Chiral Quark Soliton Model and Nucleon Spin Structure Functions
Wakamatsu, M
2009-01-01
The chiral quark soliton model (CQSM) is one of the most successful models of baryons at quark level, which maximally incorporates the most important feature of low energy QCD, i.e. the chiral symmetry and its spontaneous breakdown. Basically, it is a relativistic mean-field theory with full account of infinitely many Dirac-sea quarks in a rotational-symmetry-breaking mean field of hedgehog shape. The numerical technique established so far enables us to make a nonperturbative evaluation of Casimir effects (i.e. effects of vacuum-polarized Dirac sea) on a variety of baryon observables. This incompatible feature of the model manifests most clearly in its predictions for parton distribution functions of the nucleon. In this talk, after briefly reviewing several basic features of the CQSM, we plan to demonstrate in various ways that this unique model of baryons provides us with an ideal tool for disentangling nonperturbative aspect of the internal partonic structure of the nucleon, especially the underlying spin ...
On the Chiral Quark Soliton Model with Pauli-Villars Regularization
Kubota, T.; Wakamatsu, M.; Watabe, T.
1999-01-01
The Pauli-Villars regularization scheme is often used for evaluating parton distributions within the framework of the chiral quark soliton model with inclusion of the vacuum polarization effects. Its simplest version with a single subtraction term should however be taken with some caution, since it does not fully get rid of divergences contained in scalar and psuedoscalar quark densities appearing in the soliton equation of motion. To remedy this shortcoming, we propose here its natural exten...
Instability of the hedgehog shape for the octet baryon in the chiral quark soliton model
Akiyama, S; Akiyama, Satoru; Futami, Yasuhiko
2003-01-01
In this paper the stability of the hedgehog shape of the chiral soliton is studied for the octet baryon with the SU(3) chiral quark soliton model. The strangeness degrees of freedom are treated by a simplified bound-state approach, which omits the locality of the kaon wave function. The mean field approximation for the flavor rotation is applied to the model. The classical soliton changes shape according to the strangeness. The baryon appears as a rotational band of the combined system of the deformed soliton and the kaon.
Akiyama, S; Akiyama, Satoru; Futami, Yasuhiko
2006-01-01
Mesonic fluctuations around the chiral solitons are investigated in the SU(3) chiral quark soliton model. Since the soliton takes the non-hedgehog shape for the hyperons and the hedgehog one for the non-hedgehog baryons in our approach, the fluctuations also change according to the baryonic state. The quantum corrections to the masses (the Casimir energies) are estimated for the octet and decuplet baryons. The lack of the confinement in this model demands the cutoff on the energy of the fluctuations. Under the assumption that the value of the cutoff energy is $2\\times$(the lightest constituent quark mass), these calculation reproduces the masses of the baryons within 15 % error.
The B=2 system in the chiral quark-soliton model with broken scale invariance
Sarti, Valentina Mantovani; Vento, Vicente
2013-01-01
We study the interaction between two B=1 states in the Chiral-Dilaton Model with scale invariance where baryons are described as non-topological solitons arising from the interaction of chiral mesons and quarks. By using the hedgehog solution for the B=1 states we construct, via a product ansatz, three possible B=2 configurations to analyse the role of the relative orientation of the hedgehog quills in the dynamics. We investigate the behaviour of these solutions in the range of long and intermediate distances between the two solitons. Since the product ansatz breaks down as the two solitons get close, we explore the short range distances regime by building up a six quarks bag and by evaluating the interaction energy as a function of the inter-soliton separation. We calculate the interaction energy as a function of the inter-soliton distance for the B=2 system and we show that for small separations the six quarks bag, assuming a hedgehog structure, provides a stable bound state that at large separations conne...
Ledwig, Tim; Goeke, Klaus
2008-01-01
We investigate the vector transition form factors of the nucleon and vector meson $K^*$ to the pentaquark baryon $\\Theta^+$ within the framework of the SU(3) chiral quark-soliton model. We take into account the rotational $1/N_c$ and linear $m_{\\rm s}$ corrections, assuming isospin symmetry and employing the symmetry-conserving quantization. It turns out that the leading-order contributions to the form factors are almost cancelled by the rotational corrections. Because of this, the flavor SU(3) symmetry-breaking terms yield sizeable effects on the transition form factors. In particular, the main contribution to the electric transition form factor comes from the wave-function corrections, which is a consequence of the generalized Ademollo-Gatto theorem derived in the present work. We estimate with the help of the vector meson dominance the $K^*$ vector and tensor coupling constants for the $\\Theta^+$: $g_{K^{*}N\\Theta}=0.74 - 0.87$ and $f_{K^{*}N\\Theta}=0.53 - 1.16$. We argue that the outcome of the present wo...
Hyun, Chang Ho; Lee, Hee-Jung
2016-01-01
We investigate the parity-violating pion-nucleon-nucleon coupling constant $h^1_{\\pi NN}$, based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating $\\pi NN$ constant $h^1_{\\pi NN}$. We obtain a value of about $10^{-7}$ at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20~\\%.
Indian Academy of Sciences (India)
H Weigel
2003-11-01
In this talk I review studies of hadron properties in bosonized chiral quark models for the quark ﬂavor dynamics. Mesons are constructed from Bethe–Salpeter equations and baryons emerge as chiral solitons. Such models require regularization and I show that the two-fold Pauli–Villars regularization scheme not only fully regularizes the effective action but also leads the scaling laws for structure functions. For the nucleon structure functions the present approach serves to determine the regularization prescription for structure functions whose leading moments are not given by matrix elements of local operators. Some numerical results are presented for the spin structure functions.
Generalized simplicial chiral models
Alimohammadi, M
2000-01-01
Using the auxiliary field representation of the simplicial chiral models on a (d-1)-dimensional simplex, we generalize the simplicial chiral models by replacing the term Tr$(AA^{\\d})$ in the Lagrangian of these models, by an arbitrary class function of $AA^{\\d}; V(AA^{\\d})$. This is the same method that has been used in defining the generalized two-dimensional Yang-Mills theories (gYM_2) from ordinary YM_2. We call these models, the " generalized simplicial chiral models ". With the help of the results of one-link integral over a U(N) matrix, we compute the large-N saddle-point equations for eigenvalue density function $\\ro (z)$ in the weak ($\\b >\\b_c$) and strong ($\\b <\\b_c$) regions. In d=2, where the model somehow relates to gYM_2 theory, we solve the saddle-point equations and find $\\ro (z)$ in two region, and calculate the explicit value of critical point $\\b_c$ for $V(B)=TrB^n (B=AA^{\\d})$. For $V(B)=Tr B^2,Tr B^3$ and Tr$B^4$, we study the critical behaviour of the model at d=2, and by calculating t...
Wang, X J; Wang, Xiao-Jun; Yan, Mu-Lin
1999-01-01
We study SU(3)$_L\\timesSU(3)_R$ chiral quark model of mesons up to next leading order of $1/N_c$ expansion. Composite vector and axial-vector mesons resonances are introduced via non-linear realization of chiral SU(3) and vector meson dominant. Effects of one-loop graphs of pseudoscalar, vector and axial-vector mesons is calculated systematically and the significant results are obtained. Correction of effective gluon interaction is studied too. The light quark masses are introduced via new mechanism which agree with phenomenology and the requirement of chiral symmetry. Up to powers four of derivatives, chiral effective lagrangian of mesons is derived and evaluated to next leading order of $1/N_c$. Low energy limit of the model is examined. Ten low energy coupling constants $L_i(i=1,2,...,10)$ in ChPT are obtained and agree with ChPT well.
Energy Technology Data Exchange (ETDEWEB)
Rahaman, Anisur, E-mail: anisur.rahman@saha.ac.in
2015-10-15
The vector type of interaction of the Thirring–Wess model was replaced by the chiral type and a new model was presented which was termed as chiral Thirring–Wess model in Rahaman (2015). The model was studied there with a Faddeevian class of regularization. Few ambiguity parameters were allowed there with the apprehension that unitarity might be threatened like the chiral generation of the Schwinger model. In the present work it has been shown that no counter term containing the regularization ambiguity is needed for this model to be physically sensible. So the chiral Thirring–Wess model is studied here without the presence of any ambiguity parameter and it has been found that the model not only remains exactly solvable but also does not lose the unitarity like the chiral generation of the Schwinger model. The phase space structure and the theoretical spectrum of this new model have been determined in the present scenario. The theoretical spectrum is found to contain a massive boson with ambiguity free mass and a massless boson.
Solutions of ward's modified chiral model
International Nuclear Information System (INIS)
We discuss the adaptation of Uhlenbeck's method of solving the chiral model in 2 Euclidean dimensions to Ward's modified chiral model in (2+1) dimensions. We show that the method reduces the problem of solving the second-order partial differential equations for the chiral field to solving a sequence of first-order partial differential equations for time dependent projector valued fields
Chiral Cosmological Models: Dark Sector Fields Description
Chervon, S V
2014-01-01
The present review is devoted to a Chiral Cosmological Model as the self-gravitating nonlinear sigma model with the potential of (self)interactions employed in cosmology. The chiral cosmological model has successive applications in descriptions of the inflationary epoch of the Universe evolution; the present accelerated expansion of the Universe also can be described by the chiral fields multiplet as the dark energy in wide sense. To be more illustrative we are often addressed to the two-component chiral cosmological model. Namely, the two-component chiral cosmological model describing the phantom field with interaction to a canonical scalar field is analyzed in details. New generalized model of quintom character is proposed and exact solutions are founded out. In the review we represented the perturbation theory for chiral cosmological model with the aim to describe the structure formation using the progress achieved in the inflation theory. It was shown that cosmological perturbations from chiral fields can...
Chiral magnetic effect in the PNJL model
Fukushima, Kenji; Gatto, Raoul
2010-01-01
We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.
Intrinsic transverse momentum and dynamical chiral symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Christian Weiss, Peter Schweitzer, Mark Strikman
2013-01-01
We study the effect of QCD vacuum structure on the intrinsic transverse momentum distribution of partons in the nucleon at a low scale. The dynamical breaking of chiral symmetry is caused by non-perturbative interactions at distances of the order rho ~ 0.2 - 0.3 fm, much smaller than the typical nucleon size R ~ 1 fm, resulting in a two-scale picture of nucleon structure. Using an effective dynamical model based on chiral constituent quark degrees of freedom and the 1/N_c expansion (chiral quark-soliton model), we calculate the transverse momentum distribution of quarks and antiquarks at a low scale. The distribution of valence quarks is localized at p_T ~ 1/R. The distribution of flavor-singlet unpolarized sea quarks exhibits a power-like tail extending up to the chiral-symmetry-breaking scale 1/{rho}. A similar tail is present in the flavor-nonsinglet polarized sea. These features are model-independent and represent the imprint of the QCD vacuum on the nucleon's partonic structure. At the level of the nucleon's light-cone wave function, we show that sea quarks partly exist in correlated pairs of transverse size {rho} << R, analogous to short-range NN correlations in nuclei. We discuss the implications of our findings for the transverse momentum distributions in hard scattering processes (semi-inclusive DIS, Drell-Yan pair production) and possible experimental tests of the non-perturbative parton correlations induced by QCD vacuum structure.
Yanagisawa, Takashi
2016-01-01
We investigate the chiral sine-Gordon model using the renormalization group method. The chiral sine-Gordon model is a model for $G$-valued fields and describes a new class of phase transitions, where $G$ is a compact Lie group. We show that the model is renormalizable by means of a perturbation expansion and we derive beta functions of the renormalization group theory. The coefficients of beta functions are represented by the Casimir invariants. The model contains both asymptotically free and ultraviolet strong coupling regions. The beta functions have a zero which is a bifurcation point that divides the parameter space into two regions; they are the weak coupling region and the strong coupling region. A large-$N$ model is also considered. This model is reduced to the conventional sine-Gordon model that describes the Kosterlitz-Thouless transition near the fixed point. In the strong-coupling limit, the model is reduced to a $U(N)$ matrix model.
Chiral dynamics of baryons in the perturbative chiral quark model
Energy Technology Data Exchange (ETDEWEB)
Pumsa-ard, K.
2006-07-01
In this work we develop and apply variants of a perturbative chiral quark model (PCQM) to the study of baryonic properties dominantly in the low-energy region. In a first step we consider a noncovariant form of the PCQM, where confinement is modelled by a static, effective potential and chiral corrections are treated to second order, in line with similar chiral quark models. We apply the PCQM to the study of the electromagnetic form factors of the baryon octet. We focus in particular on the low-energy observables such as the magnetic moments, the charge and magnetic radii. In addition, the electromagnetic N-delta transition is also studied in the framework of the PCQM. In the chiral loop calculations we consider a quark propagator, which is restricted to the quark ground state, or in hadronic language to nucleon and delta intermediate states, for simplicity. We furthermore include the low-lying excited states to the quark propagator. In particular, the charge radius of the neutron and the transverse helicity amplitudes of the N-delta transition are considerably improved by this additional effect. In a next step we develop a manifestly Lorentz covariant version of the PCQM, where in addition higher order chiral corrections are included. The full chiral quark Lagrangian is motivated by and in analogy to the one of Chiral Perturbation Theory (ChPT). This Lagrangian contains a set of low energy constants (LECs), which are parameters encoding short distance effects and heavy degrees of freedom. We evaluate the chiral Lagrangian to order O(p{sup 4}) and to one loop to generate the dressing of the bare quark operators by pseudoscalar mesons. In addition we include the vector meson degrees of freedom in our study. Projection of the dressed quark operators on the baryonic level serves to calculate the relevant matrix elements. In a first application of this scheme, we resort to a parameterization of the valence quark form factors in the electromagnetic sector. Constraints
An Extended Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANG Zong-Ye; YU You-Wen; WANG Ping; DAI Lian-Rong
2003-01-01
The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiralfields are considered, the phase shifts of 1 So wave are obviously improved.
Lambda Hypernuclei in a Chiral Hadronic Model
Institute of Scientific and Technical Information of China (English)
LIANG Yin-Hua; GUO Hua
2005-01-01
@@ Nuclear matter calculations in a chiral hadronic model have been performed. It has been found that the scalar and the vector potentials and binding energies per nucleon in the chiral hadronic model are very close to those of the microscopic relativistic Brueckner-Hartree-Fock calculations. The good results for finite nuclei can be obtained in the mean field approximation only if scalar mass ms and coupling constant gs have been improved with the fixed values of cs2 ≡ g2s(M/ms)2 as those given by the original parameter sets of the chiral hadronic model. Then the chiral hadronic model is extended to lambda hypernuclei. Our results predicted by the chiral hadronic model are compared with those by the nonlinear Walecka model. It has been shown that the hadronic model can also be used to describe lambda hypernuclei successfully.
NN Interaction in Chiral Constituent Quark Models
Valcarce, A; González, P
2003-01-01
We review the actual state in the description of the NN interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.
Chiral Schwinger model at finite temperature
International Nuclear Information System (INIS)
We discuss the chiral Schwinger model at finite temperature using Fujikawa's method. We solve this model exactly and show that the axial anomaly and the dynamically generated mass for the gauge field are temperature independent. (author). 20 refs
Effective action in general chiral superfield model
Petrov, A. Yu.
2000-01-01
The effective action in general chiral superfield model with arbitrary k\\"{a}hlerian potential $K(\\bar{\\Phi},\\Phi)$ and chiral (holomorphic) potential $W(\\Phi)$ is considered. The one-loop and two-loop contributions to k\\"{a}hlerian effective potential and two-loop (first non-zero) contribution to chiral effective potential are found for arbitrary form of functions $K(\\bar{\\Phi},\\Phi)$ and $W(\\Phi)$. It is found that despite the theory is non-renormalizable in general case two-loop contributi...
Chiral effective model with the Polyakov loop
Fukushima, Kenji
2003-01-01
We discuss how the simultaneous crossovers of deconfinement and chiral restoration can be realized. We propose a dynamical mechanism assuming that the effective potential gives a finite value of the chiral condensate if the Polyakov loop vanishes. Using a simple model, we demonstrate that our idea works well for small quark mass, though there should be further constraints to reach the perfect locking of two phenomena.
Pentaquarks in chiral color dielectric model
Indian Academy of Sciences (India)
S C Pathak
2006-04-01
Recent experiments indicate that a narrow baryonic state having strangeness +1 and mass of about 1540 MeV may be existing. Such a state was predicted in chiral model by Diakonov et al. In this work I compute the mass and width of this state in chiral color dielectric model. I show that the computed width is about 30 MeV. I find that the mass of the state can be fitted to the experimentally observed mass by invoking a color neutral vector field and its interaction with the quarks.
Ioannidou, Theodora; Zakrzewski, Wojtek
1998-01-01
A one parameter generalization of Ward's chiral model in 2+1 dimensions is given. Like the original model the present one is integrable and possesses a positive-definite and conserved energy and $y$-momentum. The details of the scattering depend on the value of the parameter of the generalisation.
N phi state in chiral quark model
Huang, F; Zhang, Z Y
2006-01-01
The structures of N phi states with spin-parity J^{p}=3/2^- and J^p=1/2^- are dynamically studied in both the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The channel coupling of N phi and Lambda K* is considered, and the effect of the tensor force which results in the mixing of S and D waves is also investigated. The results show that the N phi state has an attractive interaction, and in the extended chiral SU(3) quark model such an attraction plus the channel coupling effect can consequently make for an N phi quasi-bound state with several MeV binding energy.
Chiral quark model with relativistic kinematics
Garcilazo, H
2003-01-01
The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.
Solitons in nonlocal chiral quark models
Broniowski, W; Ripka, G; Broniowski, Wojciech; Golli, Bojan; Ripka, Georges
2002-01-01
Properties of hedgehog solitons in a chiral quark model with nonlocal regulators are described. We discuss the formation of the hedgehog soliton, the quantization of the baryon number, the energetic stability, the gauging and construction of Noether currents with help of path-ordered P-exponents, and the evaluation of observables. The issue of nonlocality is thoroughly discussed, with a focus on contributions to observables related to the Noether currents. It is shown that with typical model parameters the solitons are not far from the weak nonlocality limit. The methods developed are applicable to solitons in models with separable nonlocal four-fermion interactions.
Structure functions in the chiral bag model
Energy Technology Data Exchange (ETDEWEB)
Sanjose, V.; Vento, V.
1989-07-13
We calculate the structure functions of an isoscalar nuclear target for the deep inelastic scattering by leptons in an extended version of the chiral bag model which incorporates the qanti q structure of the pions in the cloud. Bjorken scaling and Regge behavior are satisfied. The model calculation reproduces the low-x behavior of the data but fails to explain the medium- to large-x behavior. Evolution of the quark structure functions seem inevitable to attempt a connection between the low-energy models and the high-energy behavior of quantum chromodynamics. (orig.).
Chiral and chemical oscillations in a simple dimerization model
Stich, Michael; Hochberg, David
2012-01-01
We consider the APED model (activation-polymerization-epimerization-depolymerization) for describing the emergence of chiral solutions within a non-catalytic framework for chiral polymerization. The minimal APED model for dimerization can lead to the spontaneous appearance of chiral oscillations and we describe in detail the nature of these oscillations in the enantiomeric excess, and which are the consequence of oscillations of the concentrations of the associated chemical species.
Nucleon Properties from Approximating Chiral Quark Sigma Model
Abu-Shady, M
2009-01-01
We apply the approximating chiral quark model. This chiral quark model is based on an effective Lagrangian which the interactions between quarks via sigma and pions mesons. The field equations have been solved in the mean field approximation for the hedgehog baryon state. Good results are obtained for nucleon properties in comparison with original model.
Strange Hadronic Matter in a Chiral Model
Institute of Scientific and Technical Information of China (English)
ZHANG Li-Liang; SONG Hong-Qiu; WANG Ping; SU Ru-Keng
2000-01-01
The strange hadronic matter with nucleon, Λ-hyperon and E-hyperon is studied by using a chiral symmetry model in a mean-field approximation. The saturation properties and stabilities of the strange hadronic matter are discussed. The result indicates a quite large strangeness fraction (fs) region where the strange hadronic matter is stable against particle emission. In the large fs region, the component dominates, resulting in a deep minimum in the curve of the binding energy per baryon EB versus the strangeness fraction fs with (EB, fs) -～ (-26.0MeV, 1.23).
Dihyperons in chiral color dielectric model
Indian Academy of Sciences (India)
S C Phatak
2003-11-01
The mass of the dibaryon having spin, parity =0+, isospin = 0 and strangeness -2 is computed using chiral color dielectric model. The bare wave function is constructed as a product of two color-singlet three-quark clusters and then it is properly antisymmetrized by considering appropriate exchange operators for spin, ﬂavor and color. Color magnetic energy due to gluon exchange, meson self energy and energy correction due to center of mass motion are computed. The calculation shows that the mass of the particle is 80 to 160 MeV less than twice mass.
Moduli stabilisation for chiral global models
Energy Technology Data Exchange (ETDEWEB)
Cicoli, Michele [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Mayrhofer, Christoph [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; Valandro, Roberto [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2011-10-15
We combine moduli stabilisation and (chiral) model building in a fully consistent global set-up in Type IIB/F-theory. We consider compactifications on Calabi-Yau orientifolds which admit an explicit description in terms of toric geometry. We build globally consistent compactifications with tadpole and Freed-Witten anomaly cancellation by choosing appropriate brane set-ups and world-volume fluxes which also give rise to SU(5)- or MSSM-like chiral models. We fix all the Kaehler moduli within the Kaehler cone and the regime of validity of the 4D effective field theory. This is achieved in a way compatible with the local presence of chirality. The hidden sector generating the non-perturbative effects is placed on a del Pezzo divisor that does not have any chiral intersections with any other brane. In general, the vanishing D-term condition implies the shrinking of the rigid divisor supporting the visible sector. However, we avoid this problem by generating r
Lagrangian Formulation of the General Modified Chiral Model
Ioannidou, Theodora; Zakrzewski, Wojtek
1998-01-01
We present a Lagrangian formulation for the general modified chiral model. We use it to discuss the Hamiltonian formalism for this model and to derive the commutation relations for the chiral field. We look at some explicit examples and show that the Hamiltonian, containing a contribution involving a Wess-Zumino term, is conserved, as required.
Circular dichroism of graphene oxide： the chiral structure model
Institute of Scientific and Technical Information of China (English)
Jing CAO; Hua-Jie YIN; Rui SONG
2013-01-01
We have observed the circular dichroism signal of dilute graphene oxide （GO）, then systematically investigated the chirality of GO and established a probable chiral unit model, This study may open up a new field for understanding the structure of GO and lay the foundation for fabrication of GO-based materials.
On SU(3 Effective Models and Chiral Phase Transition
Directory of Open Access Journals (Sweden)
Abdel Nasser Tawfik
2015-01-01
Full Text Available Sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL model and Polyakov linear sigma-model (PLSM has been utilized in studying QCD phase-diagram. From quasi-particle model (QPM a gluonic sector is integrated into LSM. The hadron resonance gas (HRG model is used in calculating the thermal and dense dependence of quark-antiquark condensate. We review these four models with respect to their descriptions for the chiral phase transition. We analyze the chiral order parameter, normalized net-strange condensate, and chiral phase-diagram and compare the results with recent lattice calculations. We find that PLSM chiral boundary is located in upper band of the lattice QCD calculations and agree well with the freeze-out results deduced from various high-energy experiments and thermal models. Also, we find that the chiral temperature calculated from HRG is larger than that from PLSM. This is also larger than the freeze-out temperatures calculated in lattice QCD and deduced from experiments and thermal models. The corresponding temperature and chemical potential are very similar to that of PLSM. Although the results from PNJL and QLSM keep the same behavior, their chiral temperature is higher than that of PLSM and HRG. This might be interpreted due the very heavy quark masses implemented in both models.
Meson phenomenology and phase transitions in nonlocal chiral quark models
Carlomagno, J. P.; Gomez Dumm, D.; Pagura, V.; Scoccola, N. N.
2015-07-01
We study the features of nonlocal chiral quark models that include wave function renormalization. Model parameters are determined from meson phenomenology, considering different nonlocal form factor shapes. In this context we analyze the characteristics of the deconfinement and chiral restoration transitions at finite temperature and chemical potential, introducing the couplings of fermions to the Polyakov loop for different Polyakov potentials. The results for various thermodynamical quantities are compared with data obtained from lattice QCD calculations.
Ogino, Yoshiyuki; Asahi, Toru
2015-05-21
In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies.
On SU(3) effective models and chiral phase-transition
Tawfik, Abdel Nasser
2015-01-01
The sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model as an effective theory of quark dynamics to chiral symmetry has been utilized in studying the QCD phase-diagram. Also, Poyakov linear sigma-model (PLSM), in which information about the confining glue sector of the theory was included through Polyakov-loop potential. Furthermore, from quasi-particle model (QPM), the gluonic sector of QPM is integrated to LSM in order to reproduce recent lattice calculations. We review PLSM, QLSM, PNJL and HRG with respect to their descriptions for the chiral phase-transition. We analyse chiral order-parameter M(T), normalized net-strange condensate Delta_{q,s}(T) and chiral phase-diagram and compare the results with lattice QCD. We conclude that PLSM works perfectly in reproducing M(T) and Delta_{q,s}(T). HRG model reproduces Delta_{q,s}(T), while PNJL and QLSM seem to fail. These differences are present in QCD chiral phase-diagram. PLSM chiral boundary is located in upper band of lattice QCD calculations and agree we...
Yu, Lang; Huang, Mei
2015-01-01
We study the chiral phase transition in the presence of the chiral chemical potential $\\mu_5$ using the two-flavor Nambu--Jona-Lasinio model. In particular, we analyze the reason why one can obtain two opposite behaviors of the chiral critical temperature as a function of $\\mu_5$ in the framework of different regularization schemes. We compare the modifications of the chiral condensate and the critical temperature due to $\\mu_5$ in different regularization schemes, analytically and numerically. Finally, we find that, for the conventional hard-cutoff regularization scheme, the increasing dependence of the critical temperature on the chiral chemical potential is an artifact, which is caused by the fact that it does not include complete contribution from the thermal fluctuations. When the thermal contribution is fully taken into account, the chiral critical temperature should decrease with $\\mu_5$.
Integrability of a master chiral quantum field model
International Nuclear Information System (INIS)
The paper deals with solution of a master chiral field model in two-dimensional space-time using the quantum method of inverse problem. A dominant role in the approach is played by the idea of relativistic model production on the basis of magnetic model in the scaling limit at S→ infinity. L-M pair of a master chiral field model is discussed. Formulae for regularized quantum Hamiltonian and Bethe-Ansatz above pseudovacuum are derived. The description of excitations and Dirac filling for the ground state is given. Continuous limit from magnetic model above physical vacuum is considered
Chiral soliton model vs. pentaquark structure for (1540)
Indian Academy of Sciences (India)
R Ramachandran
2005-09-01
The exotic baryon + (1540 MeV) is visualized as an expected (iso) rotational excitation in the chiral soliton model. It is also argued as a pentaquark baryon state in a constituent quark model with strong diquark correlations. I contrast these two points of view; observe the similarities and differences between the two pictures. Collective excitation, the characteristic of chiral soliton model, points toward small mixing of representations in the wake of (3) breaking. In contrast, constituent quark models prefer near `ideal' mixing, similar to - mixing.
Quark matter inside neutron stars in an effective chiral model
International Nuclear Information System (INIS)
An effective chiral model which describes properties of a single baryon predicts that the quark matter relevant to neutron stars, close to the deconfinement density, is in a chirally broken phase. We find the SU(2) model that pion-condensed up and down quark matter is preferred energetically at neutron star densities. It exhibits spin ordering and can posses a permanent magnetization. The equation of state of quark matter with chiral condensate is very well approximated by bag model equation of the state with suitably chosen parameters. We study quark cores inside neutron stars in this model using realistic nucleon equations of state. The biggest quark core corresponds to the second order phase transition to quark matter. Magnetic moment of the pion-condensed quark core is calculated. (author). 19 refs, 10 refs, 1 tab
Ω(ε)States in a Chiral Quark Model
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The structures of Ω(ε) states with spin-parity Jp = 5/2-, 3/2-, and 1/2- are dynamically studied in both the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The calculated results show that theΩ(ε) state has an attractive interaction, and in the extended chiral SU(3) quark model such attraction can make for aΩ(ε) quasi-bound state with spin-parity Jp = 3/2- or 5/2- and tie binding energy of about several MeV.
Relation Between Chiral Susceptibility and Solutions of Gap Equation in Nambu--Jona-Lasinio Model
Zhao, Y; Liu, Y; Yuan, W; Chang, Lei; Liu, Yu-xin; Yuan, Wei; Zhao, Yue
2006-01-01
We study the solutions of the gap equation, the thermodynamic potential and the chiral susceptibility in and beyond the chiral limit at finite chemical potential in the Nambu--Jona-Lasinio (NJL) model. We give an explicit relation between the chiral susceptibility and the thermodynamic potential in the NJL model. We find that the chiral susceptibility is a quantity being able to represent the furcation of the solutions of the gap equation and the concavo-convexity of the thermodynamic potential in NJL model. It indicates that the chiral susceptibility can identify the stable state and the possibility of the chiral phase transition in NJL model.
Spontaneous Magnetization of the Integrable Chiral Potts Model
Au-Yang, Helen
2010-01-01
We show how $Z$-invariance in the chiral Potts model provides a strategy to calculate the pair correlation in the general integrable chiral Potts model using only the superintegrable eigenvectors. When the distance between the two spins in the correlation function becomes infinite it becomes the square of the order parameter. In this way, we show that the spontaneous magnetization can be expressed in terms of the inner products of the eigenvectors of the $N$ asymptotically degenerate maximum eigenvalues. Using our previous results on these eigenvectors, we are able to obtain the order parameter as a sum almost identical to the one given by Baxter. This gives the known spontaneous magnetization of the chiral Potts model by an entirely different approach.
Dissipative vibrational model for chiral recognition in olfaction
Tirandaz, Arash; Taher Ghahramani, Farhad; Shafiee, Afshin
2015-09-01
We examine the olfactory discrimination of left- and right-handed enantiomers of chiral odorants based on the odorant-mediated electron transport from a donor to an acceptor of the olfactory receptors embodied in a biological environment. The chiral odorant is effectively described by an asymmetric double-well potential whose minima are associated to the left- and right-handed enantiomers. The introduced asymmetry is considered an overall measure of chiral interactions. The biological environment is conveniently modeled as a bath of harmonic oscillators. The resulting spin-boson model is adapted by a polaron transformation to derive the corresponding Born-Markov master equation with which we obtain the elastic and inelastic electron tunneling rates. We show that the inelastic tunneling through left- and right-handed enantiomers occurs with different rates. The discrimination mechanism depends on the ratio of tunneling frequency to localization frequency.
Chiral transition, eigenmode localisation and Anderson-like models
Giordano, Matteo; Pittler, Ferenc
2016-01-01
We discuss chiral symmetry restoration and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We argue that the features of QCD relevant to both phenomena are the presence of order in the Polyakov line configuration, and the correlations that this induces between spatial links across time slices. This ties the fate of chiral symmetry and of localisation of the lowest Dirac eigenmodes to the confining properties of the theory. We then show numerical results obtained in a QCD-inspired Anderson-like toy model, derived by radically simplifying the QCD dynamics while keeping the important features mentioned above. The toy model reproduces all the important qualitative aspects of chiral symmetry breaking and localisation in QCD, thus supporting the central role played by the confinement/deconfinement transition in triggering both phenomena.
Strangeness s = -3 dibaryons in a chiral quark model
Lian-Rong, D; Chun-Ran, L; Lei, T; Lian-Rong, Dai; Dan, Zhang; Chun-Ran, Li; Lei, Tong
2006-01-01
The structures of $N\\Omega_{(2,1/2)}$ and $\\Delta\\Omega_{(3,3/2)}$ with strangeness $s=-3$ are dynamically studied in both the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving a resonating group method (RGM) equation. The first model parameters are taken from our previous work, which gave a satisfactory description of the energies of the baryon ground states, the binding energy of the deuteron, the nucleon-nucleon(NN) scattering phase shifts, and the hyperon-nucleon (YN) cross sections. The effect from the vector meson fields is very similar to that from the one-gluon exchange interaction, both in the chiral SU(3) quark model and the extended chiral SU(3) quark model, the $N\\Omega_{(2,1/2)}$ and $\\Delta\\Omega_{(3,3/2)}$ systems are wealy bound states. The second model parameters are also taken from our previous work by fitting the KN scattering process. when the mixing of scalar mesons are considered, the $N\\Omega_{(2,1/2)}$ and $\\Delta\\Omega_{(3,3/2)}$ systems change into unbound...
Gapless chiral spin liquid in a kagome Heisenberg model
Bieri, Samuel; Messio, Laura; Bernu, Bernard; Lhuillier, Claire
2015-08-01
Motivated by recent experiments on the Heisenberg S =1 /2 quantum spin liquid candidate material kapellasite, we classify all possible chiral (time-reversal symmetry breaking) spin liquids with fermionic spinons on the kagome lattice. We obtain the phase diagram for the physically relevant extended Heisenberg model, comparing the energies of a wide range of microscopic variational wave functions. We propose that, at low temperature, kapellasite exhibits a gapless chiral spin liquid phase with spinon Fermi surfaces. This two-dimensional state inherits many properties of the nearby one-dimensional phase of decoupled antiferromagnetic spin chains, but also shows some remarkable differences. We discuss the spin structure factors and other physical properties.
The effective action approach applied to nuclear chiral sigma model
International Nuclear Information System (INIS)
The nuclear chiral sigma model of nuclear matter is considered by means of the Cornwall-Jackiw-tomboulis (CTJ) effective action. The method provides a very general framework for investigating many important problems: chiral symmetry in nuclear medium, energy density of nuclear ground state, nuclear Schwinger-Dyson (SD) equations, etc. It is shown that the SD equations for sigma-omega mixing are actually not present in this formalism. For numerical computation purposes the Hartree-Fock (HF) approximation for ground state energy density is also presented. (author). 26 refs
Orbital Angular Momentum in the Chiral Quark Model
Song, Xiaotong
1998-01-01
We developed a new and unified scheme for describing both quark spin and orbital angular momenta in symmetry-breaking chiral quark model. The loss of quark spin in the chiral splitting processes is compensated by the gain of the orbital angular momentum carried by quarks and antiquarks. The sum of both spin and orbital angular momenta carried by quarks and antiquarks is 1/2. The analytic and numerical results for the spin and orbital angular momenta carried by quarks and antiquarks in the nuc...
The Many Faces of the Chiral Potts Model
Au-Yang, H; Au-Yang, Helen; Perk, Jacques H.H.
1996-01-01
In this talk, we give a brief overview of several aspects of the theory of the chiral Potts model, including higher-genus solutions of the star-triangle and tetrahedron equations, cyclic representations of affine quantum groups, basic hypergeometric functions at root of unity, and possible applications.
Dimensional regularization and perturbative solution of the chiral Schwinger model
International Nuclear Information System (INIS)
The anomalous chiral Schwinger model is regulated by the method of dimensional regularization and is solved by diagrammatic perturbative expansion. It is shown that there is a regulation ambiguity in the solution. The result disagrees with Das's assertion and agrees with that of Jackiw, Rajaraman, and others
Nucleon-antinucleon annihilation in chiral soliton model
International Nuclear Information System (INIS)
We investigate annihilation process of nucleons in the chiral soliton model by the path integral method. A soliton-antisoliton pair is shown to decay into mesons at range of about 1fm, defined by the S bar S potential. Contribution of the annihilation channel to the elastic scattering is discussed
Nucleon-antinucleon annihilation in chiral soliton model
International Nuclear Information System (INIS)
We investigate annihilation process of nucleons in chiral soliton model by path integral method. Soliton-antisoliton pair is shown to decay into pions at range of order of about 1 fm, defined by SS-bar potential. Contribution of annihilation channel into elastic scattering is discussed. (author). 14 refs, 1 fig
MULTI-LAMBDA MATTER IN A CHIRAL HADRONIC MODEL
Institute of Scientific and Technical Information of China (English)
郭华; 杨树; 胡翔; 刘玉鑫
2001-01-01
Multi-lambda matter is investigated in the framework of a chiral hadronic model It is shown that multi-lambda matter consisting of {N, A} is a metastable state as the strangeness per baryon and the density of hadronic matter are varied. The effective lambda mass decreases as the baryon density increases, and remains larger than that of the nucleon.
Chiral matrix model of the semi-QGP in QCD
Pisarski, Robert D.; Skokov, Vladimir V.
2016-08-01
Previously, a matrix model of the region near the transition temperature, in the "semi"quark gluon plasma, was developed for the theory of S U (3 ) gluons without quarks. In this paper we develop a chiral matrix model applicable to QCD by including dynamical quarks with 2 +1 flavors. This requires adding a nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y . Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. As is standard, the potential for the scalar fields is chosen to be symmetric under the flavor symmetry of S U (3 )L×S U (3 )R×Z (3 )A, except for a term linear in the current quark mass, mqk. In addition, at a nonzero temperature T it is necessary to add a new term, ˜mqkT2. The parameters of the gluon part of the matrix model are identical to those for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant and the masses of the pions, kaons, η , and η'. The temperature for the chiral crossover at Tχ=155 MeV is determined by adjusting the Yukawa coupling y . We find reasonable agreement with the results of numerical simulations on the lattice for the pressure and related quantities. In the chiral limit, besides the divergence in the chiral susceptibility there is also a milder divergence in the susceptibility between the Polyakov loop and the chiral order parameter, with critical exponent β -1 . We compute derivatives with respect to a quark chemical potential to determine the susceptibilities for baryon number, the χ2 n. Especially sensitive tests are provided by χ4-χ2 and by χ6, which changes in sign about Tχ. The behavior of the susceptibilities in the chiral matrix model strongly suggests that as the temperature increases from Tχ, that the transition to deconfinement is significantly quicker than indicated by the
An Anderson-like model of the QCD chiral transition
Giordano, Matteo; Kovács, Tamás G.; Pittler, Ferenc
2016-06-01
We study the problems of chiral symmetry breaking and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We recast the staggered Dirac operator into an unconventional three-dimensional Anderson Hamiltonian ("Dirac-Anderson Hamiltonian") carrying internal degrees of freedom, with disorder provided by the fluctuations of the gauge links. In this framework, we identify the features relevant to chiral symmetry restoration and localisation of the low-lying Dirac eigenmodes in the ordering of the local Polyakov lines, and in the related correlation between spatial links across time slices, thus tying the two phenomena to the deconfinement transition. We then build a toy model based on QCD and on the Dirac-Anderson approach, replacing the Polyakov lines with spin variables and simplifying the dynamics of the spatial gauge links, but preserving the above-mentioned relevant dynamical features. Our toy model successfully reproduces the main features of the QCD spectrum and of the Dirac eigenmodes concerning chiral symmetry breaking and localisation, both in the ordered (deconfined) and disordered (confined) phases. Moreover, it allows us to study separately the roles played in the two phenomena by the diagonal and the off-diagonal terms of the Dirac-Anderson Hamiltonian. Our results support our expectation that chiral symmetry restoration and localisation of the low modes are closely related, and that both are triggered by the deconfinement transition.
The baryon number two system in the Chiral Soliton Model
Sarti, Valentina Mantovani; Vento, Vicente; Park, Byung-Yoon
2012-01-01
We study the interaction between two B = 1 states in a Chiral Soliton Model where baryons are described as non-topological solitons. By using the hedgehog solution for the B = 1 states we construct three possible B = 2 configurations to analyze the role of the relative orientation of the hedgehog quills in the dynamics. The strong dependence of the intersoliton interaction on these relative orientations reveals that studies of dense hadronic matter using this model should take into account their implications.
Dimension 2 condensates and Polyakov Chiral Quark Models
Megias, E.; Arriola, E. Ruiz; Salcedo, L. L.
2006-01-01
We address a possible relation between the expectation value of the Polyakov loop in pure gluodynamics and full QCD based on Polyakov Chiral Quark Models where constituent quarks and the Polyakov loop are coupled in a minimal way. To this end we use a center symmetry breaking Gaussian model for the Polyakov loop distribution which accurately reproduces gluodynamics data above the phase transition in terms of dimension 2 gluon condensate. The role played by the quantum and local nature of the ...
BFFT formalism applied to the minimal chiral Schwinger model
Natividade, C P; Belvedere, L V
2000-01-01
The minimal chiral Schwinger model is discussed from the Batalin-Fradkin-Fradkina-Tyutin point of view. The conversion of second-class constraints to first-class ones results in an extended gauge-invariant theory which is equivalent for $a=2$ to the vector Schwinger model at the Lagrangian level. Here, we present arguments which show that such equivalence does no exist at the operatorial level.
Hadron Properties in a Chiral Quark-Sigma Model
Rashdan, M; El-Kholy, S; Abu-Shady, M
2011-01-01
Within a chiral quark sigma model in which quarks interact via the exchange of sigma and pi-mesons, hadron properties are investigated. This model of the nucleon and delta is based on the idea that strong QCD forces on very short distances (a small length scales 0.2- 1 fm) result in hidden chiral SU(2)xSU(2) symmetry and that there is a separation of roles between these forces which are responsible for binding quarks in hadrons and the forces which produce absolute confinement. We have solved the field equations in the mean field approximation for the hedgehog baryon state with different sets of model parameters. A new parametrization which well describe the nucleon properties has been introduced and compared with experimental data.
Opportunities for collective model and chirality studies at TRIUMF
International Nuclear Information System (INIS)
First predictions for a specific case of the particle-hole-core coupling model which takes advantage of symmetries of a triaxial rotor with γ = 90° are reviewed. Results of the model calculations point towards existence of stable chiral geometry in specific configurations involving high-j orbitals. Next, experimental information on doublet bands built on unique parity, πh11/2νh11/2 intruder states in odd-odd 134Pr is discussed; in particular observed disagreements between electromagnetic transitions within the doublet structures which is pointed out as inconsistent with the simplest models. Finally, the unique experimental infrastructure developed at the Tri-University Meson Facility (TRIUMF) Canada's National Laboratory for Particle and Nuclear Physics is presented including a range of isotopes in the mass 130 region that are accessible as beams and which can possibly yield significant new information in investigations of nuclear chirality. (author)
Chiral symmetry breaking in lattice QED model with fermion brane
Shintani, E
2012-01-01
We propose a novel approach of spontaneous chiral symmetry breaking at near zero temperature in 4 dimensional QED model with 3+1 dimensional fermion brane using Hybrid Monte Carlo simulation. We consider an anisotropic QED coupling in non-compact QED action with the manifest gauge invariant interaction and fermi-velocity which is less than speed of light. This model allows for the scaling study at low temperature and strong coupling region with reduced computational cost. We compute the chiral condensate and its susceptibility with different coupling constant, velocity parameter and flavor number, and therefore obtain a compatible behavior with gap equation in broken phase. We also discuss about the comparison of Graphene model.
ND^(*) and NB^(*) interactions in a chiral quark model
Yang, Dan; Zhang, Dan
2015-01-01
ND and ND^* interactions become a hot topic after the observation of new charmed hadrons \\Sigma_c(2800) and \\Lambda_c(2940)^+. In this letter, we have preliminary investigated S-wave ND and ND^* interactions with possible quantum numbers in the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving the resonating group method equation. The numerical results show that the interactions between N and D or N and D^* are both attractive, which are mainly from \\sigma exchanges between light quarks. Further bound-state studies indicate the attractions are strong enough to form ND or ND^* molecules, except for (ND)_{J=3/2} and (ND^*)_{J=3/2} in the chiral SU(3) quark model. In consequence ND system with J=1/2 and ND^* system with J=3/2 in the extended SU(3) quark model could correspond to the observed \\Sigma_c(2800) and \\Lambda_c(2940)^+, respectively. Naturally, the same method can be applied to research NB and NB^* interactions, and similar conclusions obtained, i.e. NB and NB^* attractive fo...
