Quark-Gluon Mixed Condensate (anti-Q sigma G Q) from Lattice QCD

TL;DR

This study calculates the quark-gluon mixed condensate using lattice QCD, revealing its significant value and potential impact on QCD operator product expansions, with initial temperature-dependent results.

Contribution

First lattice QCD calculation of the quark-gluon mixed condensate with detailed ratio analysis and preliminary finite temperature results.

Findings

Ratio m_0^2 ≈ 2.5 GeV^2 at lattice scale

Large mixed condensate indicates importance in QCD OPE

Preliminary finite temperature results presented

Abstract

We study the quark-gluon mixed condensate g<\bar{q} sigma G q>, which is another chiral order parameter, in SU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched level. Using 100 gauge configurations on the 16^4 lattice with \beta = 6.0, we measure the mixed condensate at 16 points in each gauge configuration for each current-quark mass of m_q=21, 36, 52 MeV. From the 1600 data for each m_q, we find the ratio between the mixed condensate and the quark condensate, m_0^2 = g<\bar{q} sigma G q> / <\bar{q}q> \simeq 2.5 GeV^2 at the lattice scale of 1/a \simeq 2 GeV in the chiral limit. The large value of the mixed condensate suggests its importance in the operator product expansions in QCD. We also show our preliminary results of the mixed condensate at finite temperature.