GeoTop-QMATH Seminar: J. "JX" Zhang (Tsinghua)
GeoTop-QMATH Seminar (Geometric Analysis & Mathematical Physics)
Location: Vibenshuset (QMATH), Lyngbyvej 2, 4th floor, DK-2100 Copenhagen
Title: Macroscopic Suppression of Supersonic Quantum Transport
Abstract: In 1972, Lieb and Robinson proved that for a nonequilibrium quantum spin system, there exists an upper bound on the speed at which physical effects can propagate. Constrained by particle interactions, quantum transport with speed beyond this bound is exponentially suppressed. This upper bound is far below the speed of light and is therefore often referred to as the “speed of sound.” In a recent joint work with Faupin, Lemm, and Sigal, we identified a macroscopic suppression mechanism for “supersonic” quantum transport, valid for a broad class of quantum many-body systems. The suppression strength grows exponentially with the total particle number, rendering supersonic transport effectively impossible at the macroscopic level. In this sense, our result establishes a universal dynamical large deviation principle, which we call the macroscopic suppression of supersonic macroscopic transport (MASSMAT). The goal of this talk is to explain the mathematical aspects of MASSMAT and the key idea behind its proof.
Title: Macroscopic Suppression of Supersonic Quantum Transport
Abstract: In 1972, Lieb and Robinson proved that for a nonequilibrium quantum spin system, there exists an upper bound on the speed at which physical effects can propagate. Constrained by particle interactions, quantum transport with speed beyond this bound is exponentially suppressed. This upper bound is far below the speed of light and is therefore often referred to as the “speed of sound.” In a recent joint work with Faupin, Lemm, and Sigal, we identified a macroscopic suppression mechanism for “supersonic” quantum transport, valid for a broad class of quantum many-body systems. The suppression strength grows exponentially with the total particle number, rendering supersonic transport effectively impossible at the macroscopic level. In this sense, our result establishes a universal dynamical large deviation principle, which we call the macroscopic suppression of supersonic macroscopic transport (MASSMAT). The goal of this talk is to explain the mathematical aspects of MASSMAT and the key idea behind its proof.
Dinner: After the seminar we will have dinner at Madklubben Østerbro, at 18:15.
Let Niels Martin know by email (at nmoller@math.ku.dk) beforehand, if you plan to attend, and please do so at the latest Tue Dec 2nd at 16:00.