Showing papers on "Explicit symmetry breaking published in 1990"
TL;DR: It is shown that for a specific choice of the Higgs potential the vortex satisfies a set of Bogomol'nyi-type, or self-duality, equations in an Abelian Chern-Simons theory with spontaneous symmetry breaking.
Abstract: We study vortex solutions in an Abelian Chern-Simons theory with spontaneous symmetry breaking. We show that for a specific choice of the Higgs potential the vortex satisfies a set of Bogomol'nyi-type, or ``self-duality,'' equations.
561 citations
TL;DR: In this paper, the group-theoretically allowed superconductivity states for singlet and triplet superconductors in orthorhombic and tetragonal crystals are enumerated.
Abstract: Whatever its microscopic origins, it seems likely that the superconductivity in the copper-oxides can be described by an appropriate Ginzburg-Landau theory. The possible order parameters and free energies are then determined by the symmetry breaking of the phase transition alone. The group-theoretically allowed states are enumerated here for singlet and triplet superconductors in orthorhombic and tetragonal crystals. As well as broken gauge, time reversal and rotational symmetries, broken translational symmetry states are also investigated. Experiments that might distinguish the various possible states are reviewed, concentrating especially on experiments where the outcomes are determined by the symmetry properties of the order parameter alone. These include Josephson effects, transition splitting, spontaneous strain and magnetism, critical and Gaussian fluctuations, collective modes and vortices. Current experimental results on the high-Tc materials are discussed where relevant, although in many...
153 citations
TL;DR: In this article, a dynamical SO(2, 1) symmetry for the dynamics of charged point particles interacting with point vortices is presented. And the authors also find an integral representation for the scattering wave function, discuss the angular momentum spectrum, and establish the absence of self-interactions in Chern-Simons electrodynamics, for which the two body scattering state is explicitly constructed as a definite superposition of free one-body states.
150 citations
IBM1
TL;DR: The Hubbard model possesses a SU(2) pseudospin symmetry, which contains the U(1) phase symmetry as a subgroup, which leads to interesting experimental consequences if the ground state is superconducting.
Abstract: The Hubbard model possesses a SU(2) pseudospin symmetry, which contains the U(1) phase symmetry as a subgroup. The existence of such symmetry leads to interesting experimental consequences if the U(1) phase symmetry is spontaneously broken, i.e., if the ground state is superconducting. In this case, there must exist a pair of massive collective modes which together with the usual Goldstone mode form a triplet representation of the psuedospin group. These collective modes are collisionless and couple directly to external charge disturbances with wave number \ensuremath{\pi} and can therefore be detected experimentally as sharp resonances.
129 citations
TL;DR: In this paper, the symmetry breakdown in the electroweak theory is dynamical and one should expect, in general, to have some nonuniversal interactions, given the present bounds on flavor mixing, this imposes rather strong restrictions on the dynamics and the pattern of spontaneous symmetry breaking.
125 citations
TL;DR: In this article, it was shown that chiral symmetry is broken in the continuum limit only if the number of Dirac fermions is smaller than 3.5 ± 0.5.
61 citations
TL;DR: In this article, it was shown that if extended technicolor interactions are to play a role in electroweak symmetry breaking and in particular if they are to enhance fermion masses above their values in the usual weak Extended Technicolor scenario, then the chiral symmetry breaking phase transition must be second order.
59 citations
TL;DR: It is considered the possibility that multiple four-Fermi interactions are important in symmetry breaking, leading to an effective two-Higgs-doublet model at low energies, and Higgs-induced flavor-changing neutral currents are naturally suppressed in this model.
Abstract: Recently, there has been some interest in the possibility that electroweak symmetry breaking in the standard model is driven by attractive four-Fermi interactions among heavy quarks. In this paper, we consider the possibility that multiple four-Fermi interactions are important in symmetry breaking, leading to an effective two-Higgs-doublet model at low energies. Higgs-induced flavor-changing neutral currents are naturally suppressed in this model. We consider the case where there are three generations, as well as the case of a heavy fourth generation. Predictions are made for the heavy-quark and Higgs-boson masses.
57 citations
01 Nov 1990
TL;DR: In this article, the authors focus on the problems of vacuum degeneration in macroscopic systems and a fundamental concept of quasiaverages by Bogolubov playing a special role in the theory of phase transitions and critical phenomena.
Abstract: This book treats the problem of phase transitions, emphasizing the generality and universality of the methods and models used. The course is basically concentrated on the problems of vacuum degeneration in macroscopic systems and a fundamental concept of quasiaverages by Bogolubov playing a special role in the theory of phase transitions and critical phenomena. An analysis of the connection between phase transition and spontaneous symmetry breaking in a macroscopic system allows a unique description of both first- and second-order phase transitions.The unique features of this book are: (i) a unique approach of describing first — as well as second-order phase transitions, based on the Bogolubov concept of quasi-averages.(ii) a detailed presentation of the material and at the same time a review of modern problems.(iii) a general character of developed ideas that could be applied to various particular systems of condensed matter physics, nuclear physics and high-energy physics.
