particular to compute the Donaldson invariants of rational algebraic surfaces. (author)

Moment invariants for particle beams

International Nuclear Information System (INIS)

Lysenko, W.P.; Overley, M.S.

1988-01-01

The rms emittance is a certain function of second moments in 2-D phase space. It is preserved for linear uncoupled (1-D) motion. In this paper, the authors present new functions of moments that are invariants for coupled motion. These invariants were computed symbolically using a computer algebra system. Possible applications for these invariants are discussed. Also, approximate moment invariants for nonlinear motion are presented

Equations of motion as constraints: superselection rules, Ward identities

Energy Technology Data Exchange (ETDEWEB)

Asorey, M. [Departamento de Física Teórica, Universidad de Zaragoza,C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain); Balachandran, A.P. [Physics Department, Syracuse University,Physics Building Syracuse, NY 13244 (United States); Institute of Mathematical Sciences, C.I.T Campus,Taramani Chennai 600113 (India); Lizzi, F. [Dipartimento di Fisica “E. Pancini” Università di Napoli Federico II,Via Cintia, 80126 Napoli (Italy); INFN - Sezione di Napoli,Via Cintia, 80126 Napoli (Italy); Departament de Estructura i Constituents de la Matèria, Institut de Ciéncies del Cosmos,Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Marmo, G. [Dipartimento di Fisica “E. Pancini” Università di Napoli Federico II,Via Cintia, 80126 Napoli (Italy); INFN - Sezione di Napoli,Via Cintia, 80126 Napoli (Italy)

2017-03-27

The meaning of local observables is poorly understood in gauge theories, not to speak of quantum gravity. As a step towards a better understanding we study asymptotic (infrared) transformations in local quantum physics. Our observables are smeared by test functions, at first vanishing at infinity. In this context we show that the equations of motion can be seen as constraints, which generate a group, the group of space and time dependent gauge transformations. This is one of the main points of the paper. Infrared nontrivial effects are captured allowing test functions which do not vanish at infinity. These extended operators generate a larger group. The quotient of the two groups generate superselection sectors, which differentiate different infrared sectors. The BMS group changes the superselection sector, a result long known for its Lorentz subgroup. It is hence spontaneously broken. Ward identities implied by the gauge invariance of the S-matrix generalize the standard results and lead to charge conservation and low energy theorems. Their validity does not require Lorentz invariance.

Direct observation of rectified motion of vortices by Lorentz microscopy

Indian Academy of Sciences (India)

We have investigated the vortex dynamics for the `ratchet' operation in a niobium superconductor via a direct imaging of Lorentz microscopy. We directly observe one-directional selective motion of field-gradient-driven vortices along fabricated channels. This results from the rectification of vortices in a spatially asymmetric ...

Evaluating the Bulk Lorentz Factors of Outflow Material: Lessons Learned from the Extremely Energetic Outburst GRB 160625B

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuan-Zhu; Wang, Hao; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming, E-mail: liangyf@pmo.ac.cn, E-mail: jin@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing, 210008 (China)

2017-02-10

GRB 160625B is an extremely bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high, up to ∼5.2 × 10{sup 52} erg or even ∼8 × 10{sup 52} erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission was characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts, as well as in GRB 090902B for the time-resolved thermal-radiation components, while the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compton scattering process. We then suggest that these spectral cutoffs are more likely related to the particle acceleration process and that one should be careful in estimating the Lorentz factors if the spectrum cuts at a rather low energy (e.g., ∼tens of MeV). The nature of the central engine has also been discussed, and a stellar-mass black hole is favored.

Measurement of job motivation in TEDS-M: testing for invariance across countries and cultures

Directory of Open Access Journals (Sweden)

Christin Laschke

2016-09-01

Full Text Available Abstract The paper presents the challenges of cross-country and cross-cultural research on the motivation to become a mathematics teacher based on data from the “Teacher Education and Development Study in Mathematics (TEDS-M”. Referring to studies from cross-cultural psychology, measurement invariance (MI of constructs representing different motivations to become a teacher was examined in confirmatory factor analysis (CFA across the countries that participated in TEDS-M. The data supported metric invariance which means that comparing relationships between motivation and other constructs across countries is permitted, with the exception of extrinsic motivation in Taiwan. Scalar invariance was not supported by the data across countries but across cultures: Scale means can be compared between Germany, Switzerland and (with regard to intrinsic motivation Norway and Poland as well as between Singapore and Taiwan (with regard to the intrinsic motivation and Malaysia, Philippines and Thailand (again regarding intrinsic motivation.

Stochastic charging of dust grains in planetary rings: Diffusion rates and their effects on Lorentz resonances

Science.gov (United States)

Schaffer, L.; Burns, J. A.

1995-01-01

Dust grains in planetary rings acquire stochastically fluctuating electric charges as they orbit through any corotating magnetospheric plasma. Here we investigate the nature of this stochastic charging and calculate its effect on the Lorentz resonance (LR). First we model grain charging as a Markov process, where the transition probabilities are identified as the ensemble-averaged charging fluxes due to plasma pickup and photoemission. We determine the distribution function P(t;N), giving the probability that a grain has N excess charges at time t. The autocorrelation function tau(sub q) for the strochastic charge process can be approximated by a Fokker-Planck treatment of the evolution equations for P(t; N). We calculate the mean square response to the stochastic fluctuations in the Lorentz force. We find that transport in phase space is very small compared to the resonant increase in amplitudes due to the mean charge, over the timescale that the oscillator is resonantly pumped up. Therefore the stochastic charge variations cannot break the resonant interaction; locally, the Lorentz resonance is a robust mechanism for the shaping of etheral dust ring systems. Slightly stronger bounds on plasma parameters are required when we consider the longer transit times between Lorentz resonances.

Modal Identification of a Time-Invariant 6-Storey Model Test RC-Frame from Free Decay Tests using Multi-Variate Models

DEFF Research Database (Denmark)

Skjærbæk, P. S.; Nielsen, Søren R. K.; Kirkegaard, Poul Henning

1997-01-01

in the comparison. The data investigated are sampled from a laboratory model of a plane 6-storey, 2-bay RC-frame. The laboratory model is excited at the top storey where two different types of excitation where considered. In the first case the structure was excited in the first mode and in the second case......The scope of the paper is to apply multi-variate time-domain models for identification of eginfrequencies and mode shapes of a time- invariant model test Reinforced Concrete (RC) frame from measured decays. The frequencies and mode shapes of interest are the two lowest ones since they are normally...

Modal Identification of a Time-Invariant 6-Storey Model Test RC-Frame from Free Decay Tests using Multi-Variate Models

DEFF Research Database (Denmark)

Skjærbæk, P. S.; Nielsen, Søren R. K.; Kirkegaard, Poul Henning

in the comparison. The data investigated are sampled from a laboratory model of a plane 6-storey, 2-bay RC-frame. The laboratory model is excited at the top storey where two different types of excitation where considered. In the first case the structure was excited in the first mode and in the second case......The scope of the paper is to apply multi-variate time-domain models for identification of eginfrequencies and mode shapes of a time- invariant model test Reinforced Concrete (RC) frame from measured decays. The frequencies and mode shapes of interest are the two lowest ones since they are normally...

Electrosensory Midbrain Neurons Display Feature Invariant Responses to Natural Communication Stimuli.

