Unified framework for open quantum dynamics with memory.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39278965.
- Also identified by DOI 10.1038/s41467-024-52081-3 and PMC identifier 11402990.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The dynamics of quantum systems coupled to baths are typically studied using the Nakajima-Zwanzig memory kernel ( <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>K</mi></math> ) or the influence functions (I), particularly when memory effects are present. Despite their significance, formal connections between the two have not been explicitly known. We establish their connections by examining the system propagator for a N-level system linearly coupled to Gaussian baths with various types of system-bath coupling. For a certain class of problems, we devised a non-perturbative, diagrammatic approach to construct <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>K</mi></math> from I for (driven) systems interacting with Gaussian baths, bypassing conventional projection-free dynamics inputs. Our work provides a way to interpret approximate path integral methods in terms of approximate memory kernels. Moreover, it offers a Hamiltonian learning procedure to extract the bath spectral density from reduced system trajectories, opening new avenues in quantum sensing and engineering. The insights we provide advance our understanding of non-Markovian dynamics and will serve as a stepping stone for future theoretical and experimental developments in this area.