Séminaire de groupe
|Conformal invariance in driven diffusive systems at high currents|
|jeudi 26 mai 2016 , 10h25|
|Salle de séminaire du groupe de Physique Statistique|
We consider space-time correlations in driven diffusive systems undergoing a fluctuation with an atypically large current or hopping activity. Specifically, for the one-dimensional simple exclusion process, where this regime is not accessible to macroscopic fluctuation theory, we show that density correlations are not governed by the diffusive or Kardar-Parisi-Zhang (KPZ) universality class (as in the typical steady state), but belong to a ballistic universality class with dynamical exponent z = 1. The scaling form of the two-point function is determined by conformal invariance. This is proved by an exact mapping of the dynamics conditioned on large current or hopping activity to the XXZ spin chain in the quantum critical regime and demonstrated explicitly for the regime of maximal current, both for periodic and open boundary conditions. The universality of the quantum critical behaviour suggests that driven diffusive systems at an atypically high current or hopping activity are generically conformally invariant.