An approximation scheme and non-Hermitian re-normalization for description of atom-field system evolution

Fuente: arXiv
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Autori principali: Ahmadi, Borhan, Rodríguez, Ricard Ravell, Alicki, Robert, Horodecki, Michał
Natura: Preprint
Pubblicazione: 2022
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author Ahmadi, Borhan
Rodríguez, Ricard Ravell
Alicki, Robert
Horodecki, Michał
author_facet Ahmadi, Borhan
Rodríguez, Ricard Ravell
Alicki, Robert
Horodecki, Michał
contents Interactions between a source of light and atoms are ubiquitous in nature. The study of them is interesting on the fundamental level as well as for applications. They are in the core of Quantum Information Processing tasks and in Quantum Thermodynamics protocols. However, even for two-level atom interacting with field in rotating wave approximation there exists no exact solution. This touches as basic problem in quantum field theory, where we can only calculate the transitions in the time asymptotic limits (i.e. minus and plus infinity), while we are not able to trace the evolution. In this paper we want to get more insight into the time evolution of a total system of a two-level atom and a continuous-mode quantum field. We propose an approximation, which we are able to apply systematically to each order of Dyson expansion, resulting in greatly simplified formula for the evolution of the combined system at any time. Our tools include a proposed novel, {\it non-Hermitian} re-normalization method. As a sanity check, by applying our framework, we derive the known optical Bloch equations.
format Preprint
id arxiv_https___arxiv_org_abs_2210_10345
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle An approximation scheme and non-Hermitian re-normalization for description of atom-field system evolution
Ahmadi, Borhan
Rodríguez, Ricard Ravell
Alicki, Robert
Horodecki, Michał
Quantum Physics
High Energy Physics - Theory
Interactions between a source of light and atoms are ubiquitous in nature. The study of them is interesting on the fundamental level as well as for applications. They are in the core of Quantum Information Processing tasks and in Quantum Thermodynamics protocols. However, even for two-level atom interacting with field in rotating wave approximation there exists no exact solution. This touches as basic problem in quantum field theory, where we can only calculate the transitions in the time asymptotic limits (i.e. minus and plus infinity), while we are not able to trace the evolution. In this paper we want to get more insight into the time evolution of a total system of a two-level atom and a continuous-mode quantum field. We propose an approximation, which we are able to apply systematically to each order of Dyson expansion, resulting in greatly simplified formula for the evolution of the combined system at any time. Our tools include a proposed novel, {\it non-Hermitian} re-normalization method. As a sanity check, by applying our framework, we derive the known optical Bloch equations.
title An approximation scheme and non-Hermitian re-normalization for description of atom-field system evolution
topic Quantum Physics
High Energy Physics - Theory
url https://arxiv.org/abs/2210.10345