期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：8
页码：1844-1849
DOI：10.1073/pnas.1618185114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We compute parameters characterizing many-body quantum chaos for a critical Fermi surface without quasiparticle excitations. We examine a theory of N species of fermions at nonzero density coupled to a U ( 1 ) gauge field in two spatial dimensions and determine the Lyapunov rate and the butterfly velocity in an extended random-phase approximation. The thermal diffusivity is found to be universally related to these chaos parameters; i.e., the relationship is independent of N , the gauge-coupling constant, the Fermi velocity, the Fermi surface curvature, and high-energy details.