Directory of Open Access Journals (Sweden)

Tristan Aumentado-Armstrong

2015-10-01

Full Text Available Neurons that respond selectively but in an invariant manner to a given feature of natural stimuli have been observed across species and systems. Such responses emerge in higher brain areas, thereby suggesting that they occur by integrating afferent input. However, the mechanisms by which such integration occurs are poorly understood. Here we show that midbrain electrosensory neurons can respond selectively and in an invariant manner to heterogeneity in behaviorally relevant stimulus waveforms. Such invariant responses were not seen in hindbrain electrosensory neurons providing afferent input to these midbrain neurons, suggesting that response invariance results from nonlinear integration of such input. To test this hypothesis, we built a model based on the Hodgkin-Huxley formalism that received realistic afferent input. We found that multiple combinations of parameter values could give rise to invariant responses matching those seen experimentally. Our model thus shows that there are multiple solutions towards achieving invariant responses and reveals how subthreshold membrane conductances help promote robust and invariant firing in response to heterogeneous stimulus waveforms associated with behaviorally relevant stimuli. We discuss the implications of our findings for the electrosensory and other systems.

Electrosensory Midbrain Neurons Display Feature Invariant Responses to Natural Communication Stimuli.

Science.gov (United States)

Aumentado-Armstrong, Tristan; Metzen, Michael G; Sproule, Michael K J; Chacron, Maurice J

2015-10-01

Neurons that respond selectively but in an invariant manner to a given feature of natural stimuli have been observed across species and systems. Such responses emerge in higher brain areas, thereby suggesting that they occur by integrating afferent input. However, the mechanisms by which such integration occurs are poorly understood. Here we show that midbrain electrosensory neurons can respond selectively and in an invariant manner to heterogeneity in behaviorally relevant stimulus waveforms. Such invariant responses were not seen in hindbrain electrosensory neurons providing afferent input to these midbrain neurons, suggesting that response invariance results from nonlinear integration of such input. To test this hypothesis, we built a model based on the Hodgkin-Huxley formalism that received realistic afferent input. We found that multiple combinations of parameter values could give rise to invariant responses matching those seen experimentally. Our model thus shows that there are multiple solutions towards achieving invariant responses and reveals how subthreshold membrane conductances help promote robust and invariant firing in response to heterogeneous stimulus waveforms associated with behaviorally relevant stimuli. We discuss the implications of our findings for the electrosensory and other systems.

Absence of the Gribov ambiguity in a special algebraic gauge

Directory of Open Access Journals (Sweden)

Raval Haresh

2016-01-01

Full Text Available The Gribov ambiguity exists in various gauges except algebraic gauges. However in general, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We show that nontrivial copies can not occur in this gauge. We then provide an example of spherically symmetric gauge field configuration and prove that with a proper boundary condition on the configuration, this gauge removes the ambiguity on a compact manifold S3${{\\mathbb S}^3}$.

Recent results on CP and CPT tests at KLOE/KLOE-2

Energy Technology Data Exchange (ETDEWEB)

Di Domenico, A., E-mail: antonio.didomenico@roma1.infn.it [Department of Physics, Sapienza University of Rome, and INFN Sezione di Roma, Rome (Italy); Silarski, M., E-mail: Michal.Silarski@lnf.infn.it [Institute of Physics, Jagiellonian University, Cracow (Poland)

2012-12-15

Neutral kaon pairs produced in ϕ decays offer a unique possibility to perform fundamental tests of discrete symmetries. Among the most recent results obtained by the KLOE experiment at DAΦNE, the Frascati ϕ-factory, there is the new best limit on the branching ratio of the CP-violating decay K{sub S}→3π{sup 0}, BR<2.6×10{sup −8} at 90% C.L.. The search for possible violations of the CPT symmetry and Lorentz invariance in the context of the Standard-Model Extension (SME) is also described; the new analysis approach fully exploits quantum interferometry in ϕ→K{sub S}K{sub L}→π{sup +}π{sup −}, π{sup +}π{sup −} decays. Finally the status and perspectives of the new data taking campaign with the KLOE-2 experiment at the upgraded DAΦNE machine are briefly reviewed.

Relating measurement invariance, cross-level invariance, and multilevel reliability

OpenAIRE

Jak, S.; Jorgensen, T.D.

2017-01-01

Data often have a nested, multilevel structure, for example when data are collected from children in classrooms. This kind of data complicate the evaluation of reliability and measurement invariance, because several properties can be evaluated at both the individual level and the cluster level, as well as across levels. For example, cross-level invariance implies equal factor loadings across levels, which is needed to give latent variables at the two levels a similar interpretation. Reliabili...

Foliated vector fields, the Godbillon-Vey invariant and the invariant I(F)

International Nuclear Information System (INIS)

Banyaga, A.; Landa, Alain Musesa

2004-03-01

We prove that if the invariant I(F) constructed in 'An invariant of contact structures and transversally oriented foliations', Ann. Global Analysis and Geom. 14(1996) 427-441 (A. Banyaga), through the Lie algebra of infinitesimal automorphisms of transversally oriented foliations F is trivial, then the Godbillon-Vey invariant GV (F) of F is also trivial, but that the converse is not true. For codimension one foliations, the restrictions I τ , (F) of I(F) to the Lie subalgebra of vector fields tangent to the leaves is the Reeb class R(F) of F. We also prove that if there exists a foliated vector field which is everywhere transverse to a codimension one foliation, then the Reeb class R(F) is trivial, hence so is the GV(F) invariant. (author)

Ultra-large distance modification of gravity from Lorentz symmetry breaking at the Planck scale

International Nuclear Information System (INIS)

Gorbunov, Dmitry S.; Sibiryakov, Sergei M.

2005-01-01

We present an extension of the Randall-Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain ghosts or tachyons and does not exhibit the van Dam-Veltman-Zakharov discontinuity. The gravitational attraction between static point masses becomes gradually weaker with increasing of separation and gets replaced by repulsion (antigravity) at exponentially large distances

Ultra-large distance modification of gravity from Lorentz symmetry breaking at the Planck scale

Energy Technology Data Exchange (ETDEWEB)

Gorbunov, Dmitry S. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect, 7a, 117312 Moscow (Russian Federation); Sibiryakov, Sergei M. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect, 7a, 117312 Moscow (Russian Federation)

2005-09-15

We present an extension of the Randall-Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain ghosts or tachyons and does not exhibit the van Dam-Veltman-Zakharov discontinuity. The gravitational attraction between static point masses becomes gradually weaker with increasing of separation and gets replaced by repulsion (antigravity) at exponentially large distances.

Yang-Mills gauge invariance of a space of Bose and Fermi coordinates

International Nuclear Information System (INIS)

Friedman, M.H.; Srivastava, Y.

1977-01-01

A complete formalism is developed for imposing Yang-Mills gauge invariance induced by general coordinate transformations on superspace (i.e., a space containing both commuting and anticommuting coordinates). The appropriate group is the graded pseudo-Lie group of real, general linear transformations on superspace analogous to the role played by GL(4,R) in general relativity. The construction of derivatives which transform covariantly under this group forces the introduction of a connection. In the usual gauge theories the connection is just the vector potential, whereas here we expect it to be a function of all the dynamical fields. In this purely affine theory, field strengths and our proposed equations of motion for them result in a self-sourced theory involving only the connection. However, we find that there exist solutions which permit us to define a metric for which an inverse does not exist. These solutions are associated with a spontaneous symmetry breakdown of the vacuum which yields only the Lorentz metric and with no restriction on the internal-symmetry group. This spontaneous symmetry breaking introduces a parameter with the dimensions of (mass) 2

Gauge invariance rediscovered

International Nuclear Information System (INIS)

Moriyasu, K.

