35314072
Geometrical structure and critical phenomena in the fermion dynamical symmetry model: Sp(6).
43058634
Dynamical symmetry breaking and mean-field chaotic motions in nuclear many-body systems.
In this paper, the dynamical symmetry concept is used to investigate the quantum integrability of nuclear many-body systems. It is found that such systems are generally nonintegrable due to the complicated inherent interactions. In fact, in certain regions of the intrinsic parameters, the time-dependent mean-field solution can be chaotic. However, when subdynamical symmetries, e.g., certain excitation modes, dominate, the corresponding dynamics will be rendered regular, thus signaling that the nuclear many-body system is not fully chaotic. Chaotic behavior emerges in the transitional region between the excitation modes where subdynamical symmetries are broken and accompanied by structural phase transitions.
41901069
Geometrical interpretation of SO(7): A critical dynamical symmetry.
Potential-energy surfaces are obtained for the three dynamical-symmetry chains of SO(8) within the fermion-dynamical-symmetry model. A remarkable feature is that the SO(7) dynamical symmetry is transitional and ..beta.. soft. The transitional or ''critical'' behavior of SO(7) is vividly demonstrated.
45750229
Geometrical structure and critical phenomena in the fermion dynamical symmetry model: SO(8).
Geometrical properties of the recently proposed fermion dynamical symmetry model via the coherent state methodology is presented. Critical phenomena of this model are discussed in detail.
27720621
Integrability and nonintegrability of quantum systems: Quantum integrability and dynamical symmetry.
In this paper we discuss the concepts of quantum integrability and nonintegrability. Based on the concept of a complete set of commuting observables and the Hilbert-space structure of a quantum system, the definitions are given for the quantum-dynamical degrees of freedom and quantum phase space from which the quantum integrability is defined. A criterion for quantum integrability then emerges; the system is integrable if it possesses dynamical symmetry. Breaking of dynamical symmetry is connected with the nonintegrability of systems and thus is the inherent mechanism of chaotic motion. A number of examples are discussed.
32989568
Constrained path quantum Monte Carlo method for fermion ground states.
We propose a new quantum Monte Carlo algorithm to compute fermion ground-state properties. The ground state is projected from an initial wave function by a branching random walk in an over-complete basis space of Slater determinants. By constraining the determinants according to a trial wave function {vert_bar}{Psi}{sub {ital T}}{r_angle}, we remove the exponential decay of signal-to-noise ratio characteristic of the sign problem. The method is variational and is exact if {vert_bar}{Psi}{sub {ital T}}{r_angle} is exact. We report results on the two-dimensional Hubbard model up to size 16{times}16, for various electron fillings and interaction strengths.
32634500
Bonn potential model at finite temperature.
By using the thermofield dynamics, we have calculated the effective coupling of nucleon-nucleon mesons by summing the three-lines vertices and the masses of nucleon and mesons by summing the corresponding self-energy diagrams of the Bonn potential model at finite temperature. Through the temperature dependence of effective couplings and the screening masses, we have extended the Bonn potential to finite temperature. {copyright} {ital 1996 The American Physical Society.}
38317170
New tripreon models with semisimple metacolor groups.
A systematic analysis of the /ital chiral/ tripreon models with SU(/ital N/)/times/SO(/ital M/)-metacolor symmetry is made. Unique solutions to the 't Hooft anomaly-matching condition with the Bars constraint are obtained for SU(3)/times/SO(5) models which also satisfy complementarity. Both the metacolor group and the gauged color-flavor subgroup of the metaflavor group are asymptotically free. A model which has a low-metacolor-energy scale and three generations of composite fermions with the quantum numbers of quarks and leptons of the standard model is obtained.
43009443
Thermodynamical properties and Coulomb instabilities in hot nuclear systems with the Gogny interaction.
The thermodynamical properties and Coulomb instability in hot nuclear system with Gogny interactions are studied by using the finite-temperature real-time Green{close_quote}s function method. The isotherms, critical temperature, limiting temperature, saturation density, and isothermal incompressibility for various temperatures and different asymmetric parameters are calculated. To illustrate the importance of the finite-range part and density-dependence part of the interaction, we have compared our results with that given by the Skyrme interaction and Brink-Boeker interaction. {copyright} {ital 1996 The American Physical Society.}
858386
Chiral symmetry, quark mass, and scaling of the overlap fermions
The chiral symmetry relation and scaling of the overlap fermions are studied numerically on the quenched lattices at 3 couplings with about the same physical volume. We find that the generalized Gell-Mann-Oakes-Renner relation is satisfied to better than 1% down to the smallest quark mass at m(0)a = 0.006. We also obtain the quark mass from the PCAC relation and the pseudoscalar masses. The renormalization group invariant quark mass is shown to be fairly independent of scale. The pi and rho masses at a fixed m(pi)/m(rho) ratio indicate small O(a(2)) corrections. It is found that the critical slowing down sets in abruptly at a very small quark mass close to those of the physical u and d quarks.