Showing papers on "Explicit symmetry breaking published in 1997"
TL;DR: In this article, a brane configuration is described that is relevant to understanding the dynamics of N = 1 supersymmetric Yang-Mills theory, and the model in which these properties can be understood semiclassically does not coincide with supersymmemic Yang-mills theory but is evidently in the same universality class.
434 citations
TL;DR: In this article, the authors point out the connection of these ''breathing'' modes to the presence of a hidden symmetry, i.e., the two-dimensional Lorentz group, allowing pulsating solutions to be constructed for the interacting quantum system and for the corresponding nonlinear Gross Pitaevskii equation.
Abstract: Atoms confined in a harmonic potential show universal oscillations in two dimensions (2D). We point out the connection of these ``breathing'' modes to the presence of a hidden symmetry. The underlying symmetry SO(2,1), i.e., the two-dimensional Lorentz group, allows pulsating solutions to be constructed for the interacting quantum system and for the corresponding nonlinear Gross-Pitaevskii equation. We point out how this symmetry can be used as a probe for recently proposed experiments of trapped atoms in 2D.
215 citations
162 citations
TL;DR: In this paper, the authors consider the self-evolution of strongly nonequilibrium interacting Bose gas and show that gauge symmetry is not destroyed even when the long-range ordering is completed, owing to the inevitable averaging over the ensemble.
Abstract: We consider the self-evolution of strongly nonequilibrium interacting Bose gas. Because of the mere fact of large (relative to unity) occupation numbers in the initial state the problem is directly reduced to the question of temporal evolution of the statistical matrix diagonal in the coherent-state representation. Strictly speaking, gauge symmetry is not destroyed even when the long-range ordering is completed, owing to the inevitable averaging over the ensemble. Actual symmetry breaking can occur only as a result of introducing a small term of the Hamiltonian violating conservation of particles, or quantum-mechanical measurement, also implying nonconservation of particles.
118 citations
TL;DR: In this article, a low energy effective lagrangian for the nonet of pseudo-Goldstone bosons that appear in the large N c limit of QCD is presented including terms up to four derivatives and explicit symmetry in the quark masses.
111 citations
TL;DR: The minimal supersymmetric left-right theory of as mentioned in this paper predicts the existence of a triplet of Higgs scalars much lighter than the $B\ensuremath{-}L$ breaking scale.
Abstract: We construct the minimal supersymmetric left-right theory and show that at the renormalizable level it requires the existence of an intermediate $B\ensuremath{-}L$ breaking scale. The subsequent symmetry breaking down to the minimal supersymmetric standard model automatically preserves $R$ symmetry. Furthermore, unlike in the nonsupersymmetric version of the theory, the see-saw mechanism takes its canonical form. The theory predicts the existence of a triplet of Higgs scalars much lighter than the $B\ensuremath{-}L$ breaking scale.
96 citations
TL;DR: In this paper, the superconductivity of layered high-T c materials with different internal topology was investigated and the current carrying boundary between domains with different topological invariants was considered.
Abstract: Superconducting states with different internal topology are discussed for the layered high-T
c
materials. If the time inversion symmetry is broken, the superconductivity is determined not only by the symmetry of the superconducting state but also by the topology of the ground state. The latter is determined by the integer-valued momentum-space topological invariant N. The current carrying boundary between domains with different N (N
2≠N
1) is considered. The current is produced by fermion zero modes, the number of which per layer is 2(N
2−2N
1).
95 citations
TL;DR: In this paper, a new proof of the theorem of Wigner on the symmetry transformations is worked out and various mathematical formulations of the symmetry group in quantum mechanics are investigated and shown to be mutually equivalent.
Abstract: Various mathematical formulations of the symmetry group in quantum mechanics are investigated and shown to be mutually equivalent. A new proof of the theorem of Wigner on the symmetry transformations is worked out.
64 citations
TL;DR: In this paper, the SO(10) × U(1)A model was proposed to solve the doublet-triplet splitting problem via the missing VEV mechanism, and it was shown that all relevant GUT scales are related to a single dimensional parameter in the Higgs superpotential.
62 citations
TL;DR: In this paper, the Boussinesq model of surface-forced thermohaline flow in a two-dimensional rectangular basin is studied, and it is shown that symmetry breaking originates from a codimension-two singularity which arises through the intersection of the paths of two symmetry-breaking pitchfork bifurcations.
