2–27 May 2016
Nordita, Stockholm
Europe/Stockholm timezone

Universal Signatures of Quantum Critical Points from Finite-Size Torus Spectra: A Window into the Operator Content of Higher-Dimensional Conformal Field Theories.

3 May 2016, 11:15
1h
122:026 (Nordita, Stockholm)

122:026

Nordita, Stockholm

Speaker

Andreas Läuchli

Description

The low-energy spectra of many body systems on a torus, of finite size L, are well understood in magnetically ordered and gapped topological phases. However, the spectra at quantum critical points separating such phases are largely unexplored for 2+1D systems. Using a combination of analytical and numerical techniques, we show that the low-energy torus spectrum at criticality provides a universal fingerprint of the underlying quantum field theory, with the energy levels given by universal numbers times 1/L. We highlight the implications of a neighboring topological phase on the spectrum by studying the Ising* transition, in the example of the toric code in a longitudinal field, and advocate a phenomenological picture that provides insight into the operator content of the critical field theory.

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