Ainesh Bakshi, Massachusetts Institute of Technology

Abstract

Entanglement is the crucial phenomenon that distinguishes quantum systems from classical ones. Specifically, we consider entanglement in many-body systems at thermal equilibrium as a function of the temperature. Systems at thermal equilibrium at sufficiently low temperatures are demonstrably entangled. We investigate whether these systems remain entangled as the temperature increases.   

We prove that above a fixed constant temperature, the system does not exhibit any entanglement and behaves entirely classically. This proof of the sudden death of thermal entanglement cuts against a large body of prior work, both rigorous and computational, which only gives mild limits on entanglement at constant temperatures. Our proof falls out of a new connection between lack of entanglement and an algorithm for preparing thermal states on a quantum computer.

Based on joint work with Allen Liu, Ankur Moitra and Ewin Tang.

See: https://theory.cs.rutgers.edu/theory_seminar