arXiv subjects

X. Cai

Publications and source records attributed to X. Cai.

888 records · Page 50Linked to original sources

arXiv1998

Local Spontaneous Symmetry Breaking for Film System Within Scalar $ϕ^4$ Model for Phase Transition

The difficulty is analysed in evaluating fluctuations in phase transition of finite-size system at temperature far below the critical point. Film system is discussed with one-component order parameter $ϕ^4$ model for phase transition. Non-trivial vacuum state corresponding to minimum Hamiltonian is given approximately for various boundary conditions. It is shown that the spontaneous symmetry breaking plays an important role for such systems, and that perturbative calculations can be done safely when the effect of the vacuum state or the local spontaneous symmetry breaking is taken into consideration.

cond-mat↗

arXiv1997

Multiplicity difference correlators under first-order QGP phase transition

The multiplicity difference correlators between two well-separated bins in high-energy heavy-ion collisions are studied as a means to detect evidence of a first-order quark-hadron phase transition. Analytical expressions for the scaled factorial moments of multiplicity difference distribution are obtained for small bin size $δ$ with mean multiplicity in the bin ${\bar s}\le 1.0$ within Ginzburg-Landau description. The scaling behaviors between the moments are still valid, though they behave completely different from the so-called intermittency patterns. A universal exponent $γ=1.4066$ is given to describe the dynamical fluctuations in the phase transition in small $δ$ limit.

hep-ph↗

arXiv1997

Analytical investigation for multiplicity difference correlators under QGP phase transition

It is suggested that the study of multiplicity difference correlators between two well-separated bins in high-energy heavy-ion collisions can be used as a means to detect evidence of a quark-hadron phase transition. Analytical expressions for the scaled factorial moments of multiplicity difference distribution are obtained in a kinetical region ${\bar s}\le 0.3$ within Ginzburg-Landau description. It is shown that the scaling behaviors between the moments are still valid, though the behaviors of the moments with respect to the bin size are completely different from the so-called intermittency patterns. A universal exponent $γ$ is given to describe the dynamical fluctuations in the phase transition.

hep-ph↗

arXiv1997

Finite-Size Effects in Critical Phenomena from Mean Field Approach with $ϕ^4$ Model

The finite-size effects in critical phenomena of a thin film system are studied from a mean field (MF) approach with $ϕ^4$ model for second-order phase transition. The influence of boundary condition on the critical properties are emphasized. Scaling functions for relative free-energy and relative specific heat capacity are given.

cond-mat↗

arXiv1996

On the Polarization Dependence of Electromagnetic Vertex for Proton

The polarization dependence of the electromagnetic vertex for polarized proton is discussed. Such a dependence is shown to be a result of gluon polarization and gluon interactions with the constituents within proton. One more form factor is introduced to give such a dependence in the electromagnetic vertex for proton. Due the polarization dependence of the vertex, a nonzero single-spin asymmetry for unpolarized lepton scattering off transversely polarized proton is predicted.

hep-ph↗

arXiv1996

A New Perturbation Theory of Finite-Size Effects Near Critical Point

A new perturbation theory is proposed for studying finite-size effects near critical point of the $ϕ^4$ model with a one-component order parameter. The new approach is based on the techniques of generating functional and functional derivative with respect to external source field and can be used for temperatures both above and below the critical point of the bulk system. It is shown that this approach is much simpler comparing with available perturbation theories. Particularly, this new method avoids renormalization in calculating many physical quantities such as correlation functions etc..

cond-mat↗