53 citations
47 citations
TL;DR: In this paper, the authors discuss how one can differentiate between various theories of the symmetry breaking sector of electroweak interactions using WW scattering at high energies, and the tool is the study of deviations from the universal lowest order nonlinear sigma model predictions for these amplitudes.
TL;DR: In this article, the existence of a generalized anti-BRST symmetry in the space of fields and antifields was shown and explicit expressions for irreducible and off-shell reducible theories with a closed gauge algebra were given.
TL;DR: In this paper, the existence of approximate dynamical constants of motion for statistical analysis of highly excited vibrational spectra is investigated, and two possible kinds of approximate constants, for a total polyad number and a bend normal mode, are discussed in relation to two coupling schemes that could govern the transition to chaos in H2O.
Abstract: The implications of approximate dynamical constants of motion for statistical analysis of highly excited vibrational spectra are investigated. The existence of approximate dynamical constants is related to localized chaos and partial assignability of a ‘‘chaotic spectrum.’’ Approximate dynamical constants are discussed in a dynamical symmetry breaking formulation of the transition from periodic to quasiperiodic motion, and from quasiperiodic to chaotic motion. Level repulsion, leading to a Wigner distribution in the case of a strongly chaotic system, is shown to originate in dynamical symmetry breaking via the noncrossing rule that states of the same symmetry do not cross. It is argued that quantum numbers for dynamical constants must be correctly assigned to detect localized chaos in statistical spectroscopy. Two possible kinds of approximate constants, for a ‘‘total polyad number’’ and a bend normal mode, are discussed in relation to two coupling schemes that could govern the transition to chaos in H2O.
Book•
01 Jan 1990
TL;DR: In this paper, the basis functions of tensor field representations are derived for modulated structures and superspace groups are derived from the complete rational integrity basis of invariants, and the symmetry changes with the thermodynamic potential depending on the rational integrity.
Abstract: Contents. Chapter 1. Group-theoretical methods. Introduction. Group actions. The complete rational integrity basis of invariants. Crystallographic colour groups. Magnetic group corepresentations. The basis functions of tensor field representations. Superspace groups. Symmetry of modulated crystals. Chapter 2. Developments of Landau's theory. Introduction. Landau's theory and group actions. The inverse Landau problem in symmetry changes. Symmetry changes with the thermodynamic potential depending on complete rational integrity basis. Phase transitions with two order parameters. Phase transitions to modulated structures. Space-dependent basis functions and space-independent expansion coefficients in modulated structure calculations. Chapter 3. Developments of Birman's theory. Introduction. Symmetry restoration. Physical applications of crystallographic colour groups. Hermann's space-group decomposition theorem and chain subduction criterion. Symmetry restrictions implied by group-subgroup relation. Symmetry changes in two-dimensional systems. Chapter 4. Improper ferroelectrics. Introduction. The phase transition in gadolinium molybdate. Phase transitions in boracites. Improper ferroelectric-nonferroelastic phase transitions. The susceptibility tensor. Chapter 5. Symmetry changes in ferroic crystals. Introduction. Ferroic crystals. Purely ferroelastic phase transitions. Phase transitions of nonmagnetic ferroics. Nonferroic phase transitions. Chapter 6. Modulated structures. Introduction. Examples of incommensurate crystal phases. The internal dimensions of a supercrystal. Bravais classes for incommensurate crystals. Superspace-group symmetry operations. Determination of superspace groups for modulated crystals. Space-group representations and superspace symmetry. Superspace symmetry without a supercrystal. The commensurate-to-incommensurate phase transition in dysprosium crystal. The commensurate-to-incommensurate phase transition in a neodymium crystal. Chapter 7. Symmetry changes in metamagnets. Introduction. Field-induced metamagnetic phase transitions. Phase transitions at the tricritical point in metamagnets. Symmetry changes in the tricritical point in metamagnets. Symmetry changes at the tricritical point of a FeCl 2 -type crystal. Symmetry changes in the tricritical point of a metamagnet with P6 3 mmc(D) space-group symmetry and an hcp lattice. Chapter 8. Symmetries of liquid crystals. Introduction. ``Statistical'' symmetry with applications to phase transitions. Phase transitions from an isotropic liquid to liquid crystals. Symmetry of ferroelectric liquid crystals. The subgroups of the symmetry group of an A-type smectic with a symmetry centre. Critical X-ray scattering and the symmetry of liquid crystals. Appendix. Bibliography. Author index. Subject index.
TL;DR: In this paper, it was shown that Andrews' theorem holds in the general context of classical mechanics with symmetry, and that stability modulo the symmetry group of solution classes is not special to fluid mechanics.