Microscopically constrained mean-field models from chiral nuclear thermodynamics
Rrapaj, Ermal; Roggero, Alessandro; Holt, Jeremy W.
2016-06-01
We explore the use of mean-field models to approximate microscopic nuclear equations of state derived from chiral effective field theory across the densities and temperatures relevant for simulating astrophysical phenomena such as core-collapse supernovae and binary neutron star mergers. We consider both relativistic mean-field theory with scalar and vector meson exchange as well as energy density functionals based on Skyrme phenomenology and compare to thermodynamic equations of state derived from chiral two- and three-nucleon forces in many-body perturbation theory. Quantum Monte Carlo simulations of symmetric nuclear matter and pure neutron matter are used to determine the density regimes in which perturbation theory with chiral nuclear forces is valid. Within the theoretical uncertainties associated with the many-body methods, we find that select mean-field models describe well microscopic nuclear thermodynamics. As an additional consistency requirement, we study as well the single-particle properties of nucleons in a hot/dense environment, which affect e.g., charged-current weak reactions in neutron-rich matter. The identified mean-field models can be used across a larger range of densities and temperatures in astrophysical simulations than more computationally expensive microscopic models.
An Anderson-like model of the QCD chiral transition
Giordano, Matteo; Pittler, Ferenc
2016-01-01
We study the problems of chiral symmetry breaking and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We recast the staggered Dirac operator into an unconventional three-dimensional Anderson Hamiltonian ("Dirac-Anderson Hamiltonian") carrying internal degrees of freedom, with disorder provided by the fluctuations of the gauge links. In this framework, we identify the features relevant to chiral symmetry restoration and localisation of the low-lying Dirac eigenmodes in the ordering of the local Polyakov lines, and in the related correlation between spatial links across time slices, thus tying the two phenomena to the deconfinement transition. We then build a toy model based on QCD and on the Dirac-Anderson approach, replacing the Polyakov lines with spin variables and simplifying the dynamics of the spatial gauge links, but preserving the above-mentioned relevant dynamical features. Our toy model successfully reproduces the main features of the...
Continuum model for chiral induced spin selectivity in helical molecules
Energy Technology Data Exchange (ETDEWEB)
Medina, Ernesto [Centro de Física, Instituto Venezolano de Investigaciones Científicas, 21827, Caracas 1020 A (Venezuela, Bolivarian Republic of); Groupe de Physique Statistique, Institut Jean Lamour, Université de Lorraine, 54506 Vandoeuvre-les-Nancy Cedex (France); Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); González-Arraga, Luis A. [IMDEA Nanoscience, Cantoblanco, 28049 Madrid (Spain); Finkelstein-Shapiro, Daniel; Mujica, Vladimiro [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); Berche, Bertrand [Centro de Física, Instituto Venezolano de Investigaciones Científicas, 21827, Caracas 1020 A (Venezuela, Bolivarian Republic of); Groupe de Physique Statistique, Institut Jean Lamour, Université de Lorraine, 54506 Vandoeuvre-les-Nancy Cedex (France)
2015-05-21
A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented p{sub z} type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective π{sub z} − π{sub z} coupling via interbase p{sub x,y} − p{sub z} hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-adiabatic Aharonov-Anandan phase. To describe room temperature transport, we assume that the total transmission is the result of a product of coherent steps.
Chiral-Symmetric Technicolor with Standard Model Higgs boson
Pasechnik, Roman; Kuksa, Vladimir; Vereshkov, Grigory
2013-01-01
Most of the traditional Technicolor-based models are known to be in a strong tension with the electroweak precision data. We show that this serious issue is naturally cured in strongly coupled sectors with chiral-symmetric vector-like gauge interactions in the framework of gauged linear sigma model. We discuss possible phenomenological implications of such non-standard chiral-symmetric Technicolor scenario in its simplest formulation preserving the standard Higgs mechanism and (possibly) elementary Higgs boson of the Standard Model (SM). For this purpose, we assume the existence of an extra technifermion sector confined under extra SU(3)_TC at the energy scales reachable at the LHC, Lambda_TC ~ 0.1-1 TeV, and interacting with the SM gauge bosons in a chiral-symmetric (vector-like) way. In the framework of this scenario, the SM Higgs vev acquires natural interpretation in terms of the condensate of technifermions in confinement. We study the influence of the lowest lying composite physical states, namely, tech...
Can sigma models describe finite temperature chiral transitions?
Kocic, Aleksandar; Aleksandar KOCIC; John KOGUT
1995-01-01
Large-N expansions and computer simulations indicate that the universality class of the finite temperature chiral symmetry restoration transition in the 3D Gross-Neveu model is mean field theory. This is a counterexample to the standard 'sigma model' scenario which predicts the 2D Ising model universality class. We trace the breakdown of the standard scenario (dimensional reduction and universality) to the absence of canonical scalar fields in the model. We point out that our results could be generic for theories with dynamical symmetry breaking, such as Quantum Chromodynamics.
Pion Effect of Nuclear Matter in a Chiral Sigma Model
Institute of Scientific and Technical Information of China (English)
HU Jin-niu; Y.Ogawa; H.Toki; A.Hosaka; SHEN Hong
2009-01-01
We develop a new framework for the study of the nuclear matter based on the linear sigma model.We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion.We extend the relativistic chiral mean field model by using the similar method in the tensor optimized shell model.We also regulate the pion-nucleon interaction by considering the form-factor and short range repulsion effects.We obtain the equation of state of nuclear matter and study the importance of the pion effect.
Deep inelastic structure functions in the chiral bag model
Energy Technology Data Exchange (ETDEWEB)
Sanjose, V. (Valencia Univ. (Spain). Dept. de Didactica de las Ciencias Experimentales); Vento, V. (Valencia Univ. (Spain). Dept. de Fisica Teorica; Centro Mixto CSIC/Valencia Univ., Valencia (Spain). Inst. de Fisica Corpuscular)
1989-10-02
We calculate the structure functions for deep inelastic scattering on baryons in the cavity approximation to the chiral bag model. The behavior of these structure functions is analyzed in the Bjorken limit. We conclude that scaling is satisfied, but not Regge behavior. A trivial extension as a parton model can be achieved by introducing the structure function for the pion in a convolution picture. In this extended version of the model not only scaling but also Regge behavior is satisfied. Conclusions are drawn from the comparison of our results with experimental data. (orig.).
Relativistic Chiral Mean Field Model for Finite Nuclei
Ogawa, Yoko; Toki, Hiroshi; Tamenaga, Setsuo; Haga, Akihiro
2012-01-01
We present a relativistic chiral mean field (RCMF) model, which is a method for the proper treatment of pion-exchange interaction in the nuclear many-body problem. There the dominant term of the pionic correlation is expressed in two-particle two-hole (2p-2h) states with particle-holes having pionic quantum number, J^{pi}. The charge-and-parity-projected relativistic mean field (CPPRMF) model developed so far treats surface properties of pionic correlation in 2p-2h states with J^{pi} = 0^{-} ...
On the chiral phase transition in the linear sigma model
International Nuclear Information System (INIS)
The Cornwall- Jackiw-Tomboulis (CJT) effective action for composite operators at finite temperature is used to investigate the chiral phase transition within the framework of the linear sigma model as the low-energy effective model of quantum chromodynamics (QCD). A new renormalization prescription for the CJT effective action in the Hartree-Fock (HF) approximation is proposed. A numerical study, which incorporates both thermal and quantum effect, shows that in this approximation the phase transition is of first order. However, taking into account the higher-loop diagrams contribution the order of phase transition is unchanged. (author)
NN Scattering Phase Shifts in a Chiral Constituent Quark Model
Bartz, D.; Stancu, Fl
2000-01-01
We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces succesfully the baryon spectra. We calculate the 3S1 and 1S0 phase shifts by using the resonating group method. They clearly indicate the presence of a strong repulsive interaction at short distance, due to the spin-flavor symmetry of the quark-quark interaction and of the quark interchange between the two interacting nucleons. A sigma-exchange quark-quark interaction, providing a medium-range at...
Finite-temperature corrections in the dilated chiral quark model
International Nuclear Information System (INIS)
We calculate the finite-temperature corrections in the dilated chiral quark model using the effective potential formalism. Assuming that the dilaton limit is applicable at some short length scale, we interpret the results to represent the behavior of hadrons in dense and hot matter. We obtain the scaling law, fπ(T)/fπ = mQ(T)/mQ ≅ mσ(T)/mσwhile we argue, using PCAC, that pion mass does not scale within the temperature range involved in our Lagrangian. It is found that the hadron masses and the pion decay constant drop faster with temperature in the dilated chiral quark model than in the conventional linear sigma model that does not take into account the QCD scale anomaly. We attribute the difference in scaling in heat bath to the effect of baryonic medium on thermal properties of the hadrons. Our finding would imply that the AGS experiments (dense and hot matter) and the RHIC experiments (hot and dilute matter) will ''see'' different hadron properties in the hadronization exit phase
Solitons in a chiral quark model with non-local interactions
Golli, B; Ripka, G; Golli, Bojan; Broniowski, Wojciech; Ripka, Georges
1998-01-01
Hedgehog solitons are found in a chiral quark model with non-local interactions. The solitons are stable without the chiral-circle constraint for the meson fields, as was assumed in previous Nambu-Jona--Lasinio model with local interactions.
Fluctuations and the Phase Transition in a Chiral Model with Polyakov Loops
Sasaki, C.; Friman, B.; Redlich, K.
2007-01-01
We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation, where both chiral symmetry and confinement are taken into account. We focus on the phase structure of the model and study the chiral and Polyakov loop susceptibilities.
Baryon resonances in a chiral confining model, 1
Umino, Y
1998-01-01
In this two part series a chiral confining model of baryons is used to describe low--lying negative parity resonances $N^*$, $\\Delta^*$, $\\Lambda^*$ and $\\Sigma^*$ in the mean field approximation. A physical baryon in this model consists of interacting valence quarks, mesons and a color and chiral singlet hybrid field coexisting inside a dynamically generated confining region. This first paper presents the quark contribution to the masses and wave functions of negative parity baryons calculated with an effective spin--isospin dependent instanton induced interaction. It does not include meson exchanges between quarks. The three--quark wave functions are used to calculate meson--excited baryon vertex functions to lowest order in meson--quark coupling. When the baryons are on mass--shell each of these vertex functions is a product of a coupling constant and a form factor. As examples, quark contributions to $N^*$ hadronic form factors as well as axial coupling constants are extracted from the vertex functions an...
Chiral Phase Transition at Finite Isospin Density in Linear Sigma Model
Institute of Scientific and Technical Information of China (English)
SHU Song; LI Jia-Rong
2005-01-01
Using the linear sigma model, we have introduced the pion isospin chemical potential. The chiral phase transition is studied at finite temperatures and finite isospin densities. We have studied the μ - T phase diagram for the chiral phase transition and found the transition cannot happen below a certain low temperature because of the BoseEinstein condensation in this system. Above that temperature, the chiral phase transition is studied by the isotherms of pressure versus density. We indicate that the transition, in the chiral limit, is a first-order transition from a low-density phase to a high-density phase like a gas-liquid phase transition.
Explicit chiral symmetry breaking in Gross-Neveu type models
Energy Technology Data Exchange (ETDEWEB)
Boehmer, Christian
2011-07-25
This thesis is devoted to the study of a 1+1-dimensional, fermionic quantum field theory with Lagrangian L= anti {psi}i{gamma}{sup {mu}}{partial_derivative}{sub {mu}}{psi}-m{sub 0} anti {psi}{psi}+(g{sup 2})/(2)(anti {psi}{psi}){sup 2}+(G{sup 2})/(2)(anti {psi}i{gamma}{sub 5}{psi}){sup 2} in the limit of an infinite number of flavors, using semiclassical methods. The main goal of the present work was to see what changes if we allow for explicit chiral symmetry breaking, either by a bare mass term, or a splitting of the scalar and pseudo-scalar coupling constants, or both. In the first case, this becomes the massive NJL{sub 2} model. In the 2nd and 3rd cases we are dealing with a model largely unexplored so far. The first half of this thesis deals with the massive NJL{sub 2} model. Before attacking the phase diagram, it was necessary to determine the baryons of the model. We have carried out full numerical Hartree-Fock calculations including the Dirac sea. The most important result is the first complete phase diagram of the massive NJL{sub 2} model in ({mu},T,{gamma}) space, where {gamma} arises from m{sub 0} through mass renormalization. In the 2nd half of the thesis we have studied a generalization of the massless NJL{sub 2} model with two different (scalar and pseudoscalar) coupling constants, first in the massless version. Renormalization of the 2 coupling constants leads to the usual dynamical mass by dynamical transmutation, but in addition to a novel {xi} parameter interpreted as chiral quenching parameter. As far as baryon structure is concerned, the most interesting result is the fact that the new baryons interpolate between the kink of the GN model and the massless baryon of the NJL{sub 2} model, always carrying fractional baryon number 1/2. The phase diagram of the massless model with 2 coupling constants has again been determined numerically. At zero temperature we have also investigated the massive, generalized GN model with 3 parameters. It is well
Confined Chiral Solitons in the Spectral Quark Model
Ruiz-Arriola, E; Golli, B; Arriola, Enrique Ruiz; Broniowski, Wojciech; Golli, Bojan
2006-01-01
Chiral solitons with baryon number one are investigated in the spectral quark model. In this model the quark propagator is a superposition of complex mass propagators with a suitable spectral function. As a result, the constituent quark mass is identified with saddle points of the Dirac eigenvalues. Due to this feature the valence quarks never become unbound nor dive into the negative spectrum, hence providing stable solitons as absolute minima of the action. This a manifestation of the built-in analytic confinement in the spectral quark model. Self-consistent mean field hedgehog solutions are found and some of their properties determined. Our analysis constitutes an example of a treatment of a relativistic complex mass system.
Alajmi, Mohammed F; Hussain, Afzal; Suhail, Mohd; Mukhtar, Sofi Danish; Sahoo, Dibya Ranjan; Asnin, Leonid; Ali, Imran
2016-09-01
Chiral high-performance liquid chromatography (HPLC) separation and modeling of four stereomers of DL-leucine-tryptophan DL-dipeptide on AmyCoat-RP column are described. The mobile phase applied was ammonium acetate (10 mM)-methanol-acetonitrile (50:5:45, v/v). The flow rate of the mobile phases was 0.8 mL/min with UV detection at 230 nm. The values of retention factors for LL-, DD-, DL-, and LD- stereomers were 2.25, 3.60, 5.00, and 6.50, respectively. The values of separation and resolution factors were 1.60, 1.39, and 1.30 and 7.76, 8.05, and 7.19. The limits of detection and quantitation were ranging from 1.0-2.3 and 5.6-14.0 μg/mL. The simulation studies established the elution orders and the mechanism of chiral recognition. It was seen that π-π connections and hydrogen bondings were the main forces for enantiomeric resolution. The reported chiral HPLC method may be applied for the enantiomeric separation of DL-leucine-DL-tryptophan in unknown matrices. Chirality 28:642-648, 2016. © 2016 Wiley Periodicals, Inc. PMID:27474783
Selected problems of baryons spectroscopy: chiral soliton versus quark models
Kopeliovich, Vladimir B
2008-01-01
Inconsistency between rigid rotator and bound state models at arbitrary number of colors, rigid rotator -- soft rotator dilemma and some other problems of baryon spectroscopy are discussed in the framework of the chiral soliton approach (CSA). Consequences of the comparison of CSA results with simple quark models are considered and the $1/N_c$ expansion for the effective strange antiquark mass is presented, as it follows from the CSA. Strong dependence of the effective strange antiquark mass on the SU(3) multiplet is required to fit the CSA predictions. The difference of `good' and `bad' diquark masses, which is about 100 Mev, is in reasonable agreement with other estimates. Multibaryons (hypernuclei) with strangeness are described and some states of interest are predicted within CSA as well.
SIMP model at NNLO in chiral perturbation theory
DEFF Research Database (Denmark)
Hansen, Martin Rasmus Lundquist; Langaeble, K.; Sannino, F.
2015-01-01
We investigate the phenomenological viability of a recently proposed class of composite dark matter models where the relic density is determined by 3 to 2 number-changing processes in the dark sector. Here the pions of the strongly interacting field theory constitute the dark matter particles....... By performing a consistent next-to-leading and next-to-next-to-leading order chiral perturbative investigation we demonstrate that the leading order analysis cannot be used to draw conclusions about the viability of the model. We further show that higher order corrections substantially increase the tension...... with phenomenological constraints challenging the viability of the simplest realisation of the strongly interacting massive particle (SIMP) paradigm....
Chiral Dynamics and Dubna-Mainz-Taipei Dynamical Model for Pion-Photoproduction Reaction
Yang, Shin Nan
2010-01-01
We demonstrate that the Dubna-Mainz-Taipei (DMT) meson-exchange dynamical model, which starts from an effective chiral Lagrangian, for pion photoproduction provides an excellent and economic framework to describe both the pi^0 threshold production and the Delta deformation, two features dictated by chiral dynamics.
Finite-Temperature Phase Structure in the Chiral σ-ω Model with Dilatons
Institute of Scientific and Technical Information of China (English)
ZHANG Xiao-Bing ZHANG Xiao-Bing; LI Xue-Qian; NING Ping-Zhi
2000-01-01
We investigate the finite-temperature phase structure in a scaled chiral model which includes the dilaton (glueball) field. It is shown that hot nuclear matter undergoes a discontinuous transition in the mean field of scalar mesons as well as the Lee-Wick abnormal transition. The corresponding behavior of the gluon condensate during the chiral phase transition is also studied.
Non-uniform chiral phase studied within the Polyakov NJL model
Partyka, Tomasz L.
2010-01-01
We consider how does the introduction of a Polyakov loop affects the spatially inhomogeneous quark condensate. The primary result of our work is that the existence of the spatially non-uniform chiral phase is confirmed within the Polyakov NJL model in a chiral limit. These findings are obtained both in a 3d-cutoff and in a Schwinger (proper time) regularization schemes.
Numerical Evidence of Spin-Chirality Decoupling in the Three-Dimensional Heisenberg Spin Glass Model
Viet, Dao Xuan; Kawamura, Hikaru
2009-01-01
Ordering of the three-dimensional Heisenberg spin glass with Gaussian coupling is studied by extensive Monte Carlo simulations. The model undergoes successive chiral-glass and spin-glass transitions at nonzero temperatures TCG>TSG>0, exhibiting spin-chirality decoupling.
Chiral magnetic conductivity in an interacting lattice model of parity-breaking Weyl semimetal
Buividovich, P. V.; Puhr, M.; Valgushev, S. N.
2015-11-01
We report on the mean-field study of the chiral magnetic effect (CME) in static magnetic fields within a simple model of parity-breaking Weyl semimetal given by the lattice Wilson-Dirac Hamiltonian with constant chiral chemical potential. We consider both the mean-field renormalization of the model parameters and nontrivial corrections to the CME originating from resummed ladder diagrams with arbitrary number of loops. We find that onsite repulsive interactions affect the chiral magnetic conductivity almost exclusively through the enhancement of the renormalized chiral chemical potential. Our results suggest that nontrivial corrections to the chiral magnetic conductivity due to interfermion interactions are not relevant in practice since they only become important when the CME response is strongly suppressed by the large gap in the energy spectrum.
Finite nuclei in relativistic models with a light chiral scalar meson
Furnstahl, R. J.; Serot, Brian D.
1993-05-01
Relativistic chiral models with a light scalar meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. The scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. These deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed.
△△ Dibaryon Structure in Extended Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
DAI Lian-Rong
2005-01-01
@@ The structure of △△ dibaryon is studied in the extended chiral SU(3) quark model in which vector meson exchanges are included. The effect of the vector meson fields is very similar to that of the one-gluon exchange (OGE) interaction. Both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model, the resultant mass of the △△ dibaryon is lower than the threshold of the △△ channel but higher than that of the△Nπ channel.
QCD topological susceptibility from the nonlocal chiral quark model
Nam, Seung-il
2016-01-01
We investigate the QCD topological susceptibility $\\chi_t$ by using the nonlocal chiral quark model (NL$\\chi$QM). This model is based on the liquid instanton QCD-vacuum configuration in which $\\mathrm{SU}(3)$ flavor symmetry is explicitly broken by the current quark mass $(m_{u,d},m_s)\\approx(5,135)$ MeV. To compute $\\chi_t$, the local topological charge density operator $Q_t(x)$ is derived from the effective partition function of NL$\\chi$QM. We take into account the contributions from the leading-order (LO) ones $\\sim\\mathcal{O}(N_c)$ in the $1/N_c$ expansion. We also verify that the analytical expression of $\\chi_t$ in NL$\\chi$QM satisfy the Witten-Veneziano (WV) and the Leutwyler-Smilga (LS) formulae. Once the average instanton size and inter-instanton distance are fixed with $\\bar{\\rho}=1/3$ fm and $\\bar{R}=1$ fm, respectively, all the associated model parameters are all determined self-consistently within the model, including the $\\eta$ and $\\eta'$ weak decay constants. We obtain the results such as $F_{...
Two-loop effective potentials in general N=2, d=3 chiral superfield model
International Nuclear Information System (INIS)
We study local superspace contributions to the low-energy effective action in general chiral three-dimensional superfield model. The effective Kähler and chiral potentials are computed in an explicit form up to the two-loop order. In accordance with the non-renormalization theorem, the ultraviolet divergences appear only in the full superspace while the effective chiral potential receives only finite quantum contributions in the massless case. As an application, the two-loop effective scalar potential is found for the three-dimensional N=2 supersymmetric Wess-Zumino model.
Non-leptonic decays in an extended chiral quark model
Eeg, J O
2012-01-01
We consider the color suppressed (nonfactorizable) amplitude for the decay mode $\\bar{B_{d}^0} \\rightarrow \\pi^0 \\pi^{0} $. We treat the $b$-quark in the heavy quark limit and the energetic light ($u,d,s$) quarks within a variant of Large Energy Effective Theory combined with an extension of chiral quark models. Our calculated amplitude for $\\bar{B_{d}^0} \\rightarrow \\pi^0 \\pi^{0} $ is suppressed by a factor of order $\\Lambda_{QCD}/m_b$ with respect to the factorized amplitude, as it should according to QCD-factorization. Further, for reasonable values of the (model dependent) gluon condensate and the constituent quark mass, the calculated nonfactorizable amplitude for $\\bar{B_{d}^0} \\rightarrow \\pi^0 \\pi^{0} $ can easily accomodate the experimental value. Unfortunately, the color suppressed amplitude is very sensitive to the values of these model dependent parameters. Therefore fine-tuning is necessary in order to obtain an amplitude compatible with the experimental result for $\\bar{B_{d}^0} \\rightarrow \\pi^...
Chiral condensate in the Schwinger model with matrix product operators
Bañuls, Mari Carmen; Cichy, Krzysztof; Jansen, Karl; Saito, Hana
2016-05-01
Tensor network (TN) methods, in particular the matrix product states (MPS) ansatz, have proven to be a useful tool in analyzing the properties of lattice gauge theories. They allow for a very good precision, much better than standard Monte Carlo (MC) techniques for the models that have been studied so far, due to the possibility of reaching much smaller lattice spacings. The real reason for the interest in the TN approach, however, is its ability, shown so far in several condensed matter models, to deal with theories which exhibit the notorious sign problem in MC simulations. This makes it prospective for dealing with the nonzero chemical potential in QCD and other lattice gauge theories, as well as with real-time simulations. In this paper, using matrix product operators, we extend our analysis of the Schwinger model at zero temperature to show the feasibility of this approach also at finite temperature. This is an important step on the way to deal with the sign problem of QCD. We analyze in detail the chiral symmetry breaking in the massless and massive cases and show that the method works very well and gives good control over a broad range of temperatures, essentially from zero to infinite temperature.
Conformal chiral boson models on twisted doubled tori and non-geometric string vacua
Avramis, Spyros D; Prezas, Nikolaos
2009-01-01
We derive and analyze the conditions for quantum conformal and Lorentz invariance of the duality symmetric interacting chiral boson sigma-models, which are conjectured to describe non-geometric string theory backgrounds. The one-loop Weyl and Lorentz anomalies are computed for the general case using the background field method. Subsequently, our results are applied to a class of (on-shell) Lorentz invariant chiral boson models which are based on twisted doubled tori. Our findings are in agreement with those expected from the effective supergravity approach, thereby firmly establishing that the chiral boson models under consideration provide the string worldsheet description of N=4 gauged supergravities with electric gaugings. Furthermore, they demonstrate that twisted doubled tori are indeed the doubled internal geometries underlying a large class of non-geometric string compactifications. For compact gaugings the associated chiral boson models are automatically conformal, a fact that is explained by showing ...
Antikaon induced Ξ production from a chiral model at NLO
Directory of Open Access Journals (Sweden)
Feijoo A.
2014-01-01
Full Text Available We study the meson-baryon interaction in the strangeness S = −1 sector using a chiral unitary approach, paying particular attention to the K̄N → KΞ reaction, especially important for constraining the next-to-leading order chiral terms, and considering also the effect of high spin hyperonic resonances. We also present results for the production of Ξ hyperons in nuclei
Triaxial projected shell model study of chiral rotation in odd-odd nuclei
Energy Technology Data Exchange (ETDEWEB)
Bhat, G.H. [Department of Physics, University of Kashmir, Srinagar, 190 006 (India); Sheikh, J.A. [Department of Physics, University of Kashmir, Srinagar, 190 006 (India); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Palit, R., E-mail: palit@tifr.res.in [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005 (India)
2012-01-20
Chiral rotation observed in {sup 128}Cs is studied using the newly developed microscopic triaxial projected shell model (TPSM) approach. The observed energy levels and the electromagnetic transition probabilities of the nearly degenerate chiral dipole bands in this isotope are well reproduced by the present model. This demonstrates the broad applicability of the TPSM approach, based on a schematic interaction and angular-momentum projection technique, to explain a variety of low- and high-spin phenomena in triaxial rotating nuclei.
An Emergent Universe with Dark Sector Fields in a Chiral Cosmological Model
Beesham, A.; Chervon, S. V.; S. D. Maharaj; Kubasov, A. S.
2013-01-01
We consider the emergent universe scenario supported by a chiral cosmological model with two interacting dark sector fields: phantom and canonical. We investigate the general properties of the evolution of the kinetic and potential energies as well as the development of the equation of state with time. We present three models based on asymptotic solutions and investigate the phantom part of the potential and chiral metric components. The exact solution corresponding to a global emergent unive...
Weak magnetic field effects on chiral critical temperature in a nonlocal Nambu--Jona-Lasinio model
Loewe, M; Villavicencio, C; Zamora, R
2014-01-01
In this article we study the nonlocal Nambu--Jona-Lasinio model with a Gaussian regulator in the chiral limit. Finite temperature effects and the presence of a homogeneous magnetic field are considered. The magnetic evolution of the critical temperature for chiral symmetry restoration is then obtained. Here we restrict ourselves to the case of low magnetic field values, being this a complementary discussion to the exisiting analysis in nonlocal models in the strong magnetic field regime.
Chiral geometry in multiple chiral doublet bands
Zhang, Hao
2015-01-01
The chiral geometry of the multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters $\\gamma$ in the particle rotor model with $\\pi h_{11/2}\\otimes \
Molecular modeling study of chiral drug crystals: lattice energy calculations.
Li, Z J; Ojala, W H; Grant, D J
2001-10-01
The lattice energies of a number of chiral drugs with known crystal structures were calculated using Dreiding II force field. The lattice energies, including van der Waals, Coulombic, and hydrogen-bonding energies, of homochiral and racemic crystals of some ephedrine derivatives and of several other chiral drugs, are compared. The calculated energies are correlated with experimental data to probe the underlying intermolecular forces responsible for the formation of racemic species, racemic conglomerates, or racemic compounds, termed chiral discrimination. Comparison of the calculated energies among ephedrine derivatives reveals that a greater Coulombic energy corresponds to a higher melting temperature, while a greater van der Waals energy corresponds to a larger enthalpy of fusion. For seven pairs of homochiral and racemic compounds, correlation of the differences between the two forms in the calculated energies and experimental enthalpy of fusion suggests that the van der Waals interactions play a key role in the chiral discrimination in the crystalline state. For salts of the chiral drugs, the counter ions diminish chiral discrimination by increasing the Coulombic interactions. This result may explain why salt forms favor the formation of racemic conglomerates, thereby facilitating the resolution of racemates.
Huang, Da
2011-01-01
By applying the closed-time-path Green function formalism to the chiral dynamical model based on an effective Lagrangian of chiral quarks with the nonlinear-realized meson fields as bosonized auxiliary fields, we then arrive at a chiral thermodynamic model for the meson fields with finite temperature. Particular attention is paid to the spontaneous chiral symmetry breaking and restoration from the dynamically generated effective composite Higgs potential of meson fields at finite temperature. It is shown that the minimal condition of the effective composite Higgs potential of meson fields leads to the thermodynamic gap equation at finite temperature, which enables us to investigate the critical behavior of the effective chiral thermodynamical model and to explore the QCD phase transition. After fixing the free parameters in the effective chiral Lagrangian at low energies with zero temperature, we determine the critical temperature of the chiral symmetry restoration and present a consistent prediction for the ...
Chiral spin liquid in the extended Heisenberg model on the Kagome lattice
Hu, Wenjun; Zhu, Wei; Zhang, Yi; Gong, Shoushu; Becca, Federico; Sheng, Dongning; Donna Sheng Team
2015-03-01
We investigate the extended Heisenberg model on the Kagome lattice by using Gutzwiller projected fermionic states and the variational Monte Carlo technique. In particular, when both second- and third-neighbor super-exchanges are considered, we find that a gapped spin liquid described by non-trivial magnetic fluxes and long-range chiral-chiral correlations is energetically favored compared to the gapless U(1) Dirac state. Furthermore, the topological Chern number, obtained by integrating the Berry curvature, and the degeneracy of the ground state, by constructing linearly independent states, lead us to identify this flux state as the chiral spin liquid with C = 1 / 2 fractionalized Chern number.
Resurgence in $\\eta$-deformed Principal Chiral Models
Demulder, Saskia; Thompson, Daniel C
2016-01-01
We study the $SU(2)$ Principal Chiral Model (PCM) in the presence of an integrable $\\eta$-deformation. We put the theory on $\\mathbb{R}\\times S^1$ with twisted boundary conditions and then reduce the circle to obtain an effective quantum mechanics associated with the Whittaker-Hill equation. Using resurgent analysis we study the large order behaviour of perturbation theory and recover the fracton events responsible for IR renormalons. The fractons are modified from the standard PCM due to the presence of this $\\eta$-deformation but they are still the constituents of uniton-like solutions in the deformed quantum field theory. We also find novel $SL(2,\\mathbb{C})$ saddles, thus strengthening the conjecture that the semi-classical expansion of the path integral gives rise to a resurgent transseries once written as a sum over Lefschetz thimbles living in a complexification of the field space. We conclude by connecting our quantum mechanics to a massive deformation of the $\\mathcal{N}=2~$ $4$-d gauge theory with g...
Emerging Potentials in Higher-Derivative Gauged Chiral Models Coupled to N=1 Supergravity
Farakos, Fotis
2012-01-01
We present a new method to introduce scalar potentials to gauge-invariant chiral models coupled to supergravity. The theories under consideration contain consistent higher-derivative terms which do not give rise to instabilities and ghost states. The chiral auxiliaries are not propagating and can be integrated out. Their elimination gives rise to emerging potentials even when there is not a superpotential to start with. We present the case of a single chiral multiplet with and without a superpotential and, in the gauged theory, up to two chiral multiplets coupled to supergravity with no superpotential. A general feature of the emergent potential is that it is negative defined leading to anti-de Sitter vacua. In the gauge models, competing D-terms may lift the potential leading to stable and metastable de Sitter and Minkowski vacua as well with spontaneously broken supersymmetry.
Partially conserved axial-vector current and model chiral field theories in nuclear physics
International Nuclear Information System (INIS)
We comment on the relation between the two standard approaches to chiral symmetry--namely, the current algebra/partially conserved axial-vector current approach and the chiral Lagrangian method--in a manner intended to clarify recent and probable future applications of this symmetry in nuclear physics. Specifically, we show that in explicit chiral field theories the canonical πN scattering amplitude does not have the famed ''Adler zero'' unless partial conservation of axial-vector current holds as an operator equation. This implies that there are a number of familiar chiral models in which the ''Adler self-consistency'' condition does not apply to the canonical pion field. Among the problems of current interest for which our remarks are relevant are the studies of the pion-nucleus optical potential, pion condensation, and the attempts to formulate a model field theory having both reasonable nuclear saturation and good low energy pion phenomenology
Chiral symmetry breaking in d=3 NJL model in external gravitational and magnetic fields
Gitman, D M
1996-01-01
The phase structure of d=3 Nambu-Jona-Lasinio model in curved spacetime with magnetic field is investigated in the leading order of the 1/N-expansion and in linear curvature approximation (an external magnetic field is treated exactly). The possibility of the chiral symmetry breaking under the combined action of the external gravitational and magnetic fields is shown explicitly. At some circumstances the chiral symmetry may be restored due to the compensation of the magnetic field by the gravitational field.
Chiral symmetry breaking in d=3 NJL model in external gravitational and magnetic fields
Gitman, D. M.; Odintsov, S. D.; Shil'nov, Yu. I.
1996-01-01
The phase structure of $d=3$ Nambu-Jona-Lasinio model in curved spacetime with magnetic field is investigated in the leading order of the $1/N$-expansion and in linear curvature approximation (an external magnetic field is treated exactly). The possibility of the chiral symmetry breaking under the combined action of the external gravitational and magnetic fields is shown explicitly. At some circumstances the chiral symmetry may be restored due to the compensation of the magnetic field by the ...
Energy Technology Data Exchange (ETDEWEB)
Saito, H; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Ba nuls, M.C.; Cirac, J.I. [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Poznan Univ. (Poland). Faculty of Physics
2014-12-15
We present our recent results for the tensor network (TN) approach to lattice gauge theories. TN methods provide an efficient approximation for quantum many-body states. We employ TN for one dimensional systems, Matrix Product States, to investigate the 1-flavour Schwinger model. In this study, we compute the chiral condensate at finite temperature. From the continuum extrapolation, we obtain the chiral condensate in the high temperature region consistent with the analytical calculation by Sachs and Wipf.
Coupling of pion condensate, chiral condensate and Polyakov loop in an extended NJL model
Zhang, Zhao; Liu, Yu-Xin
2006-01-01
The Nambu Jona-Lasinio model with a Polyakov loop is extended to finite isospin chemical potential case, which is characterized by simultaneous coupling of pion condensate, chiral condensate and Polyakov loop. The pion condensate, chiral condensate and the Polyakov loop as functions of temperature and isospin chemical potential are investigated by minimizing the thermodynamic potential of the system. The resulting $(T,\\mu_I)$ phase diagram is studied with emphasis on the critical point and Po...
Saito, Hana; Cichy, Krzysztof; Cirac, J Ignacio; Jansen, Karl
2014-01-01
We present our recent results for the tensor network (TN) approach to lattice gauge theories. TN methods provide an efficient approximation for quantum many-body states. We employ TN for one dimensional systems, Matrix Product States, to investigate the 1-flavour Schwinger model. In this study, we compute the chiral condensate at finite temperature. From the continuum extrapolation, we obtain the chiral condensate in the high temperature region consistent with the analytical calculation by Sachs and Wipf.
Solutions of the Modified Chiral Model in (2+1) Dimensions
Ioannidou, Theodora; Zakrzewski, Wojtek
1998-01-01
This paper deals with classical solutions of the modified chiral model on $R^{2+1}$. Such solutions are shown to correspond to products of various factor which we call time-dependent unitons. Then the problem of solving the system of second-order partial differential equations for the chiral field is reduced to solving a sequence of systems of first-order partial differential equations for the unitons.
Influence of the Polyakov loop on the chiral phase transition in the two flavor chiral quark model
Markó, G.; Szép, Zs.
2010-09-01
The SU(2)L×SU(2)R chiral quark model consisting of the (σ,π→) meson multiplet and the constituent quarks propagating on the homogeneous background of a temporal gauge field is solved at finite temperature and quark baryon chemical potential μq using an expansion in the number of flavors Nf, both in the chiral limit and for the physical value of the pion mass. Keeping the fermion propagator at its tree level, several approximations to the pion propagator are investigated. These approximations correspond to different partial resummations of the perturbative series. Comparing their solution with a diagrammatically formulated resummation relying on a strict large-Nf expansion of the perturbative series, one concludes that only when the local part of the approximated pion propagator resums infinitely many orders in 1/Nf of fermionic contributions a sufficiently rapid crossover transition at μq=0 is achieved allowing for the existence of a tricritical point or a critical end point in the μq-T phase diagram. The renormalization and the possibility of determining the counterterms in the resummation provided by a strict large-Nf expansion are investigated.
Unified dark matter and dark energy description in a chiral cosmological model
Abbyazov, Renat R
2014-01-01
We show the way of dark matter and dark energy presentation via ansatzs on the kinetic energies of the fields in the two-component chiral cosmological model. To connect a kinetic interaction of dark matter and dark energy with observational data the reconstruction procedure for the chiral metric component $h_{22}$ and the potential of (self)interaction $V$ has been developed. The reconstruction of $h_{22}$ and $V$ for the early and later inflation have been performed. The proposed model is confronted to $\\Lambda CDM$ model as well.
Unified Dark Matter and Dark Energy Description in a Chiral Cosmological Model
Abbyazov, Renat R.; Chervon, Sergey V.
2013-03-01
We show the way of dark matter and dark energy presentation via ansatzs on the kinetic energies of the fields in the two-component chiral cosmological model (CCM). To connect a kinetic interaction of dark matter and dark energy with observational data the reconstruction procedure for the chiral metric component h22 and the potential of (self-)interaction V has been developed. The reconstruction of h22 and V for the early and later inflation have been performed. The proposed model is confronted to ΛCDM model as well.
Chirality and Circular Polarization in Models of Inflation
Alexander, Stephon; Sims, Robert
2016-01-01
We investigate the possibility that a chiral asymmetry during inflation can manifest as net circular polarization in photons. Using an example known to produce a helicity imbalance in fermions, we show that superhorizon photon modes produced during inflation acquire net circular polarization. Modes that reenter the horizon around last scattering can thermalize into the Cosmic Microwave Background while retaining a portion of their net circular polarization. We also consider the possibility of direct detection of the circular polarization in the CMB.
Formulation and quantization of a generalized model related to the chiral Schwinger model
Bracken, Paul
2009-07-01
A generalized theory which describes fermions interacting with a gauge field is investigated. In 1 + 1 dimensions such a model is equivalent to a theory in which a boson field appears in the Lagrangian density rather than a fermion field. In this form, the Lagrangian density can be diagonalized and then quantized in terms of the transformed fields. The case of the chiral Schwinger model can be obtained from the general model and the physics with respect to the operator form is discussed. It is shown how the theory can be made nonanomalous by means of a Wess-Zumino field.
Chiral Phase Transition in the Soft-Wall Model of AdS/QCD
Chelabi, Kaddour; Huang, Mei; Li, Danning; Wu, Yue-Liang
2015-01-01
We investigate the chiral phase transition in the soft-wall model of AdS/QCD at zero chemical potential for two-flavor and three-flavor cases, respectively. We show that there is no spontaneous chiral symmetry breaking in the original soft-wall model. After detailed analysis, we find that in order to realize chiral symmetry breaking and restoration, both profiles for the scalar potential and the dilaton field are essential. The scalar potential determines the possible solution structure of the chiral condensate, except the mass term, it takes another quartic term for the two-flavor case, and for the three-flavor case, one has to take into account an extra cubic term due to the t'Hooft determinant interaction. The profile of the dilaton field reflects the gluodynamics, which is negative at a certain ultraviolet scale and approaches positive quadratic behavior at far infrared region. With this set-up, the spontaneous chiral symmetry breaking in the vacuum and its restoration at finite temperature can be realize...
The baryon mass calculation in the chiral soliton model at finite temperature and density
International Nuclear Information System (INIS)
In the mean-field approximation, we have studied the soliton which is embedded in a thermal medium within the chiral soliton model. The energy of the soliton or the baryon mass in the thermal medium has been carefully evaluated, in which we emphasize that the thermal effective potential in the soliton energy should be properly treated in order to derive a finite and well-defined baryon mass out of the thermal background. The result of the baryon mass at finite temperatures and densities in chiral soliton model are clearly presented. (author)
1/N/sup 2/ expansion of the mean field for lattice chiral and gauge models
Energy Technology Data Exchange (ETDEWEB)
Brihaye, Y.; Taormina, A.
1985-08-21
For lattice chiral and gauge models the authors develop an /sup 1//N/sup 2/ expansion of the mean-field approximation. Special attention is paid to the free energy for which the effect of fluctuations around the mean-field solution is presented as an /sup 1//N/sup 2/ expansion. The differences between U(N) and SU(N) are pointed out. Finally, for the chiral model the mean-field saddle-point technique is applied to compute the two-point correlation function. (author).
Non-local regularization of chiral quark models in the soliton sector
Ripka, G; Ripka, Georges; Golli, Bojan
1999-01-01
A chiral quark model is described which is regularized in terms of Lorentz invariant non-local interactions. The model is regularized to all loop orders and it ensures the proper quantization of the baryon number. It sustains bound hedgehog solitons which, after suitable centre of mass corrections, can adequately describe the nucleon.
Quantum solitons of the nonlinear sigma-model with broken chiral symmetry
Kostyuk, A P; Chepilko, N M; Okazaki, T
1995-01-01
It is proved that the quantum-mechanical consideration of global breathing of a hedgehog-like field configuration leads to the dynamically stable soliton solutions in the nonlinear sigma-model without the Skyrme term. Such solutions exist only when chiral symmetry of the model is broken.
Efficient modeling of chiral media using SCN-TLM method
Directory of Open Access Journals (Sweden)
Yaich M.I.
2004-01-01
Full Text Available An efficient approach allowing to include linear bi-isotropic chiral materials in time-domain transmission line matrix (TLM calculations by employing recursive evaluation of the convolution of the electric and magnetic fields and susceptibility functions is presented. The new technique consists to add both voltage and current sources in supplementary stubs of the symmetrical condensed node (SCN of the TLM method. In this article, the details and the complete description of this approach are given. A comparison of the obtained numerical results with those of the literature reflects its validity and efficiency.
Orientifold ABJM Matrix Model: Chiral Projections and Worldsheet Instantons
Moriyama, Sanefumi
2016-01-01
We study the partition function of the orientifold ABJM theory, which is a superconformal Chern-Simons theory associated with the orthosymplectic supergroup. We find that the partition function associated with any orthosymplectic supergroup can be realized as that of a Fermi gas system whose density matrix is identical to that associated with the corresponding unitary supergroup with a projection to the even or odd chirality. Furthermore we propose an identity and use it to identify all of the Gopakumar-Vafa invariants for the worldsheet instanton effects systematically.
Chiral density wave versus pion condensation in the 1+1 dimensional NJL model
Adhikari, Prabal
2016-01-01
In this paper, we study the possibility of an inhomogeneous quark condensate in the 1+1 dimensional Nambu-Jona-Lasinio model in the large-$N_c$ limit at finite temperature $T$ and quark chemical potential $\\mu$ using dimensional regularization. The phase diagram in the $\\mu$--$T$ plane is mapped out. At zero temperature, an inhomogeneous phase with a chiral-density wave exists for all values of $\\mu>\\mu_c$. Performing a Ginzburg-Landau analysis, we show that in the chiral limit, the critical point and the Lifschitz point coincide. We also consider the competition between a chiral-density wave and a constant pion condensate at finite isospin chemical potential $\\mu_I$. The phase diagram in the $\\mu_I$--$\\mu$ plane is mapped out and shows a rich phase structure.