1978-01-01

A pedagogical approach to gauge invariance is presented which is based on the analogy between gauge transformations and relativity. By using the concept of an internal space, purely geometrical arguments are used to teach the physical ideas behind gauge invariance. Many of the results are applicable to general gauge theories

Assessing cross-cultural differences through use of multiple-group invariance analyses.

Science.gov (United States)

Stein, Judith A; Lee, Jerry W; Jones, Patricia S

2006-12-01

The use of structural equation modeling in cross-cultural personality research has become a popular method for testing measurement invariance. In this report, we present an example of testing measurement invariance using the Sense of Coherence Scale of Antonovsky (1993) in 3 ethnic groups: Chinese, Japanese, and Whites. In a series of increasingly restrictive constraints on the measurement models of the 3 groups, we demonstrate how to assess differences among the groups. We also provide an example of construct validation.

Differential invariants in nonclassical models of hydrodynamics

Science.gov (United States)

Bublik, Vasily V.

2017-10-01

In this paper, differential invariants are used to construct solutions for equations of the dynamics of a viscous heat-conducting gas and the dynamics of a viscous incompressible fluid modified by nanopowder inoculators. To describe the dynamics of a viscous heat-conducting gas, we use the complete system of Navier—Stokes equations with allowance for heat fluxes. Mathematical description of the dynamics of liquid metals under high-energy external influences (laser radiation or plasma flow) includes, in addition to the Navier—Stokes system of an incompressible viscous fluid, also heat fluxes and processes of nonequilibrium crystallization of a deformable fluid. Differentially invariant solutions are a generalization of partially invariant solutions, and their active study for various models of continuous medium mechanics is just beginning. Differentially invariant solutions can also be considered as solutions with differential constraints; therefore, when developing them, the approaches and methods developed by the science schools of academicians N. N. Yanenko and A. F. Sidorov will be actively used. In the construction of partially invariant and differentially invariant solutions, there are overdetermined systems of differential equations that require a compatibility analysis. The algorithms for reducing such systems to involution in a finite number of steps are described by Cartan, Finikov, Kuranishi, and other authors. However, the difficultly foreseeable volume of intermediate calculations complicates their practical application. Therefore, the methods of computer algebra are actively used here, which largely helps in solving this difficult problem. It is proposed to use the constructed exact solutions as tests for formulas, algorithms and their software implementations when developing and creating numerical methods and computational program complexes. This combination of effective numerical methods, capable of solving a wide class of problems, with

K-theory for discrete subgroups of the Lorentz groups

International Nuclear Information System (INIS)

Schwalbe, D.A.

1986-01-01

In the thesis, a conjecture on the structure of the topological K theory groups associated to an action of a discrete group on a manifold is verified in the special case when the group is a closed discrete subgroup of a Lorentz group. The K theory is the topological K theory of the reduced crossed product C algebra arising from the action of a countable discrete group acting by diffeomorphisms on a smooth, Hausdorf, and second and countable manifold. The proof uses the geometric K theory of Baum and Connes. In this situation, they have developed a geometrically realized K theory which they conjecture to be isomorphic to the analytic K theory. Work of Kasparov is used to show the geometric K groups and the analytic K groups are isomorphic for actions of the Lorentz groups on a manifold. Work of Marc Rieffel on Morita equivalence of C/sup */ algebras, shows the analytic K theory for a closed discrete subgroup of a Lie group acting on a manifold is isomorphic to the K theory of the Lie group itself, acting on an induced manifold

What Governs Lorentz Factors of Jet Components in Blazars? Xinwu ...

Indian Academy of Sciences (India)

Abstract. We use a sample of radio-loud Active Galactic Nuclei. (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is ...

Link invariants from finite Coxeter racks

OpenAIRE

Nelson, Sam; Wieghard, Ryan

2008-01-01

We study Coxeter racks over $\\mathbb{Z}_n$ and the knot and link invariants they define. We exploit the module structure of these racks to enhance the rack counting invariants and give examples showing that these enhanced invariants are stronger than the unenhanced rack counting invariants.

Singularities of lightcone pedals of spacelike curves in Lorentz-Minkowski 3-space

Directory of Open Access Journals (Sweden)

Chen Liang

2016-01-01

Full Text Available In this paper, geometric properties of spacelike curves on a timelike surface in Lorentz-Minkowski 3-space are investigated by applying the singularity theory of smooth functions from the contact viewpoint.

Testing measurement invariance of the schizotypal personality questionnaire-brief scores across Spanish and Swiss adolescents.

Directory of Open Access Journals (Sweden)

Javier Ortuño-Sierra

Full Text Available BACKGROUND: Schizotypy is a complex construct intimately related to psychosis. Empirical evidence indicates that participants with high scores on schizotypal self-report are at a heightened risk for the later development of psychotic disorders. Schizotypal experiences represent the behavioural expression of liability for psychotic disorders. Previous factorial studies have shown that schizotypy is a multidimensional construct similar to that found in patients with schizophrenia. Specifically, using the Schizotypal Personality Questionnaire-Brief (SPQ-B, the three-dimensional model has been widely replicated. However, there has been no in-depth investigation of whether the dimensional structure underlying the SPQ-B scores is invariant across countries. METHODS: The main goal of this study was to examine the measurement invariance of the SPQ-B scores across Spanish and Swiss adolescents. The final sample was made up of 261 Spanish participants (51.7% men; M = 16.04 years and 241 Swiss participants (52.3% men; M = 15.94 years. RESULTS: The results indicated that Raine et al.'s three-factor model presented adequate goodness-of-fit indices. Moreover, the results supported the measurement invariance (configural and partial strong invariance of the SPQ-B scores across the two samples. Spanish participants scored higher on Interpersonal dimension than Swiss when latent means were compared. DISCUSSION: The study of measurement equivalence across countries provides preliminary evidence for the Raine et al.'s three-factor model and of the cross-cultural validity of the SPQ-B scores in adolescent population. Future studies should continue to examine the measurement invariance of the schizotypy and psychosis-risk syndromes across cultures.

The principle of relativity and the special relativity triple

International Nuclear Information System (INIS)

Guo Hanying; Wu Hongtu; Zhou Bin

2009-01-01

Based on the principle of relativity and the postulate on universal invariant constants (c,l) as well as Einstein's isotropy conditions, three kinds of special relativity form a triple with a common Lorentz group as isotropy group under full Umov-Weyl-Fock-Lorentz transformations among inertial motions

Image mosaicking based on feature points using color-invariant values

Science.gov (United States)

Lee, Dong-Chang; Kwon, Oh-Seol; Ko, Kyung-Woo; Lee, Ho-Young; Ha, Yeong-Ho

2008-02-01

In the field of computer vision, image mosaicking is achieved using image features, such as textures, colors, and shapes between corresponding images, or local descriptors representing neighborhoods of feature points extracted from corresponding images. However, image mosaicking based on feature points has attracted more recent attention due to the simplicity of the geometric transformation, regardless of distortion and differences in intensity generated by camera motion in consecutive images. Yet, since most feature-point matching algorithms extract feature points using gray values, identifying corresponding points becomes difficult in the case of changing illumination and images with a similar intensity. Accordingly, to solve these problems, this paper proposes a method of image mosaicking based on feature points using color information of images. Essentially, the digital values acquired from a real digital color camera are converted to values of a virtual camera with distinct narrow bands. Values based on the surface reflectance and invariant to the chromaticity of various illuminations are then derived from the virtual camera values and defined as color-invariant values invariant to changing illuminations. The validity of these color-invariant values is verified in a test using a Macbeth Color-Checker under simulated illuminations. The test also compares the proposed method using the color-invariant values with the conventional SIFT algorithm. The accuracy of the matching between the feature points extracted using the proposed method is increased, while image mosaicking using color information is also achieved.

