Are fermionic conformal field theories more entangled?

ORAL

Abstract

We study the entanglement between disjoint subregions in quantum critical systems through the lens of the logarithmic negativity. We work with conformal field theories (CFTs) in general dimensions, and their corresponding lattice Hamiltonians. At small separations, the logarithmic negativity is big and displays universal behaviour, but we show non-perturbatively that it decays faster than any power at large separations. This can already be seen in the minimal setting of single-spin subregions. The corresponding absence of distillable entanglement at large separations generalises the 1d result, and indicates that quantum critical groundstates do not possess long range bipartite entanglement, at least for bosons. For systems with fermions, a more suitable definition of the logarithmic negativity exists that takes into account fermion parity, and we show that it decays algebraically. Along the way we obtain general CFT results for the moments of the partially transposed density matrix.

Presenters

  • Gilles Parez

    Centre de Recherches Mathématiques, Université de Montréal

Authors

  • Gilles Parez

    Centre de Recherches Mathématiques, Université de Montréal

  • William Witczak-Krempa

    Universite de Montreal