Light-Cone Effect and Supersonic Correlations in Bosonic Superfluids

Giuseppe Carleo (1) , Federico Becca (2) , Laurent Sanchez-Palencia (3) , Sandro Sorella (2) , Michele Fabrizio (2)

1 LCF - Laboratoire Charles Fabry
2 SISSA / ISAS - Scuola Internazionale Superiore di Studi Avanzati / International School for Advanced Studies
3 Laboratoire Charles Fabry / Optique atomique

We study the spreading of density-density correlations in Bose-Hubbard models after a quench of the interaction strength, using time-dependent variational Monte Carlo simulations. It gives access to unprecedented long propagation times and to dimensions higher than one. In both one and two dimensions, we find ballistic light-cone spreading of correlations and extract accurate values of the light-cone velocity in the superfluid regime. We show that the propagation of correlations is generally supersonic, with a light-cone velocity larger than twice the sound velocity, except at the Mott transition, where the characteristic velocities are equal. Further, we show that in two dimensions the correlation spreading is highly anisotropic and presents nontrivial interference effects.

Domaines: Physique Quantique [quant-ph]

Giuseppe Carleo, Federico Becca, Laurent Sanchez-Palencia, Sandro Sorella, Michele Fabrizio. Light-Cone Effect and Supersonic Correlations in Bosonic Superfluids. 2013. ⟨hal-00871090v1⟩