Importance of Lorentz structure in the parton model: Target mass corrections, transverse momentum dependence, positivity bounds

International Nuclear Information System (INIS)

D'Alesio, U.; Leader, E.; Murgia, F.

2010-01-01

We show that respecting the underlying Lorentz structure in the parton model has very strong consequences. Failure to insist on the correct Lorentz covariance is responsible for the existence of contradictory results in the literature for the polarized structure function g 2 (x), whereas with the correct imposition we are able to derive the Wandzura-Wilczek relation for g 2 (x) and the target-mass corrections for polarized deep inelastic scattering without recourse to the operator product expansion. We comment briefly on the problem of threshold behavior in the presence of target-mass corrections. Careful attention to the Lorentz structure has also profound implications for the structure of the transverse momentum dependent parton densities often used in parton model treatments of hadron production, allowing the k T dependence to be derived explicitly. It also leads to stronger positivity and Soffer-type bounds than usually utilized for the collinear densities.

Heat conduction in caricature models of the Lorentz gas

International Nuclear Information System (INIS)

Kramli, A.; Simanyi, N.; Szasz, D.

1987-01-01

Heat transport coefficients are calculated for various random walks with internal states (the Markov partition of the Sinai billiard connects these walks with the Lorentz gas among a periodic configuration of scatterers). Models with reflecting or absorbing barriers and also those without or with local thermal equilibrium are investigated. The method is unified and is based on the Keldysh expansion of the resolvent of a matrix polynomial

Rotation Invariance Neural Network

OpenAIRE

Li, Shiyuan

2017-01-01

Rotation invariance and translation invariance have great values in image recognition tasks. In this paper, we bring a new architecture in convolutional neural network (CNN) named cyclic convolutional layer to achieve rotation invariance in 2-D symbol recognition. We can also get the position and orientation of the 2-D symbol by the network to achieve detection purpose for multiple non-overlap target. Last but not least, this architecture can achieve one-shot learning in some cases using thos...

Chern–Simons theory in SIM(1) superspace

International Nuclear Information System (INIS)

Vohánka, Jiří; Faizal, Mir

2015-01-01

In this paper, we will analyze a three-dimensional supersymmetric Chern–Simons theory in SIM(1) superspace formalism. The breaking of the Lorentz symmetry down to the SIM(1) symmetry breaks half the supersymmetry of the Lorentz invariant theory. So, the supersymmetry of the Lorentz invariant Chern–Simons theory with N=1 supersymmetry will break down to N=1/2 supersymmetry, when the Lorentz symmetry is broken down to the SIM(1) symmetry. First, we will write the Chern–Simons action using SIM(1) projections of N=1 superfields. However, as the SIM(1) transformations of these projections are very complicated, we will define SIM(1) superfields which transform simply under SIM(1) transformations. We will then express the Chern–Simons action using these SIM(1) superfields. Furthermore, we will analyze the gauge symmetry of this Chern–Simons theory. This is the first time that a Chern–Simons theory with N=1/2 supersymmetry will be constructed on a manifold without a boundary

Modeling Item-Level and Step-Level Invariance Effects in Polytomous Items Using the Partial Credit Model

Science.gov (United States)

Gattamorta, Karina A.; Penfield, Randall D.; Myers, Nicholas D.

2012-01-01

Measurement invariance is a common consideration in the evaluation of the validity and fairness of test scores when the tested population contains distinct groups of examinees, such as examinees receiving different forms of a translated test. Measurement invariance in polytomous items has traditionally been evaluated at the item-level,…

Restoring locality with faster-than-light velocities

International Nuclear Information System (INIS)

Eberhard, P.H.

1993-01-01

The idea of ''locality'' is a deep rooted concept. It does not have to be abandoned even if ''loophole free'' EPR experiments are performed and confirm the predictions of quantum theory. To satisfy locality, one can imagine that influences at a distance are exerted via mechanisms involving an ether and effects propagating in that ether a velocity V > c. Such model of physical phenomena is not Lorentz invariant but, with V large enough, the model can be made to reproduce the results of all experiments where quantum mechanics and Lorentz invariance have been verified

Bohm's theory versus dynamical reduction

International Nuclear Information System (INIS)

Ghirardi, G.C.; Grassi, R.

1995-10-01

This essay begins with a comparison between Bohm's theory and the dynamical reduction program. While there are similarities (e.g., the preferred basis), there are also important differences (e.g., the type of nonlocality or of Lorentz invariance). In particular, it is made plausible that theories which exhibit parameter dependence effects cannot be ''genuinely Lorentz invariant''. For the two approaches under consideration, this analysis provides a comparison that can produce a richer understanding both of the pilot wave and of the dynamical reduction mechanism. (author). 33 refs, 1 fig

Bohm`s theory versus dynamical reduction

Energy Technology Data Exchange (ETDEWEB)

Ghirardi, G C [International Centre for Theoretical Physics, Trieste (Italy); Grassi, R [Udine Univ., Udine (Italy). Dept. of Civil Engineering

1995-10-01

This essay begins with a comparison between Bohm`s theory and the dynamical reduction program. While there are similarities (e.g., the preferred basis), there are also important differences (e.g., the type of nonlocality or of Lorentz invariance). In particular, it is made plausible that theories which exhibit parameter dependence effects cannot be ``genuinely Lorentz invariant``. For the two approaches under consideration, this analysis provides a comparison that can produce a richer understanding both of the pilot wave and of the dynamical reduction mechanism. (author). 33 refs, 1 fig.

The Dynamical Invariant of Open Quantum System

OpenAIRE

Wu, S. L.; Zhang, X. Y.; Yi, X. X.

2015-01-01

The dynamical invariant, whose expectation value is constant, is generalized to open quantum system. The evolution equation of dynamical invariant (the dynamical invariant condition) is presented for Markovian dynamics. Different with the dynamical invariant for the closed quantum system, the evolution of the dynamical invariant for the open quantum system is no longer unitary, and the eigenvalues of it are time-dependent. Since any hermitian operator fulfilling dynamical invariant condition ...

Local relativistic invariant flows for quantum fields

International Nuclear Information System (INIS)

Albeverio, S.; Hoeegh-Krahn, R.; Sirugue, M.

1983-01-01

For quantum fields with trigonometric interaction in arbitrary space dimension we construct a representation of the Lorentz group by automorphisms on a Banach space generated by the Weyl algebra. (orig.)

Modified Einstein and Finsler Like Theories on Tangent Lorentz Bundles

CERN Document Server

Stavrinos, Panayiotis; Vacaru, Sergiu I.

