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.
120753030
Coherent states: Theory and some Applications
In this review, a general algorithm for constructing coherent states of dynamical groups for a given quantum physical system is presented. The result is that, for a given dynamical group, the coherent states are isomorphic to a coset space of group geometrical space. Thus the topological and algebraic structure of the coherent states as well as the associated dynamical system can be extensively discussed. In addition, a quantum-mechanical phase-space representation is constructed via the coherent-state theory. Several useful methods for employing the coherent states to study the physical phenomena of quantum-dynamic systems, such as the path integral, variational principle, classical limit, and thermodynamic limit of quantum mechanics, are described.
119019195
Examination of Wandzura-Wilczek relation for g2(x, Q2) in pQCD
Abstract In order to examine the validity of Wandzura-Wilczek relation for the polarized DIS structure function g 2 ( x , Q 2 ), we use the light-front time-ordering pQCD to calculate g 2 ( x , Q 2 ) at order α s on a quark target. We find that the study of the transverse polarized structure function in pQCD is only meaningful if we begin with massive quarks. The result shows that the Wandzura-Wilczek relation for g 2 ( x , Q 2 ) is strongly violated by the quark mass in pQCD.
117753364
Quantum Heisenberg Antiferromagnets versus Nonlinear $\sigma$ Model Without the Large S Limit
In this letter, I develop a new topologically invariant coherent state path integral for spin systems, and apply it to the quantum Heisenberg model on a square lattice. As a result, the quantum nonlinear $\sigma$ model for arbitrary values of spin can be directly obtained. The effective coupling constant and spin wave velocity are modified by $g_s= {2\over S}\sqrt{d+{T_\Lambda\over 2SJ}}$ and $c_s=2JSa \sqrt{d+{T_\Lambda\over 2SJ}}$, where $T_\Lambda$ is a natural temperature scale for the reliability of the theory. The formulation can also be extended to other generalized coherent state path integrals.
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.
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.
29922444
Grassmannian Kaluza-Klein theory and the standard model.
By appending anticommuting coordinates to the four commuting space-time coordinates it is possible to amalgamate gravity and internal forces without introducing infinitely many massive modes. We carry out this synthesis for the standard model.
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.
34188098
Stochastic quantization and random surface approach to Polyakov string theory.
1003631
Masses of hadrons and nucleon-nucleon interaction at finite temperature and density in a quantum hadrodynamics model.
The effective masses and the screening masses of hadrons at finite temperature and density for the quantum hadrodynamics two (QHD-II) model have been investigated under the one-loop approximation. The nucleon-nucleon interaction through pion, sigma, omega, and rho mesons exchange in hot nuclear matter is given. We have found that the potential well of the nucleon-nucleon interaction becomes shallow as the temperature and/or density increases. At a critical temperature and/or a critical density, the potential well disappears.
32394428
Thermodynamical fluctuations of meson fields for a quantum hadrodynamics model.
Using the real-time Green's-function method with a pair-cutoff approximation up to second order, the thermodynamical fluctuation effects of meson fields on the QHD-II model are studied. We find that the fluctuation effects of meson fields, in particular, the \ensuremath{\pi} meson field, on saturation energy, effective mass of nucleon, and pressure are remarkable in the low-density region and/or high-temperature region. The results given by the QHD-I and QHD-II models are compared. The value of the critical point of the liquid-gas phase transition for the QHD-II model is given.