QQqq Four-Quark Bound States in Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANG Ming; ZHANG Hai-Xia; ZHANG Zong-Ye
2008-01-01
The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q is the light quark (u, d, or s). We obtain a bound state for the bbnn configuration with quantum number JP=1+, I=0 and for the ccnn (JP=1+, I=0) configuration, which is not bound but slightly above the D*D* threshold (n is u or d quark). Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.
A New Model of Holographic QCD and Chiral Condensate in Dense Matter
Seki, Shigenori
2013-01-01
We consider the model of holographic QCD with asymptotic freedom and gluon condensation in its vacuum. It consists of the color D4-branes and D0-branes as a background and the flavor D8-branes as a probe. By taking a specific field theory limit, the effective coupling decreases to vanish in UV region. We then introduce the uniformly distributed baryons in terms of the baryon vertices and study the density dependence of chiral condensate, which is evaluated using the worldsheet instanton method. In the confined phase, the chiral condensate as a function of density monotonically decreases in high baryon density. Such behavior is in agreement with the expectation, while in extremely low density it increases. We attribute this anomaly to the incorrect approximation of uniformity in very low density. In the deconfined phase the chiral condensate monotonically decreases in the whole region of density.
Liu, Yizhuang; Nowak, Maciej A.; Zahed, Ismail
2016-08-01
We derive an exact formula for the stochastic evolution of the characteristic determinant of a class of deformed Wishart matrices following from a chiral random matrix model of QCD at finite chemical potential. In the WKB approximation, the characteristic determinant describes a sharp droplet of eigenvalues that deforms and expands at large stochastic times. Beyond the WKB limit, the edges of the droplet are fuzzy and described by universal edge functions. At the chiral point, the characteristic determinant in the microscopic limit is universal. Remarkably, the physical chiral condensate at finite chemical potential may be extracted from current and quenched lattice Dirac spectra using the universal edge scaling laws, without having to solve the QCD sign problem.
Surface second harmonic generation of chiral molecules using three-coupled-oscillator model
Institute of Scientific and Technical Information of China (English)
Wang Xiao-Ou; Li Chun-Fei; Li Jun-Qing
2006-01-01
Based on the three-coupled-oscillator molecular model we proposed, the relation between the second-order susceptibilities of a chiral film and the molecular hyperpolarizabilities is given. The effect of microscopic parameters on the second-order susceptibilities is simulated numerically and the difference between the efficiencies of s-polarized second-harmonic fields induced by the left- and the right-handed circularly-polarized fundamental beams is discussed. The theoretical basis for studying second-order nonlinear optical properties of the chiral molecular media with a tripod-like structure is provided in this paper.
Pion Form Factor in Chiral Limit of Hard-Wall AdS/QCD Model
Energy Technology Data Exchange (ETDEWEB)
Anatoly Radyushkin; Hovhannes Grigoryan
2007-12-01
We develop a formalism to calculate form factor and charge density distribution of pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic expressions for these functions and for the pion form factor. They allow to relate such observables as the pion decay constant and the pion charge electric radius to the values of chiral condensate and hard-wall cutoff scale. The evolution of the pion form factor to large values of the momentum transfer is discussed, and results are compared to existing experimental data.
Anomalies and the chiral magnetic effect in the Sakai-Sugimoto model
Rebhan, Anton; Schmitt, Andreas; Stricker, Stefan A.
2009-01-01
In the chiral magnetic effect an imbalance in the number of left- and right-handed quarks gives rise to an electromagnetic current parallel to the magnetic field produced in noncentral heavy-ion collisions. The chiral imbalance may be induced by topologically nontrivial gluon configurations via the QCD axial anomaly, while the resulting electromagnetic current itself is a consequence of the QED anomaly. In the Sakai-Sugimoto model, which in a certain limit is dual to large-N_c QCD, we discuss...
Chiral and U(1) axial symmetry restoration in linear sigma models with two quark flavors
Michalski, S
2006-01-01
We study the restoration of chiral symmetry in linear sigma models with two quark flavors. The models taken into consideration have a U(2) x U(2) and an O(N) internal symmetry. The physical mesons of these models are sigma, pion, \\eta and a_0 where the latter two are not present in the O(N) model. Including two-loop contributions through sunset graphs we calculate the temperature behavior of the order parameter and the masses for explicit chiral symmetry breaking with and without a U(1) axial anomaly. Decay threshold effects introduced by the sunset graphs alter the temperature dependence of the condensate and consequently that of the masses as well. Chiral symmetry tends to be restored at higher temperatures in the two-loop approximation than in the Hartree-Fock approximation. To model a dynamical restoration of the U(1) axial symmetry we imply a temperature-dependent anomaly parameter that sharply drops at about 175 MeV. This triggers the restoration of chiral symmetry before the full symmetry is restored a...
Explicit and Dynamical Chiral Symmetry Bresking in an Effective Quark-Quark Interaction Model
Institute of Scientific and Technical Information of China (English)
宗红石; 吴小华; 侯丰尧; 赵恩广
2004-01-01
A method for obtaining the small current quark mass effect on the dressed quark propagator from an effective quark-quark interaction model is developed. Within this approach both the explicit and dynamical chiral symmetry breakings are analysed. A comparison with the previous results is given.
From Chiral quark dynamics with Polyakov loop to the hadron resonance gas model
Arriola, E Ruiz; Salcedo, L L
2012-01-01
Chiral quark models with Polyakov loop at finite temperature have been often used to describe the phase transition. We show how the transition to a hadron resonance gas is realized based on the quantum and local nature of the Polyakov loop.
A Chiral Schwinger model, its Constraint Structure and Applications to its Quantization
Bracken, Paul
2007-01-01
The Jackiw-Rajaraman version of the chiral Schwinger model is studied as a function of the renormalization parameter. The constraints are obtained and they are used to carry out canonical quantization of the model by means of Dirac brackets. By introducing an additional scalar field, it is shown that the model can be made gauge invariant. The gauge invariant model is quantized by establishing a pair of gauge fixing constraints in order that the method of Dirac can be used.
a Chiral Schwinger Model, its Constraint Structure and Applications to its Quantization
Bracken, Paul
The Jackiw-Rajaraman version of the chiral Schwinger model is studied as a function of the renormalization parameter. The constraints are obtained and they are used to carry out canonical quantization of the model by means of Dirac brackets. By introducing an additional scalar field, it is shown that the model can be made gauge invariant. The gauge invariant model is quantized by establishing a pair of gauge fixing constraints in order that the method of Dirac can be used.
A Chiral Schwinger model, its Constraint Structure and Applications to its Quantization
Bracken, Paul
2007-01-01
The Jackiw-Rajaraman version of the chiral Schwinger model is studied as a function of the renormalization parameter. The constraints are obtained and they are used to carry out canonical quantization of the model by means of Dirac brackets. By introducing an additional scalar field, it is shown that the model can be made gauge invariant. The gauge invariant model is quantized by establishing a pair of gauge fixing constraints, so the method of Dirac can be used.
Ecker, G
1999-01-01
Broken chiral symmetry has become the basis for a unified treatment of hadronic interactions at low energies. After reviewing mechanisms for spontaneous chiral symmetry breaking, I outline the construction of the low--energy effective field theory of the Standard Model called chiral perturbation theory. The loop expansion and the renormalization procedure for this nonrenormalizable quantum field theory are developed. Evidence for the standard scenario with a large quark condensate is presented, in particular from high--statistics lattice calculations of the meson mass spectrum. Elastic pion--pion scattering is discussed as an example of a complete calculation to O(p^6) in the low--energy expansion. The meson--baryon system is the subject of the last lecture. After a short summary of heavy baryon chiral perturbation theory, a recent analysis of pion--nucleon scattering to O(p^3) is reviewed. Finally, I describe some very recent progress in the chiral approach to the nucleon--nucleon interaction.
Chiral Gravitational Waves from Chiral Fermions
Anber, Mohamed M
2016-01-01
We report on a new mechanism that leads to the generation of primordial chiral gravitational waves, and hence, the violation of the parity symmetry in the Universe. We show that nonperturbative production of fermions with a definite helicity is accompanied by the generation of chiral gravitational waves. This is a generic and model-independent phenomenon that can occur during inflation, reheating and radiation eras, and can leave imprints in the cosmic microwave background polarization and may be observed in future ground- and space-based interferometers. We also discuss a specific model where chiral gravitational waves are generated via the production of light chiral fermions during pseudoscalar inflation.
Integrable String Models in Terms of Chiral Invariants of SU(n, SO(n, SP(n Groups
Directory of Open Access Journals (Sweden)
Victor D. Gershun
2008-05-01
Full Text Available We considered two types of string models: on the Riemmann space of string coordinates with null torsion and on the Riemman-Cartan space of string coordinates with constant torsion. We used the hydrodynamic approach of Dubrovin, Novikov to integrable systems and Dubrovin solutions of WDVV associativity equation to construct new integrable string equations of hydrodynamic type on the torsionless Riemmann space of chiral currents in first case. We used the invariant local chiral currents of principal chiral models for SU(n, SO(n, SP(n groups to construct new integrable string equations of hydrodynamic type on the Riemmann space of the chiral primitive invariant currents and on the chiral non-primitive Casimir operators as Hamiltonians in second case. We also used Pohlmeyer tensor nonlocal currents to construct new nonlocal string equation.
Thermodynamic phases and mesonic fluctuations in a chiral nucleon-meson model
Drews, Matthias; Klein, Bertram; Weise, Wolfram
2013-01-01
Studies of the QCD phase diagram must properly include nucleonic degrees of freedom and their thermodynamics in the range of baryon chemical potentials characteristic of nuclear matter. A useful framework for incorporating relevant nuclear physics constraints in this context is a chiral nucleon-meson effective Lagrangian. In the present paper, such a chiral nucleon-meson model is extended with systematic inclusion of mesonic fluctuations using the functional renormalization group approach. The resulting description of the nuclear liquid-gas phase transition shows a remarkable agreement with three-loop calculations based on in-medium chiral effective field theory. No signs of a chiral first-order phase transition and its critical endpoint are found in the region of applicability of the model, at least up to twice the density of normal nuclear matter and at temperatures T<100 MeV. Fluctuations close to the critical point of the first-order liquid-gas transition are also examined with a detailed study of the ...
Polyakov SU(3) extended linear $\\sigma$-model: Sixteen mesonic states in chiral phase-structure
Tawfik, Abdel Nasser
2014-01-01
The derivative of the grand potential in mean field approximation, non-strange and strange condensates and deconfinement phase-transition in thermal and dense hadronic medium are verified in extended SU(3) linear sigma-model (eLSM). In determining the chiral phase-transition, the chiral condensates sigma_x and sigma_y are analysed. The chiral mesonic phase-structures in temperature- and density-dependence are taken as free parameters to be fitted. These parameters are classified corresponding to scalar meson nonets; (pseudo)-scalar and (axial)-vector. For deconfinement phase-transition, effective Polyakov loop-potentials phi and phi^* are utilized. We investigated the in-medium effects on the masses of sixteen mesonic states states. The results are presented for two different forms for the effective Polyakov loop-potential and compared with other models with and without anomalous terms. The Polyakov loop potential in LSM has considerable effects on the chiral phase-transition in meson masses so that the resto...
Structure of the vacuum in the color dielectric model: confinement and chiral symmetry
International Nuclear Information System (INIS)
Two of the most important properties of Quantum Chromodynamic (QCD), spontaneous symmetry breaking of the vacuum and quark confinement at low energy, are first presented. Some important effective models for hadronic physics are then described. Putting QCD on the lattice and using the block-spin method, the color-dielectric model effective Lagrangian is obtained. The structure of the vacuum and the behaviour of uniform quark matter at high intensity are investigated in this model. Its original formulation is extended to handle chiral symmetry (by use of sigma model) and to include negative energy orbitals. At high baryonic density, the model describes the two phase transitions which are expected in QCD: deconfinement of quarks and chiral symmetry restoration. Finally, a heavy meson composed by a charmed quark anti-quark pair, is constructed, and the valence quarks confinement and the vacuum structure around them are studied
Highly nonlinear wave solutions in a dual to the chiral model
Rajeev, S. G.; Ranken, Evan
2016-05-01
We consider a two-dimensional scalar field theory with a nilpotent current algebra, which is dual to the Principal Chiral Model. The quantum theory is renormalizable and not asymptotically free; the theory is strongly coupled at short distances (encountering a Landau pole). We suggest it can serve as a toy model for λ ϕ4 theory in four dimensions, just as the principal chiral model is a useful toy model for Yang-Mills theory. We find some classical wave solutions that survive the strong coupling limit and quantize them by the collective variable method. They describe excitations with an unusual dispersion relation ω ∝|k |2/3 . Perhaps they are the "preons" at strong coupling, the bound states of which form massless particles over long distances.
Highly nonlinear wave solutions in a dual to the chiral model
Rajeev, S G
2016-01-01
We consider a two-dimensional scalar field theory with a nilpotent current algebra, which is dual to the Principal Chiral Model. The quantum theory is renormalizable and not asymptotically free: the theory is strongly coupled at short distances (encountering a Landau pole). We suggest it can serve as a toy model for $\\lambda\\phi^{4}$ theory in four dimensions, just as the principal chiral model is a useful toy model for Yang-Mills theory. We find some classical wave solutions that survive the strong coupling limit and quantize them by the collective variable method. They describe excitations with an unusual dispersion relation $\\omega\\propto|k|^{\\frac{2}{3}}$ . Perhaps they are the "preons" at strong coupling, whose bound states form massless particles over long distances.
Haupert, Levi M.; Simpson, Garth J.
2009-05-01
The past decade has witnessed the emergence of new measurement approaches and applications for chiral thin films and materials enabled by the observations of the high sensitivity of second-order nonlinear optical measurements to chirality. In thin films, the chiral response to second harmonic generation and sum frequency generation (SFG) from a single molecular monolayer is often comparable with the achiral response. The chiral specificity also allows for symmetry-allowed SFG in isotropic chiral media, confirming predictions made ˜50 years ago. With these experimental demonstrations in hand, an important challenge is the construction of intuitive predictive models that allow the measured chiral response to be meaningfully related back to molecular and macromolecular structure. This review defines and considers three distinct mechanisms for chiral effects in uniaxially oriented assemblies: orientational chirality, intrinsic chirality, and isotropic chirality. The role of each is discussed in experimental and computational studies of bacteriorhodopsin films, binaphthol, and collagen. Collectively, these three model systems support a remarkably simple framework for quantitatively recovering the measured chiral-specific activity.
Vector and axial vector mesons in a nonlocal chiral quark model
Izzo Villafañe, M. F.; Gómez Dumm, D.; Scoccola, N. N.
2016-09-01
Basic features of nonstrange vector and axial vector mesons are analyzed in the framework of a chiral quark model that includes nonlocal four-fermion couplings. Unknown model parameters are determined from some input values of masses and decay constants, while nonlocal form factors are taken from a fit to lattice QCD results for effective quark propagators. Numerical results show a good agreement with the observed meson phenomenology.
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
Energy Technology Data Exchange (ETDEWEB)
Biernat, Elmer P. [CFTP, Instituto Superior TÃ©cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; Pena, Maria Teresa [CFTP, Instituto Superior TÃ©cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; Departamento de FÃsica, Instituto Superior TÃ©cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; Ribiero, Jose' Emilio F. [CeFEMA, Instituto Superior TÃ©cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; Stadler, Alfred [Departamento de FÃsica, Universidade de Ãvora, 7000-671 Ãvora, Portugal; Gross, Franz L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-03-01
We propose a model for the quark-antiquark interaction in Minkowski space using the Covariant Spectator Theory. We show that with an equal-weighted scalar-pseudoscalar structure for the confining part of our interaction kernel the axial-vector Ward-Takahashi identity is preserved and our model complies with the Adler-zero constraint for pi-pi-scattering imposed by chiral symmetry.
Vector and axial vector mesons in a nonlocal chiral quark model
Villafañe, M F Izzo; Scoccola, N N
2016-01-01
Basic features of nonstrange vector and axial vector mesons are analyzed in the framework of a chiral quark model that includes nonlocal four fermion couplings. Unknown model parameters are determined from some input values of masses and decay constants, while nonlocal form factors are taken from a fit to lattice QCD results for effective quark propagators. Numerical results show a good agreement with the observed meson phenomenology.
Higgs-Yukawa model in chirally-invariant lattice field theory
Energy Technology Data Exchange (ETDEWEB)
Bulava, John [CERN, Geneva (Switzerland). Physics Department; Gerhold, Philipp; Kallarackal, Jim; Nagy, Attila [Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Knippschild, Bastian [National Taiwan Univ., Taipei (China). Dept. of Physics; Lin, C.J. David [National Chiao-Tung Univ., Hsinchu (China). Inst. of Physics; National Centre for Theoretical Sciences, Hsinchu (China). Div. of Physics; Nagai, Kei-Ichi [Nagoya Univ., Nagoya, Aichi (Japan). Kobayashi-Maskawa Institute; Ogawa, Kenji [Chung-Yuan Christian Univ., Chung-Li (China). Dept. of Physics
2012-10-15
Non-perturbative numerical lattice studies of the Higgs-Yukawa sector of the standard model with exact chiral symmetry are reviewed. In particular, we discuss bounds on the Higgs boson mass at the standard model top quark mass, and in the presence of heavy fermions. We present a comprehensive study of the phase structure of the theory at weak and very strong values of the Yukawa coupling as well as at non-zero temperature.
UA(1) breaking and phase transition in chiral random matrix model
Sano, T; Ohtani, M
2009-01-01
We propose a chiral random matrix model which properly incorporates the flavor-number dependence of the phase transition owing to the \\UA(1) anomaly term. At finite temperature, the model shows the second-order phase transition with mean-field critical exponents for two massless flavors, while in the case of three massless flavors the transition turns out to be of the first order. The topological susceptibility satisfies the anomalous \\UA(1) Ward identity and decreases gradually with the temperature increased.
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
Directory of Open Access Journals (Sweden)
Biernat Elmar P.
2016-01-01
Full Text Available We propose a model for the quark-antiquark interaction in Minkowski space using the Covariant Spectator Theory. We show that with an equal-weighted scalar-pseudoscalar structure for the confining part of our interaction kernel the axial-vector Ward-Takahashi identity is preserved and our model complies with the Adler-zero constraint for π-π-scattering imposed by chiral symmetry.
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
Biernat, Elmar P; Ribeiro, J E; Stadler, A; Gross, F
2015-01-01
We propose a model for the quark-antiquark interaction in Minkowski space using the Covariant Spectator Theory. We show that with an equal-weighted scalar-pseudoscalar structure for the confining part of our interaction kernel the axial-vector Ward-Takahashi identity is preserved and our model complies with the Adler-zero constraint for pi-pi-scattering imposed by chiral symmetry.
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
Biernat, Elmar P.; Peña, M. T.; Ribeiro, J. E.; Stadler, A.; Gross, F.
2016-03-01
We propose a model for the quark-antiquark interaction in Minkowski space using the Covariant Spectator Theory. We show that with an equal-weighted scalar-pseudoscalar structure for the confining part of our interaction kernel the axial-vector Ward-Takahashi identity is preserved and our model complies with the Adler-zero constraint for π-π-scattering imposed by chiral symmetry.
Chiral Symmetry Breaking on the Lattice a Study of the Strongly Coupled Lattice Schwinger Model
Berruto, F; Semenoff, Gordon W; Sodano, P
1998-01-01
We revisit the strong coupling limit of the Schwinger model on the lattice using staggered fermions and the hamiltonian approach to lattice gauge theories. Although staggered fermions have no continuous chiral symmetry, they posses a discrete axial invari ance which forbids fermion mass and which must be broken in order for the lattice Schwinger model to exhibit the features of the spectrum of the continuum theory. We show that this discrete symmetry is indeed broken spontaneously in the strong coupling li mit. Expanding around a gauge invariant ground state and carefully considering the normal ordering of the charge operator, we derive an improved strong coupling expansion and compute the masses of the low lying bosonic excitations as well as the chiral co ndensate of the model. We find very good agreement between our lattice calculations and known continuum values for these quantities already in the fourth order of strong coupling perturbation theory. We also find the exact ground state of the antiferromag ...
A large N phase transition in the continuum two dimensional SU(N) X SU(N) principal chiral model
R. Narayanan; Neuberger, H.; Vicari, E.
2008-01-01
It is established by numerical means that the continuum large N principal chiral model in two dimensions has a phase transition in a smoothed two point function at a critical distance of the order of the correlation length.
Zhukovskii, V C; Khudyakov, V V
2000-01-01
The influence of an external constant and homogeneous magnetic field H on the phase structure of the P-symmetric, chiral invariant 3-dimensional field theory model with two four-fermion interaction structures is considered. An arbitrary small (nonzero) magnetic field is shown to induce spontaneous violation of the initial symmetry (magnetic catalysis). Moreover, vacuum of the model at H>0 can be either P-symmetric or chiral invariant, depending on the values of the coupling constants.
Chirality and Z2 vortices in a Heisenberg spin model on the kagome lattice
Domenge, J.-C.; Lhuillier, C.; Messio, L.; Pierre, L.; Viot, P.
2008-05-01
The phase diagram of the classical J1-J2 model on the kagome lattice is investigated by using extensive Monte Carlo simulations. In a realistic range of parameters, this model has a low-temperature chiral-ordered phase without long-range spin order. We show that the critical transition marking the destruction of the chiral order is preempted by the first-order proliferation of Z2 point defects. The core energy of these vortices appears to vanish when approaching the T=0 phase boundary, where both Z2 defects and gapless magnons contribute to disordering the system at very low temperatures. This situation might be typical of a large class of frustrated magnets. Possible relevance for real materials is also discussed.
Modelling the Global Solar Corona II: Coronal Evolution and Filament Chirality Comparison
Yeates, A R; Van Ballegooijen, A A
2007-01-01
The hemispheric pattern of solar filaments is considered using newly-developed simulations of the real photospheric and 3D coronal magnetic fields over a 6-month period, on a global scale. The magnetic field direction in the simulation is compared directly with the chirality of observed filaments, at their observed locations. In our model the coronal field evolves through a continuous sequence of nonlinear force-free equilibria, in response to the changing photospheric boundary conditions and the emergence of new magnetic flux. In total 119 magnetic bipoles with properties matching observed active regions are inserted. These bipoles emerge twisted and inject magnetic helicity into the solar atmosphere. When we choose the sign of this active-region helicity to match that observed in each hemisphere, the model produces the correct chirality for up to 96% of filaments, including exceptions to the hemispheric pattern. If the emerging bipoles have zero helicity, or helicity of the opposite sign, then this percenta...
Zamorano, M.; Torres-Silva, H.
2006-04-01
A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source.
Strange quark matter in a chiral SU(3) quark mean field model
Wang, P.; Lyubovitskij, V. E.; Gutsche, Th.; Faessler, Amand
2002-01-01
We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector m...
Susceptibilities and the Phase Structure of a Chiral Model with Polyakov Loops
Sasaki, C.; Friman, B.; Redlich, K.
2006-01-01
In an extension of the Nambu-Jona-Lasinio model where the quarks interact with the temporal gluon field, represented by the Polyakov loop, we explore the relation between the deconfinement and chiral phase transitions. The effect of Polyakov loop dynamics on thermodynamic quantities, on the phase structure at finite temperature and baryon density and on various susceptibilities is presented. Particular emphasis is put on the behavior and properties of the fluctuations of the (approximate) ord...
The Quantum and Local Polyakov loop in Chiral Quark Models at Finite Temperature
Megias, E.; Arriola, E. Ruiz; Salcedo, L. L.
2006-01-01
We describe results for the confinement-deconfinement phase transition as predicted by the Nambu--Jona-Lasinio model where the local and quantum Polyakov loop is coupled to the constituent quarks in a minimal way (PNJL). We observe that the leading correlation of two Polyakov loops describes the chiral transition accurately. The effects of the current quark mass on the transition are also analysed.
Hu, Wen-Jun; Zhu, Wei; Zhang, Yi; Gong, Shoushu; Becca, Federico; Sheng, D. N.
2015-01-01
We investigate the extended Heisenberg model on the kagome lattice by using Gutzwiller projected fermionic states and the variational Monte Carlo technique. In particular, when both second- and third-neighbor superexchanges are considered, we find that a gapped spin liquid described by nontrivial magnetic fluxes and long-range chiral-chiral correlations is energetically favored compared to the gapless U(1) Dirac state. Furthermore, the topological Chern number, obtained by integrating the Berry curvature, and the degeneracy of the ground state, by constructing linearly independent states, lead us to identify this flux state as the chiral spin liquid with a C =1 /2 fractionalized Chern number.
Ebert, D; Klimenko, K G
2016-01-01
In this paper we investigate the phase structure of a (1+1)-dimensional schematic quark model with four-quark interaction and in the presence of baryon ($\\mu_B$), isospin ($\\mu_I$) and chiral isospin ($\\mu_{I5}$) chemical potentials. It is established that in the large-$N_c$ limit ($N_c$ is the number of colored quarks) there exists a duality correspondence between the chiral symmetry breaking phase and the charged pion condensation (PC) one. The role and influence of this property on the phase structure of the model are studied. Moreover, it is shown that the chemical potential $\\mu_{I5}$ promotes the appearance of the charged PC phase with nonzero baryon density.
A chiral matrix model of the semi-Quark Gluon Plasma in QCD
Pisarski, Robert D
2016-01-01
A chiral matrix model applicable to QCD with 2+1 flavors is developed. This requires adding a SU(3)_L x SU(3)_R x Z(3)_A nonet of scalar fields, with both parities, and coupling these to quarks through a Yukawa coupling, y. Treating the scalar fields in mean field approximation, the effective Lagrangian is computed by integrating out quarks to one loop order. In addition to the usual symmetry breaking term, linear in the current quark mass m_qk, at a nonzero temperature T it is necessary to add a new term, ~ m_qk T^2. The parameters of the gluon part of the matrix model, including especially the deconfining transition temperature T_d = 270 MeV, are identical to that for the pure glue theory without quarks. The parameters in the chiral matrix model are fixed by the values, at zero temperature, of the pion decay constant the masses of the pions, kaons, eta, and eta'. The temperature for the chiral crossover at T_chi = 155 MeV is determined by adjusting the Yukawa coupling y. We find reasonable agreement with th...
Chiral phase transition in a lattice fermion-gauge-scalar model with U(1) gauge symmetry
International Nuclear Information System (INIS)
The chiral phase transition induced by a charged scalar field is investigated numerically in a lattice fermion-gauge-scalar model with U(1) gauge symmetry, proposed recently as a model for dynamical fermion mass generation. For very strong gauge coupling the transition is of second order and its scaling properties are very similar to those of the Nambu-Jona-Lasinio model. However, in the vicinity of the tricritical point at somewhat weaker coupling, where the transition changes the order, the scaling behavior is different. Therefore it is worthwhile to investigate the continuum limit of the model at this point. (orig.)
Understanding complex chiral plasmonics
Duan, Xiaoyang; Yue, Song; Liu, Na
2015-10-01
Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant and simple analytical model, which can describe, predict, and comprehend the chiroptical spectra in detail. Our study will shed light on designing well-controlled chiral-achiral coupling platforms for reliable chiral sensing.Chiral nanoplasmonics exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response within nanoscale metallic structures. Recently, a number of different approaches have been utilized to create chiral nanoplasmonic structures. However, particularly for tailoring nanooptical chiral sensing devices, the understanding of the resulting chiroptical response when coupling chiral and achiral structures together is crucial and has not been completely understood to date. Here, we present a thorough and step-by-step experimental study to understand the intriguing chiral-achiral coupling scheme. We set up a hybrid plasmonic system, which bears resemblance to the `host-guest' system in supramolecular chemistry to analyze and explain the complex chiral response both at the chiral and achiral plasmonic resonances. We also provide an elegant
Poisson bracket algebra for chiral group elements in the WZNW model
Bimonte, G; Simoni, A; Stern, A
1992-01-01
We examine the Wess-Zumino-Novikov-Witten (WZNW) model on a circle and compute the Poisson bracket algebra for left and right moving chiral group elements. Our computations apply for arbitrary groups and boundary conditions, the latter being characterized by the monodromy matrix. Unlike in previous treatments, they do not require specifying a particular parametrization of the group valued fields in terms of angles spanning the group. We do however find it necessary to make a gauge choice, as the chiral group elements are not gauge invariant observables. (On the other hand, the quadratic form of the Poisson brackets may be defined independent of a gauge fixing.) Gauge invariant observables can be formed from the monodromy matrix and these observables are seen to commute in the quantum theory.
Non-Abelian twisted kinks in chiral Gross-Neveu model with isospin
Thies, Michael
2015-01-01
The two-dimensional, massless Gross-Neveu model with Nc colors and SU(2) isospin is studied analytically in the large Nc limit. The chiral SU(2)L X SU(2)R symmetry is broken spontaneously in the vacuum. Twisted kinks connecting two arbitrary points on the vacuum manifold S3 are constructed, and their properties are explored. The phase diagram as a function of temperature, baryon- and isospin chemical potential is discussed, with special emphasis on inhomogeneous phases. The preferred form of the condensate is a product of the real kink crystal and the chiral spiral. Kink-kink scattering is solved, using the general solution of the multicomponent Bogoliubov-de Gennes equation recently presented by Takahashi.
Chiral Symmetry Breaking and External Fields in the Kuperstein-Sonnenschein Model
Alam, M Sohaib; Kundu, Arnab
2012-01-01
A novel holographic model of chiral symmetry breaking has been proposed by Kuperstein and Sonnenschein by embedding non-supersymmetric probe D7 and anti-D7 branes in the Klebanov-Witten background. We study the dynamics of the probe flavours in this model in the presence of finite temperature and a constant electromagnetic field. In keeping with the weakly coupled field theory intuition, we find the magnetic field promotes spontaneous breaking of chiral symmetry whereas the electric field restores it. The former effect is universally known as the "magnetic catalysis" in chiral symmetry breaking. In the presence of an electric field such a condensation is inhibited and a current flows. Thus we are faced with a steady-state situation rather than a system in equilibrium. We conjecture a definition of thermodynamic free energy for this steady-state phase and using this proposal we study the detailed phase structure when both electric and magnetic fields are present in two representative configurations: mutually p...
Jiang, Wei-Zhou; Li, Bao-An; Chen, Lie-Wen
2007-01-01
Using in-medium hadron properties according to the Brown-Rho scaling due to the chiral symmetry restoration at high densities and considering naturalness of the coupling constants, we have newly constructed several relativistic mean-field Lagrangians with chiral limits. The model parameters are adjusted such that the symmetric part of the resulting equation of state at supra-normal densities is consistent with that required by the collective flow data from high energy heavy-ion reactions, whi...
Hu, Zhan-Ning
In this letter, the connection is found between the "star-square" relation in the Baxter-Bazhanov model and the "star-triangle" relation in the chiral Potts model, which means that the tetrahedron equation of the Baxter-Bazhanov model is a consequence of the latter. The four additional constraints in the tetrahedron equation given by Kashaev et al. hold naturally in respect to the spherical trigonometry parametrizations.
Fragmentation functions of pions and kaons in the nonlocal chiral quark model
Directory of Open Access Journals (Sweden)
Kao Chung Wen
2014-03-01
Full Text Available We investigate the unpolarized pion and kaon fragmentation functions using the nonlocal chiral-quark model. In this model the interactions between the quarks and pseudoscalar mesons is manifested nonlocally. In addition, the explicit flavor SU(3 symmetry breaking effect is taken into account in terms of the current quark masses. The results of our model are evaluated to higher Q2 value Q2 = 4 GeV2 by the DGLAP evolution. Then we compare them with the empirical parametrizations. We find that our results are in relatively good agreement with the empirical parametrizations and the other theoretical estimations.
Magnetic catalysis and inverse magnetic catalysis in nonlocal chiral quark models
Pagura, V P; Noguera, S; Scoccola, N N
2016-01-01
We study the behavior of strongly interacting matter under an external constant magnetic field in the context of nonlocal chiral quark models within the mean field approximation. We find that at zero temperature the behavior of the quark condensates shows the expected magnetic catalysis effect, our predictions being in good quantitative agreement with lattice QCD results. On the other hand, in contrast to what happens in the standard local Nambu-Jona-Lasinio model, when the analysis is extended to the case of finite temperature our results show that nonlocal models naturally lead to the Inverse Magnetic Catalysis effect.
Chirally Invariant Avatar in a Model of Neutrinos with Light Cone Reflection Symmetry
Chodos, Alan
2016-01-01
In previous work we developed a model of neutrinos based on a new symmetry, Light Cone Reflection (LCR), that interchanges spacelike and timelike intervals. In this paper we start with the four-dimensional model, and construct a two-dimensional avatar that obeys the same equations of motion, and preserves both the light-cone reflection symmetry and the chiral symmetry of the original theory. The avatar also contains the interaction that rendered the four-dimensional model gauge invariant. In an addendum, we make some remarks about how to determine the scalar field that enters into the definition of the LCR-covariant derivative.
The chiral magnetic effect in hydrodynamical approach
Sadofyev, A. V.; Isachenkov, M. V.
2010-01-01
In quark-gluon plasma nonzero chirality can be induced by the chiral anomaly. When a magnetic field is applied to a system with nonzero chirality an electromagnetic current is induced along the magnetic field. This phenomenon is called the chiral magnetic effect. In this paper appearance of the chiral magnetic effect in hydrodynamical approximation is shown. We consider a hydrodynamical model for chiral liquid with two independent currents of left and right handed particles in the presence of...
Model studies of the chiral and deconfinement transitions in QCD
Naylor, William R
2015-01-01
The Doctoral thesis of William Naylor. Gives the background of the three papers included, specifically introducing both the quark meson model and the NJL model, the basic formalism of thermal field theory, and functional renormalization group (including some details on numerically solving the FRG equation for the QM model).
Kalaydzhyan, Tigran
2014-01-01
We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields or rotation the motion of the "superfluid" component gives rise to the chiral magnetic, chiral vortical, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model.
Abu-Shady, M
2015-01-01
The chiral symmetry breaking in the presence of external magnetic field is studied in the framework of logarithmic quark-sigma model. The effective logarithmic mesonic potential is employed and is numerically solved in the mean-field approximation. We find that the chiral symmetry breaking enhances in comparison with the original sigma model. Two sets of parameterization are investigated in the present model. We find that increasing coupling constant enhances the breaking symmetry while increasing sigma mass inhibits enhancing chiral broken vacuum state. A comparison with the Numbu-Jona-Lasinio model and the Schwinger-Dyson equation is discussed. We conclude that the logarithmic sigma model enhances the magnetic catalysis in comparison with the original sigma model and other models.
Eta and kaon production in a chiral quark model
Golli, Bojan
2016-01-01
We apply a coupled-channel formalism incorporating quasi-bound quark-model states to calculate pion scattering into eta N, K Lambda and K Sigma channels, as well eta p, eta n, K+Lambda, and K0Sigma+ photo-production processes. The meson-baryon and photon-baryon vertices are determined in a SU(3) version of the Cloudy Bag Model. Our model predicts sizable amplitudes in the P11, P13, P33 and S11 partial waves in agreement with the latest MAID isobar model and the recent partial-wave analyses of the Bonn-Gatchina group. We are able to give a quark-model explanation for the apparent resonance at 1685 MeV in the eta n channel.
Kaon semileptonic decay (K_{l3}) form factor in the nonlocal chiral quark model
Nam, Seung-il
2007-01-01
We investigate the kaon semileptonic decay (K_{l3}) form factors within the framework of the nonlocal chiral quark model from the instanton vacuum, taking into account the effects of flavor SU(3) symmetry breaking. All theoretical calculations are carried out without any adjustable parameter. We also show that the present results satisfy the Callan-Treiman low-energy theorem as well as the Ademollo-Gatto theorem. It turns out that the effects of flavor SU(3) symmetry breaking are essential in reproducing the kaon semileptonic form factors. The present results are in a good agreement with experiments, and are compatible with other model calculations.
Anomalous transport model study of chiral magnetic effects in heavy ion collisions
Sun, Yifeng; Li, Feng
2016-01-01
Using an anomalous transport model for massless quarks, we study the effect of magnetic field on the elliptic flows of quarks and antiquarks in relativistic heavy ion collisions. With initial conditions from a blast wave model and assuming that the strong magnetic field produced in non-central heavy ion collisions can last for a sufficiently long time, we obtain an appreciable electric quadrupole moment in the transverse plane of a heavy ion collision, which subsequently leads to a splitting between the elliptic flows of quarks and antiquarks as expected from the chiral magnetic wave formed in the produced QGP and observed in experiments at the Relativistic Heavy Ion Collider (RHIC).
A chiral random matrix model with 2+1 flavors at finite temperature and density
Fujii, H
2009-01-01
Phase diagram of a chiral random matrix model with the degenerate ud quarks and the s quark at finite temperature and density is presented. The model exhibits a first-order transition at finite temperature for three massless flavors, owing to the U_A(1) breaking determinant term. We study the order of the transition with changing the quark masses and the quark chemical potential, and show that the first-order transition region expands as the chemical potential increases. We also discuss the behavior of the meson masses and the susceptibilities near the critical point.
Generalized vector form factors of the pion in a chiral quark model
Broniowski, Wojciech
2008-01-01
Generalized vector form factors of the pion, related to the moments of the generalized parton distribution functions, are evaluated in the Nambu--Jona-Lasinio model with the Pauli-Villars regularization. The lowest moments (the electromagnetic and the gravitational form factors) are compared to recent lattice data, with fair agreement. Predictions for higher-order moments are also made. Relevant features of the generalized form factors in the chiral quark models are highlighted and the role of the QCD evolution for the higher-order GFFs is stressed.
The Role of Stochastic Models in Interpreting the Origins of Biological Chirality
Directory of Open Access Journals (Sweden)
Gábor Lente
2010-04-01
Full Text Available This review summarizes recent stochastic modeling efforts in the theoretical research aimed at interpreting the origins of biological chirality. Stochastic kinetic models, especially those based on the continuous time discrete state approach, have great potential in modeling absolute asymmetric reactions, experimental examples of which have been reported in the past decade. An overview of the relevant mathematical background is given and several examples are presented to show how the significant numerical problems characteristic of the use of stochastic models can be overcome by non-trivial, but elementary algebra. In these stochastic models, a particulate view of matter is used rather than the concentration-based view of traditional chemical kinetics using continuous functions to describe the properties system. This has the advantage of giving adequate description of single-molecule events, which were probably important in the origin of biological chirality. The presented models can interpret and predict the random distribution of enantiomeric excess among repetitive experiments, which is the most striking feature of absolute asymmetric reactions. It is argued that the use of the stochastic kinetic approach should be much more widespread in the relevant literature.
The nonstrange dibaryon and hidden-color effect in a chiral quark model
Dai, L. R.; Zhang, Y. N.; Sun, Y. L.; Shao, S. J.
2016-09-01
The exotic nonstrange ΔΔ dibaryon with I(JP) = 0(3+) has been confirmed by the experimental data reported by WASA-at-COSY Collaboration, and the result is consistent with our theoretical prediction in the chiral SU(3) quark model and extended chiral SU(3) quark model, showing that the effect from hidden-color channel ( CC is important. In the present work, we further investigate another exotic nonstrange ΔΔ dibaryon with I(JP) = 3(0+) in the chiral SU(3) quark model that describes the energies of baryon ground states and the nucleon-nucleon (NN) scattering data satisfactorily. We perform a dynamical coupled-channel study of the ΔΔ - CC system with I(JP) = 3(0+) within the framework of resonating group method (RGM). We find that the binding energy of I(JP) = 3(0+) state is about 22.3 MeV and a root-mean-square radius (RMS) of 1.03 fm in single-channel calculation. Then we extend the model to include the CC channel to further study the I(JP) = 3(0+) state and find that the binding energy is about 31.3 MeV and RMS is 0.97 fm in coupled-channel calculation. We can see that the CC channel coupling has a relatively large effect on this state. The color screening effect is further considered and we find that the bound state property will not change much. It is shown that the binding energy of this state is stably ranged around several tens of MeV; it means that its mass is always lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ.
Chiral condensate in the Schwinger model with Matrix Product Operators
Bañuls, Mari Carmen; Jansen, Karl; Saito, Hana
2016-01-01
Tensor network (TN) methods, in particular the Matrix Product States (MPS) ansatz, have proven to be a useful tool in analyzing the properties of lattice gauge theories. They allow for a very good precision, much better than standard Monte Carlo (MC) techniques for the models that have been studied so far, due to the possibility of reaching much smaller lattice spacings. The real reason for the interest in the TN approach, however, is its ability, shown so far in several condensed matter models, to deal with theories which exhibit the notorious sign problem in MC simulations. This makes it prospective for dealing with the non-zero chemical potential in QCD and other lattice gauge theories, as well as with real-time simulations. In this paper, using matrix product operators, we extend our analysis of the Schwinger model at zero temperature to show the feasibility of this approach also at finite temperature. This is an important step on the way to deal with the sign problem of QCD. We analyze in detail the chir...
On Exotic Systems of Baryons in Chiral Soliton Models
Kopeliovich, Vladimir
2016-01-01
The role of zero mode quantum corrections to the energy of baryonic systems with exotic quantum numbers (strangeness) is discussed. A simple expression for the contribution depending on strange inertia is obtained in the $SU(3)-$collective coordinate quantization approach, and it is shown that this correction stabilizes the systems the stronger the greater their baryon number is. Furthemore, systems are considered which could be interpreted in the quark model language as containing additional $q\\bar q-$pairs. It is argued that a strange skyrmion crystal should have additional binding in comparison with the $SU(2)-$quantized neutron crystal.
Meson cloud effects on the pion quark distribution function in the chiral constituent quark model
Watanabe, Akira; Suzuki, Katsuhiko
2016-01-01
We investigate the valence quark distribution function of the pion $v^{\\pi}(x,Q^2)$ in the framework of the chiral constituent quark model and evaluate the meson cloud effects on $v^{\\pi}(x,Q^2)$. We explicitly demonstrate how the meson cloud effects affect $v^{\\pi}(x,Q^2)$ in detail. We find that the meson cloud correction causes an overall 32\\% reduction of the valence quark distribution and an enhancement at the small Bjorken $x$ regime. Besides, we also find that the dressing effect of the meson cloud will make the valence quark distribution to be softer in the large $x$ region.
$Z_b(10650)$ and $Z_b(10610)$ states in a chiral quark model
Li, M. T.; Wang, W L; Dong, Y. B.; Zhang, Z. Y.
2012-01-01
We perform a systematic study of $B\\bar{B}^*$, $B^*\\bar{B}^*$, $D\\bar{D}^*$ and $D^*\\bar{D}^*$ systems by using effective interaction in our chiral quark model. Our results show that the interactions of $B\\bar{B}^*$, $B^*\\bar{B}^*$, $D\\bar{D}^*$ and $D^*\\bar{D}^*$ states are attractive, which consequently result in $B\\bar{B}^*$, $B^*\\bar{B}^*$, $D\\bar{D}^*$ and $D^*\\bar{D}^*$ bound states. The recent observed exotic-like hadrons of $Z_b(10610)$ and $Z_b(10650)$ are, therefore in our approach,...
Chiral phase transition in an extended linear sigma model: initial results
Wolf, Gy; Szép, Zs
2014-01-01
We investigate the scalar meson mass dependence on the chiral phase transition in the framework of an SU(3), (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops. We determine the parameters of the Lagrangian at zero temperature in a hybrid approach, where we treat the mesons at tree-level, while the constituent quarks at 1-loop level. We assume two nonzero scalar condensates and together with the Polyakov-loop variables we determine their temperature dependence according to the 1-loop level field equations.
Nucleon shape and electromagnetic form factors in the chiral constituent quark model
Dahiya, Harleen
2010-01-01
The electromagnetic form factors are the most fundamental quantities to describe the internal structure of the nucleon and the shape of a spatially extended particle is determined by its intrinsic quadrupole moment which can be related to the charge radii. We have calculated the electromagnetic form factors, nucleon charge radii and the intrinsic quadrupole moment of the nucleon in the framework of chiral constituent quark model. The results obtained are comparable to the latest experimental studies and also show improvement over some theoretical interpretations.
