CPM Seminar

Entanglement entropy at strongly-interacting critical points

Roger Melko

University of Waterloo & Perimeter Institute

Information-theoretic quantities, such as entanglement entropies, can provide a novel window on universal physics at continuous phase transitions. Unlike traditional correlation functions, which for example are known to only incompletely classify topological phases, the entanglement entropy gives universal quantities dependent on the geometry of a spatial bipartition. At a 1+1 dimensional quantum critical point (QCP), measurement of the entanglement entropy provides the central charge of the associated conformal field theory - a universal quantity classifying the theory. In two or more spatial dimensions, leading-order contributions to the scaling of entanglement entropy typically follow the “area” law, while sub-leading behavior contains universal physics. Although such universal quantities are routinely studied in non-interacting field theories, it requires numerical simulation to access them in interacting theories. In this talk, we discuss numerical calculations of entanglement entropies at strongly-interacting QCPs in lattice models of condensed-matter systems. We calculate universal coefficients of several scaling term, and compare to non-interacting field theory, as well as recent results from holographic entanglement entropy formulas using the AdS/CFT correspondence.