Spectral representation of thermal OTO correlators

• Main Authors: Soumyadeep Chaudhuri, Chandramouli Chowdhury, R. Loganayagam
• Format: Article
• Language: English
• Published: SpringerOpen 2019-02-01
• Series: Journal of High Energy Physics
• Subjects: Thermal Field Theory; Quantum Dissipative Systems; Nonperturbative Effects
• Online Access: http://link.springer.com/article/10.1007/JHEP02(2019)018

Abstract We study the spectral representation of finite temperature, out of time ordered (OTO) correlators on the multi-time-fold generalised Schwinger-Keldysh contour. We write the contour-ordered correlators as a sum over time-order permutations acting on a fundamental array of Wightman correlators. We decompose this Wightman array in a basis of column vectors, which provide a natural generalisation of the familiar retarded-advanced basis in the finite temperature Schwinger-Keldysh formalism. The coefficients of this decomposition take the form of generalised spectral functions, which are Fourier transforms of nested and double commutators. Our construction extends a variety of classical results on spectral functions in the SK formalism at finite temperature to the OTO case.