Chiral symmetry and chiral-symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Peskin, M.E.
1982-12-01
These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)
Two chiral preon models with SU(N) metacolor satisfying complementarity
Geng, C. Q.; Marshak, R. E.
1987-04-01
We have constructed two chiral preon models based on the group SU(N)MC×SU(N+4)F×U(1)F (MC is gauged metacolor and F is global color flavor), the simplest (M=0) version of a class of models SU(N)MC×SU(N+M+4)F×SU(M)F×U(1)F 2 studied by bars and Yankielowicz. In contrast with earlier work, our models satisfy the principle of complementarity between the Higgs and confining phases. In one model, N=16 and four generations of ordinary quarks and leptons are found at the gauged SO(10) level. The second model predicts three quark-lepton families at the gauged SU(5) level without a right-handed neutrino. We also show that complementarity holds for the M≠0 models but that, for N=15 or 16, the results at the gauged level are identical with the M=0 case.
Scaling violation and the magnetic equation of state in chiral models
Almasi, Gabor Andras; Friman, Bengt; Redlich, Krzysztof
2016-01-01
The critical behavior of the order parameter at the chiral phase transition of strongly interacting matter and the corresponding magnetic equation of state is studied within effective models. We explore universal and non-universal structures near the critical point. These include the scaling functions, the leading corrections to scaling and the corresponding size of the critical region as well as their dependence on an external symmetry breaking field. We consider two models in the mean-field approximation, the quark-meson (QM) and the Polyakov loop extended quark-meson (PQM) models, and compare their critical properties with a purely bosonic theory, the $O(N)$ linear sigma (LS) model in the $N\\to\\infty$ limit. In these models the order parameter scaling function is found analytically using the high temperature expansion of the thermodynamic potential. The effects of a gluonic background on the non-universal scaling parameters are quantified within the PQM model.
The projected chiral soliton model with vector mesons
International Nuclear Information System (INIS)
We investigate the solitonic sector of the massive Yang-Mills Lagrangian including σ-, π-, ω-, ρ-, A-mesons as well as valence quarks and apply it to the calculation of some baryonic properties. We perform the canonical quantization which requires the explicit elimination of the time-like components of the vector fields. A mean-field Fock state with hedgehog symmetry is defined as a product of a Slater determinant for the quarks in a 1s-state and coherent states for the mesons. We project this mean-field Fock state onto good spin and isospin by means of Peierls-Yoccoz operators and obtain, after fitting the nucleon mass, a NΔ splitting which is about 80% of the experimental value. A good description of electromagnetic and axial static properties as well as form factors of the nucleon is achieved. Furthermore, the spin content of the nucleon is analyzed in terms of the flavor singlet axial vector coupling constant giving g0A similar 0.44 independently of the input parameters. Finally, the proton-neutron hadronic mass spitting is estimated in the model giving Mn-Mp=2.38±0.55 MeV, the errors reflecting the uncertainty in the up and down quark masses. (orig.)
Structures of (ΩΩ)0+ and (([1])Ω)1+ in Extended Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANG Zong-Ye; YU You-Wen; DAI Lian-Rong
2003-01-01
The structures of (ΩΩ)0+ and (([1])Ω)1+ are studied in the extended chiral SU(3) quark model in whichvector meson exchanges are included. The effect from the vector meson fields is very similar to that from the one-gluonexchange (OGE) interaction. Both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model,di-omega (ΩΩ)0+ is always deeply bound, with over one hundred MeV binding energy, and (([1])Ω)1+ 's binding energyis around 20 MeV. An analysis shows that the quark exchange effect plays a very important role for making di-omega(ΩΩ)0+ deeply bound.
International Nuclear Information System (INIS)
We show that in certain limits the (1+1)-dimensional massive Thirring model at finite temperature T is equivalent to a one-dimensional Coulomb gas of charged particles at the same T. This equivalence is then used to explore the phase structure of the massive Thirring model. For strong coupling and T >>m (the fermion mass), the system is shown to behave as a free gas of 'molecules' (charge pairs in the Coulomb gas terminology) made of pairs of chiral condensates. This binding of chiral condensates is responsible for the restoration of chiral symmetry as T→∞. In addition, when a fermion chemical potential μ≠0 is included, the analogy with a Coulomb gas still holds with μ playing the role of a purely imaginary external electric field. For small T and μ we find a typical massive Fermi gas behaviour for the fermion density, whereas for large μ it shows chiral restoration by means of a vanishing effective fermion mass. Some similarities with the chiral properties of low-energy QCD at finite T and baryon chemical potential are discussed
Path Integral Quantization of the Chiral Schwinger Model in Bosonized Form
Bracken, Paul
The development of the Wess-Zumino action or one-cycle is reviewed from the path integral approach. This is related to the occurrence of anomalies in the theory, and generally signifies a breakdown of gauge invariance. The Jackiw-Rajaraman version of the chiral Schwinger model is studied by means of path integrals. It is shown how the model can be made gauge invariant by using a Wess-Zumino term to write a gauge invariant Lagrangian. The model is considered only in bosonized form without any reference to fermions. The constraints are determined. These components are then used to write a path integral quantization for the bosonized form of the model. Some physical quantities and information, in particular, propagators are derived from the path integral.
Blanco, Celia; Ribó, Josep M; Hochberg, David
2015-02-01
We derive the class of population balance equations (PBE), recently applied to model the Viedma deracemization experiment, from an underlying microreversible kinetic reaction scheme. The continuum limit establishing the relationship between the micro- and macroscopic processes and the associated particle fluxes erases the microreversible nature of the molecular interactions in the population growth rate functions and limits the scope of such PBE models to strict kinetic control. The irreversible binary agglomeration processes modeled in those PBEs contribute an additional source of kinetic control. These limitations are crucial regarding the question of the origin of biological homochirality, where the interest in any model lies precisely in its ability for absolute asymmetric synthesis and the amplification of the tiny inherent statistical chiral fluctuations about the ideal racemic composition up to observable enantiometric excess levels.
Directory of Open Access Journals (Sweden)
Yifeng Chai
2012-01-01
Full Text Available Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol were studied by capillary electrophoresis using six cyclodextrins (CDs as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the –OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.
Anomalous transport model study of chiral magnetic effects in heavy ion collisions
Sun, Yifeng; Ko, Che Ming; Li, Feng
2016-10-01
Using an anomalous transport model for massless quarks and antiquarks, we study the effect of a magnetic field on the elliptic flows of quarks and antiquarks in relativistic heavy ion collisions. With initial conditions from a blast wave model and assuming that the strong magnetic field produced in noncentral heavy ion collisions can last for a sufficiently long time, we obtain an appreciable electric quadrupole moment in the transverse plane of a heavy ion collision. The electric quadrupole moment subsequently leads to a splitting between the elliptic flows of quarks and antiquarks. The slope of the charge asymmetry dependence of the elliptic flow difference between positively and negatively charged particles is positive, which is expected from the chiral magnetic wave formed in the produced QGP and observed in experiments at the BNL Relativistic Heavy Ion Collider, only if the Lorentz force acting on the charged particles is neglected and the quark-antiquark scattering is assumed to be dominated by the chirality changing channel.
Chiral Quark-Meson model of N and DELTA with vector mesons
International Nuclear Information System (INIS)
Vector mesons rho, A1 and ω are introduced in the Chiral Quark-Meson Theory (CQMT) of N and Δ. We propose a new viewpoint for developing CQMT from QCD at the mean-field level. The SU(2) x SU(2) chiral Lagrangian incorporates universal coupling. Accordingly, rho is coupled to the conserved isospin current, A to the partially conserved axial-vector current (PCAC), and ω to the conserved baryon current. As a result the only parameter of the model not directly related to experiment is the quark-pion coupling constant. A fully self-consistent mean-field solution to the model is found for fields in the hedgehog ansatz. The vector mesons play a very important role in the system. They contribute significantly to the values of observables and produce a high-quality fit to many data. The classical stability of the system with respect to hedgehog excitations is analyzed through the use of the Quark-Meson RPA equations (QMRPA)
Vanderheyden, B J; Vanderheyden, Benoit
2000-01-01
We consider a random matrix model which describes the competition between chiral symmetry breaking and the formation of quark Cooper pairs in QCD at finite density. We study the evolution of the phase structure in temperature and chemical potential with variations of the strength of the interaction in the quark-quark channel and demonstrate that the phase diagram can realize a total of six different topologies. A vector interaction representing single-gluon exchange reproduces a topology commonly encountered in previous QCD models, in which a low-density chiral broken phase is separated from a high-density diquark phase by a first-order line. The other five topologies either do not possess a diquark phase or display a new phase and new critical points. Since these five cases require large variations of the coupling constants away from the values expected for a vector interaction, we conclude that the phase diagram of finite density QCD has the topology suggested by single-gluon exchange and that this topology...
Some aspects of pion physics in the Nambu- and Jona-Lasinio model and chiral Lagrangians
International Nuclear Information System (INIS)
I discuss here to what extent the original two-flavour NJL model (which has a minimal number of adjustable parameters) reproduces pion observables. In particular, the sensitivity of the recently calculated electromagnetic mass shift to these NJL parameters is pointed out and a new way to fix them is suggested. A new set of O(1/Nc) diagrams, which are the first meson loop corrections to the RPA, is presented and its effect on the pionic Goldstone mode, its electromagnetic form factor, weak decay constant, and on the constituent quark mass m is discusseed. The relation of these NJL model results to some other chiral Lagrangians is pointed out, where ever possible. The here presented higher order diagrams indicate how one could systematically generate the next-order diagrams. It is, however, questionable whether the simplistic but mathematically manageable contact interaction of the NJL model should be maintained also in these higher order diagrams. (orig.)
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Energy Technology Data Exchange (ETDEWEB)
Gerhold, Philipp; Kallarackal, Jim [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-11-15
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling. (orig.)
The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice
Gerhold, Philipp; Kallarackal, Jim
2011-01-01
The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling.
Modeling Textural Processes during Self-Assembly of Plant-Based Chiral-Nematic Liquid Crystals
Directory of Open Access Journals (Sweden)
Yogesh K. Murugesan
2010-12-01
Full Text Available Biological liquid crystalline polymers are found in cellulosic, chitin, and DNA based natural materials. Chiral nematic liquid crystalline orientational order is observed frozen-in in the solid state in plant cell walls and is known as a liquid crystal analogue characterized by a helicoidal plywood architecture. The emergence of the plywood architecture by directed chiral nematic liquid crystalline self assembly has been postulated as the mechanism that leads to optimal cellulose fibril organization. In natural systems, tissue growth and development takes place in the presence of inclusions and secondary phases leaving behind characteristic defects and textures, which provide a unique testing ground for the validity of the liquid crystal self-assembly postulate. In this work, a mathematical model, based on the Landau-de Gennes theory of liquid crystals, is used to simulate defect textures arising in the domain of self assembly, due to presence of secondary phases representing plant cells, lumens and pit canals. It is shown that the obtained defect patterns observed in some plant cell walls are those expected from a truly liquid crystalline phase. The analysis reveals the nature and magnitude of the viscoelastic material parameters that lead to observed patterns in plant-based helicoids through directed self-assembly. In addition, the results provide new guidance to develop biomimetic plywoods for structural and functional applications.
Modeling chiral sculptured thin films as platforms for surface-plasmonic-polaritonic optical sensing
Mackay, Tom G
2010-01-01
Biomimetic nanoengineered metamaterials called chiral sculptured thin films (CSTFs) are attractive platforms for optical sensing because their porosity, morphology and optical properties can be tailored to order. Furthermore, their ability to support more than one surface-plasmon-polariton (SPP) wave at a planar interface with a metal offers functionality beyond that associated with conventional SPP--based sensors. An empirical model was constructed to describe SPP-wave propagation guided by the planar interface of a CSTF--infiltrated with a fluid which supposedly contains analytes to be detected--and a metal. The inverse Bruggeman homogenization formalism was first used to determine the nanoscale model parameters of the CSTF. These parameters then served as inputs to the forward Bruggeman homogenization formalism to determine the reference relative permittivity dyadic of the infiltrated CSTF. By solving the coresponding boundary-value problem for a modified Kretschmann configuration, the characteristics of t...
Chiral phase transition scenarios from the vector meson extended Polyakov quark meson model
Kovács, Péter
2015-01-01
Chiral phase transition is investigated in an $SU(3)_L \\times SU(3)_R$ symmetric vector meson extended linear sigma model with additional constituent quarks and Polyakov loops (extended Polyakov quark meson model). The parameterization of the Lagrangian is done at zero temperature in a hybrid approach, where the mesons are treated at tree-level, while the constituent quarks at 1-loop level. The temperature and baryochemical potential dependence of the two assumed scalar condensates are calculated from the hybrid 1-loop level equations of states. The order of the phase transition along the $T=0$ and $\\mu_B=0$ axes are determined for various parameterization scenarios. We find that in order to have a first order phase transition at $T=0$ as a function of $\\mu_B$ a light isoscalar particle is needed.
Adler function and hadronic contribution to the muon g-2 in a nonlocal chiral quark model
International Nuclear Information System (INIS)
The behavior of the vector Adler function at spacelike momenta is studied in the framework of a covariant chiral quark model with instantonlike quark-quark interaction. This function describes the transition between the high-energy asymptotically free region of almost massless current quarks to the low-energy hadronized regime with massive constituent quarks. The model reproduces the Adler function and V-A correlator extracted from the ALEPH and OPAL data on hadronic τ lepton decays, transformed into the Euclidean domain via dispersion relations. The leading order contribution from the hadronic part of the photon vacuum polarization to the anomalous magnetic moment of the muon, aμhvp(1), is estimated
Charge radii of octet and decuplet baryons in chiral constituent quark model
Indian Academy of Sciences (India)
Neetika Sharma; Harleen Dahiya
2013-09-01
The charge radii of the spin-$\\dfrac{1}{2}^{+}$ octet and spin-$\\dfrac{3}{2}^{+}$ decuplet baryons have been calculated in the framework of chiral constituent quark model ( CQM) using a general parametrization method (GPM). Our results are not only comparable with the latest experimental studies but also agree with other phenomenological models. The effects of (3) symmetry breaking pertaining to the strangeness contribution and GPM parameters pertaining to the one-, two- and three-quark contributions have also been investigated in detail and are found to be the key parameters in understanding the non-zero values for the neutral octet $(n, \\sum^{0}, \\Xi, )$ and decuplet $(^{0}, \\sum^{*0}, \\Xi^{*0})$ baryons.
Applications of chiral symmetry
Energy Technology Data Exchange (ETDEWEB)
Pisarski, R.D.
1995-03-01
The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T{sub {chi}} implies that the {rho} and a{sub 1} vector mesons are degenerate in mass. In a gauged linear sigma model the {rho} mass increases with temperature, m{sub {rho}}(T{sub {chi}}) > m{sub {rho}}(0). The author conjectures that at T{sub {chi}} the thermal {rho} - a{sub 1}, peak is relatively high, at about {approximately}1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The {omega} meson also increases in mass, nearly degenerate with the {rho}, but its width grows dramatically with temperature, increasing to at least {approximately}100 MeV by T{sub {chi}}. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from {open_quotes}quenched{close_quotes} heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates.
Chiral forces and molecular dissymmetry
International Nuclear Information System (INIS)
Chiral molecules leading to helical macromolecules seem to preserve information and extend it better. In the biological world RNA is the very paradigm for self-replication, elongation and autocatalytic editing. The nucleic acid itself is not chiral. It acquires its chirality by association with D-sugars. Although the chiral information or selectivity put in by the unit monomer is no longer of much interest to the biologists - they tend to leave it to the Darwinian selection principle to take care of it as illustrated by Frank's model - it is vital to understand the origin of chirality. There are three different approaches for the chiral origin of life: (1) Phenomenological, (2) Electromagnetic molecular and Coriolis forces and (3) Atomic or nuclear force, the neutral weak current. The phenomenological approach involves spontaneous symmetry breaking fluctuations in far for equilibrium systems or nucleation and crystallization. Chance plays a major role in the chiral molecule selected
$\\Delta$(1232) electroproduction amplitudes in chiral soliton models of the nucleon
Amoreira, L; Fiolhais, M; Amoreira, Luis; Alberto, Pedro; Fiolhais, Manuel
2000-01-01
The multipole amplitudes for the N - Delta electromagnetic transition are computed in the framework of the linear sigma model and the chiral chromodielectric model for small and moderate photon virtualities. The models include quark and meson degrees of freedom and the nucleon and the delta are clusters of three valence hedgehog quarks surrounded by meson clouds described by coherent states. Angular momentum and isospin projections are performed to endow model states representing the nucleon and the delta with proper quantum numbers. Recoil corrections involved in the process $\\gamma_{\\rm v} N \\to \\Delta$ are taken into account by performing linear momentum projection of the initial and final baryon states. The ratios $E2/M1$ and $C2/M1$ are in good agreement with the data in the two models, but the magnetic amplitude is better reproduced in the Linear Sigma Model. The ratios show little dependence with the model parameters. Both in the Linear Sigma Model and in the Chromodielectric Model the charged pions ar...
Chiral symmetry breaking from two-loop effective potential of the holographic non-local NJL model
International Nuclear Information System (INIS)
We calculate the two-loop effective potential of the non-local Nambu–Jona–Lasinio (NJL) model derived from the Sakai–Sugimoto model in string theory. In contrast to the conventional NJL with 4-fermion contact interaction, the chiral symmetry was previously found to be dynamically broken for an arbitrary weak coupling at the one-loop level. As a confirmation, the approximate numerical solutions to the gap equation at the one-loop level are explicitly demonstrated for weak couplings. We then calculate the one- and two-loop contributions to the effective potential of the non-local NJL model and found that the two-loop contribution is negative. The two-loop potential for the chiral-symmetric vacuum is also negative but larger than the combined effective potential of the chiral broken vacuum at the two-loop level. The chiral symmetry breaking thus persists for the arbitrary weak coupling at the two-loop level. (paper)
Strong decays of N~*(1535) in an extended chiral quark model
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The strong decays of the N*(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqq components in addition to the qqq component.The results show that these five-quark components in N*(1535) contribute significantly to the N*(1535)→ Nπ and N*(1535) → Nη decays.The contributions to the Nη decay come from both the lowest energy and the next-to-lowest energy five-quarks components,while the contributions to the Nπ decay come from only the latter one.Taking these contributions into account,the description for the strong decays of N*(1535) is improved,especially for the puzzling large ratio of the decays to Nη and Nπ.
Chiral phase transition in the vector meson extended linear sigma model
Kovács, Péter; Wolf, György
2015-01-01
In the framework of an SU(3) (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops, we investigate the effects of (axial)vector mesons on the chiral phase transition. The parameters of the Lagrangian are set at zero temperature and we use a hybrid approach where in the effective potential the constituent quarks are treated at one-loop level and all the mesons at tree-level. We have four order parameters, two scalar condensates and two Polyakov loop variables and their temperature and baryochemical potential dependence are determined from the corresponding field equations. We also investigate the changes of the tree-level scalar meson masses in the hot and dense medium.
Neutral kaon mixing beyond the standard model with nf=2+1 chiral fermions
Boyle, P A; Hudspith, R J
2012-01-01
We compute the hadronic matrix elements of the four-quark operators needed for the study of neutral kaon mixing beyond the Standard Model (SM). We use nf=2+1 flavours of domain-wall fermions (DWF) which exhibit good chiral-flavour symmetry. The renormalization is performed non-perturbatively through the RI-MOM scheme and our results are converted perturbatively to MSbar. The computation is performed on a single lattice spacing a=0.086 fm with a lightest unitary pion mass of 290 MeV. The various systematic errors, including the discretisation effects, are estimated and discussed. Our results confirm a previous quenched study, where large ratios of non-SM to SM matrix elements were obtained.
The phase structure of a chirally invariant lattice Higgs-Yukawa model. Numerical simulations
International Nuclear Information System (INIS)
The phase diagram of a chirally invariant lattice Higgs-Yukawa model is explored by means of numerical simulations. The results revealing a rich phase structure are compared to analytical large Nf calculations which we performed earlier. The analytical and numerical results are in excellent agreement at large values of Nf. In the opposite case the large Nf computation still gives a good qualitative description of the phase diagram. In particular we find numerical evidence for the predicted ferrimagnetic phase at intermediate values of the Yukawa coupling constant and for the symmetric phase at strong Yukawa couplings. Emphasis is put on the finite size effects which can hide the existence of the latter symmetric phase. (orig.)
Kharzeev, Dmitri E.; Yee, Ho-Ung
2012-01-01
We consider the properties of electric circuits involving Weyl semimetals. The existence of the anomaly-induced chiral magnetic current in a Weyl semimetal subjected to magnetic field causes an interesting and unusual behavior of such circuits. We consider two explicit examples: i) a circuit involving the "chiral battery" and ii) a circuit that can be used as a "quantum amplifier" of magnetic field. The unique properties of these circuits stem from the chiral anomaly and may be utilized for c...
Inoue, Yoshihisa
2004-01-01
Direct Asymmetric Photochemistry with Circularly Polarized Light, H. RauCoherent Laser Control of the Handedness of Chiral Molecules, P. Brumer and M. ShapiroMagnetochiral Anisotropy in Asymmetric Photochemistry, G.L.J.A.RikkenEnantiodifferentiating Photosensitized Reactions, Y. InoueDiastereodifferentiating Photoreactions, N. Hoffmann and J.-P. PeteChirality in Photochromism, Y. Yokoyama and M. SaitoChiral Photochemistry with Transition Metal Complexes, S. Sakaki and T. HamadaTemplate-Induced Enantioselective Photochemical Reactions in S
Sensitivity to properties of the phi-meson in the nucleon structure in the chiral soliton model
Energy Technology Data Exchange (ETDEWEB)
Mukhopadhyay, N.C.; Zhang, L. [Rensselaer Polytechnic Inst., Troy, NY (United States)
1994-04-01
The influence of the {phi}-meson on the nucleon properties in the chiral soliton model is discussed. Properties of the {phi}-meson and its photo- and electroproduction are of fundamental interest to CEBAF and its possible future extension. The quark model assigns {phi} an s{bar s} structure, thus forbidding the radiative decay {phi}{yields}{pi}{sup 0}{gamma}. Experimentally it is also found to be suppressed, yielding a branching fraction of 1.3{times}10{sup {minus}3}. However, {phi}{yields}{rho}{pi} and {phi}{yields}{pi}{sup +}{pi}{sup {minus}}{pi}{sup 0} are not suppressed at all. Thus, it is possible to incorporate the widths of these decays into the framework of the chiral soliton model, by making use of a specific model for the compliance with OZI rule. Such a model is for example, the {omega}-{phi} mixing model. Consequence of this in the context of a chiral soliton model, which builds on the {pi}{rho}{omega}a{sub 1}(f{sub 1}) meson effective Lagrangian, is the context of this report.
Chiral geometry in multiple chiral doublet bands
Zhang, Hao; Chen, Qibo
2016-02-01
The chiral geometry of multiple chiral doublet bands with identical configuration is discussed for different triaxial deformation parameters γ in the particle rotor model with . The energy spectra, electromagnetic transition probabilities B(M1) and B(E2), angular momenta, and K-distributions are studied. It is demonstrated that the chirality still remains not only in the yrast and yrare bands, but also in the two higher excited bands when γ deviates from 30°. The chiral geometry relies significantly on γ, and the chiral geometry of the two higher excited partner bands is not as good as that of the yrast and yrare doublet bands. Supported by Plan Project of Beijing College Students’ Scientific Research and Entrepreneurial Action, Major State 973 Program of China (2013CB834400), National Natural Science Foundation of China (11175002, 11335002, 11375015, 11461141002), National Fund for Fostering Talents of Basic Science (NFFTBS) (J1103206), Research Fund for Doctoral Program of Higher Education (20110001110087) and China Postdoctoral Science Foundation (2015M580007)
Chiral Crystal Growth under Grinding
Saito, Yukio; Hyuga, Hiroyuki
2008-01-01
To study the establishment of homochirality observed in the crystal growth experiment of chiral molecules from a solution under grinding, we extend the lattice gas model of crystal growth as follows. A lattice site can be occupied by a chiral molecule in R or S form, or can be empty. Molecules form homoclusters by nearest neighbor bonds. They change their chirality if they are isolated monomers in the solution. Grinding is incorporated by cutting and shafling the system randomly. It is shown ...
Thimble regularization at work: From toy models to chiral random matrix theories
Di Renzo, F.; Eruzzi, G.
2015-10-01
We apply the Lefschetz thimble formulation of field theories to a couple of different problems. We first address the solution of a complex zero-dimensional ϕ4 theory. Although very simple, this toy model makes us appreciate a few key issues of the method. In particular, we will solve the model by a correct accounting of all the thimbles giving a contribution to the partition function and we will discuss a number of algorithmic solutions to simulate this (simple) model. We will then move to a chiral random matrix (CRM) theory. This is a somehow more realistic setting, giving us once again the chance to tackle the same couple of fundamental questions: How many thimbles contribute to the solution? How can we make sure that we correctly sample configurations on the thimble? Since the exact result is known for the observable we study (a condensate), we can verify that, in the region of parameters we studied, only one thimble contributes and that the algorithmic solution that we set up works well, despite its very crude nature. The deviation of results from phase quenched ones highlights that in a certain region of parameter space there is a quite important sign problem. In view of this, the success of our thimble approach is quite a significant one.
Chiral heavy fermions in a two Higgs doublet model: 750 GeV resonance or not
Bar-Shalom, Shaouly
2016-01-01
We revisit models where a heavy chiral 4th generation doublet of fermions is embedded in a class of two Higgs doublets models (2HDM) with a discrete $Z_2$ symmetry, which couples the "heavy" scalar doublet only to the 4th generation fermions and the "light" one to the Standard Model (SM) fermions - the so-called 4G2HDM introduced by us several years ago. We study the constraints imposed on the 4G2HDM from direct searches of heavy fermions, from precision electroweak data (PEWD) and from the measured production and decay signals of the 125 GeV scalar, which in the 4G2HDM corresponds to the lightest CP-even scalar h. We then show that the recently reported excess in the $\\gamma\\gamma$ spectrum around 750 GeV can be accommodated by the heavy CP-even scalar of the 4G2HDM, H, resulting in a unique choice of parameter space: negligible mixing (sin\\alpha ~ O(0.001)) between the two CP-even scalars h,H and heavy 4th generation quark and lepton masses m_t',m_b' 900 GeV, respectively. Whether or not the 750 GeV \\gamma...
Thimble regularization at work: from toy models to chiral random matrix theories
Di Renzo, Francesco
2015-01-01
We apply the Lefschetz thimble formulation of field theories to a couple of different problems. We first address the solution of a complex 0-dimensional phi^4 theory. Although very simple, this toy-model makes us appreciate a few key issues of the method. In particular, we will solve the model by a correct accounting of all the thimbles giving a contribution to the partition function and we will discuss a number of algorithmic solutions to simulate this (simple) model. We will then move to a chiral random matrix (CRM) theory. This is a somehow more realistic setting, giving us once again the chance to tackle the same couple of fundamental questions: how many thimbles contribute to the solution? how can we make sure that we correctly sample configurations on the thimble? Since the exact result is known for the observable we study (a condensate), we can verify that, in the region of parameters we studied, only one thimble contributes and that the algorithmic solution that we set up works well, despite its very ...
Signature and parity splitting in rotational bands and chiral bands. Double minimum potential model
International Nuclear Information System (INIS)
The effects of the signature and parity splitting in nuclear spectra and the properties of the chiral bands are analyzed basing on a one-dimensional Schrödinger equation with a double-minimum potential. Rotational bands in odd axial nuclei, alternating parity bands in even-even nuclei and the chiral bands in odd-odd nuclei are considered. The results obtained are discussed.
Chiral U(1) flavor models and flavored Higgs doublets: the top FB asymmetry and the W jj
Energy Technology Data Exchange (ETDEWEB)
Ko, P.; Omura, Yuji; Yu, Chaehyun
2012-01-01
We present U(1) flavor models for leptophobic Z' with flavor dependent couplings to the right-handed up-type quarks in the Standard Model (SM), which can accommodate the recent data on the top forward-backward (FB) asymmetry and the dijet resonance associated with a W boson reported by CDF Collaboration. Such flavor-dependent leptophobic charge assignments generally require extra chiral fermions for anomaly cancellation. Also the chiral nature of U(1)' flavor symmetry calls for new U(1)'-charged Higgs doublets in order for the SM fermions to have realistic renormalizable Yukawa couplings. The stringent constraints from the top FB asymmetry at the Tevatron and the same sign top pair production at the LHC can be evaded due to contributions of the extra Higgs doublets. We also show that the extension could realize cold dark matter candidates.
Properties of mesons and nucleons in chiral topological models of QCD
Rakhimov, A
2005-01-01
The problem under consideration in this thesis has, actually, two aspects. The first one concerns the case when a nucleon is in free space that is in vacuum, while the second one studies a nucleon embedded into a nuclear environment. Both of these two aspects have been considered in the framework of chiral topological models of QCD. The whole content of the thesis may be divided into two main parts. In the first part the original Skyrme model with finite pion mass has been extended by inclusion of the light scalar - isoscalar sigma - meson. The Lagrangian has been further extended by explicit inclusion of sigma, rho and omega - mesons as well. In order to get a more complete picture of NN potential the appropriate meson - nucleon vertex form - factors are obtained. The second part of the thesis considers a nucleon immersed into a nuclear medium. For this purpose a medium modified Skyrme Lagrangian has been proposed. The Lagrangian describes well such well known medium effects as decreasing of nucleon mass and...
A Chiral Composite Model for the 750 GeV Diphoton Resonance
Bai, Yang; Osborne, James; Stefanek, Ben A
2016-01-01
The 750 GeV diphoton resonance could be a big-pion of a new QCD-like strong dynamics with a confinement scale around a few TeV. The new fermion constituents of the big-pions, vector-like under the strong dynamics group, could be chiral under a $U(1)^\\prime$ gauge symmetry, such that their bare masses are related to the $U(1)^\\prime$-breaking and the new confinement scales. Based on a minimal GUT-motivated and gauge anomaly-free model, we have found that the 750 GeV resonance could have an observable branching ratio into $Z^\\prime \\gamma$. The $Z^\\prime$ naturally has a large leptonic branching ratio because of its kinetic mixing with the hypercharge gauge boson. Searching for an $\\ell^+ \\ell^- \\gamma$ 750 GeV resonance with the two lepton invariant mass away from the $Z$-boson pole can confirm our model. Furthermore, the heavier color-octet big-pion can decay into $Z^\\prime g$ and could also be discovered by the LHC Run 2.
Energy Technology Data Exchange (ETDEWEB)
Chu, David Y.J. [National Chiao-Tung Univ., Hsinchu (China). Dept. of Electrophysics; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Knippschild, Bastian [HISKP, Bonn (Germany); Lin, C.J. David [National Chiao-Tung Univ., Hsinchu (China). Inst. of Physics; Nagy, Attila [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik
2015-01-15
We discuss the non-thermal phase structure of a chirally invariant Higgs-Yukawa model on the lattice in the presence of a higher dimensional Φ{sup 6}-term. For the exploration of the phase diagram we use analytical, lattice perturbative calculations of the constraint effective potential as well as numerical simulations. We also present first results of the effects of the Φ{sup 6}-term on the lower Higgs boson mass bounds.
Possible $D\\bar{D}$ and $B\\bar{B}$ Molecular states in a chiral quark model
Li, M T; Dong, Y B; Zhang, Z Y
2012-01-01
We perform a systematic study of the bound state problem of $D\\bar{D}$ and $B\\bar{B}$ systems by using effective interaction in our chiral quark model. Our results show that both the interactions of $D\\bar{D}$ and $B\\bar{B}$ states are attractive, which consequently result in $I^G(J^{PC})=0^+(0^{++})$ $D\\bar{D}$ and $B\\bar{B}$ bound states.
Energy-Momentum Tensor Form Factors of the Nucleon in Nuclear Matter in the Chiral Soliton Model
Yakhshiev, Ulugbek; Kim, Hyun-Chul; Schweitzer, Peter
2013-08-01
In the present talk, we report a recent investigation on the nucleon form factors of the energy-momentum tensor in nuclear matter, based on the in-medium modified chiral soliton model. The results in free space are in agreement with those from other approaches. We have discussed the changes of the energy-momentum tensor form factors in nuclear matter and the modification of the soliton structure due to the surrounding nuclear environment.
Wen, Xiao-Gang
2013-01-01
The standard model is a chiral gauge theory where the gauge fields couple to the right-hand and the left-hand fermions differently. The standard model is defined perturbatively and describes all elementary particles (except gravitons) very well. However, for a long time, we do not know if we can have a non-perturbative definition of the standard model as a Hamiltonian quantum mechanical theory. Here we propose a way to give a modified standard model (with 48 two-component Weyl fermions) a non...
Wen, Xiao-Gang
2013-01-01
The standard model is a chiral gauge theory where the gauge fields couple to the right-hand and the left-hand fermions differently. The standard model is defined perturbatively and describes all elementary particles (except gravitons) very well. However, for a long time, we do not know if we can have a non-perturbative definition of standard model as a Hamiltonian quantum mechanical theory. In this paper, we propose a way to give a modified standard model (with 48 two-component Weyl fermions)...
Nucleon structure functions and longitudinal spin asymmetries in the chiral quark constituent model
Dahiya, Harleen; Randhawa, Monika
2016-06-01
We have analyzed the phenomenological dependence of the spin independent (F1p ,n and F2p ,n) and the spin dependent (g1p ,n) structure functions of the nucleon on the Bjorken scaling variable x using the unpolarized distribution functions of the quarks q (x ) and the polarized distribution functions of the quarks Δ q (x ) respectively. The chiral constituent quark model, which is known to provide a satisfactory explanation of the proton spin crisis and related issues in the nonperturbative regime, has been used to compute explicitly the valence and sea quark flavor distribution functions of p and n . In light of the improved precision of the world data, the p and n longitudinal spin asymmetries [A1p(x ) and A1n(x )] have been calculated. The implication of the presence of the sea quarks has been discussed for the ratio of polarized to unpolarized quark distribution functions for up and down quarks in the p and n Δ/up(x ) up(x ) , Δ/dp(x ) dp(x ) , Δ/un(x ) un(x ) , and Δ/dn(x ) dn(x ) . The ratio of the n and p structure functions Rn p(x )=F/2n(x ) F2p(x ) has also been presented. The results have been compared with the recent available experimental observations. The results on the spin sum rule have also been included and compared with data and other recent approaches.
Sheikh, J A; Dar, W A; Jehangir, S; Ganai, P A
2015-01-01
A systematic investigation of the nuclear observables related to the triaxial degree of freedom is presented using the multi-quasiparticle triaxial projected shell model (TPSM) approach. These properties correspond to the observation of $\\gamma$-bands, chiral doublet bands and the wobbling mode. In the TPSM approach, $\\gamma$-bands are built on each quasiparticle configuration and it is demonstrated that some observations in high-spin spectroscopy that have remained unresolved for quite some time could be explained by considering $\\gamma$-bands based on two-quasiparticle configurations. It is shown in some Ce-, Nd- and Ge-isotopes that the two observed aligned or s-bands originate from the same intrinsic configuration with one of them as the $\\gamma$-band based on a two-quasiparticle configuration. In the present work, we have also performed a detailed study of $\\gamma$-bands observed up to the highest spin in Dysposium, Hafnium, Mercury and Uranium isotopes. Furthermore, several measurements related to chira...
Nucleon structure functions and longitudinal spin asymmetries in the chiral quark constituent model
Dahiya, Harleen
2016-01-01
We have analysed the phenomenological dependence of the spin independent ($F_1^{p,n}$ and $F_2^{p,n}$) and the spin dependent ($g_1^{p,n}$) structure functions of the nucleon on the the Bjorken scaling variable $x$ using the unpolarized distribution functions of the quarks $q(x)$ and the polarized distribution functions of the quarks $\\Delta q(x)$ respectively. The chiral constituent quark model ($\\chi$CQM), which is known to provide a satisfactory explanation of the proton spin crisis and related issues in the nonperturbative regime, has been used to compute explicitly the valence and sea quark flavor distribution functions of $p$ and $n$. In light of the improved precision of the world data, the $p$ and $n$ longitudinal spin asymmetries ($A_1^p(x)$ and $A_1^n(x)$) have been calculated. The implication of the presence of the sea quarks has been discussed for ratio of polarized to unpolarized quark distribution functions for up and down quarks in the $p$ and $n$ $\\frac{\\Delta u^p(x)}{u^p(x)}$, $\\frac{\\Delta d...
Properties of single cluster structure of $d^*(2380)$ in chiral SU(3) quark model
Lü, Qi-Fang; Dong, Yu-Bing; Shen, Peng-Nian; Zhang, Zong-Ye
2016-01-01
The structure of $d^*(2380)$ is re-studied with the single cluster structure in the chiral SU(3) quark model which has successfully been employed to explain the scattering and binding behaviors of baryonic systems. The mass and width are explicitly calculated with two types of trial wave functions. The result shows that the $(0s)^6 [6]_{orb}$ configuration is easy to convert to the configuration with the same $[6]_{orb}$ symmetry but $2\\hbar \\omega$ excitation back and forth, however, it is seldom to turn into a two-cluster configuration with a (1s) relative motion in between. The resultant mass and width are about $2394$MeV and $25$MeV, respectively, and the stable size is about $0.75fm$, which are consistent with both the results in the two-cluster configuration calculation and the data measured by the COSY collaboration. It seems that the observed $d^*$ is a six-quark dominated exotic state with a spherical shape and breath mode in the coordinate space. Moreover, if $d^*$ does have $2\\hbar \\omega$ excitati...
Chiral phase transitions in the linear sigma model in the Tsallis nonextensive statistics
Ishihara, Masamichi
2016-01-01
We studied chiral phase transitions in the Tsallis nonextensive statistics which has two parameters, the temperature $T$ and entropic parameter $q$. The linear sigma model was used in this study. The critical temperature, condensate, masses, and energy density were calculated under the massless free particle approximation. The critical temperature decreases as $q$ increases. The condensate at $q>1$ is smaller than that at $q=1$. The sigma mass at $q>1$ is heavier than the mass at $q=1$ at high temperature, while the sigma mass at $q>1$ is lighter than the mass at $q=1$ at low temperature. The pion mass at $q>1$ is heavier than the mass at $q=1$. The energy density increases remarkably as $q$ increases. The $q$ dependence in the case of the $q$-expectation value is weaker than that in the case of the conventional expectation value with a Tsallis distribution. The parameter $q$ should be smaller than $4/3$ from energetic point of view. The validity of the Tsallis statistics can be determined by the difference i...
Suliman, FakhrEldin O.; Elbashir, Abdalla A.
2012-07-01
Using capillary electrophoresis baclofen (BF) enantiomers were separated only in the presence of β-cyclodextrin (βCD) as a chiral selector when added to the background electrolyte. Proton nuclear magnetic resonance and electrospray ionization mass spectrometry (ESI-MS) techniques were used to determine the structure of the BF-βCD inclusion complexes. From the MS data BF was found to form a 1:1 complex with α- and βCD, while the NMR data suggest location of the aromatic ring of BF into the cyclodextrin cavity. A molecular modeling study, using the semiempirical PM6 calculations was used to investigate the mechanism of enantiodifferentiation of BF with cyclodextrins. Optimization of the structures of the complexes by PM6 method indicated that separation is obtained in the presence of β-CD due to a large binding energy difference (ΔΔE) of 46.8 kJ mol-1 between S-BF-βCD and R-BF-βCD complexes. In the case of αCD complexes ΔΔE was 1.3 kJ mol-1 indicating poor resolution between the two enantiomers. Furthermore, molecular dynamic simulations show that the formation of more stable S-BF-βCD complex compared to R-BF-β-CD complex is primarily due to differences in intermolecular hydrogen bonding.
International Nuclear Information System (INIS)
Chirality has recently been proposed as a novel feature of rotating nuclei [1]. Because the chiral symmetry is dichotomic, its spontaneous breaking by the axial angular momentum vector leads to doublets of closely lying rotational bands of the same parity. To investigate nuclear chirality, next to establish the existence of almost degenerate rotational bands, it is necessary to measure also other observables and compare them to the model predictions. The crucial test for the suggested nuclei as candidates to express chirality is based on precise lifetime measurements. Two lifetime experiments and theoretical approaches for the description of the experimental results will be presented. Lifetimes of exited states in 134Pr were measured [2,3] by means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The branching ratios and the electric or magnetic character of the transitions were also investigated [3]. The experiments were performed at IReS, Strasbourg, using the EUROBALL IV spectrometer, in conjunction with the inner bismuth germanate ball and the Cologne coincidence plunger apparatus. Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F, 4n)134Pr. The possible chiral interpretation of twin bands was investigated in the two-quasiparticle triaxial rotor [1] and interacting boson-fermion-fermion models [4]. Both theoretical approaches can describe the level-scheme of 134Pr. The analysis of the wave functions has shown that the possibility for the angular momenta of the proton, neutron, and core to find themselves in the favorable, almost orthogonal geometry, is present but is far from being dominant [3,5]. The structure is characterized by large β and γ fluctuations. The existence of doublets of bands in 134Pr can be attributed to weak chirality dominated by shape fluctuations. In a second experiment branching ratios and lifetimes in 136Pm were measured by means of the recoil distance Doppler-shift and
Energy Technology Data Exchange (ETDEWEB)
Floss, H.G. [Univ. of Washington, Seattle, WA (United States)
1994-12-01
This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.
Kallin, Catherine; Berlinsky, John
2015-01-01
Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a c...
Quark structure of chiral solitons
Diakonov, D
2004-01-01
There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ``chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ``soliton'', however, with computable relativistic corrections and additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.
Numerical modelling of chirality-induced bi-directional swimming of artificial flagella
Namdeo, S.; Khaderi, S. N.; Onck, P. R.
2014-01-01
Biomimetic micro-swimmers can be used for various medical applications, such as targeted drug delivery and micro-object (e. g. biological cells) manipulation, in lab-on-a-chip devices. Bacteria swim using a bundle of flagella (flexible hair-like structures) that form a rotating cork-screw of chiral
A Conformational Model for MTPA Esters of Chiral N-(2-Hydroxyalkylacrylamides
Directory of Open Access Journals (Sweden)
Eduardo M. Rustoy
2014-01-01
Full Text Available The absolute stereochemistry of novel chiral N-(2-hydroxylalkylacrylamides prepared by a lipase-catalyzed resolution was successfully determined by 1H NMR of their MTPA esters. The method was validated for this particular case by computational experiments.
Wagdy, Hebatallah A; Hanafi, Rasha S; El-Nashar, Rasha M; Aboul-Enein, Hassan Y
2013-09-01
Pharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics-based columns (Chirobiotic V and T), polysaccharide-based chiral column (Chiralpak AD-RH), and protein-based chiral column (Ultron ES-OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. PMID:23775938
Transition State Models for Understanding the Origin of Chiral Induction in Asymmetric Catalysis.
Sunoj, Raghavan B
2016-05-17
In asymmetric catalysis, a chiral catalyst bearing chiral center(s) is employed to impart chirality to developing stereogenic center(s). A rich and diverse set of chiral catalysts is now available in the repertoire of synthetic organic chemistry. The most recent trends point to the emergence of axially chiral catalysts based on binaphthyl motifs, in particular, BINOL-derived phosphoric acids and phosphoramidites. More fascinating ideas took shape in the form of cooperative multicatalysis wherein organo- and transition-metal catalysts are made to work in concert. At the heart of all such manifestations of asymmetric catalysis, classical or contemporary, is the stereodetermining transition state, which holds a perennial control over the stereochemical outcome of the catalytic process. Delving one step deeper, one would find that the origin of the stereoselectivity is delicately dependent on the relative stabilization of one transition state, responsible for the formation of the predominant stereoisomer, over the other transition state for the minor stereoisomer. The most frequently used working hypothesis to rationalize the experimentally observed stereoselectivity places an undue emphasis on steric factors and tends to regard the same as the origin of facial discrimination between the prochiral faces of the reacting partners. In light of the increasing number of asymmetric catalysts that rely on hydrogen bonding as well as other weak non-covalent interactions, it is important to take cognizance of the involvement of such interactions in the sterocontrolling transition states. Modern density functional theories offer a pragmatic and effective way to capture non-covalent interactions in transition states. Aided by the availability of such improved computational tools, it is quite timely that the molecular origin of stereoselectivity is subjected to more intelligible analysis. In this Account, we describe interesting molecular insights into the stereocontrolling
Transition State Models for Understanding the Origin of Chiral Induction in Asymmetric Catalysis.
