Note: Nonuniqueness of generalized quantum master equations for a single observable
Quantum Physics
2021-10-20 v2 Atomic Physics
Chemical Physics
Abstract
When deriving exact generalized master equations for the evolution of a reduced set of degrees of freedom, one is free to choose what quantities are relevant by specifying projection operators. However, obtaining a reduced description does not always need to be achieved through projections--one can also use conservation laws for this purpose. Such an operation should be considered as distinct from any kind of projection; that is, projection onto a single observable yields a different form of master equation compared to that resulting from a projection followed by the application of a constraint. We give a simple example to show this point and give relationships that the different memory kernels must satisfy to yield the same dynamics.
Cite
@article{arxiv.2108.10937,
title = {Note: Nonuniqueness of generalized quantum master equations for a single observable},
author = {Nathan Ng and David T. Limmer and Eran Rabani},
journal= {arXiv preprint arXiv:2108.10937},
year = {2021}
}