Composite reweighting SU(2) QCD at Finite Temperature

TL;DR

This paper evaluates the Glasgow reweighting method for SU(2) lattice gauge theory at finite temperature and chemical potential, addressing sampling issues and identifying phase transition features relevant to diquark condensation.

Contribution

It demonstrates the persistence of the overlap problem in SU(2), combines data from multiple ensembles to improve sampling, and confirms the phase transition structure predicted by effective theories.

Findings

Overlap problem persists in SU(2) reweighting.

Combining ensembles alleviates sampling bias.

Identifies Lee-Yang zeros related to phase transition.

Abstract

The Glasgow reweighting method is evaluated for SU(2) lattice gauge theory at nonzero \mu and finite T. We establish that the ' overlap problem' of SU(3) measurements, in which the transition points determined from thermodynamic observables have an unphysical dependence on the value of \mu used in the reweighting persists for SU(2). By combining the information from different lattice ensembles we alleviate sampling bias in the fugacity expansion, and identify the Lee-Yang zeros associated with the transition to a high density phase that can plausibly be associated with diquark condensation. We also confirm the existence of a line of first order transitions above a critical point in the T-\mu plane previously identified by effective chiral lagrangian calculations.