2014-01-01

We study modifications of general relativity, GR, with nonlinear dispersion relations which can be geometrized on tangent Lorentz bundles. Such modified gravity theories, MGTs, can be modeled by gravitational Lagrange density functionals $f(\\mathbf{R},\\mathbf{T},F)$ with generalized/ modified scalar curvature $\\mathbf{R}$, trace of matter field tensors $\\mathbf{T}$ and modified Finsler like generating function $F$. In particular, there are defined extensions of GR with extra dimensional "velocity/ momentum" coordinates. For four dimensional models, we prove that it is possible to decouple and integrate in very general forms the gravitational fields for $f(\\mathbf{R},\\mathbf{T},F)$--modified gravity using nonholonomic 2+2 splitting and nonholonomic Finsler like variables $F$. We study the modified motion and Newtonian limits of massive test particles on nonlinear geodesics approximated with effective extra forces orthogonal to the four-velocity. We compute the constraints on the magnitude of extra-acceleration...

Effects of lorentz force on flow fields of free burning arc and wall stabilized non-transferred arc

International Nuclear Information System (INIS)

Peng Yi; Huang Heji; Pan Wenxia

2013-01-01

The flow fields of two typical DC plasma arcs, namely the transferred free burning arc and the non-transferred arc were simulated by solving hydrodynamic equations and electromagnetic equations. The effects of the Lorentz force on the characteristics of the flow fields of these two typical DC plasma arcs were estimated. Results show that in the case of the free burning arc, the Lorentz force due to the current self-induced magnetic field has significant impact on the flow fields, as the self-induced magnetic compression is the main arc constraint mechanism. However, in the case of the non-transferred arc generated in a torch with long and narrow inter-electrode inserts and an abruptly expanded anode, the Lorentz force has limited impact on the flow fields of the plasma especially at the downstream of the inter-electrode inserts, compared with the strong wall constraints and relatively high aerodynamic force. This is because the ratio of the electromagnetic force to the aerodynamic force is only about 0.01 in this region. When the main consideration is outlet parameters of the wall stabilized non-transferred DC arc plasma generator, in order to improve the efficiency of the numerical simulation program, the Lorentz force could be neglected in the non-transferred arc in some cases. (authors)

Hidden scale invariance of metals

DEFF Research Database (Denmark)

Hummel, Felix; Kresse, Georg; Dyre, Jeppe C.

2015-01-01

Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations of the virial and the potential energy in the isochoric ensemble. This demonstrates a general “hidden” scale invariance...... of metals making the condensed part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Grüneisen parameter, are in good agreement with experimental values for the 16 elements where reliable data were...... available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant...

Special Relativity in Week One: 3) Introducing the Lorentz Contraction

Science.gov (United States)

Huggins, Elisha

2011-01-01

This is the third of four articles on teaching special relativity in the first week of an introductory physics course. With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie…

Reducing Lookups for Invariant Checking

DEFF Research Database (Denmark)

Thomsen, Jakob Grauenkjær; Clausen, Christian; Andersen, Kristoffer Just

2013-01-01

This paper helps reduce the cost of invariant checking in cases where access to data is expensive. Assume that a set of variables satisfy a given invariant and a request is received to update a subset of them. We reduce the set of variables to inspect, in order to verify that the invariant is still...

Application of the reduction of scale range in a Lorentz boosted frame to the numerical simulation of particle acceleration devices

International Nuclear Information System (INIS)

Vay, J.; Fawley, W.M.; Geddes, C.G.; Cormier-Michel, E.; Grote, D.P.

2009-01-01

It has been shown that the ratio of longest to shortest space and time scales of a system of two or more components crossing at relativistic velocities is not invariant under Lorentz transformation. This implies the existence of a frame of reference minimizing an aggregate measure of the ratio of space and time scales. It was demonstrated that this translated into a reduction by orders of magnitude in computer simulation run times, using methods based on first principles (e.g., Particle-In-Cell), for particle acceleration devices and for problems such as: free electron laser, laser-plasma accelerator, and particle beams interacting with electron clouds. Since then, speed-ups ranging from 75 to more than four orders of magnitude have been reported for the simulation of either scaled or reduced models of the above-cited problems. In it was shown that to achieve full benefits of the calculation in a boosted frame, some of the standard numerical techniques needed to be revised. The theory behind the speed-up of numerical simulation in a boosted frame, latest developments of numerical methods, and example applications with new opportunities that they offer are all presented

Algorithms in invariant theory

CERN Document Server

Sturmfels, Bernd

2008-01-01

J. Kung and G.-C. Rota, in their 1984 paper, write: "Like the Arabian phoenix rising out of its ashes, the theory of invariants, pronounced dead at the turn of the century, is once again at the forefront of mathematics". The book of Sturmfels is both an easy-to-read textbook for invariant theory and a challenging research monograph that introduces a new approach to the algorithmic side of invariant theory. The Groebner bases method is the main tool by which the central problems in invariant theory become amenable to algorithmic solutions. Students will find the book an easy introduction to this "classical and new" area of mathematics. Researchers in mathematics, symbolic computation, and computer science will get access to a wealth of research ideas, hints for applications, outlines and details of algorithms, worked out examples, and research problems.

The Loneliness Questionnaire: Establishing Measurement Invariance Across Ethnic Groups.

Science.gov (United States)

Ritchwood, Tiarney D; Ebesutani, Chad K; Chin, Eu Gene; Young, John

2017-09-01

A state of loneliness describes an individual's perception of having dissatisfying social connections to others. Though it is notable across the life span, it may have particularly deleterious effects in childhood and adolescence, leading to increased risk of emotional impairment. The current study evaluates a widely used test of loneliness, the Loneliness Questionnaire, for measurement invariance across ethnic groups in a large, representative sample of youth in the 2nd to 12th grades ( N = 12,344; 41% African American) in Mississippi. Analyses were conducted using multigroup confirmatory factor analysis following a published, sequential method to examine invariance in form, factor loadings, and item intercepts. Overall, our results indicated that the instrument was invariant across ethnicities, suggesting that youth with equivalent manifest scores can be discerned as having comparable levels of latent loneliness. The loneliness scores also corresponded significantly with depression and anxiety scores for most subsamples, with one exception. These findings are discussed in the context of previous results comparing levels of loneliness across ethnicities. Additionally, the broader context of the need to expand invariance studies in instrumentation work is highlighted.

Chiral Thirring–Wess model with Faddeevian regularization

International Nuclear Information System (INIS)

Rahaman, Anisur

2015-01-01

Replacing vector type of interaction of the Thirring–Wess model by the chiral type a new model is presented which is termed here as chiral Thirring–Wess model. Ambiguity parameters of regularization are so chosen that the model falls into the Faddeevian class. The resulting Faddeevian class of model in general does not possess Lorentz invariance. However we can exploit the arbitrariness admissible in the ambiguity parameters to relate the quantum mechanically generated ambiguity parameters with the classical parameter involved in the masslike term of the gauge field which helps to maintain physical Lorentz invariance instead of the absence of manifestly Lorentz covariance of the model. The phase space structure and the theoretical spectrum of this class of model have been determined through Dirac’s method of quantization of constraint system

Symanzik–Becchi–Rouet–Stora lessons on renormalizable models with broken symmetry: The case of Lorentz violation

Energy Technology Data Exchange (ETDEWEB)

Del Cima, Oswaldo M.; Franco, Daniel H.T.; Piguet, Olivier, E-mail: opiguet@pq.cnpq.br

2016-11-15

In this paper, we revisit the issue intensively studied in recent years on the generation of terms by radiative corrections in models with broken Lorentz symmetry. The algebraic perturbative method of handling the problem of renormalization of the theories with Lorentz symmetry breaking, is used. We hope to make clear the Symanzik's aphorism: “Whether you like it or not, you have to include in the lagrangian all counter terms consistent with locality and power-counting, unless otherwise constrained by Ward identities.”{sup 1}.

