Fundamental limits on quantum dynamics based on entropy change
Abstract
It is well known in the realm of quantum mechanics and information theory that the entropy is non-decreasing for the class of unital physical processes. However, in general, the entropy does not exhibit monotonic behavior. This has restricted the use of entropy change in characterizing evolution processes. Recently, a lower bound on the entropy change was provided in the work of Buscemi, Das, and Wilde [Phys. Rev. A 93(6), 062314 (2016)]. We explore the limit that this bound places on the physical evolution of a quantum system and discuss how these limits can be used as witnesses to characterize quantum dynamics. In particular, we derive a lower limit on the rate of entropy change for memoryless quantum dynamics, and we argue that it provides a witness of non-unitality. This limit on the rate of entropy change leads to definitions of several witnesses for testing memory effects in quantum dynamics. Furthermore, from the aforementioned lower bound on entropy change, we obtain a measure of non-unitarity for unital evolutions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 01, 2018
- Source ID
- 10.1063/1.4997044
Entities
People
- George Siopsis
- Mark M. Wilde
- Siddhartha Das
- Sumeet Khatri
Organizations
- Louisiana State University
- National Science Foundation
- Office of Naval Research
- University of Tennessee