Universal scaling laws for correlation spreading in quantum systems with short- and long-range interactions

Cevolani, Lorenzo and Despres, Julien and Carleo, Giuseppe and Tagliacozzo, Luca and Sanchez-Palencia, Laurent (2018) Universal scaling laws for correlation spreading in quantum systems with short- and long-range interactions. Physical Review B, 98. ISSN 2469-9950

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    Abstract

    The spreading of correlations after a quantum quench is studied in a wide class of lattice systems, with short- and long-range interactions. Using a unifying quasiparticle framework, we unveil a rich structure of the correlation cone, which encodes the footprints of several microscopic properties of the system. When the quasiparticle excitations propagate with a bounded group velocity, we show that the correlation edge and correlation maxima move with different velocities that we derive. For systems with a divergent group velocity, especially relevant for long-range interacting systems, the correlation edge propagates slower than ballistic. In contrast, the correlation maxima propagate faster than ballistic in gapless systems but ballistic in gapped systems. Our results shed light on existing experimental and numerical observations and pave the way to the next generation of experiments. For instance, we argue that the dynamics of correlation maxima can be used as a witness of the elementary excitations of the system.