Abstract: The bifurcation structure of thermohaline-driven flows is studied within one of the simplest zonally averaged models which captures thermohaline transport: a Boussinesq model of surface-forced thermohaline flow in a two-dimensional rectangular basin. Under mixed boundary conditions, i.e. prescribed surface temperature and fresh-water flux, it is shown that symmetry breaking originates from a codimension-two singularity which arises through the intersection of the paths of two symmetry-breaking pitchfork bifurcations. The physical mechanism of symmetry breaking of both the thermally and salinity dominated symmetric solution is described in detail from the perturbation structures near bifurcation. Limit cycles with an oscillation period in the order of the overturning time scale arise through Hopf bifurcations on the branches of asymmetric steady solutions. The physical mechanism of oscillation is described in terms of the most unstable mode just at the Hopf bifurcation. The occurrence of these oscillations is quite sensitive to the shape of the prescribed fresh-water flux. Symmetry breaking still occurs when, instead of a fixed temperature, a Newtonian cooling condition is prescribed at the surface. There is only quantitative sensitivity, i.e. the positions of the bifurcation points shift with the surface heat transfer coefficient. There are no qualitative changes in the bifurcation diagram except in the limit where both the surface heat flux and fresh-water flux are prescribed. The bifurcation structure at large aspect ratio is shown to converge to that obtained by asymptotic theory. The complete structure of symmetric and asymmetric multiple equilibria is shown to originate from a codimension-three bifurcation, which arises through the intersection of a cusp and the codimension-two singularity responsible for symmetry breaking.
60 citations
TL;DR: In this paper, the authors present time-independent and time-dependent theories for frequency-dependent resonant x-ray scattering beyond the Born-Oppenheimer approximation in order to explore under what circumstances one can anticipate symmetry breaking in the spectra of polyatomic molecules.
Abstract: Although resonant x-ray scattering of molecules fulfills strict electronic symmetry selection rules, as now firmly proven by spectra of diatomic molecules, the accumulated body of data for polyatomic molecules indicates that an apparent breaking of these rules represents the common situation rather than the exception. The CO2 molecule provides a good example of symmetry breaking, with the oxygen x-ray emission spectra showing strong intensity for transitions that are forbidden by the parity selection rule. We present time-independent and time-dependent theories for frequency-dependent resonant x-ray scattering beyond the Born–Oppenheimer approximation in order to explore under what circumstances one can anticipate symmetry breaking in the spectra of polyatomic molecules. The theory starts out from the Kramers–Heisenberg dispersion relation and is generalized for vibrational degrees of freedom and for nonadiabatic coupling of the electronic (vibronic) states, including the frequency dependency of the scatt...
TL;DR: In this paper, the catalysis of chiral symmetry breaking in a massless weakly coupled QED in a magnetic field at finite temperature was studied and the temperature of the symmetry restoration was estimated analytically.
Abstract: The catalysis of chiral symmetry breaking in the massless weakly coupled QED in a magnetic field at finite temperature is studied. The temperature of the symmetry restoration is estimated analytically as ${T}_{c}\ensuremath{\approx}{m}_{\mathrm{dyn}},$ where ${m}_{\mathrm{dyn}}$ is the dynamical mass of a fermion at zero temperature.
TL;DR: In this article, a simple model of dynamical gauge-mediated SUSY breaking is proposed, which incorporates a dynamical relaxation mechanism which solves the mu-problem with no light fields beyond those of the MSSM.
TL;DR: In this article, a high-temperature gas-phase electron diffraction analysis of manganese trifluoride, combined with high-level quantum chemical calculations, provides direct geometrical evidence of a Jahn−Teller distortion in a free molecule.
Abstract: A new high-temperature gas-phase electron diffraction analysis of manganese trifluoride, combined with high-level quantum chemical calculations, provides direct geometrical evidence of a Jahn−Teller distortion in a free molecule. The potential energy surface of the molecule was scanned extensively by computation at the SCF level. CASSCF and CASPT2 calculations established that of the many C2v symmetry stationary points on the potential energy surface the lowest energy ones are quintets. The global minimum is a quintet state of 5A1 symmetry. In this planar C2v symmetry structure there are two longer and one somewhat shorter Mn−F bonds, with two bond angles close to 106° and one bond angle of about 148°. The second lowest energy state was of 5B2 symmetry, which turned out to be a transition state with an imaginary b2 (in plane) bending frequency. A constrained planar structure of D3h molecular symmetry has appreciably higher energy than the 5B2 symmetry structure. The experimental data are in complete agree...
TL;DR: In this article, it has been shown that the symmetry of the order parameter in the high-cuprates is dominated by a -component and the implications of the unconventional symmetry on devices and on large-scale applications of high-superconductors are discussed.
Abstract: It has been shown that the symmetry of the order parameter in the high- cuprates is dominated by a -component. In this contribution, the implications of the unconventional symmetry on devices and on large-scale applications of high- superconductors are discussed.
TL;DR: In this paper, the authors considered the problem of symmetry restoration as treated by the method of variation after projection (VAP) on good quantum numbers and proposed a method which generates approximations of increasing precision which are periodic with respect to the gauge angle while differing from truncations of the Fourier expansion of the VAP kernels.
TL;DR: In this paper, the authors studied the non restoration of symmetries with a local order parameter in field theory at finite temperature and showed that hierarchy preblems are a necessary condition for its realization in renormalizable theories.
TL;DR: In this article, the existence of a co-dual BRST symmetry for the usual BRST invariant Lagrangian density of an Abelian gauge theory in two dimensions of space-time where a U(1) gauge field is coupled to the Noether conserved current (constructed by the Dirac fields).