Sunoj, Raghavan B
2016-05-17
In asymmetric catalysis, a chiral catalyst bearing chiral center(s) is employed to impart chirality to developing stereogenic center(s). A rich and diverse set of chiral catalysts is now available in the repertoire of synthetic organic chemistry. The most recent trends point to the emergence of axially chiral catalysts based on binaphthyl motifs, in particular, BINOL-derived phosphoric acids and phosphoramidites. More fascinating ideas took shape in the form of cooperative multicatalysis wherein organo- and transition-metal catalysts are made to work in concert. At the heart of all such manifestations of asymmetric catalysis, classical or contemporary, is the stereodetermining transition state, which holds a perennial control over the stereochemical outcome of the catalytic process. Delving one step deeper, one would find that the origin of the stereoselectivity is delicately dependent on the relative stabilization of one transition state, responsible for the formation of the predominant stereoisomer, over the other transition state for the minor stereoisomer. The most frequently used working hypothesis to rationalize the experimentally observed stereoselectivity places an undue emphasis on steric factors and tends to regard the same as the origin of facial discrimination between the prochiral faces of the reacting partners. In light of the increasing number of asymmetric catalysts that rely on hydrogen bonding as well as other weak non-covalent interactions, it is important to take cognizance of the involvement of such interactions in the sterocontrolling transition states. Modern density functional theories offer a pragmatic and effective way to capture non-covalent interactions in transition states. Aided by the availability of such improved computational tools, it is quite timely that the molecular origin of stereoselectivity is subjected to more intelligible analysis. In this Account, we describe interesting molecular insights into the stereocontrolling
Quarks, baryons and chiral symmetry
Hosaka, Atsushi
2001-01-01
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w
Gleiser, Marcelo; Thorarinson, Joel; Walker, Sara Imari
2008-12-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively L-amino acids, while only D-sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high intensity and long duration events may drive achiral initial conditions towards chirality. We argue that life’s homochirality resulted from sequential chiral symmetry breaking triggered by environmental events, thus extending the theory of punctuated equilibrium to the prebiotic realm. Applying our arguments to other potentially life-bearing planetary platforms, we predict that a statistically representative sampling will be racemic on average.
Gleiser, Marcelo; Walker, Sara Imari
2008-01-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively levorotatory (L) amino acids, while only dextrorotatory (R) sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high intensity and long duration events may drive achiral initial conditions towards chirality. We argue that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events, thus extending the theory of punctuated equilibrium to the prebiotic realm. Applying our arguments to other potentially life-bearing planetary platforms, we predict that a statistically representative sampling will be racemic on average.
Nonequilibrium chiral perturbation theory and disoriented chiral condensates
Nicola, A G
1999-01-01
We analyse the extension of Chiral Perturbation Theory to describe a meson gas out of thermal equilibrium. For that purpose, we let the pion decay constant be a time-dependent function and work within the Schwinger-Keldysh contour technique. A useful connection with curved space-time QFT allows to consistently renormalise the model, introducing two new low-energy constants in the chiral limit. We discuss the applicability of our approach within a Relativistic Heavy-Ion Collision environment. In particular, we investigate the formation of Disoriented Chiral Condensate domains in this model, via the parametric resonance mechanism.
Chiral Nanoscience and Nanotechnology
Dibyendu S. Bag; T.C. Shami; K.U. Bhasker Rao
2008-01-01
The paper reviews nanoscale science and technology of chiral molecules/macromolecules-under twosubtopics-chiral nanotechnology and nano-chiral technology. Chiral nanotechnology discusses thenanotechnology, where molecular chirality plays a role in the properties of materials, including molecularswitches, molecular motors, and other molecular devices; chiral supramolecules and self-assembled nanotubesand their functions are also highlighted. Nano-chiral technology describes the nanoscale appr...
Hypernucleus-16O in the density-dependent Hartree approach based on the chiral-σ model
International Nuclear Information System (INIS)
A relativistic density-dependent interaction has been used to study hypernucleus 16O. The density-dependent coupling constants of the relativistic effective Hartree-Lagrangian are obtained from the relativistic Brueckner-Bethe-Goldstone results of nuclear matter in the chiral-σ model. With these density-dependent coupling constants, the bound states and the single-particle energy spectra of the hypernuclei Λ16O and Σ16O are obtained. The theoretical results of Λ16O are in agreement with the experimental data fairly well
On the p4-corrections to K → 3π decay amplitudes in nonlinear and linear chiral models
International Nuclear Information System (INIS)
The calculations of isotopic amplitudes and their results for the direct CP-violating charge asymmetry in K± → 3π decays within the nonlinear and linear (σ-model) chiral Lagrangian approach are compared with each other. It is shown, that the latter, taking into account intermediate scalar resonances, does not reproduce the p4-corrections of the nonlinear approach introduced by Gasser and Leutwyler, being saturated mainly by vector resonance exchange. The resulting differences concerning the CP violation effect are traced in some detail. (author). 31 refs., 1 tab
On Chiral Space Groups and Chiral Molecules
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
This note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations). For a chiral molecule, which must crystallize in a chiral space group, the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant.
Taşdemir, Demet; Karaküçük-İyidoğan, Ayşegül; Ulaşli, Mustafa; Taşkin-Tok, Tuğba; Oruç-Emre, Emİne Elçİn; Bayram, Hasan
2015-02-01
A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF-7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC-27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound exhibited the most potent activity (IC50 4.6 μM) against HGC-27 as compared with the reference compound, sindaxel (IC50 10.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents. PMID:25399965
Structures of（ΩΩ）0＋and（[1]Ω）1＋in Extended Chiral SU（3） Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANGZong-Ye; YUYou-Wen; DAILian-Rong
2003-01-01
The structures of (ΩΩ)0+ and ([1]Ω)1+ are studied in the extended chiral SU(3) quark model in which vector meson exchanges are included. The effect from the vector meson fields is very similar to that from the one-gluon exchange (OGE) interaction. Both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model,di-omega (ΩΩ)0+ is always deeply bound, with over one hundred MeV binding energy, and ([1]Ω)1+ 's binding energy is around 20 MeV. An analysis shows that the quark exchange effect plays a very important role for making di-omega (ΩΩ)0+ deeply bound.
Lattice simulation of the SU(2) chiral model at zero and non-zero pion density
Rindlisbacher, Tobias
2015-01-01
We propose a flux representation based lattice formulation of the partition function corresponding to the SU(2) principal chiral Lagrangian, including a chemical potential and scalar/pseudo-scalar source terms. Lattice simulations are then used to obtain non-perturbative properties of the theory, in particular its mass spectrum at zero and non-zero pion density. We also sketch a method to efficiently measure general one- and two-point functions during the worm updates.
Mechanism of chirality conversion by periodic change of temperature: Role of chiral clusters
Katsuno, Hiroyasu; Uwaha, Makio
2016-01-01
By grinding crystals in a solution, the chirality of crystal structure (and the molecular chirality for the case of chiral molecules as well) can be converted, and the cause of the phenomenon is attributed to crystal growth with chiral clusters. We show that the recently found chirality conversion with a periodic change of temperature can also be explained by crystal growth with chiral clusters. With the use of a generalized Becker-Döring model, which includes enantio-selective incorporation of small chiral clusters to large solid clusters, the change of cluster distribution and the mass flow between clusters are studied. The chiral clusters act as a reservoir to pump out the minority species to the majority, and the exponential amplification of the enantiomeric excess found in the experiment is reproduced in the numerical calculation.
The Higgs boson resonance from a chiral Higgs-Yukawa model on the lattice
Energy Technology Data Exchange (ETDEWEB)
Kallarackal, Jim
2011-04-28
Despite the fact that the standard model of particle physics has been confirmed in many high energy experiments, the existence of the Higgs boson is not assured. The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for fermions and the weak gauge bosons. The goal of this work is to set limits on the mass and the decay width of the Higgs boson. The basis to compute the physical quantities is the path integral which is here evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. A polynomial hybrid Monte Carlo algorithm is used to incorporate dynamical fermions. The chiral symmetry of the electroweak model is incorporated by using the Neuberger overlap operator. Here, the standard model is considered in the limit of a Higgs-Yukawa sector which does not contain the weak gauge bosons and only a degenerate doublet of top- and bottom quarks are incorporated. Results from lattice perturbation theory up to one loop of the Higgs boson propagator are compared with those obtained from Monte Carlo simulations at three different values of the Yukawa coupling. At all values of the investigated couplings, the perturbative results agree very well with the Monte Carlo data. A main focus of this work is the investigation of the resonance parameters of the Higgs boson. The resonance width and the resonance mass are investigated at weak and at large quartic couplings. The parameters of the model are chosen such that the Higgs boson can decay into any even number of Goldstone bosons. Thus, the Higgs boson does not appear as an asymptotic stable state but as a resonance. In all considered cases the Higgs boson resonance width lies below 10% of the resonance mass. The obtained resonance mass is compared with the mass obtained from the Higgs boson propagator. The results agree perfectly at all values of the quartic coupling considered. Finally, the effect of a heavy fourth generation of fermions on the
Kojo, Toru; Fukushima, Kenji; McLerran, Larry; Pisarski, Robert D
2011-01-01
We elaborate how to construct the interweaving chiral spirals in (2+1) dimensions, that is defined as a superposition of differently oriented chiral spirals. We divide the two-dimensional Fermi sea into distinct wedges characterized by the opening angle 2 Theta and the depth Q \\simeq pF, where pF is the Fermi momentum. Each wedge earns an energy gain by forming a single chiral spiral. The optimal values for Theta and Q are chosen by the balance between this energy gain and the energy costs from the deformed Fermi surface (dominant at large Theta) and patch-patch interactions (dominant at small Theta). We estimate these energy gains and costs by means of the expansions in terms of 1/Nc, Lambda_QCD/Q, and Theta using a non-local four-Fermi interaction model: At small 1/Nc the mass gap (chiral condensate) is large enough and the interaction among quarks and the condensate is local in momentum space thanks to the form factor in our non-local model. The fact that patch-patch interactions lie only near the patch bo...
Fluctuations and the Phase Transition in a Chiral Model with Polyakov Loops%引入Polyakov环路的手征模型中的涨落与相变
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation, where both chiral symmetry and confinement are taken into account. We focus on the phase structure of the model and study the chiral and Polyakov loop susceptibilities.
Gleiser, Marcelo; Thorarinson, Joel; Walker, Sara Imari
2008-01-01
Most biomolecules occur in mirror, or chiral, images of each other. However, life is homochiral: proteins contain almost exclusively levorotatory (L) amino acids, while only dextrorotatory (R) sugars appear in RNA and DNA. The mechanism behind this fundamental asymmetry of life remains an open problem. Coupling the spatiotemporal evolution of a general autocatalytic polymerization reaction network to external environmental effects, we show through a detailed statistical analysis that high int...
Energy Technology Data Exchange (ETDEWEB)
Zou, Dandan; Cao, Xin [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Lu, Xinpei, E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Ostrikov, Kostya [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000 (Australia); Comonwealth Scientific and Industrial Research Organization, P.O. Box 218, Sydney, New South Wales 2070 (Australia)
2015-10-15
The interaction of time-varying electromagnetic fields and solid, liquid, and gaseous matter may lead to electrical breakdown phenomena through the excitation of ionization waves or streamers that control the dynamics of localized plasma propagation through the media. The streamers usually propagate along straight lines, either between random points in space or along a certain direction in a guided mode. Here, we report on a new type of plasma discharges with the regular helical propagation pattern driven by a pulsed dc voltage in nitrogen at sub-atmospheric-pressure conditions. The helical guided streamers, named chiral streamers or chi-streamers, are excited without any external magnetic fields, which commonly cause helical plasma motions. We also demonstrate a hybrid propagation mode involving the interchangeable chiral streamers and the straight-line propagating plasmas. High-speed, time-resolved optical imaging reveals that the chiral streamers and the hybrid patterns are made of spatially localized discrete plasma bullets, similar to the straight-line guided streamers. These results may enable effective control of propagation of confined plasmas and electromagnetic energy along pre-determined, potentially deterministic paths, which have important implications for the development of next-generation plasma-based radiation sources, communication devices, and medical treatments.
Zou, Dandan; Cao, Xin; Lu, Xinpei; Ostrikov, Kostya Ken
2015-10-01
The interaction of time-varying electromagnetic fields and solid, liquid, and gaseous matter may lead to electrical breakdown phenomena through the excitation of ionization waves or streamers that control the dynamics of localized plasma propagation through the media. The streamers usually propagate along straight lines, either between random points in space or along a certain direction in a guided mode. Here, we report on a new type of plasma discharges with the regular helical propagation pattern driven by a pulsed dc voltage in nitrogen at sub-atmospheric-pressure conditions. The helical guided streamers, named chiral streamers or chi-streamers, are excited without any external magnetic fields, which commonly cause helical plasma motions. We also demonstrate a hybrid propagation mode involving the interchangeable chiral streamers and the straight-line propagating plasmas. High-speed, time-resolved optical imaging reveals that the chiral streamers and the hybrid patterns are made of spatially localized discrete plasma bullets, similar to the straight-line guided streamers. These results may enable effective control of propagation of confined plasmas and electromagnetic energy along pre-determined, potentially deterministic paths, which have important implications for the development of next-generation plasma-based radiation sources, communication devices, and medical treatments.
Chiral phases of fundamental and adjoint quarks
Energy Technology Data Exchange (ETDEWEB)
Natale, A. A. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC 09210-170, Santo André, SP (Brazil); Instituto de Física Teórica - UNESP Rua Dr. Bento T. Ferraz, 271, Bl.II - 01140-070, São Paulo, SP (Brazil)
2016-01-22
We consider a QCD chiral symmetry breaking model where the gap equation contains an effective confining propagator and a dressed gluon propagator with a dynamically generated mass. This model is able to explain the ratios between the chiral transition and deconfinement temperatures in the case of fundamental and adjoint quarks. It also predicts the recovery of the chiral symmetry for a large number of quarks (n{sub f} ≈ 11 – 13) in agreement with lattice data.
Chiral Relaxation Time at the Chiral Crossover of Quantum Chromodynamics
Ruggieri, M; Chernodub, M
2016-01-01
We study microscopic processes responsible for chirality flips in the thermal bath of Quantum Chromodynamics at finite temperature and zero baryon chemical potential. We focus on the temperature range where the crossover from chirally broken phase to quark-gluon plasma takes place, namely $T \\simeq (150, 200)$ MeV. The processes we consider are quark-quark scatterings mediated by collective excitations with the quantum number of pions and $\\sigma$-meson, hence we refer to these processes simply as \\sugg{to} one-pion (one-$\\sigma$) exchange\\sugg{s}. We use a Nambu-Jona-Lasinio model to compute equilibrium properties of the thermal bath, as well as the relevant scattering kernel to be used in the collision integral to estimate the chiral relaxation time $\\tau$. We find $\\tau\\simeq 0.1 \\div 1$ fm/c around the chiral crossover.
Field induced spin chirality and chirality switching in magnetic multilayers
Energy Technology Data Exchange (ETDEWEB)
Tartakovskaya, Elena V., E-mail: elena_tartakovskaya@yahoo.com [Institute of Magnetism NAS of Ukraine, Vernadsky blvd 36b, 03142 Kiev (Ukraine); Institute of High Technologies, Taras Shevchenko National University of Kiev, 03022 Kiev (Ukraine)
2015-05-01
The physical origin of the field-induced spin chirality experimentally observed in rare earth multilayers is determined. It is shown that the effect is possible due to the interplay between solid-state exchange interactions (the Ruderman–Kittel–Kasuya–Yosida and the Dsyaloshinsky–Moriya interactions), the external magnetic field and a special confinement of magnetic constituents. The presented model describes a certain temperature dependence of the chirality factor in agreement with experimental data and opens a new way to design nanostructured objects with predicted handedness. - Highlights: • Field-induced spin chirality in magnetic multilayers is explained. • The roles of the RKKY, the DM and the Zeeman interactions are clarified. • Theoretical analysis of the chirality factor is in agreement with experimental data.
de Boer, T; Bijma, R; Ensing, K
1999-01-01
A two-factor central composite design was used to determine a mathematical model for prediction of the optimal conditions for the separation of the enantiomers of some widely used beta(2)-sympathicomimetic drugs (beta(2)-agonists) by capillary electrophoresis using cyclodextrins (CD) as a chiral sel
Implications of Local Chiral Symmetry Breaking
La, H S
2003-01-01
The spontaneous symmetry breaking of a local chiral symmetry to its diagonal vector symmetry naturally realizes a complete geometrical structure more general than that of Yang-Mills (YM) theory, rather similar to that of gravity. A good example is the Quantum Chromodynamics (QCD) with respect to the Chiral Color model. Also, a new anomaly-free particle content for a Chiral Color model is introduced: the Chiral Color can be realized without introducing whole new generations of quarks and leptons, but by simply enlarging each generation with new exotic fermions.
Chiral Particle Separation by a Nonchiral Microlattice
Bogunovic, Lukas; Fliedner, Marc; Eichhorn, Ralf; Wegener, Sonja; Regtmeier, Jan; Anselmetti, Dario; Reimann, Peter
2012-09-01
We conceived a model experiment for a continuous separation strategy of chiral molecules (enantiomers) without the need of any chiral selector structure or derivatization agents: Microparticles that only differ by their chirality are shown to migrate along different directions when driven by a steady fluid flow through a square lattice of cylindrical posts. In accordance with our numerical predictions, the transport directions of the enantiomers depend very sensitively on the orientation of the lattice relative to the fluid flow.
Tsai, J.-C.; Ye, Fangfu; Rodriguez, Juan; Gollub, J. P.; Lubensky, T. C.
2005-05-01
Inspired by rattleback toys, we created small chiral wires that rotate in a preferred direction on a vertically oscillating platform and quantified their motion with experiment and simulation. We demonstrate experimentally that angular momentum of rotation about particle centers of mass is converted to collective angular momentum of center-of-mass motion in a granular gas of these wires, and we introduce a continuum model that explains our observations.
Energy Technology Data Exchange (ETDEWEB)
Biguet, Alexandre; Hansen, Hubert; Brugiere, Timothee [Universite Claude Bernard de Lyon, Institut de Physique Nucleaire de Lyon, CNRS/IN2P3, Villeurbanne Cedex (France); Costa, Pedro [Universidade de Coimbra, Centro de Fisica Computacional, Departamento de Fisica, Coimbra (Portugal); Borgnat, Pierre [CNRS, l' Ecole normale superieure de Lyon, Laboratoire de Physique, Lyon Cedex 07 (France)
2015-09-15
The measurement of the position of the chiral critical end point (CEP) in the QCD phase diagram is under debate. While it is possible to predict its position by using effective models specifically built to reproduce some of the features of the underlying theory (QCD), the quality of the predictions (e.g., the CEP position) obtained by such effective models, depends on whether solving the model equations constitute a well- or ill-posed inverse problem. Considering these predictions as being inverse problems provides tools to evaluate if the problem is ill-conditioned, meaning that infinitesimal variations of the inputs of the model can cause comparatively large variations of the predictions. If it is ill-conditioned, it has major consequences because of finite variations that could come from experimental and/or theoretical errors. In the following, we shall apply such a reasoning on the predictions of a particular Nambu-Jona-Lasinio model within the mean field + ring approximations, with special attention to the prediction of the chiral CEP position in the (T-μ) plane. We find that the problem is ill-conditioned (i.e. very sensitive to input variations) for the T-coordinate of the CEP, whereas, it is well-posed for the μ-coordinate of the CEP. As a consequence, when the chiral condensate varies in a 10MeV range, μ {sub CEP} varies far less. As an illustration to understand how problematic this could be, we show that the main consequence when taking into account finite variation of the inputs, is that the existence of the CEP itself cannot be predicted anymore: for a deviation as low as 0.6% with respect to vacuum phenomenology (well within the estimation of the first correction to the ring approximation) the CEP may or may not exist. (orig.)
Rosen, Brad M; Roche, Cécile; Percec, Virgil
2013-01-01
Biological macromolecules are homochiral, composed of sequences of stereocenters possessing the same repeated absolute configuration. This chapter addresses the mechanism of homochiral selection in polypeptides. In particular, the relationship between the stereochemistry (L or D) of structurally distinct α-amino acids is explored. Through functionalization of Tyr-Xaa dipeptides with self-assembling dendrons, the effect of stereochemical sequence of the dipeptide on the thermodynamics of self-assembly and the resulting structural features can be quantified. The dendritic dipeptide approach effectively isolates the stereochemical information of the shortest sequence of stereochemical information possible in polypeptide, while simultaneously allowing for dendron driven tertiary and quaternary structure formation and subsequent transfer of chiral information from the dipeptide to the dendritic sheath. This approach elucidates a mechanism of selecting a homochiral relationship between dissimilar but neighboring α-amino acids through thermodynamic preference for homochirality in solution-phase and bulk supramolecular helical polymerization. PMID:23306867
Asymmetric synthesis using chiral-encoded metal
Yutthalekha, Thittaya; Wattanakit, Chularat; Lapeyre, Veronique; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander
2016-08-01
The synthesis of chiral compounds is of crucial importance in many areas of society and science, including medicine, biology, chemistry, biotechnology and agriculture. Thus, there is a fundamental interest in developing new approaches for the selective production of enantiomers. Here we report the use of mesoporous metal structures with encoded geometric chiral information for inducing asymmetry in the electrochemical synthesis of mandelic acid as a model molecule. The chiral-encoded mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and the chiral template molecule, perfectly retains the chiral information after removal of the template. Starting from a prochiral compound we demonstrate enantiomeric excess of the (R)-enantiomer when using (R)-imprinted electrodes and vice versa for the (S)-imprinted ones. Moreover, changing the amount of chiral cavities in the material allows tuning the enantioselectivity.
Asymmetric synthesis using chiral-encoded metal.
Yutthalekha, Thittaya; Wattanakit, Chularat; Lapeyre, Veronique; Nokbin, Somkiat; Warakulwit, Chompunuch; Limtrakul, Jumras; Kuhn, Alexander
2016-01-01
The synthesis of chiral compounds is of crucial importance in many areas of society and science, including medicine, biology, chemistry, biotechnology and agriculture. Thus, there is a fundamental interest in developing new approaches for the selective production of enantiomers. Here we report the use of mesoporous metal structures with encoded geometric chiral information for inducing asymmetry in the electrochemical synthesis of mandelic acid as a model molecule. The chiral-encoded mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and the chiral template molecule, perfectly retains the chiral information after removal of the template. Starting from a prochiral compound we demonstrate enantiomeric excess of the (R)-enantiomer when using (R)-imprinted electrodes and vice versa for the (S)-imprinted ones. Moreover, changing the amount of chiral cavities in the material allows tuning the enantioselectivity. PMID:27562028
Szabó, Zoltán-István; Tóth, Gergő; Völgyi, Gergely; Komjáti, Balázs; Hancu, Gabriel; Szente, Lajos; Sohajda, Tamás; Béni, Szabolcs; Muntean, Daniela-Lucia; Noszál, Béla
2016-01-01
The enantiomers of asenapine maleate (ASN), a novel antipsychotic against schizophrenia and mania with bipolar I disorder have been separated by cyclodextrin (CD) modified capillary zone electrophoresis for the first time. 15 different CDs were screened as complexing agents and chiral selectors, investigating the stability of the inclusion complexes and their enantiodiscriminating capacities. Although initially, none of the applied chiral selectors gave baseline separation, β-CD proved to be the most effective chiral selector. In order to improve resolution, an orthogonal experimental design was employed, altering the concentration of background electrolyte, organic modifier, pH, capillary temperature and applied voltage in a multivariate manner. The developed method (160 mM TRIS-acetate buffer pH 3.5, 7 mM β-CD, at 20 °C, applying 15 kV) was successful for baseline separation of ASN enantiomers (R(s)=2.40±0.04). Our method was validated according to ICH guidelines and proved to be sensitive, linear, accurate and precise for the chiral separation of ASN. Properties of the inclusion complexes, such as stoichiometry, atomic level intermolecular host-guest connections are proposed on the basis of ROESY NMR measurement, ESI-MS spectrometry and molecular modeling studies. It was found that the ASN-β-CD complex is of 1:1 composition, and either of the aromatic rings can be accommodated in the β-CD cavity. PMID:26440287
Energy Technology Data Exchange (ETDEWEB)
Plum, Eric, E-mail: erp@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Zheludev, Nikolay I., E-mail: niz@orc.soton.ac.uk [Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637378 (Singapore)
2015-06-01
Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media.
Chiral Baryon with Quantized Pions
McNeil, J A
1993-01-01
We study a hybrid chiral model for the nucleon based on the linear sigma model with explicit quarks. We solve the model using a Fock-space configuration consisting of three quarks plus three quarks and a pion as the ground state ansatz in place of the ``hedgehog'' ansatz. We minimize the expectation value of the chiral hamiltonian in this ground state configuration and solve the resulting equations for nucleon quantum numbers. We calculate the canonical set of nucleon observables and compare with previous work.
Laser Writing of Multiscale Chiral Polymer Metamaterials
Directory of Open Access Journals (Sweden)
E. P. Furlani
2012-01-01
Full Text Available A new approach to metamaterials is presented that involves laser-based patterning of novel chiral polymer media, wherein chirality is realized at two distinct length scales, intrinsically at the molecular level and geometrically at a length scale on the order of the wavelength of the incident field. In this approach, femtosecond-pulsed laser-induced two-photon lithography (TPL is used to pattern a photoresist-chiral polymer mixture into planar chiral shapes. Enhanced bulk chirality can be realized by tuning the wavelength-dependent chiral response at both the molecular and geometric level to ensure an overlap of their respective spectra. The approach is demonstrated via the fabrication of a metamaterial consisting of a two-dimensional array of chiral polymer-based L-structures. The fabrication process is described and modeling is performed to demonstrate the distinction between molecular and planar geometric-based chirality and the effects of the enhanced multiscale chirality on the optical response of such media. This new approach to metamaterials holds promise for the development of tunable, polymer-based optical metamaterials with low loss.
Chiral symmetry in rotating systems
Malik, Sham S.
2015-08-01
The triaxial rotating system at critical angular momentum I ≥Iband exhibits two enatiomeric (the left- and right-handed) forms. These enatiomers are related to each other through dynamical chiral symmetry. The chiral symmetry in rotating system is defined by an operator χ ˆ =Rˆy (π) T ˆ, which involves the product of two distinct symmetries, namely, continuous and discrete. Therefore, new guidelines are required for testing its commutation with the system Hamiltonian. One of the primary objectives of this study is to lay down these guidelines. Further, the possible impact of chiral symmetry on the geometrical arrangement of angular momentum vectors and investigation of observables unique to nuclear chiral-twins is carried out. In our model, the angular momentum components (J1, J2, J3) occupy three mutually perpendicular axes of triaxial shape and represent a non-planar configuration. At certain threshold energy, the equation of motion in angular momentum develops a second order phase transition and as a result two distinct frames (i.e., the left- and right-handed) are formed. These left- and right-handed states correspond to a double well system and are related to each other through chiral operator. At this critical angular momentum, the centrifugal and Coriolis interactions lower the barrier in the double well system. The tunneling through the double well starts, which subsequently lifts the degeneracy among the rotational states. A detailed analysis of the behavior of rotational energies, spin-staggering, and the electromagnetic transition probabilities of the resulting twin-rotational bands is presented. The ensuing model results exhibit similarities with many observed features of the chiral-twins. An advantage of our formalism is that it is quite simple and it allows us to pinpoint the understanding of physical phenomenon which lead to chiral-twins in rotating systems.
Ribó, Josep M; El-Hachemi, Zoubir; Moyano, Albert; Blanco, Celia; Hochberg, David; 10.1089/ast.2012.0904
2013-01-01
The emergence of chirality in enantioselective autocatalysis for compounds unable to transform according to the Frank-like reaction network is discussed with respect to the controversial limited enantioselectivity (LES) model composed of coupled enantioselective and non-enantioselective autocatalyses. The LES model cannot lead to spontaneous mirror symmetry breaking (SMSB) either in closed systems with a homogeneous temperature distribution nor in closed systems with a stationary non-uniform temperature distribution. However, simulations of chemical kinetics in a two-compartment model demonstrate that SMSB may occur if both autocatalytic reactions are spatially separated at different temperatures in different compartments but coupled under the action of a continous internal flow. In such conditions the system can evolve, for certain reaction and system parameters, towards a chiral stationary state, i.e., the system is able to reach a bifurcation point leading to SMSB. Numerical simulations using reasonable ch...
Chiral doublet bands and energy-level crossing
Institute of Scientific and Technical Information of China (English)
QI Bin; MENG Jie; ZHANG Shuang-Quan; WANG Shou-Yu; PENG Jing
2009-01-01
Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.
Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates
Directory of Open Access Journals (Sweden)
Tomoya Hayata
2015-05-01
Full Text Available We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement of heavy quarks.
Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates
Energy Technology Data Exchange (ETDEWEB)
Hayata, Tomoya, E-mail: hayata@riken.jp [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Yamamoto, Arata [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)
2015-05-11
We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement of heavy quarks.
Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates
Hayata, Tomoya; Yamamoto, Arata
2015-05-01
We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement of heavy quarks.
Inhomogeneous Polyakov loop induced by inhomogeneous chiral condensates
Tomoya Hayata; Arata Yamamoto
2015-01-01
We study the spatial inhomogeneity of the Polyakov loop induced by inhomogeneous chiral condensates. We formulate an effective model of gluons on the background fields of chiral condensates, and perform its lattice simulation. On the background of inhomogeneous chiral condensates, the Polyakov loop exhibits an in-phase spatial oscillation with the chiral condensates. We also analyze the heavy quark potential and show that the inhomogeneous Polyakov loop indicates the inhomogeneous confinement...
Szabó, Zoltán-István; Szőcs, Levente; Horváth, Péter; Komjáti, Balázs; Nagy, József; Jánoska, Ádám; Muntean, Daniela-Lucia; Noszál, Béla; Tóth, Gergő
2016-08-01
A sensitive and validated liquid chromatography with mass spectrometry method was developed for the enantioseparation of the racemic mixture of pomalidomide, a novel, second-generation immunomodulatory drug, using β-cyclodextrin-bonded stationary phases. Four cyclodextrin columns (β-, hydroxypropyl-β-, carboxymethyl-β-, and sulfobutyl-β-cyclodextrin) were screened and the effects of eluent composition, flow rate, temperature, and organic modifier on enantioseparation were studied. Optimized parameters, offering baseline separation (resolution = 2.70 ± 0.02) were the following: β-cyclodextrin stationary phase, thermostatted at 15°C, and mobile phase consisting of methanol/0.1% acetic acid 10:90 v/v, delivered with 0.8 mL/min flow rate. For the optimized parameter at multiple reaction monitoring mode 274.1-201.0 transition with 20 eV collision energy and 100 V fragmentor voltage the limit of detection and limit of quantitation were 0.75 and 2.00 ng/mL, respectively. Since enantiopure standards were not available, elution order was determined upon comparison of the circular dichroism signals of the separated pomalidomide enantiomers with that of enantiopure thalidomide. The mechanisms underlying the chiral discrimination between the enantiomers were also investigated. Pomalidomide-β-cyclodextrin inclusion complex was characterized using nuclear magnetic resonance spectroscopy and molecular modeling. The thermodynamic aspects of chiral separation were also studied. PMID:27279456
Szabó, Zoltán-István; Szőcs, Levente; Horváth, Péter; Komjáti, Balázs; Nagy, József; Jánoska, Ádám; Muntean, Daniela-Lucia; Noszál, Béla; Tóth, Gergő
2016-08-01
A sensitive and validated liquid chromatography with mass spectrometry method was developed for the enantioseparation of the racemic mixture of pomalidomide, a novel, second-generation immunomodulatory drug, using β-cyclodextrin-bonded stationary phases. Four cyclodextrin columns (β-, hydroxypropyl-β-, carboxymethyl-β-, and sulfobutyl-β-cyclodextrin) were screened and the effects of eluent composition, flow rate, temperature, and organic modifier on enantioseparation were studied. Optimized parameters, offering baseline separation (resolution = 2.70 ± 0.02) were the following: β-cyclodextrin stationary phase, thermostatted at 15°C, and mobile phase consisting of methanol/0.1% acetic acid 10:90 v/v, delivered with 0.8 mL/min flow rate. For the optimized parameter at multiple reaction monitoring mode 274.1-201.0 transition with 20 eV collision energy and 100 V fragmentor voltage the limit of detection and limit of quantitation were 0.75 and 2.00 ng/mL, respectively. Since enantiopure standards were not available, elution order was determined upon comparison of the circular dichroism signals of the separated pomalidomide enantiomers with that of enantiopure thalidomide. The mechanisms underlying the chiral discrimination between the enantiomers were also investigated. Pomalidomide-β-cyclodextrin inclusion complex was characterized using nuclear magnetic resonance spectroscopy and molecular modeling. The thermodynamic aspects of chiral separation were also studied.
Chiral particle separation by a non-chiral micro-lattice
Bogunovic, Lukas; Fliedner, Marc; Eichhorn, Ralf; Wegener, Sonja; Regtmeier, Jan; Anselmetti, Dario; Reimann, Peter
2012-01-01
We conceived a model experiment for a continuous separation strategy of chiral molecules (enantiomers) without the need of any chiral selector structure or derivatization agents: Micro-particles that only differ by their chirality are shown to migrate along different directions when driven by a steady fluid flow through a square lattice of cylindrical posts. In accordance with our numerical predictions, the transport directions of the enantiomers depend very sensitively on the orientation of ...
Changlani, Hitesh; Kumar, Krishna; Clark, Bryan; Fradkin, Eduardo
Frustrated spin systems in two dimensions provide a fertile ground for discovering exotic states of matter, often with topologically non-trivial properties. In this work, we investigate the possible existence of a chiral spin liquid state in the spin 1/2 XXZ model on the frustrated kagome lattice in the presence of a magnetic field. This model is equivalent to a hard-core bosonic one with density-density interactions at finite filling fraction. Motivated by previous field theoretic predictions utilizing a Chern-Simons theory adapted for this lattice, we focus our attention to understanding the XY limit for the 2/3 magnetization plateau (equivalent to a system of hard-core bosons at 1/6 filling with weak nearest-neighbor repulsive interactions). Performing exact or accurate numerical computations, and based on energetics and construction of minimally entangled states and associated modular matrices, we provide evidence for such a spin liquid. We study the nature of this phase and examine its stability to additional interactions. We acknowledge support from the SciDAC program under Award Number DE-FG02-12ER46875.
Indian Academy of Sciences (India)
Susanto Chakraborty; Pranab Krishna Chanda
2006-06-01
It has been shown that the field equations for Charap's chiral invariant model of the pion dynamics pass the Painlevé test for complete integrability in the sense of Weiss et al. The truncation procedure of the same analysis leads to auto-Backlund transformation between two pairs of solutions. With the help of this transformation non-trivial exact solutions have been rediscovered.
Field induced spin chirality and chirality switching in magnetic multilayers
Tartakovskaya, Elena V.
2015-05-01
The physical origin of the field-induced spin chirality experimentally observed in rare earth multilayers is determined. It is shown that the effect is possible due to the interplay between solid-state exchange interactions (the Ruderman-Kittel-Kasuya-Yosida and the Dsyaloshinsky-Moriya interactions), the external magnetic field and a special confinement of magnetic constituents. The presented model describes a certain temperature dependence of the chirality factor in agreement with experimental data and opens a new way to design nanostructured objects with predicted handedness.
Anomalous Chiral Superfluidity
Lublinsky, Michael(Physics Department, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel); Zahed, Ismail
2009-01-01
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavour anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is ...
Abuki, H; Gatto, R; Nardulli, G; Ruggieri, M
2008-01-01
We study the interplay between the chiral and the deconfinement transitions, both at high temperature and high quark chemical potential, by a non local Nambu-Jona Lasinio model with the Polyakov loop in the mean field approximation and requiring neutrality of the ground state. We consider three forms of the effective potential of the Polyakov loop: two of them with a fixed deconfinement scale, cases I and II, and the third one with a $\\mu$ dependent scale, case III. In the cases I and II, at high chemical potential $\\mu$ and low temperature $T$ the main contribution to the free energy is due to the Z(3)-neutral three-quark states, mimicking the quarkyonic phase of the large $N_c$ phase diagram. On the other hand in the case III the quarkyonic window is shrunk to a small region. Finally we comment on the relations of these results to lattice studies and on possible common prospects. We also briefly comment on the coexistence of quarkyonic and color superconductive phases.
Xiao, Li-Ye; Zhong, Xian-Hui
2016-01-01
A combined analysis of the reactions $\\pi^-p\\rightarrow K^0\\Lambda$ and $\\eta n$ is carried out with a chiral quark model. The data in the center-of-mass (c.m.) energy range from threshold up to $W\\simeq 1.8$ GeV are reasonably described. For $\\pi^-p\\rightarrow K^0\\Lambda$, it is found that $N(1535)S_{11}$ and $N(1650)S_{11}$ paly crucial roles near threshold. The $N(1650)S_{11}$ resonance contributes to the reaction through configuration mixing with $N(1535)S_{11}$. The constructive interference between $N(1535)S_{11}$ and $N(1650)S_{11}$ is responsible for the peak structure around threshold in the total cross section. The $n$-pole, $u$- and $t$-channel backgrounds provide significant contributions to the reaction as well. While, for the $\\pi^-p\\rightarrow \\eta n$ process, the "first peak" in the total cross section is dominant by $N(1535)S_{11}$, which has a sizeable destructive interference with $N(1650)S_{11}$. Around $P_\\pi \\simeq $ 1.0 GeV/c ($W\\simeq 1.7$ GeV), there seems to be a small bump structure...
Chiral symmetry on the lattice
International Nuclear Information System (INIS)
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model
Chiral Superfluidity for the Heavy Ion Collisions
Kalaydzhyan, T
2013-01-01
We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the "superfluid" component gives rise to the chiral magnetic, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model. By considering probe quarks one can show that the fermionic spectrum at the intermediate tempera...
Liu, Keh-Fei
2016-01-01
The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of $\\pi N \\sigma$ term and strangeness. The third one is the role of chiral $U(1)$ anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.
The chiral symplectic universality class
Asada, Yoichi; Slevin, Keith; Ohtsuki, Tomi
2003-01-01
We report a numerical investigation of localization in the SU(2) model without diagonal disorder. At the band center, chiral symmetry plays an important role. Our results indicate that states at the band center are critical. States away from the band center but not too close to the edge of the spectrum are metallic as expected for Hamiltonians with symplectic symmetry.
Speciation and gene flow between snails of opposite chirality.
Directory of Open Access Journals (Sweden)
Angus Davison
2005-09-01
Full Text Available Left-right asymmetry in snails is intriguing because individuals of opposite chirality are either unable to mate or can only mate with difficulty, so could be reproductively isolated from each other. We have therefore investigated chiral evolution in the Japanese land snail genus Euhadra to understand whether changes in chirality have promoted speciation. In particular, we aimed to understand the effect of the maternal inheritance of chirality on reproductive isolation and gene flow. We found that the mitochondrial DNA phylogeny of Euhadra is consistent with a single, relatively ancient evolution of sinistral species and suggests either recent "single-gene speciation" or gene flow between chiral morphs that are unable to mate. To clarify the conditions under which new chiral morphs might evolve and whether single-gene speciation can occur, we developed a mathematical model that is relevant to any maternal-effect gene. The model shows that reproductive character displacement can promote the evolution of new chiral morphs, tending to counteract the positive frequency-dependent selection that would otherwise drive the more common chiral morph to fixation. This therefore suggests a general mechanism as to how chiral variation arises in snails. In populations that contain both chiral morphs, two different situations are then possible. In the first, gene flow is substantial between morphs even without interchiral mating, because of the maternal inheritance of chirality. In the second, reproductive isolation is possible but unstable, and will also lead to gene flow if intrachiral matings occasionally produce offspring with the opposite chirality. Together, the results imply that speciation by chiral reversal is only meaningful in the context of a complex biogeographical process, and so must usually involve other factors. In order to understand the roles of reproductive character displacement and gene flow in the chiral evolution of Euhadra, it will be
Ahmed, Mohammad W.; Gao, Haiyan; Weller, Henry R.; Holstein, Barry
2007-10-01
.5 GeV with BABAR / A. Denig. The pion vector form-factor and (g-2)u / C. Smith. Partially quenched CHPT results to two loops / J. Bijnens. Pion-pion scattering with mixed action lattice QCD / P.F. Bedaque. Meson systems with Ginsparg-Wilson valence quarks / A. Walker-Loud. Low energy constants from the MILC collaboration / C. Bernard. Finite volume effects: lattice meets CHPT / G. Schierholz. Lattice QCD simulations with two light dynamical (Wilson) quarks / L. Giusti. Do we understand the low-energy constant L8? / M. Golterman. Quark mass dependence of LECs in the two-flavour sector / M. Schmid. Progress report on the [Pie symbol]0 Lifetime experiment (PRIMEX) at Jlab / D.E. McNulty. Determination of the charged pion polarizabilities / L.V. Fil'kov. Proposed measurement of electroproduction of [Pie symbol]0 near threshold using a large acceptance spectrometer / R.A. Lindgren. The [Pie symbol] meson in [Pie symbol]K scattering / B. Moussallam. Strangeness -1 Meson-Baryon scattering S-wave / J.A. Oller. Results on light mesons decays and dynamics at KLOE / M. Martini. Studies of decays of [symbol] and [symbol] mesons with WASA detector / A. Kupsc. Heavy Quark-Diquark symmetry and X PT for doubly heavy baryons / T. Mehen. HHChPT applied to the charmed-strange parity partners/ R.P. Springer. Study of pion structure through precise measurements of the [Pie symbol]+ --> e+[symbol] decay / D. Pocanic. Exceptional and non-exceptional contributions to the radiative [Pie symbol] decay / V. Mateu. Leading chiral logarithms from unitarity, analyticity and the Roy equations / A. Fuhrer. All orders symmetric subtraction of the nonlinear sigma model in D=4 / A. Quadri -- pt. C. Chiral dynamics in few-nucleon systems. Working group summary: chiral dynamics in few-nucleon systems / H.W Hammer, N. Kalantar-Nayestanaki, and D.R. Phillips. Power counting in nuclear chiral effective field theory / U. van Kolck. On the consistency of Weinberg's power counting / U-G Mei ner. Renormalization
Chiral Rotational Spectroscopy
Cameron, Robert P; Barnett, Stephen M
2015-01-01
We introduce chiral rotational spectroscopy: a new technique that enables the determination of the individual optical activity polarisability components $G_{XX}'$, $G_{YY}'$, $G_{ZZ}'$, $A_{X,YZ}$, $A_{Y,ZX}$ and $A_{Z,XY}$ of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample whilst yielding an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral by virtue of their isotopic constitution and molecules with multiple chiral centres. The principles that underpin chiral rotational spectroscopy can also be exploited in the search for molecular chirality in space, which, if found, may add weight to hypotheses that biological homochirality and indeed life itself are of cosmic origin.
