arXiv subjects

Chi-Yong Lin

Publications and source records attributed to Chi-Yong Lin.

43 records · Page 3Linked to original sources

arXiv2000

Quasinormal modes of Reissner-Nordstr$\ddot{o}$m Anti-de Sitter Black Holes

Complex frequencies associated with quasinormal modes for large Reissner-Nordstr$\ddot{o}$m Anti-de Sitter black holes have been computed. These frequencies have close relation to the black hole charge and do not linearly scale with the black hole temperature as in Schwarzschild Anti-de Sitter case. In terms of AdS/CFT correspondence, we found that the bigger the black hole charge is, the quicker for the approach to thermal equilibrium in the CFT. The properties of quasinormal modes for $l>0$ have also been studied.

hep-th↗

arXiv1999

Time-Dependent Variational Analysis of Josephson Oscillations in a Two-component Bose-Einstein Condensate

The dynamics of Josephson-like oscillations between two coupled Bose-Einstein condensates is studied using the time-dependent variational method. We suppose that the quantum state of the condensates is a gaussian wave-packet which can translate and perform breathing shape oscillations. Under this hypotheses we study the influence of these degrees of freedom on the tunneling dynamics by comparing the full-model with one where these degrees of freedom are ``frozen'' at its equilibrium values. The result of our calculation shows that when the traps are not displaced the two models agree, whereas when they are, the models differ considerably, the former being now closer to its linear approximation.

cond-mat.soft↗

arXiv1999

Collective Excitation of a Hybrid Atomic/Molecular Bose Einstein Condensate$^{\ast}$

The collective excitation of hybrid atomic-molecular condensate are studied using variational method. The dipole response of the system is studied in detail. We found that the out-of-phase dipole oscillation frequency increasing slowly with the detuning parameter and is only few times large than the trap frequency making the experimental observation of this mode of vibration feasible.

cond-mat.soft↗

arXiv1999

Fermion Pairing Dynamics in the Relativistic Scalar Plasma

Using many-body techniques we obtain the time-dependent Gaussian approximation for interacting fermion-scalar field models. This method is applied to an uniform system of relativistic spin-1/2 fermion field coupled, through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called quantum scalar plasma model. The renormalization for the resulting Gaussian mean-field equations, both static and dynamical, are examined and initial conditions discussed. We also investigate solutions for the gap equation and show that the energy density has a single minimum.

hep-th↗

arXiv1999

Initial-Value Problem for Inhomogeneous Condensate: Gaussian Approximation and Beyond

Using many-body theory we develop a set of formally exact kinetic equations for inhomogeneous condensate and one-body observables. The method is illutrated for phi^4 field theory in 1+1 dimensions. These equations, when computed with the help of time-dependent projection technique, lead to a systematic mean-field expansion. The lowest and the higher order terms correspond to, respectively, the gaussian approximation and the dynamical correlation effect.

cond-mat↗

arXiv1999

Elementary Excitations of a Relativistic Scalar Plasma System

We investigate the physics of elementary excitations for the so called relativistic scalar plasma system. Following the standard many-body procedure we have obtained the RPA equations for this model by linearizing the TDHFB equations of motion around equilibrium and shown that these oscillation modes give one-meson and two-fermion state of the theory. The resulting equations have a closed solution, from which one can examinate the spectrum of excitation modes. In partticular, our results indicate existence of bound state for certain region of phase diagram.

hep-ph↗

arXiv1998

Time-Dependent Variational Principle for $ϕ^4$ Field Theory: RPA Approximation and Renormalization (II)

The Gaussian-time-dependent variational equations are used to explored the physics of $(ϕ^4)_{3+1}$ field theory. We have investigated the static solutions and discussed the conditions of renormalization. Using these results and stability analysis we show that there are two viable non-trivial versions of $(ϕ^4)_{3+1}$. In the continuum limit the bare coupling constant can assume $b\to 0^{+}$ and $b\to 0^{-}$, which yield well defined asymmetric and symmetric solutions respectively. We have also considered small oscillations in the broken phase and shown that they give one and two meson modes of the theory. The resulting equation has a closed solution leading to a ``zero mode'' and vanished scattering amplitude in the limit of infinite cutoff.

hep-th↗