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.
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.
18229984
Effective Field Theory of Heavy Mesons
In this paper we present a detailed formulation for a recently proposed effective field theory to describe the nonperturbative QCD dynamics of heavy mesons. This effective theory incorporates with heavy quark symmetry (HQS) and the heavy quark effective theory (HQET). Heavy mesons in this theory are constructed as composite particles of a heavy quark bounded with the light degrees of freedom. The heavy meson properties in the heavy quark limit and the 1/mQ corrections can then be explicitly evaluated from this effective theory. All the basic parameters of the HQET, namely, the heavy quark mass mQ, the heavy meson residual mass �, and the HQS breaking mass parameters λ1 and λ2, are consistently determined. λ1 is found to be small due to a large cancellation between the heavy quark kinetic energy and the chromo-electric interaction between the heavy quark and light degrees of freedom. We also evaluate the Isgur-Wise function, the decay constant, and the axial-vector coupling constant of heavy mesons.
1382332
Quantum nonlinear sigma model for arbitrary spin Heisenberg antiferromagnets.
We derive a quantum nonlinear sigma model (QNLSM) for quantum Heisenberg antiferromagnets (QHA) with arbitrary S (spin) values. A upper limit of the low temperature is naturally carried out for the reliability of the QNLSM. The S dependence of the effective coupling constant and the spin-wave velocity in the QNLSM are also obtained explicitly. The resulting spin-wave velocity for 2D spin-1/2 QHA highly concurs with the experimental data of high T(c) compound La(2)CuO(4). The predicted correlation lengths for 2D QHA and spin-gap magnitudes for 1D QHA also agrees with the accurate numerical results.
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.
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.
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.
6589068
Top quark as a topological color soliton.
In this paper I propose a scenario for the top quark as a topological color soliton. I illustrate some features of the top quark as a soliton in a toy model based on a nonlinear realization of SU{sub {ital L}}(3){times}SU{sub {ital R}}(3)/SU{sub {ital L}+{ital R}}(3) with SU{sub {ital L}+{ital R}}(3) being the color gauge group.
32391471
Gluon propagator and transverse vertices.
It is shown explicitly that in the axial gauge the Slavnov-Taylor identity contains no useful information for determining the gluon propagator through the Dyson-Schwinger equation; rather, it is the transverse vertex which plays the crucial role.
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.