From the double-stranded helix to the chiral nematic phase of B-DNA: a molecular model
Tombolato, F
2004-01-01
B-DNA solutions of suitable concentration form left-handed chiral nematic phases (cholesterics). Such phases have also been observed in solutions of other stiff or semiflexible chiral polymers; magnitude and handedness of the cholesteric pitch are uniquely related to the molecular features. In this work we present a theoretical method and a numerical procedure which, starting from the structure of polyelectrolytes, lead to the prediction of the cholesteric pitch. Molecular expressions for the free energy of the system are obtained on the basis of steric and electrostatic interactions between polymers; the former are described in terms of excluded volume, while a mean field approximation is used for the latter. Calculations have been performed for 130 bp fragments of B-DNA. The theoretical predictions provide an explanation for the experimental behavior, by showing the counteracting role played by shape and charge chirality of the molecule.
Tawfik, Abdel Nasser
2015-01-01
Effects of external magnetic field on various properties of the quantum chromodynamics under extreme conditions of temperature and density have been analysed. To this end, we use SU(3) Polyakov linear sigma-model and assume that the external magnetic field eB adds some restrictions to the quarks energy due to the existence of free charges in the plasma phase. In doing this, we apply the Landau theory of quantization. This requires an additional temperature to drive the system through the chiral phase-transition. Accordingly, the dependence of the critical temperature of chiral and confinement phase-transitions on the magnetic field is characterized. Based on this, we have studied the thermal evolution of thermodynamic quantities and the first four higher-order moment of particle multiplicity. Having all these calculations, we have studied the effects of magnetic field on chiral phase-transition. We found that both critical temperature T_c and critical chemical potential increase with increasing the magnetic f...
On chiral and non chiral 1D supermultiplets
Energy Technology Data Exchange (ETDEWEB)
Toppan, Francesco, E-mail: toppan@cbpf.b [Centro Brasileiro de Pesquisas Fisicas (TEO/CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Fisica Teorica
2011-07-01
In this talk I discuss and clarify some issues concerning chiral and non chiral properties of the one-dimensional supermultiplets of the N-extended supersymmetry. Quaternionic chirality can be defined for N = 4, 5, 6, 7, 8. Octonionic chirality for N = 8 and beyond. Inequivalent chiralities only arise when considering several copies of N = 4 or N = 8 supermultiplets. (author)
Personal recollections on chiral symmetry breaking
Kobayashi, Makoto
2016-07-01
The author's work on the mass of pseudoscalar mesons is briefly reviewed. The emergence of the study of CP violation in the renormalizable gauge theory from consideration of chiral symmetry in the quark model is discussed.
Kondratyuk, S; Myhrer, F; Scholten, O
2004-01-01
The Adler-Weisberger and Goldberger-Miyazawa-Oehme sum rules are calculated within a relativistic, unitary and crossing symmetric dynamical model for pion-nucleon scattering using two different methods: 1) by evaluating of the scattering amplitude at the corresponding low-energy kinematics and 2) by evaluating the sum-rule integrals with the calculated total cross section. The discrepancy between the results of the two methods provides a measure of the breaking of analyticity and chiral symmetry in the model. The contribution of the $\\Delta$ resonance, including its dressing with meson loops, is discussed in some detail and found to be small.
A chiral quark model for meson electro-production in the S11 partial wave
Golli, Bojan
2011-01-01
We calculate the meson scattering and electroproduction amplitudes in the S11 partial wave in a coupled-channel approach that incorporates quasi-bound quark-model states. Using the quark wave functions and the quark-meson interaction from the Cloudy Bag Model, we obtain consistent predictions for the partial widths of the N(1535) and the N(1650) resonances as well as for the pion, eta and kaon electroproduction amplitudes. Our model suggests that the N(1535) resonance is dominantly a genuine three-quark state rather than a quasi-bound state of mesons and baryons.
Popov, Alexander P.; Gloria Pini, Maria; Rettori, Angelo
2016-03-01
The metastable states of a finite-size chain of N classical spins described by the chiral XY-model on a discrete one-dimensional lattice are calculated by means of a general theoretical method recently developed by one of us. This method allows one to determine all the possible equilibrium magnetic states in an accurate and systematic way. The ground state of a chain consisting of N classical XY spins is calculated in the presence of (i) a symmetric ferromagnetic exchange interaction, favoring parallel alignment of nearest neighbor spins, (ii) a uniaxial anisotropy, favoring a given direction in the film plane, and (iii) an antisymmetric Dzyaloshinskii-Moriya interaction (DMI), favoring perpendicular alignment of nearest neighbor spins. In addition to the ground state with a non-uniform helical spin arrangement, which originates from the energy competition in the finite-size chain with open boundary conditions, we have found a considerable number of higher-energy equilibrium states. In the investigated case of a chain with N=10 spins and a DMI much smaller than the in-plane uniaxial anisotropy, it turns out that a metastable (unstable) state of the finite chain is characterized by a configuration where none (at least one) of the inner spins is nearly parallel to the hard axis. The role of the DMI is to establish a unique rotational sense for the helical ground state. Moreover, the number of both metastable and unstable equilibrium states is doubled with respect to the case of zero DMI. This produces modifications in the Peierls-Nabarro potential encountered by a domain wall during its displacement along the discrete spin chain.
Institute of Scientific and Technical Information of China (English)
ZHAO Xu; WANG Yan; YU Zhi-Ping
2006-01-01
@@ Current-voltage characteristics of ballistic carbon-nanotube field-effect transistors are characterized with an it-erative simulation program. The influence of carbon-nanotube chirality and diameter on the output current is considered. An analytical current-voltage expression under the quantum capacitance limit and low-voltage application is derived. Our simulation results are compared with actual measurement data.
Classification of the chiral Z2XZ2 fermionic models in the heterotic superstring
Faraggi, A E; Nooij, S E M; Rizos, J
2004-01-01
The first particle physics observable whose origin may be sought in string theory is the triple replication of the matter generations. The class of Z2XZ2 orbifolds of six dimensional compactified tori, that have been most widely studied in the free fermionic formulation, correlate the family triplication with the existence of three twisted sectors in this class. In this work we seek an improved understanding of the geometrical origin of the three generation free fermionic models. Using fermionic and orbifold techniques we classify the Z2XZ2 orbifold with symmetric shifts on six dimensional compactified internal manifolds. We show that perturbative three generation models are not obtained in the case of Z2XZ2 orbifolds with symmetric shifts on complex tori, and that the perturbative three generation models in this class necessarily employ an asymmetric shift. We present a class of three generation models in which the SO(10) gauge symmetry cannot be broken perturbatively, while preserving the Standard Model mat...
On stability of solutions of the U(N) chiral model in two dimensions
International Nuclear Information System (INIS)
We discuss the stability properties of classical solutions of the U(N) sigma models in two Euclidean dimensions. We show that all nontrivial solutions are unstable. For a general case we exhibit one mode of instability; in some special cases (corresponding to a grassmannian solution and an instantonic grassmannian embedding) we exhibit two such independent modes. (orig.)
Mechanical separation of chiral dipoles by chiral light
Canaguier-Durand, Antoine; Genet, Cyriaque; Ebbesen, Thomas W
2013-01-01
Optical forces take on a specific form when involving chiral light fields interacting with chiral objects. We show that optical chirality density and flow can have mechanical effects through reactive and dissipative components of chiral forces exerted on chiral dipoles. Remarkably, these force components are directly related to standard observables: optical rotation and circular dichroism, respectively. As a consequence, resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This leads to promising strategies for the mechanical separation of chiral objects using chiral light forces.
Pion scattering and electro-production on nucleons in the resonance region in chiral quark models
Sirca, Simon; Fiolhais, Manuel; Alberto, Pedro
2011-01-01
Pion scattering and electro-production amplitudes have been computed in a coupled-channel framework incorporating quasi-bound quark-model states, based on the Cloudy Bag model. All relevant low-lying nucleon resonances in the P33, P11, and S11 partial waves have been covered, including the Delta(1232), the N*(1440), N*(1535), and N*(1650). Consistent results have been obtained for elastic and inelastic scattering (two-pion, eta-N, and K-Lambda channels), as well as for electro-production. The meson cloud has been shown to play a major role, in particular in electro-magnetic observables in the P33 and P11 channels.
Exact thermodynamics and phase diagram of integrable t-J model with chiral interaction
Tavares, T. S.; Ribeiro, G. A. P.
2016-09-01
We study the phase diagram and finite temperature properties of an integrable generalization of the one-dimensional super-symmetric t-J model containing interactions explicitly breaking parity-time reversal (PT) symmetries. To this purpose, we apply the quantum transfer matrix method which results in a finite set of non-linear integral equations. We obtain numerical solutions to these equations leading to results for thermodynamic quantities as a function of temperature, magnetic field, particle density and staggering parameter. Studying the maxima lines of entropy at low but non zero temperature reveals the phase diagram of the model. There are ten different phases which we may classify in terms of the qualitative behaviour of auxiliary functions, closely related to the dressed energy functions.
Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong
2016-06-01
Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.
Anomalous chiral superfluidity
Energy Technology Data Exchange (ETDEWEB)
Lublinsky, Michael, E-mail: lublinsky@phys.uconn.ed [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Physics Department, Ben-Gurion University, Beer Sheva 84105 (Israel); Zahed, Ismail [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)
2010-02-08
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavor anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy-momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is briefly noted.
Sen, Srimoyee
2016-01-01
We study shock waves in relativistic chiral matter. We argue that the conventional Rankine- Hugoinot relations are modified due to the presence of chiral transport phenomena. We show that the entropy discontinuity in a weak shock wave is linearly proportional to the pressure discontinuity when the effect of chiral transport becomes sufficiently large. We also show that rarefaction shock waves, which do not exist in usual nonchiral fluids, can appear in chiral matter. These features are exemplified by shock propagation in dense neutrino matter in the hydrodynamic regime.
Chiral Ground States in a Frustrated Holographic Superconductor
Nishida, Mitsuhiro
2015-01-01
Frustration is an important phenomenon in condensed matter physics because it can introduce a new order parameter such as chirality. Towards understanding a mechanism of the frustration in strongly correlated systems, we study a holographic superconductor model with three scalar fields and an interband Josephson coupling, which is important for the frustration. We analyze free energy of solutions of the model to determine ground states. We find chiral ground states, which have nonzero chirality.
An epistemological note on chirality
International Nuclear Information System (INIS)
The terms ''chiral'' and ''achiral'' are sharply defined when applied to geometric figures or models. The same terms are also commonly used to refer to the real systems to which these models have been adjoined. e.g., molecules, solvents, or reagents. Here, the terms are not sharply defined but depend upon conditions or measurement. The contrast between the geometric and operational usages is discussed in detail
Doped Chiral Polymer Metamaterials Project
National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...
Proton Spin Based On Chiral Dynamics
Weber, H. J.
1999-01-01
Chiral spin fraction models agree with the proton spin data only when the chiral quark-Goldstone boson couplings are pure spinflip. For axial-vector coupling from soft-pion physics this is true for massless quarks but not for constituent quarks. Axial-vector quark-Goldstone boson couplings with {\\bf constituent} quarks are found to be inconsistent with the proton spin data.
Energy Technology Data Exchange (ETDEWEB)
Zeeb, G.
2006-07-01
In this thesis the thermodynamical properties of strongly interacting hadronic matter and the microscopic in-medium properties of hadrons are investigated at high temperatures and high baryonic densities within a chiral flavor-SU(3) model. The applied model is a generalized {sigma}-{omega} model in mean-field approximation with baryons and mesons as effective degrees of freedom. It is built on spontaneously broken chiral symmetry and scale invariance. The phase transition behavior is systematically analyzed and is thus shown to depend significantly on the couplings of additional heavier hadronic degrees of freedom. A phase diagram in qualitative agreement with current lattice QCD (lQCD) calculations can result from an according coupling of the lowest lying baryonic decuplet to the model. Alternatively, the coupling of a heavy baryonic test-resonance is investigated, which effectively represents the spectrum of the heavy hadronic states. For a certain range of parameters one can even obtain a phase diagram in quantitative agreement with the lQCD calculations and, simultaneously, a successful description of the ground state properties of nuclear matter. It is shown that (within the model assumptions) the phase transition region is experimentally accessible for the CBM experiment at the upcoming FAIR facility at GSI Darmstadt. The chiral model is further applied to particle yield ratios measured in heavy-ion collisions from AGS, SPS and RHIC. For these investigations parameter sets with strongly differing phase diagrams due to different couplings of the baryon decuplet are used and in addition an ideal hadron gas. At the lower and mid collision energies the chiral parameter sets show an improved description as compared to the ideal hadron gas, especially for parameter sets with phase diagrams similar to the lQCD predictions. The interaction within the chiral model leads to in-medium modifications of the chemical potentials and the hadron masses. Therefore the
Reducible chiral metamaterials
Ciattoni, Alessandro; Rizza, Carlo
2016-01-01
We introduce the concept of 3D reducible metamaterials whose constituent permittivity can be modelled by a factorized profile. The separated cartesian coordinates dependence, easily achieved in all-optical reconfigurable materials, allows to physically regard a reducible metamaterial as a superposition of three fictitious 1D generating media. We prove that, in the long-wavelength limit, the electromagnetic response of reducible metamaterials can be reconstructed from the properties of the 1D generating media whose interplay provides large freedom to control the electromagnetic chirality. Our approach introduces an unprecedented decomposition strategy in metamaterial science which allows the full ab-initio and flexible design of a complex 3D bianisotropic response by using 1D metamaterials as basic building blocks.
Njiojob, Costyl N; Bozell, Joseph J; Long, Brian K; Elder, Thomas; Key, Rebecca E; Hartwig, William T
2016-08-22
We describe an efficient five-step, enantioselective synthesis of (R,R)- and (S,S)-lignin dimer models possessing a β-O-4 linkage, by using the Evans chiral aldol reaction as a key step. Mitsunobu inversion of the (R,R)- or (S,S)-isomers generates the corresponding (R,S)- and (S,R)-diastereomers. We further extend this approach to the enantioselective synthesis of a lignin trimer model. These lignin models are synthesized with excellent ee (>99 %) and high overall yields. The lignin dimer models can be scaled up to provide multigram quantities that are not attainable by using previous methodologies. These lignin models will be useful in degradation studies probing the selectivity of enzymatic, microbial, and chemical processes that deconstruct lignin. PMID:27459234
Ko, P; Yu, Chaehyun
2013-01-01
An extra $U(1)'$ model with $Z'$ coupled only to the right-handed (RH) up-type quarks has been one of the popular models for the Tevatron top forward-backward asymmetry (FBA), and has been excluded by the same-sign top-pair productions at the LHC. However, the original $Z'$ model is not physical, since the up-type quarks are massless including the top quark. This disaster can be evaded if the Higgs sector is extended by including new Higgs doublets with nonzero $U(1)'$ charges. We find that some parameter regions could achieve not only the top FBA at the Tevatron, but also the charge asymmetry at the LHC without exceeding the upper limit of the same-sign top-quark pair production at the LHC. The lesson is that it is mandatory to extend the Higgs sector whenever one considers chiral gauge symmetries beyond the SM gauge group. Otherwise some fermions remain massless, and thus it is meaningless to work on phenomenology without the extra Higgs doublets with new chiral gauge charges.
Combined analysis of the π-p →K0Λ , η n reactions in a chiral quark model
Xiao, Li-Ye; Ouyang, Fan; Wang, Kai-Lei; Zhong, Xian-Hui
2016-09-01
A combined analysis of the reactions π-p →K0Λ and η n is carried out with a chiral quark model. The data in the center-of-mass (c.m.) energy range from threshold up to W ≃1.8 GeV are reasonably described. For π-p →K0Λ , it is found that N (1535 ) S11 and N (1650 ) S11 play crucial roles near threshold. The N (1650 ) S11 resonance contributes to the reaction through configuration mixing with N (1535 ) S11 . The constructive interference between N (1535 ) S11 and N (1650 ) S11 is responsible for the peak structure around threshold in the total cross section. The n -pole, u -, and t -channel backgrounds provide significant contributions to the reaction as well. For the π-p →η n process, the "first peak" in the total cross section is dominated by N (1535 ) S11 , which has a sizeable destructive interference with N (1650 ) S11 . Around Pπ≃ 1.0 GeV/c (W ≃1.7 GeV), there seems to be a small bump structure in the total cross section, which might be explained by the interference between the u channel and N (1650 ) S11 . The N (1520 ) D13 resonance affects the angle distributions of the cross sections notably, although no obvious effects are seen in the total cross section. The role of P -wave state N (1720 ) P13 should be further confirmed by future experiments. If N (1720 ) P13 has a narrow width of Γ ≃120 MeV as found in our previous work by a study of the π0 photoproduction processes, obvious evidence should be seen in the π-p →K0Λ and η n processes as well. Finally, we give our predictions of the s -channel isospin-1/2 resonance contributions to the π N →π N reactions.
The convoluted evolution of snail chirality
Schilthuizen, M.; Davison, A.
2005-11-01
The direction that a snail (Mollusca: Gastropoda) coils, whether dextral (right-handed) or sinistral (left-handed), originates in early development but is most easily observed in the shell form of the adult. Here, we review recent progress in understanding snail chirality from genetic, developmental and ecological perspectives. In the few species that have been characterized, chirality is determined by a single genetic locus with delayed inheritance, which means that the genotype is expressed in the mother's offspring. Although research lags behind the studies of asymmetry in the mouse and nematode, attempts to isolate the loci involved in snail chirality have begun, with the final aim of understanding how the axis of left-right asymmetry is established. In nature, most snail taxa (>90%) are dextral, but sinistrality is known from mutant individuals, populations within dextral species, entirely sinistral species, genera and even families. Ordinarily, it is expected that strong frequency-dependent selection should act against the establishment of new chiral types because the chiral minority have difficulty finding a suitable mating partner (their genitalia are on the ‘wrong’ side). Mixed populations should therefore not persist. Intriguingly, however, a very few land snail species, notably the subgenus Amphidromus sensu stricto, not only appear to mate randomly between different chiral types, but also have a stable, within-population chiral dimorphism, which suggests the involvement of a balancing factor. At the other end of the spectrum, in many species, different chiral types are unable to mate and so could be reproductively isolated from one another. However, while empirical data, models and simulations have indicated that chiral reversal must sometimes occur, it is rarely likely to lead to so-called ‘single-gene’ speciation. Nevertheless, chiral reversal could still be a contributing factor to speciation (or to divergence after speciation) when
Application of cyclodextrins in chiral capillary electrophoresis.
Rezanka, Pavel; Navrátilová, Klára; Rezanka, Michal; Král, Vladimír; Sýkora, David
2014-10-01
CE represents a very powerful separation tool in the area of chiral separations. CD-mediated chiral CE is a continuously flourishing technique within the frame of the electromigration methods. In this review, a brief overview of the synthetic procedures leading to modified CDs is provided first. Next, selected aspects related to the utilization of CDs in chiral CE are discussed specifically in the view of recently published data. Advantages of CDs and basic principles of chiral CE are remained. The topic of the determination of binding constants is touched. Particular attention is paid to the effort aiming at better understanding of the molecular level of the enantiorecognition between CDs and the analyte in the solution. Powerful approaches extensively utilized in this field are NMR, molecular modeling, and computer simulations. Then, a summary of applications of CDs in the CE enantioseparations is given, covering years 2008-2013. Finally, the general trend of modified CDs use in separation science is statistically evaluated.
International Nuclear Information System (INIS)
In this paper, Lorentzian wormholes with a phantom field and chiral matter fields have been obtained. In addition, it is shown that for different values of the gravitational coupling of the chiral fields, the wormhole geometry changes. Finally, the stability of the corresponding wormholes is studied and it is shown that are unstable (eg. Ellis's wormhole instability)
Spectral signatures of chirality
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Mortensen, Asger
2009-01-01
We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast to t...
Chiral Magnetic "Superfluidity"
Sadofyev, Andrey V
2015-01-01
We study a heavy impurity moving longitudinal with the direction of an external magnetic field in an anomalous chiral medium. Such system would carry a non-dissipative current of chiral magnetic effect associated with the anomaly. We show, by generalizing Landau's criterion for superfluidity, that the "anomalous component" which gives rise to the anomalous transport will {\\it not} contribute to the drag experienced by an impurity. We argue on very general basis that those systems with a strong magnetic field would exhibit the behavior of 'superfluidity" -- the motion of the heavy impurity is frictionless, in analog to the case of a superfluid. However, this "superfluidity" exists even for chiral media at finite temperature and only in the directional longitudinal with the magnetic field, in contrast to the ordinary superfluid. We will call this novel phenomenon as the Chiral Magnetic "Superfluidity". We demonstrate and confirm our general results with two complementary examples: weakly coupled chiral fermion ...
The anomalous Hall conductivity due to the vector spin chirality
Taguchi, Katsuhisa; Tatara, Gen
2008-01-01
We study theoretically the anomalous Hall effect due to the vector spin chirality carried by the local spins in the $s$-$d$ model. We will show that the vector spin chirality indeed induces local Hall effect in the presence of the electron spin polarization, while the global Hall effect vanishes if electron transport is homogeneous. This anomalous Hall effect can be interpreted in terms of the rotational component of the spin current associated with the vector chirality.
Chiral Magnetic Effect and Chiral Phase Transition
Institute of Scientific and Technical Information of China (English)
FU Wei-Jie; LIU Yu-Xin; WU Yue-Liang
2011-01-01
We study the influence of the chiral phase transition on the chiral magnetic effect.The azimuthal chargeparticle correlations as functions of the temperature are calculated.It is found that there is a pronounced cusp in the correlations as the temperature reaches its critical value for the QCD phase transition.It is predicted that there will be a drastic suppression of the charge-particle correlations as the collision energy in RHIC decreases to below a critical value.We show then the azimuthal charge-particle correlations can be the signal to identify the occurrence of the QCD phase transitions in RHIC energy scan experiments.
Chiral symmetry in hadron physics methods and ideas of chiral symmetry
International Nuclear Information System (INIS)
Methods and ideas of chiral symmetry is presented based on a lecture note to help the future researches in hadron dynamics along with the chiral symmetry. The chiral symmetry was originally developed as the symmetry between currents before the discovery of QCD. It has come to be understood in principle by now that the symmetry is spontaneously broken and only the part of flavor symmetry remains explicitly. In QCD, however, the chiral symmetry has come to be regarded as the base of the symmetry of the global flavor space of quarks. One of the recent topics of the lattice gauge theory is how the hadron properties will change when the broken symmetry is going to be restored. Since the chiral symmetry is global, it is different from gauge symmetry which is local. It explains the degeneracy of hadron masses and relations between the elements of S-matrix in which same number of particles are included. In practice, however, the symmetry of the axial part is spontaneously broken and pions which behave like gauge particles come to play. Chiral symmetry is defined as the (internal) flavor symmetry for the two independent chirality states of quarks. It discriminates two different fundamental quarks defined for the Lorentz groups O(4) - SL(2, C). The symmetry transformation itself is, however, different from the chirality. They should not be confused. In this lecture note, fundamental properties of pions are described on the basis of the interaction with nucleons at first. General properties of the chiral symmetry and some of the low energy theorems on current algebra are introduced. Then, linear sigma model and nonlinear sigma model are introduced. Then the Skyrme-model, which provides an idea as important as quarks, is explained. One of the interesting topics at present is to restore the broken axial symmetry experimentally to investigate the mechanism of symmetry breaking. (S. Funahashi)
Institute of Scientific and Technical Information of China (English)
杨频; 韩大雄
2000-01-01
Molecular modeling methods have been applied to the structural characterization of the interaction between chiral metal complexes [Co(phen)2dppz]3+ (where phen = 1, 10-phenanthroline, dppz = dipyrido[3,2-a: 2’, 3’-c]phenazine) and the oligonucleotide (B-DNA fragment). The natures of two kinds of the binding modes, which are currently intense controversy, have been explored. Barton proposed that there is enantio-selective DMA binding by the octahedral complexes and intercalative access by these complexes from the major groove; but Norden suggested that both enantiomers bind extremely strongly to DNA from the minor groove without any noticeable enantio-selectivity. Our results support and extend structural models based upon Norden’s studies, and conflict with Barton’s model.
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Molecular modeling methods have been applied to the structural characterization of the interaction between chiral metal complexes [Co(phen)2dppz]3+ (where phen = 1, 10-phenanthroline, dppz = dipyrido[3,2-a: 2′, 3′-c]phenazine) and the oligonucleotide (B-DNA fragment). The natures of two kinds of the binding modes, which are currently intense controversy, have been explored. Barton proposed that there is enantio-selective DNA binding by the octahedral complexes and intercalative access by these complexes from the major groove; but Norden suggested that both enantiomers bind extremely strongly to DNA from the minor groove without any noticeable enantio-selectivity. Our results support and extend structural models based upon Norden's studies, and conflict with Barton's model.
Interplay between chiral and deconfinement phase transitions
Directory of Open Access Journals (Sweden)
Mukherjee T.K.
2011-04-01
Full Text Available By using the dressed Polyakov loop or dual chiral condensate as an equivalent order parameter of the deconfinement phase transition, we investigate the relation between the chiral and deconfinement phase transitions at finite temperature and density in the framework of three-flavor Nambu-Jona-Lasinio (NJL model. It is found that in the chiral limit, the critical temperature for chiral phase transition coincides with that of the dressed Polyakov loop in the whole (T,µ plane. In the case of explicit chiral symmetry breaking, it is found that the phase transitions are flavor dependent. For each flavor, the transition temperature for chiral restoration $T^{mathcal{X}}_c$ is smaller than that of the dressed Polyakov loop $T^{mathcal{D}}_c$ in the low baryon density region where the transition is a crossover, and, the two critical temperatures coincide in the high baryon density region where the phase transition is of first order. Therefore, there are two critical end points, i.e, $T^{u,d}_{CEP}$ and $T^{s}_{CEP}$ at finite density. We also explain the feature of $T^{mathcal{X}}_c$ = $T^{mathcal{D}}_c$ in the case of 1st and 2nd order phase transitions, and $T^{mathcal{X}}_c$ < $T^{mathcal{D}}_c$ in the case of crossover, and expect this feature is general and can be extended to full QCD theory.
Interplay between chiral and deconfinement phase transitions
Xu, Fukun; Chen, Huan; Huang, Mei
2011-01-01
By using the dressed Polyakov loop or dual chiral condensate as an equivalent order parameter of the deconfinement phase transition, we investigate the relation between the chiral and deconfinement phase transitions at finite temperature and density in the framework of three-flavor Nambu--Jona-Lasinio (NJL) model. It is found that in the chiral limit, the critical temperature for chiral phase transition coincides with that of the dressed Polyakov loop in the whole $(T,\\mu)$ plane. In the case of explicit chiral symmetry breaking, it is found that the phase transitions are flavor dependent. For each flavor, the transition temperature for chiral restoration $T_c^{\\chi}$ is smaller than that of the dressed Polyakov loop $T_c^{{\\cal D}}$ in the low baryon density region where the transition is a crossover, and, the two critical temperatures coincide in the high baryon density region where the phase transition is of first order. Therefore, there are two critical end points, i.e, $T_{CEP}^{u,d}$ and $T_{CEP}^{s}$ a...
Chiral nucleon-nucleon forces in nuclear structure calculations
Directory of Open Access Journals (Sweden)
Coraggio L.
2016-01-01
Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.
Chiral symmetry breaking and vacuum polarization in a bag
Yasui, S
2006-01-01
We study the effects of a finite quark mass in the hedgehog configuration in the two phase chiral bag model. We discuss the chiral properties, such as the fractional baryon number and the chiral Casimir energy, by using the Debye expansion for the analytical calculation and the Strutinsky's smearing method for the numerical computation. It is shown that the fractional baryon number carried by massive quarks in the vacuum is canceled by that in the meson sector. A finite term of the chiral Casimir energy is obtained with subtraction of the logarithmic divergence term.
Chiral nucleon-nucleon forces in nuclear structure calculations
Coraggio, L; Holt, J W; Itaco, N; Machleidt, R; Marcucci, L E; Sammarruca, F
2016-01-01
Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.
Chiral symmetry and functional integral
Energy Technology Data Exchange (ETDEWEB)
Gamboa Saravi, R.E.; Muschietti, M.A.; Schaposnik, F.A.; Solomin, J.E.
1984-10-15
The change in the fermionic functional integral measure under chiral rotations is analyzed. Using the zeta-function method, the evaluation of chiral Jacobians to theories including non-hermitian Dirac operators D, can be extended in a natural way. (This being of interest, for example, in connection with the Weinberg-Salam model or with the relativistic string theory). Results are compared with those obtained following other approaches, the possible discrepancies are analyzed and the equivalence of the different methods under certain conditions on D is proved. Also shown is how to compute the Jacobian for the case of a finite chiral transformation and this result is used to develop a sort of path-integral version of bosonization in d = 2 space-time dimensions. This result is used to solve in a very simple and economical way relevant d = 2 fermionic models. Furthermore, some interesting features in connection with the theta-vacuum in d = 2,4 gauge theories are discussed.
Chiral primaries in strange metals
Energy Technology Data Exchange (ETDEWEB)
Isachenkov, Mikhail, E-mail: mikhail.isachenkov@desy.de; Kirsch, Ingo, E-mail: ingo.kirsch@desy.de; Schomerus, Volker, E-mail: volker.schomerus@desy.de
2014-08-15
It was suggested recently that the study of 1-dimensional QCD with fermions in the adjoint representation could lead to an interesting toy model for strange metals and their holographic formulation. In the high density regime, the infrared physics of this theory is described by a constrained free fermion theory with an emergent N=(2,2) superconformal symmetry. In order to narrow the choice of potential holographic duals, we initiate a systematic search for chiral primaries in this model. We argue that the bosonic part of the superconformal algebra can be extended to a coset chiral algebra of the form W{sub N}=SO(2N{sup 2}−2){sub 1}/SU(N){sub 2N}. In terms of this algebra the spectrum of the low energy theory decomposes into a finite number of sectors which are parametrized by special necklaces. We compute the corresponding characters and partition functions and determine the set of chiral primaries for N≤5.
Chiral primaries in strange metals
Energy Technology Data Exchange (ETDEWEB)
Isachenkov, Mikhail; Kirsch, Ingo; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2014-03-15
It was suggested recently that the study of 1-dimensional QCD with fermions in the adjoint representation could lead to an interesting toy model for strange metals and their holographic formulation. In the high density regime, the infrared physics of this theory is described by a constrained free fermion theory with an emergent N=(2,2) superconformal symmetry. In order to narrow the choice of potential holographic duals, we initiate a systematic search for chiral primaries in this model. We argue that the bosonic part of the superconformal algebra can be extended to a coset chiral algebra of the form W{sub N}=SO(2N{sup 2}-2){sub 1}/SU(N){sub 2N}. In terms of this algebra the spectrum of the low energy theory decomposes into a finite number of sectors which are parametrized by special necklaces. We compute the corresponding characters and partition functions and determine the set of chiral primaries for N≤5.
Li, Bing-Wei; Cai, Mei-Chun; Zhang, Hong; Panfilov, Alexander V.; Dierckx, Hans
2014-05-01
Chirality is one of the most fundamental properties of many physical, chemical, and biological systems. However, the mechanisms underlying the onset and control of chiral symmetry are largely understudied. We investigate possibility of chirality control in a chemical excitable system (the Belousov-Zhabotinsky reaction) by application of a chiral (rotating) electric field using the Oregonator model. We find that unlike previous findings, we can achieve the chirality control not only in the field rotation direction, but also opposite to it, depending on the field rotation frequency. To unravel the mechanism, we further develop a comprehensive theory of frequency synchronization based on the response function approach. We find that this problem can be described by the Adler equation and show phase-locking phenomena, known as the Arnold tongue. Our theoretical predictions are in good quantitative agreement with the numerical simulations and provide a solid basis for chirality control in excitable media.
Bourget, Antoine; Troost, Jan
2016-03-01
We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N = (4 , 4) supersymmetry in two dimensions. For seed target spaces K3 and T 4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.
Bourget, Antoine
2015-01-01
We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.
Molecular-Level Design of Heterogeneous Chiral Catalysis
Energy Technology Data Exchange (ETDEWEB)
Francisco Zaera
2012-03-21
The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration
Catalysis of Dynamical Chiral Symmetry Breaking by Chiral Chemical Potential
Braguta, V V
2016-01-01
In this paper we study the properties of media with chiral imbalance parameterized by chiral chemical potential. It is shown that depending on the strength of interaction between constituents in the media the chiral chemical potential either creates or enhances dynamical chiral symmetry breaking. Thus the chiral chemical potential plays a role of the catalyst of dynamical chiral symmetry breaking. Physically this effect results from the appearance of the Fermi surface and additional fermion states on this surface which take part in dynamical chiral symmetry breaking. An interesting conclusion which can be drawn is that at sufficiently small temperature chiral plasma is unstable with respect to condensation of Cooper pairs and dynamical chiral symmetry breaking even for vanishingly small interactions between constituents.
Novozhilov, V Yu; Novozhilov, Victor; Novozhilov, Yuri
2002-01-01
We discuss specific features of color chiral solitons (asymptotics, possibility of confainment, quantization) at example of isolated SU(2) color skyrmions, i.e. skyrmions in a background field which is the vacuum field forming the gluon condensate.
Heavy-tailed chiral random matrix theory
Kanazawa, Takuya
2016-01-01
We study an unconventional chiral random matrix model with a heavy-tailed probabilistic weight. The model is shown to exhibit chiral symmetry breaking with no bilinear condensate, in analogy to the Stern phase of QCD. We solve the model analytically and obtain the microscopic spectral density and the smallest eigenvalue distribution for an arbitrary number of flavors and arbitrary quark masses. Exotic behaviors such as non-decoupling of heavy flavors and a power-law tail of the smallest eigenvalue distribution are illustrated.
Directory of Open Access Journals (Sweden)
Goldstein Gary R.
2015-01-01
Full Text Available Nucleon spin structure, transversity and the tensor charge are of central importance to understanding the role of QCD in hadronic physics. A new approach to measuring orbital angular momenta of quarks in the proton via twist 3 GPDs is shown. The “flexible parametrization” of chiral even GPDs is reviewed and its transformation into the chiral odd sector is discussed. The resulting parametrization is applied to recent data on π0 and η electroproduction.
Chiral separation in microflows
Kostur, Marcin; Schindler, Michael; Talkner, Peter; Hänggi, Peter
2005-01-01
Molecules that only differ by their chirality, so called enantiomers, often possess different properties with respect to their biological function. Therefore, the separation of enantiomers presents a prominent challenge in molecular biology and belongs to the ``Holy Grail'' of organic chemistry. We suggest a new separation technique for chiral molecules that is based on the transport properties in a microfluidic flow with spatially variable vorticity. Because of their size the thermal fluctua...
Energy Technology Data Exchange (ETDEWEB)
Bonner, W.A. [Department of Chemistry Stanford University, Stanford, California 94305 (United States)
1996-07-01
The indispensable role played by homochirality and chiral homogeneity in the self-replication of crucial biomolecules is stressed, with the conclusion that life could neither exist nor originate without these chiral molecular attributes. Hypotheses historically proposed for the origin of chiral molecules on Earth are reviewed, including biogenic theories as well as abiotic theories embracing both indeterminate and determinate mechanisms. Indeterminate mechanisms, including autocatalytic symmetry breaking, asymmetric adsorption on quartz and clay minerals, and asymmetric syntheses in chiral crystals, are discussed and evaluated in the context of the prebiotic environment. Abiotic determinate mechanisms based on electric, magnetic and gravitational fields, on circularly polarized light (CPL), and on parity violation effects are summarized, with the emphasis that only CPL has proved practicable experimentally, but that it would be implausible on the primitive Earth. Mechanisms for the amplification of small, indigenous enantiomeric excesses are discussed, with one involving the partial polymerization of amino acids and the partial hydrolysis of polypeptides suggested as potentially viable prebiotically. Aspects of the turbulent, chirality-destructive primeval environment are described, with the conclusion that all of the above mechanisms for the {ital terrestrial} prebiotic origin of chirality would be non-viable, and that an alternative extraterrestrial source for the accumulation of chiral molecules on primitive Earth must have been operative. A scenario for this is outlined, in which we postulate that asymmetric photolysis of the organic mantles on interstellar grains in molecular clouds by circularly polarized ultraviolet synchrotron radiation from the neutron star remnants of supernovae produces chiral molecules in the grain mantles. (Abstract Truncated)
Chiral density wave in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Heinz, Achim [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Giacosa, Francesco [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Rischke, Dirk H. [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
2015-01-15
Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nuclear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4ρ{sub 0}, where ρ{sub 0} is the nuclear matter ground-state density.
The non chiral fusion rules in rational conformal field theories
Rida, A
1999-01-01
We introduce a general method to construct the non chiral fusion rules in rational conformal field theories. We are particularly interested by the models of the complementary series or like-D series which are solutions of modular invariant partition function. The form proposed of the non chiral fusion rules has a structure of Zn grading.
Chiral Boson Theory on the Light-Front
Srivastava, P P
1999-01-01
The {\\it front form} framework for describing the quantized theory of chiral boson is discussed. It avoids the conflict with the requirement of the principle of microcausality as is found in the conventional equal- time treatment. The discussion of the Floreanini-Jackiw model and its modified version for describing the chiral boson becomes very transparent on the light-front.
Relation between color-deconfinement and chiral restoration
Fukushima, Kenji
2003-01-01
We discuss the relation between the Polyakov loop and the chiral order parameter at finite temperature by using an effective model. We clarify why and how the pseudo-critical temperature associated with the Polyakov loop should coincide with that of the chiral condensate.
Tensor form factors of the octet hyperons in QCD
kucukarslan, A; Ozpineci, A
2016-01-01
Light-cone QCD sum rules to leading order in QCD are used to investigate the tensor form factors of the $\\Sigma-\\Sigma$, $\\Xi-\\Xi$ and $ \\Sigma-\\Lambda$ transitions in the range $1 GeV^2 \\leq Q^2 \\leq 10 GeV^2$. The DAs of $\\Sigma$, $\\Xi$ and $\\Lambda$ baryon have been calculated without higher order terms. Then, study including higher order corrections have been done for $\\Sigma$ and $\\Lambda$ baryon. The result of form factors are obtained using these two DAs. We make a comparison with the predictions of the chiral quark soliton model.
Extraction of radiative decay width for the non-strange partner of Theta^+
Azimov, Ya I; Polyakov, M V; Strakovsky, I I; Azimov, Ya.
2005-01-01
Using the results of the GRAAL collaboration on the \\eta photoproduction from the neutron target, we attempt to extract the partial radiative width of the possible new nucleon resonance N^*(1675). The obtained estimates support this resonance to be a very attractive candidate for the non-strange member of the exotic antidecuplet of baryons -- a partner of the \\Theta^+ pentaquark. Our phenomenological value for the transition magnetic moment \\mu(n^* n), appears to be in good agreement with predictions of the Chiral Quark Soliton Model.
Bag Model Prediction for the Nucleon's Chiral-odd Twist-3 Distribution $h_L(x,Q^2)$ at High $Q^2$
Kanazawa, Y; Koike, Yuji
1997-01-01
We study the Q^2 evolution of the nucleon's chiral-odd twist-3 distribution h_L(x,Q^2) starting from the MIT bag model calculation. A simple GLAP equation for h_L(x,Q^2) obtained at large N_c is used for the Q^2 evolution. The correction due to the finite value of N_c is O(1/N_c^2)\\sim 10% level. It turns out that the twist-3 contribution to h_L(x,Q^2) is significantly reduced at Q^2=10 GeV^2 in contrast to the g_2(x,Q^2) case. This is due to the fact that the corresponding anomalous dimension for h_L is larger than that for g_2 at small n (spin).
Chiral superfluidity for the heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Kalaydzhyan, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation)
2013-02-15
We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The ''normal'' component of the fluid is the thermalized matter in common sense, while the ''superfluid'' part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the ''superfluid'' component gives rise to the chiral magnetic, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model. By considering probe quarks one can show that the fermionic spectrum at the intermediate temperatures (T{sub c}
Absence of equilibrium chiral magnetic effect
Zubkov, M A
2016-01-01
We analyse the $3+1$ D equilibrium chiral magnetic effect (CME). We apply derivative expansion to the Wigner transform of the two - point Green function. This technique allows us to express the response of electric current to external electromagnetic field strength through the momentum space topological invariant. We consider the wide class of the lattice regularizations of quantum field theory (that includes, in particular, the regularization with Wilson fermions) and also certain lattice models of solid state physics (including those of Dirac semimetals). It appears, that in these models the mentioned topological invariant vanishes identically at nonzero chiral chemical potential. That means, that the bulk equilibrium CME is absent in those systems.
Vector solitons in nonlinear isotropic chiral metamaterials
Energy Technology Data Exchange (ETDEWEB)
Tsitsas, N L [School of Applied Mathematical and Physical Sciences, National Technical University of Athens, Zografos, Athens 15773 (Greece); Lakhtakia, A [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States); Frantzeskakis, D J, E-mail: dfrantz@phys.uoa.gr [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece)
2011-10-28
Starting from the Maxwell equations, we used the reductive perturbation method to derive a system of two coupled nonlinear Schroedinger (NLS) equations for the two Beltrami components of the electromagnetic field propagating along a fixed direction in an isotropic nonlinear chiral metamaterial. With single-resonance Lorentz models for the permittivity and permeability and a Condon model for the chirality parameter, in certain spectral regimes, one of the two Beltrami components exhibits a negative-real refractive index when nonlinearity is ignored and the chirality parameter is sufficiently large. We found that, inside such a spectral regime, there may exist a subregime wherein the system of the NLS equations can be approximated by the Manakov system. Bright-bright, dark-dark, and dark-bright vector solitons can be formed in that spectral subregime. (paper)
Chiral rings and anomalies in supersymmetric gauge theory
International Nuclear Information System (INIS)
Motivated by recent work of Dijkgraaf and Vafa, we study anomalies and the chiral ring structure in a supersymmetric U(N) gauge theory with an adjoint chiral superfield and an arbitrary superpotential. A certain generalization of the Konishi anomaly leads to an equation which is identical to the loop equation of a bosonic matrix model. This allows us to solve for the expectation values of the chiral operators as functions of a finite number of 'integration constants'. From this, we can derive the Dijkgraaf-Vafa relation of the effective superpotential to a matrix model. Some of our results are applicable to more general theories. For example, we determine the classical relations and quantum deformations of the chiral ring of N=1 super Yang-Mills theory with SU(N) gauge group, showing, as one consequence, that all supersymmetric vacua of this theory have a nonzero chiral condensate. (author)
Anomalous properties of spin-extended chiral fermions
Elbistan, M
2015-01-01
The spin-extended semiclassical chiral fermion (we call the S-model), which had been used to derive the twisted Lorentz symmetry of the "spin-enslaved" chiral chiral fermion (we call the c-model) is equivalent to the latter in the free case, however coupling to an external electromagnetic field yields inequivalent systems. The difference is highlighted by the inconsistency of spin enslavement within the spin-extended framework. The S-model exhibits nevertheless similar though slightly different anomalous properties as the usual c-model does.
Chiral anomalies and differential geometry
Energy Technology Data Exchange (ETDEWEB)
Zumino, B.
