Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field and experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time-reverse. Our result addresses the concept of irreversibility from a microscopic quantum standpoint.
|Number of pages||5|
|Journal||Physical Review Letters|
|Publication status||Published - 02 Nov 2015|
FingerprintDive into the research topics of 'Irreversibility and the Arrow of Time in a Quenched Quantum System'. Together they form a unique fingerprint.
- School of Mathematics and Physics - Head of School
- Centre for Quantum Materials and Technologies (CQMT)