Dynamical stabilisation of complex Langevin simulations of QCD

Preprint number: CP3-Origins-2018-30 DNRF90
Authors: Felipe Attanasio (Department of Physics, University of Washington) and Benjamin Jäger (CP3-Origins & DIAS, University of Southern Denmark)

Share this pageShare on FacebookTweet about this on TwitterShare on LinkedInGoogle+

The ability to describe strongly interacting matter at finite temperature and baryon density
provides the means to determine, for instance, the equation of state of QCD at non-zero baryon chemical
potential. From a theoretical point of view, direct lattice simulations are hindered by the numerical sign
problem, which prevents the use of traditional methods based on importance sampling. Despite recent
success, simulations using the complex Langevin method have been shown to exhibit instabilities, which
cause convergence to a wrong result. We introduce and discuss the method of Dynamic Stabilisation (DS),
a modification of the complex Langevin process aimed at solving these instabilities. We present results of
DS being applied to the heavy-dense approximation of QCD, as well as QCD with staggered fermions at
zero chemical potential and finite chemical potential at high temperature. Our findings show that DS can
successfully deal with the aforementioned instabilities, opening the way for further progress.