1983-10-01
Some properties of chiral anomalies are described from a geometric point of view. Topics include chiral anomalies and differential forms, transformation properties of the anomalies, identification and use of the anomalies, and normalization of the anomalies. 22 references. (WHK)
Molecular-level Design of Heterogeneous Chiral Catalysts
Energy Technology Data Exchange (ETDEWEB)
Gellman, Andrew John [Carnegie Mellon University; Sholl, David S. [Georgia Institute of Technology; Tysoe, Wilfred T. [University of Wisconsin - Milwaukee; Zaera, Francisco [University of California at Riverside
2013-04-28
Understanding and controlling selectivity is one of the key challenges in heterogeneous catalysis. Among problems in catalytic selectivity enantioselectivity is perhaps the most the most challenging. The primary goal of the project on “Molecular-level Design of Heterogeneous Chiral Catalysts” is to understand the origins of enantioselectivity on chiral heterogeneous surfaces and catalysts. The efforts of the project team include preparation of chiral surfaces, characterization of chiral surfaces, experimental detection of enantioselectivity on such surfaces and computational modeling of the interactions of chiral probe molecules with chiral surfaces. Over the course of the project period the team of PI’s has made some of the most detailed and insightful studies of enantioselective chemistry on chiral surfaces. This includes the measurement of fundamental interactions and reaction mechanisms of chiral molecules on chiral surfaces and leads all the way to rationale design and synthesis of chiral surfaces and materials for enantioselective surface chemistry. The PI’s have designed and prepared new materials for enantioselective adsorption and catalysis. Naturally Chiral Surfaces • Completion of a systematic study of the enantiospecific desorption kinetics of R-3-methylcyclohexanone (R-3-MCHO) on 9 achiral and 7 enantiomeric pairs of chiral Cu surfaces with orientations that span the stereographic triangle. • Discovery of super-enantioselective tartaric acid (TA) and aspartic acid (Asp) decomposition as a result of a surface explosion mechanism on Cu(643)R&S. Systematic study of super-enantiospecific TA and Asp decomposition on five enantiomeric pairs of chiral Cu surfaces. • Initial observation of the enantiospecific desorption of R- and S-propylene oxide (PO) from Cu(100) imprinted with {3,1,17} facets by L-lysine adsorption. Templated Chiral Surfaces • Initial observation of the enantiospecific desorption of R- and S-PO from Pt(111) and Pd(111
Chiral Electroweak Currents in Nuclei
Riska, D O
2016-01-01
The development of the chiral dynamics based description of nuclear electroweak currents is reviewed. Gerald E. (Gerry) Brown's role in basing theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative examples of the successful description of electroweak observables of light nuclei obtained from chiral effective field theory are presented.
Chiral Synthons in Pesticide Syntheses
Feringa, Bernard
1988-01-01
The use of chiral synthons in the preparation of enantiomerically pure pesticides is described in this chapter. Several routes to chiral synthons based on asymmetric synthesis or on natural products are illustrated. Important sources of chiral building blocks are reviewed. Furthermore the implicatio
Dimensional structural constants from chiral and conformal bosonization of QCD
Andrianov, A A; Ebert, D; Mann, T F; Mann, Th. Feld
1997-01-01
We derive the dimensional non-perturbative part of the QCD effective ac= tion for scalar and pseudoscalar meson fields by means of chiral and conformal bosonization. The related structural coupling constants L_5 and L_8 of th= e chiral lagrangian are estimated using general relations which are valid i= n a variety of chiral bosonization models without explicit reference to model parameters. The asymptotics for large scalar fields in QCD is elaborated,= and model-independent constraints on dimensional coupling constants of the effective meson lagrangian are evaluated. We determine also the interacti= on between scalar quarkonium and the gluon density and obtain the scalar glueball-quarkonium potential.
Lodahl, Peter; Stobbe, Søren; Schneeweiss, Philipp; Volz, Jürgen; Rauschenbeutel, Arno; Pichler, Hannes; Zoller, Peter
2016-01-01
At the most fundamental level, the interaction between light and matter is manifested by the emission and absorption of single photons by single quantum emitters. Controlling light--matter interaction is the basis for diverse applications ranging from light technology to quantum--information processing. Many of these applications are nowadays based on photonic nanostructures strongly benefitting from their scalability and integrability. The confinement of light in such nanostructures imposes an inherent link between the local polarization and propagation direction of light. This leads to {\\em chiral light--matter interaction}, i.e., the emission and absorption of photons depend on the propagation direction and local polarization of light as well as the polarization of the emitter transition. The burgeoning research field of {\\em chiral quantum optics} offers fundamentally new functionalities and applications both for single emitters and ensembles thereof. For instance, a chiral light--matter interface enables...
Holographic Chiral Magnetic Spiral
International Nuclear Information System (INIS)
We study the ground state of baryonic/axial matter at zero temperature chiral-symmetry broken phase under a large magnetic field, in the framework of holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored against previously studied phase of homogeneous distribution of axial/baryonic currents in terms of meson super-currents dictated by triangle anomalies in QCD. Our results provide an existence proof of chiral magnetic spiral in strong coupling regime via holography, at least for large axial chemical potentials, whereas we don't find the phenomenon in the case of purely baryonic chemical potential. (author)
Weighted power counting and chiral dimensional regularization
Anselmi, Damiano
2014-01-01
We define a modified dimensional-regularization technique that overcomes several difficulties of the ordinary technique, and is specially designed to work efficiently in chiral and parity violating quantum field theories, in arbitrary dimensions greater than 2. When the dimension of spacetime is continued to complex values, spinors, vectors and tensors keep the components they have in the physical dimension, therefore the gamma matrices are the standard ones. Propagators are regularized with the help of evanescent higher-derivative kinetic terms, which are of Majorana type in the case of chiral fermions. If the new terms are organized in a clever way, weighted power counting provides an efficient control on the renormalization of the theory, and allows us to show that the resulting chiral dimensional regularization is consistent to all orders. The new technique considerably simplifies the proofs of properties that hold to all orders, and makes them suitable to be generalized to wider classes of models. Typica...
Band Interaction between Chiral Doublet Bands
Institute of Scientific and Technical Information of China (English)
QI Bin; ZHANG Shuang-Quan; WANG Shou-Yu; MENG Jie
2010-01-01
@@ Band interaction between the chiral doublet bands based on πh11/2(×) vh-111/2 configuration is investigated in the particle rotor model with different triaxial deformation γ. The variation of chiral partner states with γvalues is understood qualitatively based on the basic picture of two interaction levels, which is confirmed further by the calculated overlap integral of wave functions at different γ values. It is found that the interaction strengths ofchiral partner states are obvionsly different for odd spins and even ones.
Dynamics and properties of chiral cosmic strings in Minkowski space
Davis, A C; Pickles, M; Steer, D A
2000-01-01
Chiral cosmic strings are produced naturally at the end of inflation in supersymmetric models where the symmetry is broken via a D-term. Consequently in such theories, where both inflation and cosmic strings contribute to the density and CMBR (microwave background) perturbations, it is necessary to understand the evolution of chiral cosmic string networks. We study the dynamics of chiral cosmic strings in Minkowski space and comment on a number of differences with those of Nambu-Goto strings. To do this we follow the work of Carter and Peter who showed that the equations of motion for chiral cosmic strings reduce to a wave equation and two constraints, only one of which is different from the familiar Nambu-Goto constraints. We study chiral string loop solutions consisting of many harmonics and determine their self-intersection probabilities, and comment on the possible cosmological significance of these results.
Inhomogeneous chiral symmetry breaking in dense neutron-star matter
Buballa, Michael
2015-01-01
An increasing number of model results suggests that chiral symmetry is broken inhomogeneously in a certain window at intermediate densities in the QCD phase diagram. This could have significant effects on the properties of compact stars, possibly leading to new astrophysical signatures. In this contribution we discuss this idea by reviewing recent results on inhomogeneous chiral symmetry breaking under an astrophysics-oriented perspective. After introducing two commonly studied spatial modulations of the chiral condensate, the chiral density wave and the real kink crystal, we focus on their properties and their effect on the equation of state of quark matter. We also describe how these crystalline phases are affected by different elements which are required for a realistic description of a compact star, such as charge neutrality, the presence of magnetic fields, vector interactions and the interplay with color-superconductivity. Finally, we discuss possible signatures of inhomogeneous chiral symmetry breaking...
The Quantum Group Structure of 2D Gravity and Minimal Models; 2, The Genus-Zero Chiral Bootstrap
Cremmer, E; Roussel, J F; Gervais, Jean-Loup
1994-01-01
The F and B matrices associated with Virasoro null vectors are derived in closed form by making use of the operator-approach suggested by the Liouville theory, where the quantum-group symmetry is explicit. It is found that the entries of the fusing and braiding matrices are not simply equal to quantum-group symbols, but involve additional coupling constants whose derivation is one aim of the present work. Our explicit formulae are new, to our knowledge, in spite of the numerous studies of this problem. The relationship between the quantum-group-invariant (of IRF type) and quantum-group-covariant (of vertex type) chiral operator-algebras is fully clarified, and connected with the transition to the shadow world for quantum-group symbols. The corresponding 3-j-symbol dressing is shown to reduce to the simpler transformation of Babelon and one of the author (J.-L. G.) in a suitable infinite limit defined by analytic continuation. The above two types of operators are found to coincide when applied to states with L...
Barron, Laurence D.
2008-03-01
Chirality, meaning handedness, pervades much of modern science, from the physics of elementary particles to the chemistry of life. The amino acids and sugars from which the central molecules of life—proteins and nucleic acids—are constructed exhibit homochirality, which is expected to be a key biosignature in astrobiology. This article provides a brief review of molecular chirality and its significance for the detection of extant or extinct life on other worlds. Fundamental symmetry aspects are emphasized since these bring intrinsic physical properties of the universe to bear on the problem of the origin and role of homochirality in the living world.
Chiral Heat Wave and wave mixing in chiral media
Chernodub, M N
2016-01-01
We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective excitation associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This excitation, which we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical Wave while in the presence of an external magnetic field it mixes with the Chiral Magnetic Wave. We find that the coupled waves - which are coherent fluctuations of the vector, axial and energy currents - have generally different velocities compared to the velocities of the individual waves. We also demonstrate that rotating chiral systems subjected to external magnetic field possess non-propagating metastable thermal excitations, the Dense Hot Spots.
Local topological and chiral properties of QCD
De Forcrand, Philippe; Laermann, E; Lagaë, J F; Pérez-Garcia, M; Stamatescu, I O; Forcrand, Ph. de
1999-01-01
To elucidate the role played by instantons in chiral symmetry breaking, we explore their properties in full QCD, around the critical temperature. We study in particular spatial correlations between low-lying Dirac eigenmodes and instantons. Our measurements are compared with the predictions of instanton-based models.
Hu, Li; Fang, Yurui
2016-01-01
Plasmonic chirality exhibits great potential for novel nanooptical devices due to the generation of a strong chiroptical response. Previous reports on plasmonic chirality explanations are mainly based on phase retardation and coupling. We propose a quantitative model similar to the chiral molecules for explaining the mechanism of the intrinsic plasmonic chirality quantitatively based on the interplay and mixing of electric and magnetic dipole modes, which forms a mixed electric and magnetic polarizability. The analysis method is also suitable for small chiral object down to quasi-static limit without phase delay and expected to be a universal rule.
Examining a possible cascade effect in chiral symmetry breaking
Fariborz, Amir H
2016-01-01
We examine a toy model and a cascade effect for confinement and chiral symmetry breaking which consists in several phase transitions corresponding to the formation of bound states and chiral condensates with different number of fermions for a strong group. We analyze two examples: regular QCD where we calculate the "four quark" vacuum condensate and a preon composite model based on QCD at higher scales. In this context we also determine the number of flavors at which the second chiral and confinement phase transitions occur and discuss the consequences.
Chiral Lagrangians and proton decay
International Nuclear Information System (INIS)
The phenomenological Lagrangian method is employed to obtain nucleon decay branching ratio sin conventional and supersymmetric Grand Unified Theories. After a brief survey of the theory of nucleon decay, the dominant effective baryon-number violating operators in supergravity models are derived where the observed sector is described by an SU(5) SUSY GUT. It is shown how the phenomenological Lagrangian technique may be understood from a mathematical viewpoint. This technique is then applied to calculate two- and three-body nucleon decay branching ratios in SUGRA models. Finally, the author answers criticism of the usual phenomenological Lagrangian approach when used for nucleon decay calculations by developing a hybrid chiral quark model. With this model, branching ratios for conventional and SUSY GUTs are calculated. (author)
Chiral magnetic effect without chirality source in asymmetric Weyl semimetals
Kharzeev, Dmitri; Meyer, Rene
2016-01-01
We describe a new type of the Chiral Magnetic Effect (CME) that should occur in Weyl semimetals with an asymmetry in the dispersion relations of the left- and right-handed chiral Weyl fermions. In such materials, time-dependent pumping of electrons from a non-chiral external source generates a non-vanishing chiral chemical potential. This is due to the different capacities of the left- and right-handed (LH and RH) chiral Weyl cones arising from the difference in the density of states in the LH and RH cones. The chiral chemical potential then generates, via the chiral anomaly, a current along the direction of an applied magnetic field even in the absence of an external electric field. The source of chirality imbalance in this new setup is thus due to the band structure of the system and the presence of (non-chiral) electron source, and not due to the parallel electric and magnetic fields. We illustrate the effect by an argument based on the effective field theory, and by the chiral kinetic theory calculation f...
Detecting the chirality for coupled quantum dots
Energy Technology Data Exchange (ETDEWEB)
Cao Huijuan [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China); Hu Lian [Institute for Condensed Matter Physics, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510631 (China)], E-mail: huliancaohj@yahoo.com
2008-04-21
We propose a scheme to detect the chirality for a system consisting of three coupled quantum dots. The chirality is found to be determined by the frequency of the transition between chiral states under the chiral symmetry broken perturbation. The results are important to construct quantum gates and to demonstrate chiral entangle states in the triangle spin dots.
Sum-Frequency Generation from Chiral Media and Interfaces
International Nuclear Information System (INIS)
Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers
Sum-Frequency Generation from Chiral Media and Interfaces
Energy Technology Data Exchange (ETDEWEB)
Ji, Na
2006-02-13
Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers.
Nature of chiral spin liquids on the kagome lattice
Wietek, Alexander; Sterdyniak, Antoine; Läuchli, Andreas M.
2015-09-01
We investigate the stability and the nature of the chiral spin liquids which were recently uncovered in extended Heisenberg models on the kagome lattice. Using a Gutzwiller projected wave function approach, i.e., a parton construction, we obtain large overlaps with ground states of these extended Heisenberg models. We further suggest that the appearance of the chiral spin liquid in the time-reversal invariant case is linked to a classical transition line between two magnetically ordered phases.
Static aeroelastic response of chiral-core airfoils
Spadoni, Alessandro; Ruzzene, Massimo
2007-01-01
Extensive research is being devoted to the analysis and application of cellular solids for the design of innovative structural components. The chiral geometry in particular features a unique mechanical behavior which is here exploited for the design of 2D airfoils with morphing capabilities. A coupled-physics model, comprising computational fluid dynamics and structural analyses, investigates the influence of the chiral core on the aerodynamic behavior of the airfoil. Specifically, the model ...
Chiral symmetry and parametrization of scalar resonances
Arantes, L O
2005-01-01
The linear $\\s$-model is used to study the effects of chiral symmetry in unitarized amplitudes incorporating scalar resonances. When just a single resonance is present, we show that the iteration of a chiral tree amplitude by means of regularized two-pion loops preserves the smallness of $\\p\\p$ interaction at low energies and estimate the importance of pion off-shell contributions. The inclusion of a second resonance is performed by means of a chiral extension of the linear $\\s$-model lagrangian. The new $\\p\\p$ ampitude at tree level complies with low-energy theorems, depends on a mixing angle and has a zero for a given energy between the resonance masses. The unitarization of this amplitude by means of two-pion loops preserves both its chiral low energy behavior and the position of this zero confirming, in a lagrangian framework, conclusions drawn previously by T\\"ornqvist. Finally, we approximate and generalize our results and give a friendly expression that can be used in the parametrization of $N$ coupled...
Tsui, Hung-Wei; Franses, Elias I; Wang, Nien-Hwa Linda
2014-02-01
Various displacement models in the literature have been widely used for understanding the adsorption mechanisms of solutes in various chromatography systems. The models were used for describing the often-observed linear plots of the logarithms of the retention factor versus the logarithms of the polar modifier concentration CI(0). The slopes of such a plot was inferred to be equal to the number of the displaced modifier molecules upon adsorption of one solute molecule, and were generally found to be greater than 1. In this study, the retention factors of four structurally related chiral solutes, ethyl lactate (EL), methyl mandelate (MM), benzoin (B), and pantolactone (PL), were measured for the amylose tris[(S)-α-methylbenzylcarbamate] sorbent, or AS, as a function of the concentration of isopropanol (IPA) in n-hexane. With increasing IPA concentration CI(0), the slopes increase from less than 1, at a concentration range from 0.13 to 1.3M, to slightly more than 1 at higher concentrations. Such slopes cannot be explained by the conventional retention models. It was found previously for monovalent solutes that such slopes can only be explained when the aggregation of the mobile phase modifier, isopropyl alcohol, was accounted for. A new retention model is presented here, accounting for alcohol aggregation, multivalent solute adsorption, multivalent solute-alcohol complexation, alcohol adsorption, and solute intra hydrogen-bonding, which occur in these four solutes. The slope is found to be controlled by three key dimensionless groups, the fraction of the sorbent binding sites covered by IPA, the fraction of the solute molecules in complex form, and the fraction of the IPA molecules in aggregate form. The limiting slope at a very high IPA concentration is equal to the value of (x+y)/n, where x is the number of the solute-sorbent binding sites and y is the number of the alcohol molecules in the solute-alcohol complex, and n is the alcohol aggregation number. The model
Tsui, Hung-Wei; Franses, Elias I; Wang, Nien-Hwa Linda
2014-02-01
Various displacement models in the literature have been widely used for understanding the adsorption mechanisms of solutes in various chromatography systems. The models were used for describing the often-observed linear plots of the logarithms of the retention factor versus the logarithms of the polar modifier concentration CI(0). The slopes of such a plot was inferred to be equal to the number of the displaced modifier molecules upon adsorption of one solute molecule, and were generally found to be greater than 1. In this study, the retention factors of four structurally related chiral solutes, ethyl lactate (EL), methyl mandelate (MM), benzoin (B), and pantolactone (PL), were measured for the amylose tris[(S)-α-methylbenzylcarbamate] sorbent, or AS, as a function of the concentration of isopropanol (IPA) in n-hexane. With increasing IPA concentration CI(0), the slopes increase from less than 1, at a concentration range from 0.13 to 1.3M, to slightly more than 1 at higher concentrations. Such slopes cannot be explained by the conventional retention models. It was found previously for monovalent solutes that such slopes can only be explained when the aggregation of the mobile phase modifier, isopropyl alcohol, was accounted for. A new retention model is presented here, accounting for alcohol aggregation, multivalent solute adsorption, multivalent solute-alcohol complexation, alcohol adsorption, and solute intra hydrogen-bonding, which occur in these four solutes. The slope is found to be controlled by three key dimensionless groups, the fraction of the sorbent binding sites covered by IPA, the fraction of the solute molecules in complex form, and the fraction of the IPA molecules in aggregate form. The limiting slope at a very high IPA concentration is equal to the value of (x+y)/n, where x is the number of the solute-sorbent binding sites and y is the number of the alcohol molecules in the solute-alcohol complex, and n is the alcohol aggregation number. The model
Klevansky, S P
2016-01-01
Recently Dai and Pennington have performed a comprehensive analysis of essentially all pion and kaon pair production data from two-photon collisions below 1.5 GeV, including all high statistics results from Belle, as well as the older data from Mark II at SLAC, CELLO at DESY, and Crystal Ball at SLAC. Imposing the basic constraints required by analyticity, unitarity, and crossing symmetry and making use of Low's low energy theorem for QED, they are able to extract the final-state strong-interaction scattering amplitudes for the intermediate pi pi->pi pi and pi pi-> K\\bar K reactions in a model-independent fashion. In addition, they provide good fits to the respective gamma gamma-> pi pi cross-sections that are known in the low-energy sector in the restricted angular range, | cos theta|pi pi cross-sections integrated over the full angular range. In this work, we use a version of chiral perturbation theory developed by Oller and Oset to evaluate the final-state strong-interaction amplitudes directly theoretical...
Garron, Nicolas; Lytle, Andew T
2016-01-01
We compute the hadronic matrix elements of the four-quark operators relevant for $K^0-{\\bar K^0}$ mixing beyond the Standard Model. Our results are from lattice QCD simulations with $n_f=2+1$ flavours of domain-wall fermion, which exhibit continuum-like chiral-flavour symmetry. The simulations are performed at two different values of the lattice spacing ($a\\sim0.08$ and $a\\sim 0.11 \\, \\fm $) and with lightest unitary pion mass $\\sim 300\\, \\MeV$. For the first time, the full set of relevant four-quark operators is renormalised non-perturbatively through RI-SMOM schemes; a detailed description of the renormalisation procedure is presented in a companion paper. We argue that the intermediate renormalisation scheme is responsible for the discrepancies found by different collaborations. We also study different normalisations and determine the matrix elements of the relevant four-quark operators with a precision of $\\sim 5\\%$ or better.
Which Chiral Symmetry is Restored in High Temperature QCD?
Bernard, C W; DeTar, C E; Gottlieb, S; Heller, U M; Hetrick, J E; Rummukainen, K; Sugar, R; Toussaint, D; Wingate, M; Bernard, Claude; Blum, Tom; Tar, Carleton De; Gottlieb, Steven; Heller, Urs M.; Hetrick, James E.; Wingate, Matthew
1996-01-01
Sigma models for the high temperature phase transition in quantum chromodynamics (QCD) suggest that at high temperature the SU(N_f) x SU(N_f) chiral symmetry becomes exact, but the anomalous axial U(1) symmetry need not be restored. In numerical lattice simulations, traditional methods for detecting symmetry restoration have sought multiplets in the screening mass spectrum. However, these methods were imprecise and the results, so far, incomplete. With improved statistics and methodology, we are now able to offer evidence for a restoration of the SU(2) x SU(2) chiral symmetry just above the crossover, but not of the axial U(1) chiral symmetry.
Chiral assembly of weakly curled hard rods: Effect of steric chirality and polarity
Energy Technology Data Exchange (ETDEWEB)
Wensink, H. H., E-mail: wensink@lps.u-psud.fr; Morales-Anda, L. [Laboratoire de Physique des Solides–UMR 8502, Université Paris-Sud & CNRS, 91405 Orsay (France)
2015-10-14
We theoretically investigate the pitch of lyotropic cholesteric phases composed of slender rods with steric chirality transmitted via a weak helical deformation of the backbone. In this limit, the model is amenable to analytical treatment within Onsager theory and a closed expression for the pitch versus concentration and helical shape can be derived. Within the same framework, we also briefly review the possibility of alternative types of chiral order, such as twist-bend or screw-like nematic phases, finding that cholesteric order dominates for weakly helical distortions. While long-ranged or “soft” chiral forces usually lead to a pitch decreasing linearly with concentration, steric chirality leads to a much steeper decrease of quadratic nature. This reveals a subtle link between the range of chiral intermolecular interaction and the pitch sensitivity with concentration. A much richer dependence on the thermodynamic state is revealed for polar helices where parallel and anti-parallel pair alignments along the local director are no longer equivalent. It is found that weak temperature variations may lead to dramatic changes in the pitch, despite the lyotropic nature of the assembly.
Chiral magnetic effect and holography
Energy Technology Data Exchange (ETDEWEB)
Kirsch, Ingo; Kalaydzhyan, Tigran
2013-01-15
The chiral magnetic effect (CME) is a highly discussed effect in heavy-ion collisions stating that, in the presence of a magnetic field B, an electric current is generated in the background of topologically nontrivial gluon fields. We present a holographic (AdS/CFT) description of the CME in terms of a fluid-gravity model which is dual to a strongly-coupled plasma with multiple anomalous U(1) currents. In the case of two U(1) charges, one axial and one vector, the CME formally appears as a first-order transport coefficient in the vector current. We will holographically compute this coefficient at strong coupling and compare it with the hydrodynamic result. Finally, we will discuss an anisotropic variant of the model and study a possible dependence of the CME on the elliptic flow coefficient {nu}{sub 2}.
Chiral damping of magnetic domain walls
Jué, Emilie; Safeer, C. K.; Drouard, Marc; Lopez, Alexandre; Balint, Paul; Buda-Prejbeanu, Liliana; Boulle, Olivier; Auffret, Stephane; Schuhl, Alain; Manchon, Aurelien; Miron, Ioan Mihai; Gaudin, Gilles
2016-03-01
Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics, current-induced spin-orbit torques and some topological magnetic structures. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii-Moriya interaction (DMI) exhibit identical spatial symmetry. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. ).
Weighted power counting and chiral dimensional regularization
Anselmi, Damiano
2014-06-01
We define a modified dimensional-regularization technique that overcomes several difficulties of the ordinary technique, and is specially designed to work efficiently in chiral and parity violating quantum field theories, in arbitrary dimensions greater than 2. When the dimension of spacetime is continued to complex values, spinors, vectors and tensors keep the components they have in the physical dimension; therefore, the γ matrices are the standard ones. Propagators are regularized with the help of evanescent higher-derivative kinetic terms, which are of the Majorana type in the case of chiral fermions. If the new terms are organized in a clever way, weighted power counting provides an efficient control on the renormalization of the theory, and allows us to show that the resulting chiral dimensional regularization is consistent to all orders. The new technique considerably simplifies the proofs of properties that hold to all orders, and makes them suitable to be generalized to wider classes of models. Typical examples are the renormalizability of chiral gauge theories and the Adler-Bardeen theorem. The difficulty of explicit computations, on the other hand, may increase.
Chiral damping of magnetic domain walls
Jué, Emilie
2015-12-21
Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics1, current-induced spin–orbit torques2, 3, 4, 5, 6, 7 and some topological magnetic structures8, 9, 10, 11, 12. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii–Moriya interaction (DMI) exhibit identical spatial symmetry13, 14, 15, 16, 17, 18, 19. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. 20).
Chiral damping of magnetic domain walls.
Jué, Emilie; Safeer, C K; Drouard, Marc; Lopez, Alexandre; Balint, Paul; Buda-Prejbeanu, Liliana; Boulle, Olivier; Auffret, Stephane; Schuhl, Alain; Manchon, Aurelien; Miron, Ioan Mihai; Gaudin, Gilles
2016-03-01
Structural symmetry breaking in magnetic materials is responsible for the existence of multiferroics, current-induced spin-orbit torques and some topological magnetic structures. In this Letter we report that the structural inversion asymmetry (SIA) gives rise to a chiral damping mechanism, which is evidenced by measuring the field-driven domain-wall (DW) motion in perpendicularly magnetized asymmetric Pt/Co/Pt trilayers. The DW dynamics associated with the chiral damping and those with Dzyaloshinskii-Moriya interaction (DMI) exhibit identical spatial symmetry. However, both scenarios are differentiated by their time reversal properties: whereas DMI is a conservative effect that can be modelled by an effective field, the chiral damping is purely dissipative and has no influence on the equilibrium magnetic texture. When the DW motion is modulated by an in-plane magnetic field, it reveals the structure of the internal fields experienced by the DWs, allowing one to distinguish the physical mechanism. The chiral damping enriches the spectrum of physical phenomena engendered by the SIA, and is essential for conceiving DW and skyrmion devices owing to its coexistence with DMI (ref. ). PMID:26689141
Spiral Galaxies as Chiral Objects?
Capozziello, S; Capozziello, Salvatore; Lattanzi, Alessandra
2005-01-01
Spiral galaxies show axial symmetry and an intrinsic 2D-chirality. Environmental effects can influence the chirality of originally isolated stellar systems and a progressive loss of chirality can be recognised in the Hubble sequence. We point out a preferential modality for genetic galaxies as in microscopic systems like aminoacids, sugars or neutrinos. This feature could be the remnant of a primordial symmetry breaking characterizing systems at all scales.
Chiral dynamics and baryon resonances
Hyodo, Tetsuo
2010-01-01
The structure of baryon resonance in coupled-channel meson-baryon scattering is studied from the viewpoint of chiral dynamics. The meson-baryon scattering amplitude can be successfully described together with the properties of the resonance in the scattering, by implementing the unitarity condition for the amplitude whose low energy structure is constrained by chiral theorem. Recently, there have been a major progress in the study of the structure of the resonance in chiral dynamics. We revie...
Fiorilla, Salvatore; Weise, Wolfram
2011-01-01
We calculate the equation of state of nuclear matter for arbitrary isospin-asymmetry up to three loop order in the free energy density in the framework of in-medium chiral perturbation theory. In our approach 1\\pi- and 2\\pi-exchange dynamics with the inclusion of the \\Delta-isobar excitation as an explicit degree of freedom, corresponding to the long- and intermediate-range correlations, are treated explicitly. Few contact terms fixed to reproduce selected known properties of nuclear matter encode the short-distance physics. Two-body as well as three-body forces are systematically included. We find a critical temperature of about 15 MeV for symmetric nuclear matter. We investigate the dependence of the liquid-gas first-order phase transition on isospin-asymmetry. In the same chiral framework we calculate the chiral condensate of isospin-symmetric nuclear matter at finite temperatures. The contribution of the \\Delta-isobar excitation is essential for stabilizing the condensate. As a result, we find no indicati...
Shukla, N.; Yang, D.; Gellman, A. J.
2016-06-01
Tetrahexahedral (THH, 24-sided) Au nanoparticles modified with D- or L-cysteine (Cys) have been used as enantioselective separators of the chiral pharmaceutical propranolol (PLL) in solution phase. Polarimetry has been used to measure the rotation of linearly polarized light by solutions containing mixtures of PLL and Cys/THH-Au NPs with varying enantiomeric excesses of each. Polarimetry yields clear evidence of enantiospecific adsorption of PLL onto the Cys/THH-Au NPs. This extends prior work using propylene oxide as a test chiral probe, by using the crystalline THH Au NPs with well-defined facets to separate a real pharmaceutical. This work suggests that chiral nanoparticles, coupled with a density separation method such as centrifugation, could be used for enantiomeric purification of real pharmaceuticals. A simple robust model developed earlier has also been used to extract the enantiospecific equilibrium constants for R- and S-PLL adsorption onto the D- and L-Cys/THH-Au NPs.
Chiral symmetry and scalar meson in hadron and nuclear physics
Kunihiro, T
1995-01-01
After giving a short introduction to the Nambu-Jona-Lasinio model with an anomaly term, we show the importance of the scalar-scalar correlation in the low-energy hadron dynamics, which correlation may be summarized by a scalar-isoscalar meson, the sigma meson. The discussion is based on the chiral quark model with the sigma-meson degrees of freedom. Possible experiments are proposed to produce the elusive meson in a nucleus and detect it. In relation to a precursory soft mode for the chiral transition, the reason is clarified why the dynamic properties of the superconductor may be described by the diffusive time-dependent Ginzburg-Landau (TDGL) equation. We indicate the chiral symmetry plays a significant role also in nuclei; one may say that the stability of nuclei is due to the chiral symmetry of QCD.
Ruggieri, M.; Peng, G. X.
2016-05-01
In this article, we study spontaneous chiral symmetry breaking for quark matter in the background of static and homogeneous parallel electric field E and magnetic field B . We use a Nambu-Jona-Lasinio model with a local kernel interaction to compute the relevant quantities to describe chiral symmetry breaking at a finite temperature for a wide range of E and B . We study the effect of this background on the inverse catalysis of chiral symmetry breaking for E and B of the same order of magnitude. We then focus on the effect of the equilibration of chiral density n5 , produced dynamically by an axial anomaly on the critical temperature. The equilibration of n5 , a consequence of chirality-flipping processes in the thermal bath, allows for the introduction of the chiral chemical potential μ5, which is computed self-consistently as a function of the temperature and field strength by coupling the number equation to the gap equation and solving the two within an expansion in E /T2 , B /T2 , and μ52/T2 . We find that even if chirality is produced and equilibrates within a relaxation time τM , it does not change drastically the thermodynamics, with particular reference to the inverse catalysis induced by the external fields, as long as the average μ5 at equilibrium is not too large.
Some aspects of chirality: Fermion masses and chiral p-forms
International Nuclear Information System (INIS)
The properties of fermion mass matrices are investigated from different points of view, both within the minimal Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices. One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with mass m0 implies the existence of other Dirac fields where the corresponding quanta have masses Rm0, R2m0, .. which are obtained by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices. Also extensions of the minimal Standard Model are investigated, obtained by including right-handed neutrinos in the model. The Standard Model extended by two right-handed neutrinos gives rise to a mass spectrum with two massive and three massless neutrinos. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. They are studied for the cases with two and three right-handed neutrinos, resp. The chiral fields that we find in the Standard Model have certain similarities with self-dual fields. Among other things, both chiral and self-dual fields suffer species doubling on the lattice. Chiral p-forms are self-dual fields that appear in twice odd dimensions. Chiral p-forms violate manifest covariance, in the same sense as manifest covariance is violated by non-covariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral p-forms, by introducing an infinite set of gauge fields in a carefully controlled way
Some aspects of chirality: Fermion masses and chiral p-forms
Energy Technology Data Exchange (ETDEWEB)
Kleppe, A.
1997-05-01
The properties of fermion mass matrices are investigated from different points of view, both within the minimal Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices. One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with mass m{sub 0} implies the existence of other Dirac fields where the corresponding quanta have masses Rm{sub 0}, R{sup 2}m{sub 0}, .. which are obtained by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices. Also extensions of the minimal Standard Model are investigated, obtained by including right-handed neutrinos in the model. The Standard Model extended by two right-handed neutrinos gives rise to a mass spectrum with two massive and three massless neutrinos. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. They are studied for the cases with two and three right-handed neutrinos, resp. The chiral fields that we find in the Standard Model have certain similarities with self-dual fields. Among other things, both chiral and self-dual fields suffer species doubling on the lattice. Chiral p-forms are self-dual fields that appear in twice odd dimensions. Chiral p-forms violate manifest covariance, in the same sense as manifest covariance is violated by non-covariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral p-forms, by introducing an infinite set of gauge fields in a carefully controlled way.
Criteria of backscattering in chiral one-way photonic crystals
Cheng, Pi-Ju; Chang, Shu-Wei
2016-03-01
Optical isolators are important devices in photonic circuits. To reduce the unwanted reflection in a robust manner, several setups have been realized using nonreciprocal schemes. In this study, we show that the propagating modes in a strongly-guided chiral photonic crystal (no breaking of the reciprocity) are not backscattering-immune even though they are indeed insensitive to many types of scatters. Without the protection from the nonreciprocity, the backscattering occurs under certain circumstances. We present a perturbative method to calculate the backscattering of chiral photonic crystals in the presence of chiral/achiral scatters. The model is, essentially, a simplified analogy to the first-order Born approximation. Under reasonable assumptions based on the behaviors of chiral photonic modes, we obtained the expression of reflection coefficients which provides criteria for the prominent backscattering in such chiral structures. Numerical examinations using the finite-element method were also performed and the results agree well with the theoretical prediction. From both our theory and numerical calculations, we find that the amount of backscattering critically depends on the symmetry of scatter cross sections. Strong reflection takes place when the azimuthal Fourier components of scatter cross sections have an order l of 2. Chiral scatters without these Fourier components would not efficiently reflect the chiral photonic modes. In addition, for these chiral propagating modes, disturbances at the most significant parts of field profiles do not necessarily result in the most effective backscattering. The observation also reveals what types of scatters or defects should be avoided in one-way applications of chiral structures in order to minimize the backscattering.
Extending Chiral Perturbation Theory with an Isosinglet Scalar
Hansen, Martin; Sannino, Francesco
2016-01-01
We augment the chiral Lagrangian by an isosinglet scalar and compute the one-loop radiative corrections to the pion mass and decay constant, as well as the scalar mass. The calculations are carried out for different patterns of chiral symmetry breaking of immediate relevance for phenomenology and lattice investigations. By construction our results encompass several interesting limits, ranging from the dilaton to the linear sigma model.
Effective Chiral Symmetry Restoration for Heavy-Light Mesons
Sazonov, V K; Wagenbrunn, R F
2014-01-01
We study the spectrum of heavy-light mesons within a model with linear instantaneous confining potential. The single-quark Green function and spontaneous breaking of chiral symmetry are obtained from the Schwinger-Dyson (gap) equation. For the meson spectrum we derive a Bethe-Salpeter equation (BSE). We solve thiss equation numerically in the heavy-light limit and obtain effective restoration of chiral and $U(1)_A$ symmetries at large spins.
Quantum theory of spin waves in finite chiral spin chains
Roldán-Molina, A.; Santander, M. J.; Núñez, A.S.; Fernández Rossier, Joaquín
2013-01-01
We calculate the effect of spin waves on the properties of finite-size spin chains with a chiral spin ground state observed on biatomic Fe chains deposited on iridium(001). The system is described with a Heisenberg model supplemented with a Dzyaloshinskii-Moriya coupling and a uniaxial single ion anisotropy that presents a chiral spin ground state. Spin waves are studied using the Holstein-Primakoff boson representation of spin operators. Both the renormalized ground state and the elementary ...
Ruggieri, M; Peng, G X
2016-01-01
We study the influence of external electric, $E$, and magnetic, $B$, fields parallel to each other, and of a chiral chemical potential, $\\mu_5$, on the chiral phase transition of Quantum Chromodynamics. Our theoretical framework is a Nambu-Jona-Lasinio model with a contact interaction. Within this model we compute the critical temperature of chiral symmetry restoration, $T_c$, as a function of the chiral chemical potential and field strengths. We find that the fields inhibit and $\\mu_5$ enhances chiral symmetry breaking, in agreement with previous studies.
Binary mixtures of chiral gases
Presilla, Carlo
2015-01-01
A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.
Isothermal Titration Calorimetry of Chiral Polymeric Nanoparticles.
Werber, Liora; Preiss, Laura C; Landfester, Katharina; Muñoz-Espí, Rafael; Mastai, Yitzhak
2015-09-01
Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titration calorimetry (ITC) to measure the chiral interactions and the energetics of the adsorption of enantiomers from aqueous solutions onto chiral polymeric nanoparticles. The characterization of chirality in nano-systems is a very challenging task; here, we demonstrate that ITC can be used to accurately determine the thermodynamic parameters associated with the chiral interactions of nanoparticles. The use of ITC to measure the energetics of chiral interactions and recognition at the surfaces of chiral nanoparticles can be applied to other nanoscale chiral systems and can provide further insight into the chiral discrimination processes of nanomaterials.
The properties of isolated chiral skyrmions in thin magnetic films
Leonov, A. O.; Monchesky, T. L.; Romming, N.; Kubetzka, A.; Bogdanov, A. N.; Wiesendanger, R.
2016-06-01
Axisymmetric solitonic states (chiral skyrmions) were first predicted theoretically more than two decades ago. However, until recently they have been observed in a form of skyrmionic condensates (hexagonal lattices and other mesophases). In this paper we report experimental and theoretical investigations of isolated chiral skyrmions discovered in PdFe/Ir(111) bilayers two years ago by Romming et al (2013 Science 341 636). The results of spin-polarized scanning tunneling microscopy analyzed within the continuum and discrete models provide a consistent description of isolated skyrmions in thin layers. The existence region of chiral skyrmions is restricted by strip-out instabilities at low fields and a collapse at high fields. We demonstrate that the same equations describe axisymmetric localized states in all condensed matter systems with broken mirror symmetry, and thus our findings establish basic properties of isolated skyrmions common for chiral liquid crystals, different classes of noncentrosymmetric magnets, ferroelectrics, and multiferroics.
The solution to the strong CP problem at the BCS level of chiral rotations
Bicudo, P.; Ribeiro, J
1996-01-01
We briefly review the cases of forced and spontaneous chiral symmetry breaking. In particular the chiral condensate of q anti-q pairs is parametrized with two angles, phi which measures the chiral condensation, and theta which measures the chiral rotation. The strong CP problem arises when it is assumed that the current quark masses of the Standard Model, have a theta phase that differs from the phase induced by the instanton term wich is originated in the QCD sector of the Standard Model. We...
Screw split ring resonator as building block of three-dimensional chiral metamaterials
Energy Technology Data Exchange (ETDEWEB)
Liao, Yong, E-mail: liaoy@cqu.edu.cn [Key Laboratory of Aerocraft Tracking Telemetering and Command and Communication, Ministry of Education, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Integrated Services Networks, Xidian University, Xian 710071 (China); Yang, Shizhong [Key Laboratory of Aerocraft Tracking Telemetering and Command and Communication, Ministry of Education, Chongqing University, Chongqing 400044 (China); Shi, Lina [Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China)
2014-01-17
We proposed and numerically investigated the influence of spatial topology on the infrared frequency region response of chiral metamaterials based on discrete deformed split ring resonators. Compared with the well studied continuous helix, the proposed metamaterials with discrete topology exhibit broad band chiral electromagnetic response. It is shown that the conversion between left and right circular polarization waves for our model is much broader than the continuous helix model. The observed cross-coupling between electric and magnetic fields results from the chiral electric currents on the resonators due to the broken mirror symmetry. The findings are useful for the design of future real three-dimensional chiral metamaterials with tunable optical response.
A chiral quark-motivated meson model and the CP violation in K → 3π decays
International Nuclear Information System (INIS)
The Nambu-Jona-Lasinio model is introduced as an approximation of the QCD, and in section 2 from this a meson model is derived by means of the functional integration. On the basis of the effective quark model of Vainstain-Shifman-Sacharov, which describes the weak interaction of quarks, weak and electromagnetic meson currents are derived. The so obtained meson model describes strong, weak, and electromagnetic interactions of mesons. In the 3rd section K → 2π, 3π decays are studied. After an analysis of experimental data a prediction on the direct CP violation in charged K → 3π decays is made. Starting from this estimation an experiment for the measurement of the CP asymmetry of the decay K± → π±π0π0 at an existing facility at the accelerator U-70 in Serpukhov is proposed. (orig./HSI)
Absence of equilibrium chiral magnetic effect
Zubkov, M. A.
2016-05-01
We analyze the (3 +1 )D equilibrium chiral magnetic effect (CME). We apply derivative expansion to the Wigner transform of the two-point Green function. This technique allows us to express the response of electric current to the external electromagnetic field strength through the momentum space topological invariant. We consider the wide class of the lattice regularizations of quantum field theory (that includes, in particular, the regularization with Wilson fermions) and also certain lattice models of solid state physics (including those of Dirac semimetals). It appears that in these models the mentioned topological invariant vanishes identically at nonzero chiral chemical potential. That means that the bulk equilibrium CME is absent in those systems.
Chiral fermions in asymptotically safe quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Meibohm, J. [Gothenburg University, Department of Physics, Goeteborg (Sweden); Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); Pawlowski, J.M. [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung mbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany)
2016-05-15
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions. (orig.)
Chiral fermions in asymptotically safe quantum gravity
Meibohm, J.; Pawlowski, J. M.
2016-05-01
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.
Chiral fermions in asymptotically safe quantum gravity
Meibohm, Jan
2016-01-01
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck-scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works \\cite{Christiansen:2015rva, Meibohm:2015twa}, concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models, regardless of the number of fermion flavours. This suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.
Dynamics and Properties of Chiral Cosmic Strings
Pickles, M
2001-01-01
Chiral cosmic strings naturally arise in many particle physics models, in particular in supersymmetric theories with a D-term. These strings have a single fermion zero mode in the core. We derive the general equation of motion for such strings. In Minkowski space we give the self-intersections for an arbitary varying current on the loop, showing that the self-intersection probability is dominated by the fraction of loop with maximal charge. We show how to relate the charge to the fermion condensation temperature, arguing that strings which become current carrying at formation will automatically have a maximal charge. Any daughter loops produced are likely to have the same charge as the parent loop. Possible models for chiral cosmic strings are also discussed and consequences for D-term inflation mentioned.
Tailoring the chirality of light emission with spherical Si-based antennas.
Zambrana-Puyalto, Xavier; Bonod, Nicolas
2016-05-21
Chirality of light is of fundamental importance in several enabling technologies with growing applications in life sciences, chemistry and photodetection. Recently, some attention has been focused on chiral quantum emitters. Consequently, optical antennas which are able to tailor the chirality of light emission are needed. Spherical nanoresonators such as colloids are of particular interest to design optical antennas since they can be synthesized at a large scale and they exhibit good optical properties. Here, we show that these colloids can be used to tailor the chirality of a chiral emitter. To this purpose, we derive an analytic formalism to model the interaction between a chiral emitter and a spherical resonator. We then compare the performances of metallic and dielectric spherical antennas to tailor the chirality of light emission. It is seen that, due to their strong electric dipolar response, metallic spherical nanoparticles spoil the chirality of light emission by yielding achiral fields. In contrast, thanks to the combined excitation of electric and magnetic modes, dielectric Si-based particles feature the ability to inhibit or to boost the chirality of light emission. Finally, it is shown that dual modes in dielectric antennas preserve the chirality of light emission.
