Speaker
Description
As the continuum limit is approached, conventional update algorithms in lattice QCD and other topologically non-trivial theories suffer from a particularly severe form of critical slowing down, caused by high action barriers separating distinct topological sectors. Parallel tempered Metadynamics (PT-MetaD) has been shown to overcome this problem by pairing, in the simplest case, the physical simulation with one auxiliary parallel simulation stream in which a bias potential enhances the weight of inter-sector configurations, enabling topological tunneling. Parallel tempering exchanges between the two streams then allow observables to be measured on the unbiased replica, circumventing the reweighting problem that afflicts standard Metadynamics.
In this talk we present several algorithmic advances within, but not limited to, the PT-MetaD framework and provide the first proof-of-concept demonstration in full QCD with dynamical fermions. We further discuss the current status of an ongoing study in high-temperature QCD.