Abstract: In this note it is shown that Andrews' theorem, which states that Arnol'd stability implies symmetry, is not special to fluid mechanics, but holds in the general context of classical mechanics with symmetry. More importantly, we emphasise that in Andrews' theorem one should consider stability modulo the symmetry group of solution class. We do this by using the energy-Casimir method to prove the stability of two-dimensional ABC flows, even though they are not symmetric.
TL;DR: In this article, it was shown that in the presence of spontaneous violation of these symmetries, the corresponding pseudo Goldstone bosons may acquire masses much larger than the size of the explicit breaking.
TL;DR: In this article, the one-loop effective potentials for the non-integrable phases of Wilson lines at both zero and finite temperature were derived using the zeta-function technique.
TL;DR: In this paper, the free energy of the fixed finite connectivity spin glass is investigated in detail and the equivalence of different forms which were obtained in the literature using completely different methods.
Abstract: The free energy of the fixed finite connectivity spin glass is investigated in detail and the authors prove the equivalence of different forms which were obtained in the literature using completely different methods. Furthermore, the question of replica symmetry breaking is examined for low connectivity. They find by a variational calculation that even for a first-step breaking one can obtain a more optimal value for the ground state energy by going beyond the simple ansatz of Wong-Sherrington (1988) of totally uncorrelated groups of replicas.
TL;DR: If a system of hard-core particles in {ital d}=2 is given to be a Mott insulator, then the charge must form a commensurate charge-density wave, which implies a breakdown of lattice-translation symmetry.
Abstract: We explore the connection between Mott-insulating behavior and the breakdown of lattice-translation symmetry. We find that if a system of hard-core particles in {ital d}=2 is given to be a Mott insulator, then the charge must form a commensurate charge-density wave. This is true for particles of any statistics. Our result is based on duality arguments and does not seem to depend on the details of the Hamiltonian. For average site-occupation number {ital n}{lt}1, this implies a breakdown of lattice-translation symmetry.
TL;DR: In this paper, the authors re-examine the problem of spontaneously broken gauge theories in curved spacetime and show that introducing a nonminimal coupling of the scalar field with gravity opens the possibility of inducing spontaneous symmetry breaking without the need to choose a negative value for m2.
Abstract: The authors re-examine the problem of spontaneously broken gauge theories in curved spacetime. They show that introducing a nonminimal coupling of the scalar field with gravity opens the possibility of inducing spontaneous symmetry breaking without the need to choose a negative value for m2. Using this idea in the framework of a grand unified model, they calculate the Higgs mass, the value of the cosmological constant and the effective gravitational constant.
TL;DR: In this article, nonlinear susceptibility X 2 is investigated in a quasi-two-dimensional complex magnet, CoCl 2 -GIC (graphite intercalation compound), and a negative divergence and another different singularity that X 2 changes its sign from negative to positive, are concluded to occur at the upper and lower critical points in the compound by observing nonlinear magnetic response to an AC excitation field.
Abstract: Nonlinear susceptibility X 2 is investigated in a quasi-two-dimensional complex magnet, CoCl 2 -GIC (graphite intercalation compound). A negative divergence and another different singularity that X 2 changes its sign from negative to positive, are concluded to occur at the upper and the lower critical points in the compound by observing nonlinear magnetic response to an AC excitation field. From the facts, it is shown that the symmetry of X 2 at the critical point reveals a breaking of spatial magnetic symmetry in the examined systems. On this basis, the dynamical structure of hierarchical spin ordering is discussed.
TL;DR: In this article, explicit expressions for the S operator are provided for the scattering related to any symmetric space of the noncompact type, and the scattering connected with symmetry is studied.
Abstract: Scattering connected with symmetry is studied. Explicit expressions for the S operator are provided for the scattering related to any symmetric space of the noncompact type
TL;DR: In this article, five fundamental manifestations of symmetry in physics are investigated for their essential meaning and physical significance, and the approach is conceptual, to the complete exclusion of mathematical formalism.
Abstract: Five fundamental manifestations of symmetry in physics—reproducibility as symmetry, predictability as symmetry, symmetry of evolution of isolated physical systems, symmetry of states of physical systems, and gauge symmetry—are investigated for their essential meaning and physical significance. The approach is conceptual, to the complete exclusion of mathematical formalism.
TL;DR: In this article, the chiral-quark meson model is used to study baryon properties with realistic breaking of SU(3), and the symmetry breaking is assumed to be strong, so that a random phase approximation (RPA) can be used.
TL;DR: The character of the band structure symmetry is analyzed for different types of symmetry operations for spiral magnetic structures in this paper, and it is shown that unlike the traditional cases, there are spiral structures whose band structure is described by nonsymmorphic space groups.
TL;DR: In this article, the mass difference between up and down quarks accounts for all of the observed non-electromagnetic charge symmetry breaking in particle and nuclear physics, and the uncertainty in removing Coulomb effects from the proton-proton scattering length is shown to be small.