Abstract: We show the existence of a co(dual)-BRST symmetry for the usual BRST invariant Lagrangian density of an Abelian gauge theory in two dimensions of space-time where a U(1) gauge field is coupled to the Noether conserved current (constructed by the Dirac fields). Under this new symmetry, it is the gauge-fixing term that remains invariant and the symmetry transformations on the Dirac fields are analogous to the chiral transformations. This interacting theory is shown to provide a tractable field theoretical model for the Hodge theory. The Hodge dual operation is shown to correspond to a discrete symmetry in the theory and the extended BRST algebra for the generators of the underlying symmetries turns out to be reminiscent of the algebra obeyed by the de Rham cohomology operators of differential geometry.
TL;DR: In this paper, the exact expectation value and standard deviation for the dimensionality of a Cantorian spacetime were determined and connections to time symmetry breaking and the generalization of complex numbers were considered.
Abstract: In this paper we determine the exact expectation value and standard deviation for the dimensionality of a Cantorian spacetime. We show further that the symmetry of the universe is a precondition and the origin of its asymmetry. Connections to time symmetry breaking and the generalization of complex numbers are considered. Finally, a link between general relativity and Cantorian spacetime is proposed which amounts to the claim that the Bethe lattice-like fractalization of microspace is the origin of gravity.
TL;DR: In this paper, the physical properties of an $s$-wave -normal-metal -$d$wave junction in terms of the Andreev bound-state solutions to the Bogoliubov-de Gennes equation in the normal-metal layer were studied.
Abstract: We study the physical properties of an $s$-wave--normal-metal--$d$-wave junction in terms of the Andreev bound-state solutions to the Bogoliubov--de Gennes equation in the normal-metal layer. The phase dependence of bound states with different orientations leads to superconducting states with broken time-reversal symmetry for generic orientations of the $d$-wave superconductor crystal. The occurrence of such a state and the associated spontaneous supercurrent along the junction and magnetic field is analyzed also in the framework of Ginzburg-Landau theory.
TL;DR: In this paper, the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field were presented, and a semiclassical interpretation of this effect was given.
Abstract: We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.
TL;DR: In this article, the authors construct basis independent expressions that measure the magnitude of R-parity breaking due to possible superpotential terms in the Minimal Supersymmetric extension of the Standard Model, in the absence of soft supersymmetry-breaking terms and spontaneous gauge symmetry breaking.
TL;DR: In this article, the role of spin degree of freedom in persistent current was investigated and it was shown that Zeeman coupling induces persistent current as conventional Aharonov-Bohm (AB) flux does by competing with spin-orbit (SO) interaction.
Abstract: We investigate the role that the spin degree of freedom plays in persistent current and show that Zeeman coupling induces persistent current as conventional Aharonov-Bohm (AB) flux does by competing with spin-orbit (SO) interaction. We demonstrate that, in the presence of SO interaction, Zeeman coupling and AB flux break time-reversal symmetry through intrinsically different mechanisms. A corresponding interesting observable effect for persistent current is generally found and explicitly computed for a symmetric mesoscopic ring with noninteracting electrons.
TL;DR: In this article, the authors show that the double degeneracy present is a consequence of a dynamical symmetry and derive a new symmetry group associated with the two-dimensional square-well potential.
Abstract: The two-dimensional square-well potential is one of the simplest quantum-mechanical systems that exhibits accidental degeneracy We show that the double degeneracy present is a consequence of a dynamical symmetry and derive a new symmetry group associated with the system
TL;DR: In this paper, the validity of the pseudo-spin concept for heavy triaxially deformed nuclei was explored using the correlation coefficient measure between a generalized Nilsson Model Hamiltonian and the pseudo spin-orbit interaction.
TL;DR: In this article, the exact expectation value and standard deviation for the dimensionality of a Cantorian spacetime were derived and connections to time symmetry breaking and the generalization of complex numbers were considered.
Abstract: We derive the exact expectation value and standard deviation for the dimensionality of a Cantorian spacetime. Connections to time symmetry breaking and the generalization of complex numbers are considered. Finally a link between general relativity and Cantorian spacetime is proposed which amounts to the claim that fractalization is the origin of gravity.
TL;DR: In this article, the meson sector of an effective Lagrangian was investigated in terms of the exponential integral and a method was developed for evaluating the logarithmic terms in the effective potential which involves expansion and resummation.
TL;DR: A numerical stability analysis of these bound states reveals that wave propagation in quadratic materials exhibits spatial symmetry-breaking instabilities.
Abstract: We present a study of the dynamics of multiple soliton bound states in diffractive media with second-order nonlinearity. A numerical stability analysis of these bound states reveals that wave propagation in quadratic materials exhibits spatial symmetry-breaking instabilities.
CERN1
TL;DR: In this paper, the question of inverse symmetry breaking at non-zero temperature using the exact renormalization group was discussed and the nature of the phase transition during which the symmetry is broken was investigated.