Mass-Selective Chiral Analysis.
Boesl, Ulrich; Kartouzian, Aras
2016-06-12
Three ways of realizing mass-selective chiral analysis are reviewed. The first is based on the formation of diastereomers that are of homo- and hetero- type with respect to the enantiomers of involved chiral molecules. This way is quite well-established with numerous applications. The other two ways are more recent developments, both based on circular dichroism (CD). In one, conventional or nonlinear electronic CD is linked to mass spectrometry (MS) by resonance-enhanced multiphoton ionization. The other is based on CD in the angular distribution of photoelectrons, which is measured in combination with MS via photoion photoelectron coincidence. Among the many important applications of mass-selective chiral analysis, this review focuses on its use as an analytical tool for the development of heterogeneous enantioselective chemical catalysis. There exist other approaches to combine chiral analysis and mass-selective detection, such as chiral chromatography MS, which are not discussed here. PMID:27070181
Dileptons and Chiral Symmetry Restoration
Hohler, P M
2015-01-01
We report on recent work relating the medium effects observed in dilepton spectra in heavy-ion collisions to potential signals of chiral symmetry restoration. The key connection remains the approach to spectral function degeneracy between the vector-isovector channel with its chiral partner, the axialvector-isovector channel. Several approaches are discussed to elaborate this connection, namely QCD and Weinberg sum rules with input for chiral order parameters from lattice QCD, and chiral hadronic theory to directly evaluate the medium effects of the axialvector channel and the pertinent pion decay constant as function of temperature. A pattern emerges where the chiral mass splitting between rho and a_1 burns off and is accompanied by a strong broadening of the spectral distributions.
Mass-Selective Chiral Analysis
Boesl, Ulrich; Kartouzian, Aras
2016-06-01
Three ways of realizing mass-selective chiral analysis are reviewed. The first is based on the formation of diastereomers that are of homo- and hetero- type with respect to the enantiomers of involved chiral molecules. This way is quite well-established with numerous applications. The other two ways are more recent developments, both based on circular dichroism (CD). In one, conventional or nonlinear electronic CD is linked to mass spectrometry (MS) by resonance-enhanced multiphoton ionization. The other is based on CD in the angular distribution of photoelectrons, which is measured in combination with MS via photoion photoelectron coincidence. Among the many important applications of mass-selective chiral analysis, this review focuses on its use as an analytical tool for the development of heterogeneous enantioselective chemical catalysis. There exist other approaches to combine chiral analysis and mass-selective detection, such as chiral chromatography MS, which are not discussed here.
Institute of Scientific and Technical Information of China (English)
FU Ying-huan; CHEN Jin; WU Tong-hao; BAI Xu
2005-01-01
To investigate the recovery of amino alcohols as chiral auxiliaries, optically active p-benzyloxyphenylglycinol and its corresponding oxazolidine of 1-naphthylcarboxaldehyde were prepared. Grignard additions to the oxazolidine followed by electrophilic quench and acidic hydrolysis afforded an aldehyde(compound 8)(later it was reduced to an alcohol, compound 9) in an excellent enantiomeric excess and a good recovery of the chiral amino alcohol. This research provides a model study of chiral amino alcohols in solid phase asymmetric synthesis.
Chirality dependence of the radial breathing phonon mode density in single wall carbon nanotubes
Vamivakas, A. N.; Yin, Y.; Walsh, A. G.; Unlu, M. S.; Goldberg, B. B.; Swan, A. K.
2006-01-01
A mass and spring model is used to calculate the phonon mode dispersion for single wall carbon nanotubes (SWNTs) of arbitrary chirality. The calculated dispersions are used to determine the chirality dependence of the radial breathing phonon mode (RBM) density. Van Hove singularities, usually discussed in the context of the single particle electronic excitation spectrum, are found in the RBM density of states with distinct qualitative differences for zig zag, armchair and chiral SWNTs. The in...
Effects of chiral imbalance and magnetic field on pion superfluidity and color superconductivity
Cao, Gaoqing; Zhuang, Pengfei
2015-01-01
The effects of chiral imbalance and external magnetic field on pion superfluidity and color superconductivity are investigated in extended Nambu--Jona-Lasinio models. We take Schwinger approach to treat the interaction between charged pion condensate and magnetic field at finite isospin density and include simultaneously the chiral imbalance and magnetic field at finite baryon density. For the superfluidity, the chiral imbalance and magnetic field lead to catalysis and inverse catalysis effec...
Circular Intensity Differential Scattering of chiral molecules
Energy Technology Data Exchange (ETDEWEB)
Bustamante, C.J.
1980-12-01
In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.
A chiral quark model for meson electro-production in the region of D-wave resonances
Golli, Bojan
2013-01-01
The meson scattering and electroproduction amplitudes in the D13, D33 and D15 partial waves are calculated in a coupled-channel formalism incorporating quasi-bound quark-model states, extending our previous studies of the P11, P33 and S11 partial waves. The vertices of the baryon-meson interaction including the s- and d-wave pions and $\\rho$-mesons, the s-wave $\\eta$-meson, and the $s$- and p-wave $\\sigma$-mesons are determined in the Cloudy Bag Model, with some changes of the parameters to reproduce the widths of the resonances. The helicity amplitudes and the electroproduction amplitudes exhibit consistent behavior in all channels but tend to be too weak compared to the experiment. We discuss possible origins of this discrepancy which arises also in the constituent quark model calculations.
Constructing Self-Dual Chiral Polytopes
Cunningham, Gabe
2011-01-01
An abstract polytope is chiral if its automorphism group has two orbits on the flags, such that adjacent flags belong to distinct orbits. There are still few examples of chiral polytopes, and few constructions that can create chiral polytopes with specified properties. In this paper, we show how to build self-dual chiral polytopes using the mixing construction for polytopes.
Evnin, O E
1997-01-01
Inner and empirically consistent model of elementary particles, including two matter structural levels beyond the quark one is built. Excitements spectra, masses and interactions are analysed using the phenomenological notion of non-pertubative vacuum condensate. Essential low-energy predictions of developed concepts are classified. Effective gauge U(1)xU(1)xSU(2)-theory of quark-lepton excitements behavior based on the performed analysis of preon-subpreon phenomenology is consistently built. The ability of its expansion with fermions and scalar leptoquark coupling is also considered. Shown that the coupling constants family hierarchy is the same as family hierarchy of quark masses. Using the built theory cross-sections of d-quark-positron scattering processes with both charged and neutral currents are calculated. The obtained resonance peak is proposed to be a possible explanation of deviating from Standard Model predictions discovered in DESY in the beginning of 1997 year.
Kopp, Victor I.; Zhang, Guoyin; Zhang, Sheng; Genack, Azriel Z.; Neugroschl, Dan
2009-02-01
We propose an in-fiber chiral optical isolator based on chiral fiber polarizer technology and calculate its performance by incorporating the magnetic field into the scattering matrix. The design will be implemented in a special preform, which is passed through a miniature heat zone as it is drawn and twisted. The birefringence of the fiber is controlled by adjusted the diameter of a dual-core optical fiber. By adjusting the twist, the fiber can convert linear to circular polarization and reject one component of circular polarization. In the novel central portion of the isolator, the fiber diameter is large. The effective birefringence of the circular central core with high Verdet constant embedded in an outer core of slightly smaller index of refraction is small. The central potion is a non-reciprocal polarization converter which passes forward traveling left circularly polarized (LCP) light as LCP, while converting backward propagating LCP to right circularly polarized (RCP) light. Both polarizations of light traveling backwards are scattered out of the isolator. Since it is an all-glass structure, we anticipate that the isolator will be able to handle several watts of power and will be environmentally robust.
International Nuclear Information System (INIS)
The suggestion by Jaffe that if σ is a light q2q-bar2 state 0++ then even the fundamental chiral transformation properties of the σ becomes unclear, has stimulated much interest. Adler pointed out that in fact the seminal work on chiral symmetry via PCAC consistency, is really quite consistent with the σ being predominantly q2q-bar2. This interpretation was actually backed by subsequent work on effective Lagrangian methods for linear and non linear realizations. More recent work of Achasov suggests that intermediate four-quark states determine amplitudes involving other scalars a0(980) and f0(980) below 1 GeV, and the report by Ning Wu that study on σ meson in J/ψ → ωπ+π- continue to support a non qq-bar σ with mass as low as 390 MeV. It is also noted that more recent re-analysis of πK scattering by S. Ishida et al. together with the work of the E791 Collaboration, support the existence of the scalar κ particle with comparatively light mass as well
On the Biological Advantage of Chirality
Gilat, G
1999-01-01
The presence of chirality in the main molecules of life may well be not just a structural artifact, but of pure biological advantage. The possibility of the existence of a phenomenon of a special mode of interaction, labeled as "chiral interaction" (CI), for which structural chirality is a necessary condition, is the main reason for such an advantage. In order to demonstrate such a possibility, macroscopic chiral devices are introduced and presented as analogies for such an interaction. For this purpose it is important to make a clear distinction between geometric and physical chiralities, where the latter are capable to perform chiral interactions with various media. Apart from chirality, a few other structural elements are required. In particular, the presence of an interface that separates between the chiral device and the medium with which it is interacting. The physical chirality is build into this very interface where chiral interaction is taking place. On a molecular level, soluble proteins in particul...
Vibrational evidence for chiral recognition phenomena in vacuo
Suhm, Martin A.
2007-06-01
Molecules and molecular conformations which cannot be superimposed on their mirror image are chiral. Chirality or handedness plays an important role throughout the life sciences. When two molecules interact, they can sense their relative handedness, giving rise to spectroscopic signatures of chiral recognition. This is often mediated by hydrogen bonds, most versatile and directional intermolecular interactions. If the distinction between the homo- and heteroconfigurational pairs of molecules is large enough, chiral discrimination, i.e. differences in abundance may occur. The contact between two flexible, transiently chiral molecules may induce a matching of their handedness, i.e. chirality synchronization. Such phenomena are best studied at low temperatures in vacuum isolation, without perturbing interactions [1]. Structural information on the isolated molecular complexes can be obtained by rotational spectroscopy [2], if there is a sufficient dipole moment. Vibrational spectroscopy [3] provides a more universal, but also more coarse-grained access to these phenomena. Our group has reported the first spectroscopic example of chiral recognition between constitutionally identical molecules in the gas phase [4]. We have found a case of chiral discrimination in tetrameric aggregates of methyl lactate, where the relative configuration controls the hydrogen bond topology [5]. In the case of alcohols, we have observed different degrees of chirality synchronization up to a quantitative chirality matching in dimers of trifluoroethanol [6]. These discoveries became possible through the use of a powerful combination of FTIR spectroscopy and high-throughput, pulsed supersonic nozzle expansions into large vacuum chambers [7]. The isolated and elementary character of the investigated molecular assemblies is favourable for quantum chemical treatments [8]. Valuable benchmarks for the modeling of more complex chiral recognition phenomena are thus established. [1] A. Al-Rabaa, E. Br
A Nonperturbative Regulator for Chiral Gauge Theories
Grabowska, Dorota M
2015-01-01
We propose a nonperturbative gauge invariant regulator for $d$-dimensional chiral gauge theories on the lattice. The method involves simulating domain wall fermions in $d+1$ dimensions with quantum gauge fields that reside on one $d$-dimensional surface and are extended into the bulk via gradient flow. The result is a theory of gauged fermions plus mirror fermions, where the mirror fermions couple to the gauge fields via a form factor that becomes exponentially soft with the separation between domain walls. The resultant theory has a local $d$-dimensional interpretation if and only if the chiral fermion representation is anomaly free. A physical realization of this construction leads to mirror fermions in the Standard Model with soft form factors for gauge fields and gravity. These mirror particles could evade detection except by sensitive probes at extremely low energy, and yet still affect vacuum topology, and could gravitate differently than conventional matter.
Nonperturbative Regulator for Chiral Gauge Theories?
Grabowska, Dorota M.; Kaplan, David B.
2016-05-01
We propose a nonperturbative gauge-invariant regulator for d -dimensional chiral gauge theories on the lattice. The method involves simulating domain wall fermions in d +1 dimensions with quantum gauge fields that reside on one d -dimensional surface and are extended into the bulk via gradient flow. The result is a theory of gauged fermions plus mirror fermions, where the mirror fermions couple to the gauge fields via a form factor that becomes exponentially soft with the separation between domain walls. The resultant theory has a local d -dimensional interpretation only if the chiral fermion representation is anomaly free. A physical realization of this construction would imply the existence of mirror fermions in the standard model that are invisible except for interactions induced by vacuum topology, and which could gravitate differently than conventional matter.
Random Matrices and Chiral Symmetry in QCD
Janik, R A; Papp, G; Zahed, I; Janik, Romuald A.; Nowak, Maciej A.; Papp, Gabor; Zahed, Ismail
1998-01-01
In this talk we review some recent results from random matrix models as applied to some non-perturbative issues in QCD. All of the issues we will discuss touched upon the important phenomenon related to the spontaneous breaking of chiral symmetry. The afore mentioned insights are: 1. Spontaneous breakdown of chiral symmetry and disorder. 2. Universal microscopic properties of the eigenvalues of the Dirac operator in the vacuum. 3. Universal microscopic properties of the eigenvalues of the Dirac operator in matter. 4. Structural changes of the Dirac spectrum - finite temperature. 5. Structural changes of the Dirac spectrum - finite baryonic density - ``phony vacua'' 6. Structural changes of the Dirac spectrum - finite baryonic density - ``true vacua'' . 7. Phase diagram. 8. Critical parameters. 9. Critical exponents. 10. $U(1)_A$ problem. 11. Screening of the pseudoscalar susceptibility. 12. Strong CP violation (finite $\\theta$).
Indian Academy of Sciences (India)
Susanto Chakraborty; Pranab Krishna Chandra
2007-04-01
Painlevé test for integrability for the combined equations generated from Yang's self-dual equations for (2) gauge fields and Charap's equations for chiral invariant model of pion dynamics faces some peculiar situations that allow none of the stages (leading order analysis, resonance calculation and checking of the existence of the requisite number of arbitrary functions) to be conclusive. It is also revealed from a comparative study with the previous results that the existence of abnormal behaviour at any of the stated stages may have a correlation with the existence of chaotic property or some other properties that do not correspond to solitonic behaviour.
Dynamics and Stability of Chiral Fluid
Mishustin, Igor N; Denicol, Gabriel S; Torrieri, Giorgio
2014-01-01
Starting from the linear sigma model with constituent quarks we derive the chiral fluid dynamics where hydrodynamic equations for the quark fluid are coupled to the equation of motion for the order-parameter field. In a static system at thermal equilibrium this model leads to a chiral phase transition which, depending on the choice of the quark-meson coupling constant, could be a crossover or a first order one. We investigate the stability of the chiral fluid in the static and expanding backgrounds by considering the evolution of perturbations with respect to the mean-field solution. In the static background the spectrum of plane-wave perturbations consists of two branches, one corresponding to the sound waves and another to the sigma-meson excitations. For large couplings these two branches "cross" and the excitation spectrum acquires exponentially growing modes. The stability analysis is also done for the Bjorken-like background solution by explicitly solving the time-dependent differential equation for per...
Gómez-Rocha, María
2012-01-01
In this article we point out that the unitary transformation that relates the chiral basis $\\{R; I J^{PC}\\}$ and the $\\{I; ^{2S+1}L_J \\}$ basis, which was already derived for canonical spin in instant form, is also applicable in light-cone representations. From the most general expression for the Clebsch-Gordan coefficients of the Poincar\\'e group one can see that the chiral limit brings the angular momentum coupling into a simple form that permits a clear relation in terms of SU(2) Clebsch-Gordan coefficients. It provides a tool of measurement of chiral symmetry in relativistic composite systems.
Consistent chiral kinetic theory in Weyl materials: chiral magnetic plasmons
Gorbar, E V; Shovkovy, I A; Sukhachov, P O
2016-01-01
We argue that the correct definition of the electric current in the chiral kinetic theory for Weyl materials should include the Chern--Simons contribution that makes the theory consistent with the local conservation of the electric charge in electromagnetic and strain-induced pseudoelectromagnetic fields. By making use of such a kinetic theory, we study the plasma frequencies of collective modes in Weyl materials in constant magnetic and pseudomagnetic fields taking into account the effects of dynamical electromagnetism. We show that the collective modes are chiral plasmons. While the plasma frequency of the longitudinal collective mode coincides with the Langmuir one, this mode is unusual because it is characterized not only by oscillations of the electric current density, but also oscillations of the chiral current density. The latter are triggered by a dynamical version of the chiral electric separation effect. We also find that the plasma frequencies of the transverse modes split up in a magnetic field. T...
Ruggieri, M
2016-01-01
In this article we study spontaneous chiral symmetry breaking for quark matter in the background of an electric-magnetic flux tube with static, homogeneous and parallel electric field $\\bm E$ and magnetic field $\\bm B$. We use a Nambu-Jona-Lasinio model with a local kernel interaction to compute the relevant quantities to describe chiral symmetry breaking at finite temperature for a wide range of $E$ and $B$. We study the effect of the flux tube background on inverse catalysis of chiral symmetry breaking for $E$ and $B$ of the same order of magnitude. We then focus on the effect of equilibration of chiral density, $n_5$, produced dynamically by axial anomaly on the critical temperature. The equilibration of $n_5$, a consequence of chirality flipping processes in the thermal bath, allows for the introduction of the chiral chemical potential, $\\mu_5$, which is computed self-consistently as a function of temperature and field strength by coupling the number equation to the gap equation. We find that even if chir...
Solnyshkov, Dmitry; Malpuech, Guillaume
2016-10-01
The optical modes of photonic structures are the so-called TE and TM modes that bring intrinsic spin-orbit coupling and chirality to these systems. This, combined with the unique flexibility of design of the photonic potential, and the possibility to mix photon states with excitonic resonances, sensitive to magnetic field and interactions, allows us to achieve many phenomena, often analogous to other solid-state systems. In this contribution, we review in a qualitative and comprehensive way several of these realizations, namely the optical spin Hall effect, the creation of spin currents protected by a non-trivial geometry, the Berry curvature for photons, and the photonic/polaritonic topological insulator. xml:lang="fr"
Grecsó, Nóra; Kohout, Michal; Carotti, Andrea; Sardella, Roccaldo; Natalini, Benedetto; Fülöp, Ferenc; Lindner, Wolfgang; Péter, Antal; Ilisz, István
2016-05-30
The enantiomers of trans-paroxetine were separated on four chiral stationary phases (CSPs) based on chiral zwitterionic Cinchona alkaloids fused with (R,R)- or (S,S)-trans-2-aminocyclohexanesulfonic acid. The enantioseparations were carried out in polar-ionic or in hydro-organic mobile phases with MeOH/THF, MeCN/THF, MeCN/THF/H2O and MeOH/MeCN/THF containing organic acid and base additives, in the temperature range 0-50°C. The effects of the mobile phase composition, the natures and concentrations of the additives and temperature on the separations were investigated. Thermodynamic parameters were calculated from plots of ln α vs 1/T. Δ(ΔH°) ranged between -3.0 and +1.5 kJ mol(-1), and Δ(ΔS°) between -8.8 and +5.9 J mol(-1)K(-1). The enantioseparation was generally enthalpically controlled, the retention factor and separation factor decreasing with increasing temperature, but entropically controlled separation was also observed. The elution sequences of the paroxetine enantiomers on the two pairs of pseudo-enantiomeric CSPs were investigated, and an attempt was made to explain the observed anomalies in silico in order to gain an insight into the underlying molecular recognition events between the four chiral selectors and the analyte enantiomers. PMID:26955754
Chiral Dynamics With Wilson Fermions
Splittorff, K
2012-01-01
Close to the continuum the lattice spacing affects the smallest eigenvalues of the Wilson Dirac operator in a very specific manner determined by the way in which the discretization breaks chiral symmetry. These effects can be computed analytically by means of Wilson chiral perturbation theory and Wilson random matrix theory. A number of insights on chiral Dynamics with Wilson fermions can be obtained from the computation of the microscopic spectrum of the Wilson Dirac operator. For example, the unusual volume scaling of the smallest eigenvalues observed in lattice simulations has a natural explanation. The dynamics of the eigenvalues of the Wilson Dirac operator also allow us to determine the additional low energy constants of Wilson chiral perturbation theory and to understand why the Sharpe-Singleton scenario is only realized in unquenched simulations.
Review of chiral perturbation theory
Indian Academy of Sciences (India)
B Ananthanarayan
2003-11-01
A review of chiral perturbation theory and recent developments on the comparison of its predictions with experiment is presented. Some interesting topics with scope for further elaboration are touched upon.
Life's chirality from prebiotic environments
Gleiser, Marcelo; Walker, Sara Imari
2012-10-01
A key open question in the study of life is the origin of biomolecular homochirality: almost every life-form on Earth has exclusively levorotary amino acids and dextrorotary sugars. Will the same handedness be preferred if life is found elsewhere? We review some of the pertinent literature and discuss recent results suggesting that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events. In one scenario, autocatalytic prebiotic reactions undergo stochastic fluctuations due to environmental disturbances, in a mechanism reminiscent of evolutionary punctuated equilibrium: short-lived destructive events may lead to long-term enantiomeric excess. In another, chiral-selective polymerization reaction rates influenced by environmental effects lead to substantial chiral excess even in the absence of autocatalysis. Applying these arguments to other potentially life-bearing platforms has implications to the search for extraterrestrial life: we predict that a statistically representative sampling of extraterrestrial stereochemistry will be racemic (chirally neutral) on average.
Energetic molding of chiral magnetic bubbles
Lau, Derek; Sundar, Vignesh; Zhu, Jian-Gang; Sokalski, Vincent
2016-08-01
Topologically protected magnetic structures such as skyrmions and domain walls (DWs) have drawn a great deal of attention recently due to their thermal stability and potential for manipulation by spin current, which is the result of chiral magnetic configurations induced by the interfacial Dzyaloshinskii-Moriya interaction (DMI). Designing devices that incorporate DMI necessitates a thorough understanding of how the interaction presents and can be measured. One approach is to measure growth asymmetry of chiral bubble domains in perpendicularly magnetized thin films, which has been described elsewhere by thermally activated DW motion. Here, we demonstrate that the anisotropic angular dependence of DW energy originating from the DMI is critical to understanding this behavior. Domains in Co/Ni multilayers are observed to preferentially grow into nonelliptical teardrop shapes, which vary with the magnitude of an applied in-plane field. We model the domain profile using energetic calculations of equilibrium shape via the Wulff construction, which serves as a new paradigm for describing chiral domains that explains both the teardrop shape and the reversal of growth symmetry at large fields.
Homogenization of resonant chiral metamaterials
DEFF Research Database (Denmark)
Andryieuski, Andrei; Menzel, C.; Rockstuhl, Carsten;
2010-01-01
Homogenization of metamaterials is a crucial issue as it allows to describe their optical response in terms of effective wave parameters as, e.g., propagation constants. In this paper we consider the possible homogenization of chiral metamaterials. We show that for meta-atoms of a certain size...... an analytical criterion for performing the homogenization and a tool to predict the homogenization limit. We show that strong coupling between meta-atoms of chiral metamaterials may prevent their homogenization at all....
Chiral thermodynamics of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Fiorilla, Salvatore
2012-10-23
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Chiral symmetry and lattice fermions
Creutz, Michael
2013-01-01
Lattice gauge theory and chiral perturbation theory are among the primary tools for understanding non-perturbative aspects of QCD. I review several subtle and sometimes controversial issues that arise when combining these techniques. Among these are one failure of partially quenched chiral perturbation theory when the valence quarks become lighter than the average sea quark mass and a potential ambiguity in comparisons of perturbative and lattice properties of non-degenerate quarks.
Numerical evidence of the spin-chirality decoupling in the three-dimensional Heisenberg spin glass
Viet, Dao Xuan; Kawamura, Hikaru
2008-01-01
Ordering of the three-dimensional Heisenberg spin glass with Gaussian coupling is studied by extensive Monte Carlo simulations. The model undergoes successive chiral-glass and spin-glass transitions at nonzero temperatures T_{CG} > T_{SG} > 0, exhibiting the spin-chirality decoupling.
Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping
2016-07-12
Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.
Qian, Hai-Long; Yang, Cheng-Xiong; Yan, Xiu-Ping
2016-07-01
Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.
Chirality in Bare and Passivated Gold Nanoclusters
Garzon, I L; Rodrigues-Hernandez, J I; Sigal, I; Beltran, M R; Michaelian, K
2002-01-01
Chiral structures have been found as the lowest-energy isomers of bare (Au$_{28}$ and Au$_{55}) and thiol-passivated (Au$_{28}(SCH$_{3})$_{16}$ and Au$_{38}$(SCH$_{3}$)$_{24}) gold nanoclusters. The degree of chirality existing in the chiral clusters was calculated using the Hausdorff chirality measure. We found that the index of chirality is higher in the passivated clusters and decreases with the cluster size. These results are consistent with the observed chiroptical activity recently reported for glutahione-passivated gold nanoclusters, and provide theoretical support for the existence of chirality in these novel compounds.
Spin Chains and Chiral Lattice Fermions
Thacker, H B
1995-01-01
The generalization of Lorentz invariance to solvable two-dimensional lattice fermion models has been formulated in terms of Baxter's corner transfer matrix. In these models, the lattice Hamiltonian and boost operator are given by fermionized nearest-neighbor Heisenberg spin chain operators. The transformation properties of the local lattice fermion operators under a boost provide a natural and precise way of generalizing the chiral structure of a continuum Dirac field to the lattice. The resulting formulation differs from both the Wilson and staggered (Kogut-Susskind) prescriptions. In particular, an axial $Q_5$ rotation is sitewise local, while the vector charge rotation mixes nearest neighbors on even and odd sublattices.
Institute of Scientific and Technical Information of China (English)
Chao CHE; Zhong Ning ZHANG; Gui Lan HUANG; Xin Xing WANG; Zhao Hai QIN
2004-01-01
The use of chiral organophosphorus derivatizing agents prepared in situ from chiral tartrate or chiral diamine for the 31PNMR determination of the enantiomeric composition of chiral carboxylic acids is described. The method is accurate, reliable and convenient.
Neutral B Mixing in Staggered Chiral Perturbation Theory
Bernard, C
2013-01-01
I calculate, at one loop in staggered chiral perturbation theory, the matrix elements of the complete set of five local operators that may contribute to B mixing both in the Standard Model and in beyond-the-Standard-Model theories. Lattice computations of these matrix elements by the Fermilab Lattice/MILC collaborations (and earlier by the HPQCD collaboration) convert a light staggered quark into a naive quark, and construct the relevant 4-quark operators as local products of two local bilinears, each involving the naive light quark and the heavy quark. This particular representation of the operators turns out to be important in the chiral calculation, and it results in the presence of "wrong-spin" operators, whose contributions however vanish in the continuum limit. If the matrix elements of all five operators are computed on the lattice, then no additional low energy constants are required to describe wrong-spin chiral effects.
Thermodynamics of quark matter with a chiral imbalance
Farias, Ricardo L. S.; Duarte, Dyana C.; Krein, Gastão; Ramos, Rudnei O.
2016-10-01
We show how a scheme of rewriting a divergent momentum integral can conciliate results obtained with the Nambu-Jona-Lasinio model and recent lattice results for the chiral transition in the presence of a chiral imbalance in quark matter. Purely vacuum contributions are separated from medium-dependent regularized momentum integrals in such a way that one is left with ultraviolet divergent momentum integrals that depend on vacuum quantities only. The scheme is applicable to other commonly used effective models to study quark matter with a chiral imbalance, it allows us to identify the source of their difficulties in reproducing the qualitative features of lattice results, and enhances their predictability and uses in other applications.
Projective symmetry group classification of chiral spin liquids
Bieri, Samuel; Lhuillier, Claire; Messio, Laura
2016-03-01
We present a general review of the projective symmetry group classification of fermionic quantum spin liquids for lattice models of spin S =1 /2 . We then introduce a systematic generalization of the approach for symmetric Z2 quantum spin liquids to the one of chiral phases (i.e., singlet states that break time reversal and lattice reflection, but conserve their product). We apply this framework to classify and discuss possible chiral spin liquids on triangular and kagome lattices. We give a detailed prescription on how to construct quadratic spinon Hamiltonians and microscopic wave functions for each representation class on these lattices. Among the chiral Z2 states, we study the subset of U(1) phases variationally in the antiferromagnetic J1-J2-Jd Heisenberg model on the kagome lattice. We discuss static spin structure factors and symmetry constraints on the bulk spectra of these phases.
Electrically tunable spin polarization of chiral edge modes in a quantum anomalous Hall insulator
Zhang, Rui-Xing; Hsu, Hsiu-Chuan; Liu, Chao-Xing
2016-06-01
In the quantum anomalous Hall effect, chiral edge modes are expected to conduct spin polarized current without dissipation and thus hold great promise for future electronics and spintronics with low energy consumption. However, spin polarization of chiral edge modes has never been established in experiments. In this work, we theoretically study spin polarization of chiral edge modes in the quantum anomalous Hall effect, based on both the effective model and more realistic tight-binding model constructed from first-principles calculations. We find that spin polarization can be manipulated by tuning either a local gate voltage or the Fermi energy. We also propose to extract spin information of chiral edge modes by contacting the quantum anomalous Hall insulator to a ferromagnetic lead. The establishment of spin polarization of chiral edge modes, as well as the manipulation and detection in a fully electrical manner, will pave the way to the applications of the quantum anomalous Hall effect in spintronics.
Tactoids of chiral liquid crystals
Palacio-Betancur, Viviana; Villada-Gil, Stiven; Zhou, Ye; Armas-Pérez, Julio C.; de Pablo, Juan José; Hernández-Ortiz, Juan Pablo
The phase diagram of chiral liquid crystals confined in ellipsoids is obtained, by following a theoretically informed Monte Carlo relaxation of the tensor alignment field Q. The free energy of the system is described by a functional in the framework of the Landau-de Gennes formalism. This study also includes the effect of anchoring strength, curvature, and chirality of the system. In the low chirality region of the phase diagram we found the twist bipolar (BS) phase and some cholesteric phases such as the radial spherical structure (RSS), twist cylinder (TC) and double twist cylinder (DTC) whose axis of rotation is not necessarily aligned with the major axis of the geometry. For high chirality scenarios, the disclination lines are twisted or bent near the surface preventing the formation of symmetric networks of defects, although an hexagonal pattern is formed on the surface which might serve as open sites for collocation of colloids. By analyzing the free energies of isochoric systems, prolate geometries tend to be more favorable for high chirality and low anchoring conditions. Universidad Nacional de Colombia Ph.D. grant and COLCIENCIAS under the Contract No. 110-165-843-748. CONACYT for Postdoctoral Fellowships Nos. 186166 and 203840.
Chiral superfluidity of the quark-gluon plasma
Energy Technology Data Exchange (ETDEWEB)
Kalaydzhyan, Tigran [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation)
2012-08-15
In this paper we argue that the strongly coupled quark-gluon plasma can be considered as a chiral superfluid. The ''normal'' component of the fluid is the thermalized matter in common sense, while the ''superfluid'' part consists of long wavelength (chiral) fermionic states moving independently. We use several nonperturbative techniques to demonstrate that. First, we analyze the fermionic spectrum in the deconfinement phase (T{sub c}
Preferential rotation of chiral dipoles in isotropic turbulence
Kramel, Stefan; Toschi, Federico; Voth, Greg A
2016-01-01
Particles in the shape of chiral dipoles show a preferential rotation in three dimensional homogeneous isotropic turbulence. A chiral dipole consists of a rod with two helices of opposite handedness, one at each end. We can use 3d printing to fabricate these particles with length in the inertial range and track their rotations in a turbulent flow between oscillating grids. High aspect ratio chiral dipoles will align with the extensional eigenvectors of the strain rate tensor and the helical ends will respond to the strain field by spinning around its long axis. The mean of the measured spinning rate is non-zero and reflects the average stretching the particles experience. We use Stokesian dynamics simulations of chiral dipoles in pure strain flow to quantify the dependence of spinning on particle shape. Based on the known response to pure strain, we build a model that gives the spinning rate of small chiral dipoles using Lagrangian velocity gradients from high resolution direct numerical simulations. The stat...
Inhomogeneous chiral symmetry breaking in dense neutron-star matter
International Nuclear Information System (INIS)
An increasing number of model results suggests that chiral symmetry is broken inhomogeneously in a certain window at intermediate densities in the QCD phase diagram. This could have significant effects on the properties of compact stars, possibly leading to new astrophysical signatures. In this contribution we discuss this idea by reviewing recent results on inhomogeneous chiral symmetry breaking under an astrophysics-oriented perspective. After introducing two commonly studied spatial modulations of the chiral condensate, the chiral density wave and the real kink crystal, we focus on their properties and their effect on the equation of state of quark matter. We also describe how these crystalline phases are affected by different elements which are required for a realistic description of a compact star, such as charge neutrality, the presence of magnetic fields, vector interactions and the interplay with color superconductivity. Finally, we discuss possible signatures of inhomogeneous chiral symmetry breaking in the core of compact stars, considering the cases of mass-radius relations and neutrino emissivity explicitly. (orig.)
Inhomogeneous chiral symmetry breaking in dense neutron-star matter
Energy Technology Data Exchange (ETDEWEB)
Buballa, Michael; Carignano, Stefano [Technische Universitaet Darmstadt, Theoriezentrum, Institut fuer Kernphysik, Darmstadt (Germany)
2016-03-15
An increasing number of model results suggests that chiral symmetry is broken inhomogeneously in a certain window at intermediate densities in the QCD phase diagram. This could have significant effects on the properties of compact stars, possibly leading to new astrophysical signatures. In this contribution we discuss this idea by reviewing recent results on inhomogeneous chiral symmetry breaking under an astrophysics-oriented perspective. After introducing two commonly studied spatial modulations of the chiral condensate, the chiral density wave and the real kink crystal, we focus on their properties and their effect on the equation of state of quark matter. We also describe how these crystalline phases are affected by different elements which are required for a realistic description of a compact star, such as charge neutrality, the presence of magnetic fields, vector interactions and the interplay with color superconductivity. Finally, we discuss possible signatures of inhomogeneous chiral symmetry breaking in the core of compact stars, considering the cases of mass-radius relations and neutrino emissivity explicitly. (orig.)
Chiral gap effect in curved space
Flachi, Antonino
2014-01-01
We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.
Directory of Open Access Journals (Sweden)
John A. Dixon
2015-10-01
Full Text Available An action for a complex irreducible massive superspin 12 multiplet can be constructed out of two chiral dotted spinor and two chiral undotted spinor superfields. To make this action a sensible one, additional ‘reality constraints’ are needed, and the notion of BRST recycling is needed to find the supersymmetry transformations of the theory with these additional constraints. This theory possesses three possible mass terms. An earlier paper examined the theory with the first mass term. This paper adds a second mass term and examines the consequences of that. This second mass invariant is ‘extraordinary’, which means that it is intrinsically dependent on the Zinn sources (‘antifields’ of the theory. This in turn implies that the action needs to be ‘completed’ so that it yields zero for the relevant Poisson Bracket. This ‘Completion’ meets an ‘Obstruction’, which is a ghost charge one object in the BRST cohomology space. Usually Obstructions arise from a one loop calculation, in which case they form anomalies of the theory. However this Obstruction arises at tree level from the completion. The coefficient of the Obstruction needs to be set to zero. This restores the complex irreducible massive superspin 12 multiplet to its usual structure, except that the mass is constructed out of the two mass parameters. The construction suggests interesting possibilities for related interacting theories.
Chiral Dynamics of Baryons from String Theory
Hong, D K; Yee, H U; Yi, P; Hong, Deog Ki; Rho, Mannque; Yee, Ho-Ung; Yi, Piljin
2007-01-01
We study baryons in an AdS/CFT model of QCD by Sakai and Sugimoto, realized as small instantons with fundamental string hairs. We introduce an effective field theory of the baryons in the five-dimensional setting, and show that the instanton interpretation implies a particular magnetic coupling. Dimensional reduction to four dimensions reproduces the usual chiral effective action, and in particular we estimate the axial coupling $g_A$ between baryons and pions and the magnetic dipole moments, both of which are proportional to $N_c$. We extrapolate to finite $N_c$ and discuss subleading corrections.
Chiral phase transition from string theory.
Parnachev, Andrei; Sahakyan, David A
2006-09-15
The low energy dynamics of a certain D-brane configuration in string theory is described at weak t'Hooft coupling by a nonlocal version of the Nambu-Jona-Lasinio model. We study this system at finite temperature and strong t'Hooft coupling, using the string theory dual. We show that for sufficiently low temperatures chiral symmetry is broken, while for temperatures larger then the critical value, it gets restored. We compute the latent heat and observe that the phase transition is of the first order.
Light nuclei from chiral EFT interactions
International Nuclear Information System (INIS)
Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (XEFT) provides a natural hierarchy to define two-nucleon (NN), three-nucleon (NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p-shell nuclei with NN and NNN interactions derived within XEFT. Presented at the 20th Few-Body Conference, Pisa, Italy, 10-14 September 2007. (author)
Light nuclei from chiral EFT interactions
Navratil, P.; Gueorguiev, V. G.; Vary, J. P.; Ormand, W. E.; Nogga, A.; Quaglioni, S.
2008-01-01
Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (chi EFT) provides a natural hierarchy to define two-nucleon (NN), three-nucleon (NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p...
Quenched Chiral Perturbation Theory to one loop
Colangelo, G.; Pallante, E.
1998-01-01
The divergences of the generating functional of quenched Chiral Perturbation theory (qCHPT) to one loop are computed in closed form. We show how the quenched chiral logarithms can be reabsorbed in the renormalization of the B0 parameter of the leading order Lagrangian. Finally, we do the chiral powe
Neutrino Oscillation Induced by Chiral Phase Transition
Institute of Scientific and Technical Information of China (English)
MU Cheng-Fu; SUN Gao-Feng; ZHUANG Peng-Fei
2009-01-01
Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars.Due to the sudden drop of the electron density at the first-order chiral phase transition,the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.
Shear Viscosity of Turbulent Chiral Plasma
Kumar, Avdhesh; Das, Amita; Kaw, P K
2016-01-01
It is well known that the difference between the chemical potentials of left-handed and right-handed particles in a parity violating (chiral) plasma can lead to an instability. We show that the chiral instability may drive turbulent transport. Further we estimate the anomalous viscosity of chiral plasma arising from the enhanced collisionality due to turbulence.
Chiral baryon in the coherent pair approximation
Aly, T S T
1999-01-01
We revisit the work of K. Goeke, M. Harvey, F. Grümmer, and J. N. Urbano (Phys. Rev. {\\bf D37}, 754 (1988)) who considered a chiral model for the nucleon based on the linear sigma model with scalar-isoscalar scalar-isovector mesons coupled to quarks and solved using the coherent-pair approximation. In this way the quantum pion field can be treated in a non-perturbative fashion. In this work we review this model and the coherent pair approximation correcting several errors in the earlier work. We minimize the expectation value of the chiral hamiltonian in the ansatz coherent-pair ground state configuration and solve the resulting equations for nucleon quantum numbers. We calculate the canonical set of nucleon observables and compare with the Hedgehog model and experiment. Using the corrected equations yield slightly different values for nucleon observables but do not correct the large virial deviation in the $\\pi$-nucleon coupling. Our results therefore do not significantly alter the conclusions of Goeke, et ...
Chiral cardiovascular drugs: an overview.
Ranade, Vasant V; Somberg, John C
2005-01-01
Stereochemistry in drug molecules is rapidly becoming an important aspect in drug research, design, and development. Recently, individual stereoisomers of drug molecules with asymmetric centers such as fexofenadine, cetirizine, verapamil, fluoxetine, levalbutarol, and amphetamine, for example, have been separated and developed as individual drugs. These stereoisomers have different therapeutic activity, and each isomer has contributed differently with respect to its formulation's pharmacologic activity, side effects, and toxicity. The present overview discusses chirality among a select group of cardiovascular drugs, their stereochemical synthesis/preparation, isolation techniques using chiral chromatography, methods for confirmation of their enantiomeric purity, pharmacodynamics, and pharmacokinetics. Chirality has been visualized as an important factor in cardiovascular research. It is also becoming evident in other areas of therapeutics.
Synthetic Applications of Chiral Furanboronate
Institute of Scientific and Technical Information of China (English)
CHAN; KinFai
2001-01-01
We recently uncovered that consecutive reactions of chiral furfural-boronate 1 with a lithium alkoxide and a nucleophile led to the formation of alcohols 2 with good diastereoselection in favor of S-configuration at the newly generated chiral carbon. In addition, it was also found that 2a and 2b were chromatographically separable on a silica gel column. This reaction is believed to involve a tetrahedral borate intermediate, as can be substantiated by 11BNMR spectroscopic studies. Chiral furanmethanolboronates 2a(or 2b) underwent a palladium-catalyzed Suzuki coupling to form enantiomerically pure furans 3, which can be further converted to the synthetically useful hydroxypyranones 4.1,2,3 In addition, Mukaiyama reaction of 1 also led to chromatographically separable diastereomeric aldol-products. The scope and limitation of these conversions will be discussed. ……
Chiral interaction and biomolecular evolution
International Nuclear Information System (INIS)
Recent developments in the concept of chiral interaction open now new options and dynamical possibilities for biomolecules which have so far been overlooked. A few of these possibilities are mentioned, such as the control mechanism of enzymatic activity and the role played by non-ergodicity in evolutionary processes. It is shown that chiral interaction, being a surface phenomenon, does not obey Barron's symmetry constraints, which are suitable for force fields present in bulk interactions. In particular, the situation at the ocean-air surface in the prebiotic era is described, as well as the possible role played by chiral interaction in conjunction with the terrestrial magnetic field normal to the ocean surface, which could have lead to a process of deracernization at the ocean-air interface. (author)
Power Counting Regime of Chiral Effective Field Theory and Beyond
Hall, J M M; Leinweber, D B
2010-01-01
Chiral effective field theory complements numerical simulations of quantum chromodynamics (QCD) on a space-time lattice. It provides a model-independent formalism for connecting lattice simulation results at finite volume and a variety of quark masses to the physical world. The asymptotic nature of the chiral expansion places the focus on the first few terms of the expansion. Thus, knowledge of the power-counting regime (PCR) of chiral effective field theory, where higher-order terms of the expansion may be regarded as negligible, is as important as knowledge of the expansion itself. Through the consideration of a variety of renormalization schemes and associated parameters, techniques to identify the PCR where results are independent of the renormalization scheme are established. The nucleon mass is considered as a benchmark for illustrating this general approach. Because the PCR is small, the numerical simulation results are also examined to search for the possible presence of an intrinsic scale which may b...
Chiral and Deconfining Phase Transitions from Holographic QCD Study
Fang, Zhen; Li, Danning
2015-01-01
A first attempt to accommodate the chiral and deconfining phase transitions of QCD in the bottom-up holographic framework is given. We constrain the relation between dilaton field $\\phi$ and metric warp factor $A_e$ and get several reasonable models in the Einstein-Dilaton system. Using the potential reconstruction approach, we solve the corresponding gravity background. Then we fit the background-related parameters by comparing the equation of state with the two-flavor lattice QCD results. After that we study the temperature dependent behavior of Polyakov loop and chiral condensate under those background solutions. We find that the results are in good agreement with the two-flavor lattice results. All the studies about the equation of state, the Polyakov loop and the chiral condensate signal crossover behavior of the phase transitions, which is consistent with the current understanding on the QCD phase transitions with physical quark mass. Furthermore, the extracted transition temperatures are comparable wit...