Susan Morrison

Numerical study of dense adjoint matter in two color QCD

Abstract. We identify the global symmetries of SU(2) lattice gauge theory with N flavors of staggered fermion in the presence of a quark chemical potential

SYMMETRIES AND SPECTRUM OF SU(2) LATTICE GAUGE THEORY AT FINITE CHEMICAL POTENTIAL

\mu

Lattice approach to diquark condensation in dense matter

, for fermions in both fundamental and adjoint representations, and anticipate likely patterns of symmetry breaking at both low and high densities. Results from numerical simulations of the model with N = 1 adjoint flavor on a

Numerical portrait of a relativistic thin film BCS superfluid

4^3\times8

Critical Behavior in the Dense Planar Nambu–Jona-Lasinio Model

lattice are presented, using both hybrid Monte Carlo and Two-Step Multi-Boson algorithms. It is shown that the sign of the fermion determinant starts to fluctuate once the model enters a phase with non-zero baryon charge density. HMC simulations are not ergodic in this regime, but TSMB simulations retain ergodicity even in the dense phase, and in addition appear to show superior decorrelation. The HMC results for the equation of state and the pion mass show good quantitative agreement with the predictions of chiral perturbation theory, which should hold only for

CHIRAL SYMMETRY RESTORATION AND REALISATION OF THE GOLDSTONE MECHANISM IN THE U(1) GROSS-NEVEU MODEL AT NON-ZERO CHEMICAL POTENTIAL

N\ge2

Three-dimensional QED with dynamical fermions in an external magnetic field

. The TSMB results incorporating the sign of the determinant support a delayed onset transition, consistent with the pattern of symmetry breaking expected for N = 1.

Two-colour QCD at finite fundamental quark-number density and related theories☆

Abstract We study SU(2) Lattice Gauge Theory with dynamical fermions at non-zero chemical potential μ. The symmetries special to SU(2) for staggered fermions on the lattice are discussed explicitly and their relevance to spectroscopy and condensates at non-zero chemical potential are considered. Using the molecular dynamics algorithm on small lattices we find qualitative changes in the theorys spectroscopy at small and large values of μ. This preliminary study should lay the groundwork for future large scale simulations.

Lessons from the 3d U(1) Gross-Neveu model

We present results of a Monte Carlo simulation of a three dimensional Gross-Neveu model with SU(2)xSU(2) chiral symmetry at non-zero baryon chemical potential mu, corresponding to non-zero baryon density. For mu sufficiently large there is a sharp transition between a phase where the chiral symmetry is broken by a condensate and one where the global U(1) baryon number symmetry appears to be broken by a scalar diquark condensate . There is also tentative evidence for the formation of a weaker pseudoscalar diquark condensate in the high density phase, which violoates parity.

Diquark Condensation in Dense Matter - A Lattice Perspective

We present results of numerical simulations of the 2+1d Nambu - Jona-Lasinio model with a non-zero baryon chemical potential mu including the effects of a diquark source term. Diquark condensates, susceptibilities and masses are measured as functions of source strength j. The results suggest that diquark condensation does not take place in the high density phase mu>mu_c, but rather that the condensate scales non-analytically with j implying a line of critical points and long range phase coherence. Analogies are drawn with the low temperature phase of the 2d XY model. The spectrum of the spin-1/2 sector is also studied yielding the quasiparticle dispersion relation. There is no evidence for a non-zero gap; rather the results are characteristic of a normal Fermi liquid with Fermi velocity less than that of light. We conclude that the high density phase of the model describes a relativistic gapless thin film BCS superfluid.