Testing measurement invariance in the International Social Survey Program Health 2011 – the mental well-being scale

NARCIS (Netherlands)

van Deurzen, I.A.; Roosma, F.

2014-01-01

Purpose In the present contribution we address the measurement invariance of a new mental well-being scale of three items that was applied in the International Social Survey Program (ISSP) Health 2011 module. Our aim is to establish if and for how many countries (partial) scalar invariance is

Non-dissipative electromagnetic media with two Lorentz null cones

International Nuclear Information System (INIS)

Dahl, Matias F.

2013-01-01

We study Maxwell’s equations on a 4-manifold where the electromagnetic medium is modeled by an antisymmetric (2/2 )-tensor with 21 real coefficients. In this setting the Fresnel surface is a fourth-order polynomial surface that describes the dynamical response of the medium in the geometric optics limit. For example, in an isotropic medium the Fresnel surface is a Lorentz null cone. The contribution of this paper is the pointwise description of all electromagnetic medium tensors κ with real coefficients that satisfy the following three conditions: (i)medium κ is invertible, (ii)medium κ is skewon-free, or non-dissipative, (iii)the Fresnel surface of κ is the union of two distinct Lorentz null cones. We show that there are only three classes of media with these properties and give explicit expressions in local coordinates for each class. - Highlights: ► We find two new electromagnetic media classes for which the Fresnel surface decomposes into two light cones. ► In a suitable setting we classify all electromagnetic media where this is the case. ► We find an electromagnetic medium tensor with three different signal speeds in one direction. ► The work is related to [5], which classifies all media with one light cone (in a suitable setting).

Cartan invariants and event horizon detection

Science.gov (United States)

Brooks, D.; Chavy-Waddy, P. C.; Coley, A. A.; Forget, A.; Gregoris, D.; MacCallum, M. A. H.; McNutt, D. D.

2018-04-01

We show that it is possible to locate the event horizon of a black hole (in arbitrary dimensions) by the zeros of certain Cartan invariants. This approach accounts for the recent results on the detection of stationary horizons using scalar polynomial curvature invariants, and improves upon them since the proposed method is computationally less expensive. As an application, we produce Cartan invariants that locate the event horizons for various exact four-dimensional and five-dimensional stationary, asymptotically flat (or (anti) de Sitter), black hole solutions and compare the Cartan invariants with the corresponding scalar curvature invariants that detect the event horizon.

Teen Dating Violence, Sexual Harassment, and Bullying Among Middle School Youth: Examining Measurement Invariance by Gender.

Science.gov (United States)

Cutbush, Stacey; Williams, Jason

2016-12-01

This study investigated measurement invariance by gender among commonly used teen dating violence (TDV), sexual harassment, and bullying measures. Data were collected from one cohort of seventh-grade middle school students (N = 754) from four schools. Using structural equation modeling, exploratory and confirmatory factor analyses assessed measurement models and tested measurement invariance by gender for aggression measures. Analyses invoked baseline data only. Physical and psychological TDV perpetration measures achieved strict measurement invariance, while bullying perpetration demonstrated partial strict invariance. Electronic TDV and sexual harassment perpetration achieved metric/scalar invariance. Study findings lend validation to prior and future studies using these measures with similar populations. Future research should increase attention to measurement development, refinement, and testing among study measures. © 2016 The Authors. Journal of Research on Adolescence © 2016 Society for Research on Adolescence.

A cross-national analysis of measurement invariance of the Satisfaction With Life Scale.

Science.gov (United States)

Whisman, Mark A; Judd, Charles M

2016-02-01

Measurement invariance of the Satisfaction With Life Scale (SWLS) was examined in probability samples of adults 50-79 years of age living in the United States, England, and Japan. Confirmatory factor analysis modeling was used to test for multigroup measurement invariance of a single-factor structure of the SWLS. Results support a single-factor structure of the SWLS across the 3 countries, with tests of measurement invariance of the SWLS supporting its configural invariance and metric invariance. These results suggest that the SWLS may be used as a single-factor measure of life satisfaction in the United States, England, and Japan, and that it is appropriate to compare correlates of the SWLS in middle-aged and older adults across these 3 countries. However, results provided evidence for only partial scalar invariance, with the intercept for SWLS Item 4 varying across countries. Cross-national comparisons of means revealed a lower mean at the latent variable level for the Japanese sample than for the other 2 samples. In addition, over and above the latent mean difference, the Japanese sample also manifested a significantly lower intercept on Item 4. Implications of the findings for research on cross-national comparisons of life satisfaction in European American and East Asian countries are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Mass generation within conformal invariant theories

International Nuclear Information System (INIS)

Flato, M.; Guenin, M.

1981-01-01

The massless Yang-Mills theory is strongly conformally invariant and renormalizable; however, when masses are introduced the theory becomes nonrenormalizable and weakly conformally invariant. Conditions which recover strong conformal invariance are discussed in the letter. (author)

On Einstein's kinematics and his derivation of Lorentz transformation equations

International Nuclear Information System (INIS)

Gulati, Shobha; Gulati, S.P.

1981-01-01

Recently the present authors have claimed that Einstein's historic derivation of 1905 of Lorentz transformation equations is a 'howler' - a correct result achieved through some incorrect steps. In the present contribution, this howler is fully resolved. Incidently, Einstein's kinematical considerations are found to be void of any new definitional elements or conventionality as unjustifiably claimed by Einstein and some other scientists. (author)

Characterization of associate spaces of weighted Lorentz spaces with applications

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Pick, L.; Soudský, F.

2014-01-01

Roč. 224, č. 1 (2014), s. 1-23 ISSN 0039-3223 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : weighted Lorentz spaces * weighted inequalities * non-increasing rearragement * Banach function space Subject RIV: BA - General Mathematics Impact factor: 0.610, year: 2014 http://journals.impan.gov.pl/sm/Inf/224-1-1.html

Conformal invariance an introduction to loops, interfaces and stochastic Loewner evolution

CERN Document Server

Karevski, Dragi

2012-01-01

Conformal invariance has been a spectacularly successful tool in advancing our understanding of the two-dimensional phase transitions found in classical systems at equilibrium. This volume sharpens our picture of the applications of conformal invariance, introducing non-local observables such as loops and interfaces before explaining how they arise in specific physical contexts. It then shows how to use conformal invariance to determine their properties. Moving on to cover key conceptual developments in conformal invariance, the book devotes much of its space to stochastic Loewner evolution (SLE), detailing SLE’s conceptual foundations as well as extensive numerical tests. The chapters then elucidate SLE’s use in geometric phase transitions such as percolation or polymer systems, paying particular attention to surface effects. As clear and accessible as it is authoritative, this publication is as suitable for non-specialist readers and graduate students alike.

Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

Energy Technology Data Exchange (ETDEWEB)

Raabe, Christian

2008-07-08

In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

Macroscopic QED in linearly responding media and a Lorentz-Force approach to dispersion forces

International Nuclear Information System (INIS)

Raabe, Christian

2008-01-01

In this thesis, a very general quantization scheme for the macroscopic electromagnetic field in arbitrary linearly responding media is presented. It offers a unified approach to QED in such media. Applying the quantization scheme, a theory of the dispersion forces on the basis of the Lorentz force is developed. By regarding the dispersion force as the (ground-state or thermal-state) expectation value of the Lorentz force that acts on appropriately defined charge and current densities, Casimir, Casimir-Polder, and van der Waals forces are united in a very natural way that makes transparent their common physical basis. Application of the theory to planar structures yields generalizations of well-known Lifschitz and Casimir-type formulas. (orig.)

On the classical Maxwell-Lorentz electrodynamics, the electron inertia problem, and the Feynman proper time paradigm

International Nuclear Information System (INIS)

Prykarpatsky, A.K.; Bogolubov, J.R.

2016-01-01

The classical Maxwell electromagnetic field and the Lorentz-type force equations are rederived in the framework of the Feynman proper time paradigm and the related vacuum field theory approach. The classical Ampere law origin is rederived, and its relationship with the Feynman proper time paradigm is discussed. The electron inertia problem is analyzed in detail within the Lagrangian and Hamiltonian formalisms and the related pressure-energy compensation principle of stochastic electrodynamics. The modified Abraham-Lorentz damping radiation force is derived and the electromagnetic electron mass origin is argued

Coordinate-invariant regularization

International Nuclear Information System (INIS)

Halpern, M.B.

1987-01-01

A general phase-space framework for coordinate-invariant regularization is given. The development is geometric, with all regularization contained in regularized DeWitt Superstructures on field deformations. Parallel development of invariant coordinate-space regularization is obtained by regularized functional integration of the momenta. As representative examples of the general formulation, the regularized general non-linear sigma model and regularized quantum gravity are discussed. copyright 1987 Academic Press, Inc

Invariant sets for Windows

CERN Document Server

Morozov, Albert D; Dragunov, Timothy N; Malysheva, Olga V

1999-01-01

This book deals with the visualization and exploration of invariant sets (fractals, strange attractors, resonance structures, patterns etc.) for various kinds of nonlinear dynamical systems. The authors have created a special Windows 95 application called WInSet, which allows one to visualize the invariant sets. A WInSet installation disk is enclosed with the book.The book consists of two parts. Part I contains a description of WInSet and a list of the built-in invariant sets which can be plotted using the program. This part is intended for a wide audience with interests ranging from dynamical

Development of novel tasks for studying view-invariant object recognition in rodents: Sensitivity to scopolamine.

Science.gov (United States)

Mitchnick, Krista A; Wideman, Cassidy E; Huff, Andrew E; Palmer, Daniel; McNaughton, Bruce L; Winters, Boyer D

2018-05-15

The capacity to recognize objects from different view-points or angles, referred to as view-invariance, is an essential process that humans engage in daily. Currently, the ability to investigate the neurobiological underpinnings of this phenomenon is limited, as few ethologically valid view-invariant object recognition tasks exist for rodents. Here, we report two complementary, novel view-invariant object recognition tasks in which rodents physically interact with three-dimensional objects. Prior to experimentation, rats and mice were given extensive experience with a set of 'pre-exposure' objects. In a variant of the spontaneous object recognition task, novelty preference for pre-exposed or new objects was assessed at various angles of rotation (45°, 90° or 180°); unlike control rodents, for whom the objects were novel, rats and mice tested with pre-exposed objects did not discriminate between rotated and un-rotated objects in the choice phase, indicating substantial view-invariant object recognition. Secondly, using automated operant touchscreen chambers, rats were tested on pre-exposed or novel objects in a pairwise discrimination task, where the rewarded stimulus (S+) was rotated (180°) once rats had reached acquisition criterion; rats tested with pre-exposed objects re-acquired the pairwise discrimination following S+ rotation more effectively than those tested with new objects. Systemic scopolamine impaired performance on both tasks, suggesting involvement of acetylcholine at muscarinic receptors in view-invariant object processing. These tasks present novel means of studying the behavioral and neural bases of view-invariant object recognition in rodents. Copyright © 2018 Elsevier B.V. All rights reserved.

Special Relativity: Will it Survive the Next 101 Years?

International Nuclear Information System (INIS)

Altschul, Brett D

2007-01-01

experimental tests of special relativity, especially state-of-the-art versions of 'classic' tests of rotation and boost invariance. These include Michelson-Morley experiments with high-finesse optical resonators, two-species atomic clock comparisons, and direct measurements of Doppler shifts in the radiation of moving atoms. If there is a weakness in the overall presentation, it lies in the selection of material covered. {/it Special Relativity} is more of a volume of conference proceedings than a truly cohesive set of lecture notes. This is most evident in the section on experimental tests of Lorentz invariance, which includes contributions from three different experimental groups working on optical resonator measurements. Impressive as these experiments are, this repetitive coverage is not necessary. And at the same time, there is no detailed coverage of astrophysical tests of Lorentz invariance, even though the tightest absolute bounds on deviations from relativity come from astrophysical polarimetry. However, taken as a whole, the volume presents an excellent survey of current research on Lorentz symmetry. Most of the book should be accessible to graduate students and researchers who are interested in the field but with little previous exposure to it. However, the mathematical level does vary quite a bit from one article to the next; especially in part II, facility with a fair number of mathematical physics concepts may be required. The coverage is broad enough that even an active researcher working on special relativity and possible modifications thereto will almost certainly find new material in this volume, and most of the authors provide abundant references, which should be quite valuable in a field with as many counterintuitive features as Lorentz violation research. (book review)

Constraining spacetime nonmetricity with Lorentz-violation methods

Science.gov (United States)

Xiao, Zhi; Lehnert, Ralf; Snow, W. M.; Xu, Rui

2018-01-01

In this report, we will give the first constraints on in-matter nonmetricity. We will show how the effective-field-theory (EFT) toolbox developed for the study of Lorentz violation (LV) can be employed for investigations of the “effective LV” background caused by nonmetricity, a geometric object extending the notion of a Riemannian manifold. The idea is to probe for the effects of spacetime nonmetricity sourced by liquid 4He with polarized slow neutrons. We present the first constraints on isotropic and parity-odd nonmetricity components. Further constraints on anisotropic nonmetricity components within this EFT framework may be feasible with proper experimental techniques in the near future.

What's hampering measurement invariance : Detecting non-invariant items using clusterwise simultaneous component analysis

NARCIS (Netherlands)

De Roover, K.; Timmerman, Marieke; De Leersnyder, J.; Mesquita, B.; Ceulemans, Eva

2014-01-01

The issue of measurement invariance is ubiquitous in the behavioral sciences nowadays as more and more studies yield multivariate multigroup data. When measurement invariance cannot be established across groups, this is often due to different loadings on only a few items. Within the multigroup CFA

Structural invariance of the Schroedinger equation and chronoprojective geometry

International Nuclear Information System (INIS)

Burdet, G.; Perrin, M.

