You are cordially invited to the SCL online seminar of the Center for the Study of Complex Systems, which will be held on Thursday, 24 February 2022 at 14:00 on Zoom. The talk entitled

Quantum chaos, gravity and factorization

will be given by Dr. Mihailo Čubrović (Scientific Computing Laboratory, Center for the Study of Complex Systems, Institute of Physics Belgrade). Abstract of the talk:

In this talk we will argue that the factorization of partition functions in ensembles of interacting quantum systems is a fundamental measure of chaos for a broad range of strongly and weakly interacting, few- and many-body examples. We will first introduce the factorization puzzle in the context of recent advances from the black hole information literature: the problem is likely solved if the black hole geometry is corrected by spacetime wormholes, but wormholes imply that the partition function of two independent, mutually non-interacting and non-entangled systems does not equal the product of their separate partition functions. Making use of a matrix (IKKT) model of D-branes in type IIB string theory, we will show that the factorization is restored when half-wormholes and in general fractional wormholes are taken into account, which corresponds to the regime of strong microscopic chaos on D-branes. Afterwards we will consider the opposite case: ensembles of few-body quantum mechanical systems (Schroedinger equation in the Henon-Heiles potential, quantum kicked top, random matrices) factorize into products of individual partition functions when the system is quantum-chaotic and obeys the Wigner-Dyson energy level statistics. At the end, we will discuss potential applications to strongly correlated electron systems, which bring some new difficulties because of exchange correlations brought about by Fermi statistics.

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