Engineering topics

Yuxin, Liu

Publications and source records attributed to Yuxin, Liu.

5 records

DOE OSTI2011

Simple description of odd-A nuclei around the critical point of the spherical to axially deformed shape phase transition

An analytically solvable model, X(3/2j+1), is proposed to describe odd-A nuclei near the X(3) critical point. The model is constructed based on a collective core described by the X(3) critical point symmetry coupled to a spin-j particle. A detailed analysis of the spectral patterns for cases j=1/2 and j=3/2 is provided to illustrate dynamical features of the model. By comparing theory with experimental data and results of other models, it is found that the X(3/2j+1) model can be taken as a simple yet very effective scheme to describe those odd-A nuclei with an even-even core at the critical point of the spherical to axially deformed shape phase transition.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

QCD Phase Diagram Using Dyson-Schwinger Equations

We describe briefly the Dyson-Schwinger equation approach of QCD and the study of the QCD phase diagram in this approach. The phase diagram in terms of the temperature and chemical potential, and that in the space of coupling strength and current-quark mass are given.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Phase Diagram at Finite Chemical Potentials in the Nambu-Jona-Lasinio Model

We study the phase diagram of two flavor dense QCD at finite isospin and baryon chemical potentials in the framework of Nambu-Jona-Lasinio model. The system undergoes a crossover from a Bose-Einstein condensate of charged pions to a BCS superfluid with condensed quark-antiquark Cooper pairs when {mu}{sub I} increases at {mu}{sub B} = 0, and a nonzero baryon chemical potential serves as a mismatch between the pairing species. We observe a gapless pion condensation phase near the quadruple point ({mu}{sub I},{mu}{sub B}) = (m{sub {pi}},M{sub N}-1.5m{sub {pi}}) where m{sub {pi}}, M{sub N} are the vacuum masses of pions and nucleons, respectively. At very large isospin chemical potential, {mu}{sub I}>6.36m{sub {pi}}, an inhomogeneous LOFF superfluid phase appears in a window of {mu}{sub B}. Between the gapless and the LOFF phases, the pion superfluid phase and the normal quark matter phase are connected by a first order phase transition.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Quark Spectral Function above T{sub c}

The maximum entropy method is used to calculate the dressed-quark spectral density from the self-consistent solution of the rainbow-truncated gap equation of QCD at temperatures above T{sub c}, the critical temperature for chiral symmetry restoration. We find that, besides the normal and plasmino modes, the spectral function exhibits an essentially nonperturbative zero mode at the temperatures above but near T{sub c}. In the vicinity of T{sub c}, this long-wavelength mode contains the bulk of the spectral strength. So long as this mode persists, the system may reasonably be described as a strongly-coupled state of matter.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Phase Diagram and Critical End Point for Strongly Interacting Quarks

We introduce a method based on chiral susceptibility, which enables one to draw a phase diagram in the chemical-potential-temperature plane for strongly interacting quarks whose interactions are described by any reasonable gap equation, even if the diagrammatic content of the quark-gluon vertex is unknown. We locate a critical end point at ({mu}{sup E},T{sup E}){approx}(1.0,0.9)T{sub c}, where T{sub c} is the critical temperature for chiral-symmetry restoration at {mu}=0, and find that a domain of phase coexistence opens at the critical end point whose area increases as a confinement length scale grows.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