1983-07-01

We describe an extension of the chronoprojective geometry and show how its automorphisms are related to the invariance properties of the Schroedinger equation describing a quantum test particle in any Newton-Cartan structure

Virtual Compton Scattering off a Spinless Target in the AdS/QCD correspondence

Energy Technology Data Exchange (ETDEWEB)

Wallon, Samuel [Laboratoire de Physique Theorique d' Orsay - LPT, Bat. 210, Univ. Paris-Sud 11, 91405 Orsay Cedex (France); Marquet, Cyrille [IPhT - Institut de Physique Theorique, Orme des Merisiers bat. 774, PC 136, CEA/DSM/IPhT, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Roiesnel, Claude [Centre de Physique Theorique - CPHT, UMR 7644, Ecole Polytechnique, Bat. 6, RDC, F91128 Palaiseau Cedex (France)

2010-07-01

We study the doubly virtual Compton scattering off a spinless target {gamma}* P {yields} {gamma}* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical approximation is supposed to apply best, we show that the measurements of the electric and magnetic polarizabilities of a target like the charged pion in real Compton scattering, can already serve as stringent tests. (author)

Water-Methanol Mixtures with non-Lorentz-Berthelot Combining Rules: A Feasibility Study

Czech Academy of Sciences Publication Activity Database

Moučka, F.; Nezbeda, Ivo

2011-01-01

Roč. 159, 1 Sp.I:Sl (2011), s. 47-51 ISSN 0167-7322 Institutional research plan: CEZ:AV0Z40720504 Keywords : water-alcohol mixtures * non-Lorentz-Berthelot rules * excess mixing properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.580, year: 2011

Low regularity solutions of the Chern-Simons-Higgs equations in the Lorentz gauge

Directory of Open Access Journals (Sweden)

Nikolaos Bournaveas

2009-09-01

Full Text Available We prove local well-posedness for the 2+1-dimensional Chern-Simons-Higgs equations in the Lorentz gauge with initial data of low regularity. Our result improves earlier results by Huh [10, 11].

Novel characteristics of energy spectrum for 3D Dirac oscillator analyzed via Lorentz covariant deformed algebra.

Science.gov (United States)

Betrouche, Malika; Maamache, Mustapha; Choi, Jeong Ryeol

2013-11-14

We investigate the Lorentz-covariant deformed algebra for Dirac oscillator problem, which is a generalization of Kempf deformed algebra in 3 + 1 dimension of space-time, where Lorentz symmetry are preserved. The energy spectrum of the system is analyzed by taking advantage of the corresponding wave functions with explicit spin state. We obtained entirely new results from our development based on Kempf algebra in comparison to the studies carried out with the non-Lorentz-covariant deformed one. A novel result of this research is that the quantized relativistic energy of the system in the presence of minimal length cannot grow indefinitely as quantum number n increases, but converges to a finite value, where c is the speed of light and β is a parameter that determines the scale of noncommutativity in space. If we consider the fact that the energy levels of ordinary oscillator is equally spaced, which leads to monotonic growth of quantized energy with the increment of n, this result is very interesting. The physical meaning of this consequence is discussed in detail.

CME Dynamics Using STEREO and LASCO Observations: The Relative Importance of Lorentz Forces and Solar Wind Drag

Science.gov (United States)

Sachdeva, Nishtha; Subramanian, Prasad; Vourlidas, Angelos; Bothmer, Volker

2017-09-01

We seek to quantify the relative contributions of Lorentz forces and aerodynamic drag on the propagation of solar coronal mass ejections (CMEs). We use Graduated Cylindrical Shell (GCS) model fits to a representative set of 38 CMEs observed with the Solar and Heliospheric Observatory (SOHO) and the Solar and Terrestrial Relations Observatory (STEREO) spacecraft. We find that the Lorentz forces generally peak between 1.65 and 2.45 R⊙ for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3.5 - 4 R⊙. For slow CMEs, however, they become negligible only by 12 - 50 R⊙. For these slow events, our results suggest that some of the magnetic flux might be expended in CME expansion or heating. In other words, not all of it contributes to the propagation. Our results are expected to be important in building a physical model for understanding the Sun-Earth dynamics of CMEs.

Lorentz Contraction, Bell's Spaceships and Rigid Body Motion in Special Relativity

Science.gov (United States)

Franklin, Jerrold

2010-01-01

The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier…

Relativistic transformation law of quantum fields: A slight generalization consistent with the equivalence of all Lorentz frames

International Nuclear Information System (INIS)

Ingraham, R.L.

1985-01-01

The well-known relativistic transformation law of quantum fields satisfies the relativity principle, which asserts the complete equivalence of all Lorentz (inertial) frames as far as physical measurements go. We point out a slight generalization which is allowed by the relativity principle, but violates a further, tacit assumption usually made in connection with it but which is actually logically independent of it and subject to a feasible experimental test. The interest of the generalization is that it permits the incorporation of an ultraviolet cutoff in a simple, direct way which avoids the usual difficulties

Nonlinear generalization of special relativity at very high energies

International Nuclear Information System (INIS)

Winterberg, F.

1984-01-01

It is shown, that the introduction of a fundamental length constant into the operator representation of the quantum mechanical commutation relations, as suggested by Bagge, leads to a nonlinear generalization of the Lorentz transformations. The theory requires the introduction of a substratum (ether) and which can be identified as the zero point vacuum energy. At very high energies a non-Lorentz invariant behaviour for the cross sections between elementary particles is predicted. Using the Einstein clock synchronisation definition, the velocity of light is also constant and equal to c in the new theory, but the zero point vacuum energy becomes finite, as are all other quantities which are divergent in Lorentz invariant quantum field theories. In the limiting case where the length constant is set equal to zero, the zero point vacuum energy diverges and special relativity is recovered. (orig.) [de

Foundations of symmetric spaces of measurable functions Lorentz, Marcinkiewicz and Orlicz spaces

CERN Document Server

Rubshtein, Ben-Zion A; Muratov, Mustafa A; Pashkova, Yulia S

2016-01-01

Key definitions and results in symmetric spaces, particularly Lp, Lorentz, Marcinkiewicz and Orlicz spaces are emphasized in this textbook. A comprehensive overview of the Lorentz, Marcinkiewicz and Orlicz spaces is presented based on concepts and results of symmetric spaces. Scientists and researchers will find the application of linear operators, ergodic theory, harmonic analysis and mathematical physics noteworthy and useful. This book is intended for graduate students and researchers in mathematics and may be used as a general reference for the theory of functions, measure theory, and functional analysis. This self-contained text is presented in four parts totaling seventeen chapters to correspond with a one-semester lecture course. Each of the four parts begins with an overview and is subsequently divided into chapters, each of which concludes with exercises and notes. A chapter called “Complements” is included at the end of the text as supplementary material to assist students with independent work.

Analyzing power for π-p charge exchange and a test of isospin invariance up to eta threshold

International Nuclear Information System (INIS)

Wightman, J.A.; Eichon, A.D.; Kim, G.J.; Mokhtari, A.; Nefkens, B.M.K.; Fitzgerald, D.H.; Sadler, M.E.

1987-01-01

The analyzing power for π - p→π 0 n has been measured at five incident momenta from 547 to 687 MeV/c using a transversely polarized target. Data were obtained with scintillation counters at 10 angles simultaneously covering the range -0.9 ≤ cosθ/sub c.m.//sup π/ ≤ 0.9. Our results and those of Kim et al. are used for a model-independent test of isospin invariance which is based on the triangle inequalities applied to the transversity-up as well as the transversity-down cross sections. No evidence is found for isospin violation

Analytic Lorentz integral transform of an arbitrary response function and its application to the inversion problem