Time-Resolved Optical Response of the Dicke's Model via the Nonequilibrium Green's Function Approach
(2024) In Physica Status Solidi (B) Basic Research- Abstract
Due to their conceptual appeal and computational convenience, two-level systems (TLSs) and generalizations are used to investigate nonlinear behavior in quantum optics and assess the applicability of theoretical methods. Herein, the focus is on second-harmonic generation (SHG) and, as system of interest, on the Dicke model, which consists of several TLSs inside an optical cavity. The main aspect addressed is the scope of nonequilibrium Green's function (NEGF) to describe the effect of inhomogeneities and electron–electron (e–e) interactions on the SHG signal. For benchmarking purposes, exact diagonalization (ED) results are also presented and discussed. SHG spectra obtained with NEGF and ED are found to be in very good mutual agreement... (More)
Due to their conceptual appeal and computational convenience, two-level systems (TLSs) and generalizations are used to investigate nonlinear behavior in quantum optics and assess the applicability of theoretical methods. Herein, the focus is on second-harmonic generation (SHG) and, as system of interest, on the Dicke model, which consists of several TLSs inside an optical cavity. The main aspect addressed is the scope of nonequilibrium Green's function (NEGF) to describe the effect of inhomogeneities and electron–electron (e–e) interactions on the SHG signal. For benchmarking purposes, exact diagonalization (ED) results are also presented and discussed. SHG spectra obtained with NEGF and ED are found to be in very good mutual agreement in most situations. Furthermore, inhomogeneity in the TLS and e–e interactions reduce the SHG signal, and the reduction is stronger with inhomogeneity than with interactions. This trend is consistently noted across different (small to large) system sizes. Finally, a modified NEGF approach is proposed to account for cavity leakage, where the quantum photon fields are coupled to a bath of classical oscillators. As expected, within this mixed quantum-classical scheme, a decrease in the intensity of the fluorescent spectra takes place depending on the entity of leakage.
(Less)
- author
- Gopalakrishna, Megha LU ; Pavlyukh, Yaroslav and Verdozzi, Claudio LU
- organization
- publishing date
- 2024
- type
- Contribution to journal
- publication status
- epub
- subject
- keywords
- cavity leakage, Dicke model, disordered Dicke model, exact diagonalization, nonequilibrium green's functions, second-harmonic generation
- in
- Physica Status Solidi (B) Basic Research
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- scopus:85193941134
- ISSN
- 0370-1972
- DOI
- 10.1002/pssb.202300576
- language
- English
- LU publication?
- yes
- id
- 318e0fad-4bb0-4d26-b30b-177642bf2e3c
- date added to LUP
- 2024-06-18 13:50:43
- date last changed
- 2024-06-18 13:51:43
@article{318e0fad-4bb0-4d26-b30b-177642bf2e3c,
abstract = {{<p>Due to their conceptual appeal and computational convenience, two-level systems (TLSs) and generalizations are used to investigate nonlinear behavior in quantum optics and assess the applicability of theoretical methods. Herein, the focus is on second-harmonic generation (SHG) and, as system of interest, on the Dicke model, which consists of several TLSs inside an optical cavity. The main aspect addressed is the scope of nonequilibrium Green's function (NEGF) to describe the effect of inhomogeneities and electron–electron (e–e) interactions on the SHG signal. For benchmarking purposes, exact diagonalization (ED) results are also presented and discussed. SHG spectra obtained with NEGF and ED are found to be in very good mutual agreement in most situations. Furthermore, inhomogeneity in the TLS and e–e interactions reduce the SHG signal, and the reduction is stronger with inhomogeneity than with interactions. This trend is consistently noted across different (small to large) system sizes. Finally, a modified NEGF approach is proposed to account for cavity leakage, where the quantum photon fields are coupled to a bath of classical oscillators. As expected, within this mixed quantum-classical scheme, a decrease in the intensity of the fluorescent spectra takes place depending on the entity of leakage.</p>}},
author = {{Gopalakrishna, Megha and Pavlyukh, Yaroslav and Verdozzi, Claudio}},
issn = {{0370-1972}},
keywords = {{cavity leakage; Dicke model; disordered Dicke model; exact diagonalization; nonequilibrium green's functions; second-harmonic generation}},
language = {{eng}},
publisher = {{John Wiley & Sons Inc.}},
series = {{Physica Status Solidi (B) Basic Research}},
title = {{Time-Resolved Optical Response of the Dicke's Model via the Nonequilibrium Green's Function Approach}},
url = {{http://dx.doi.org/10.1002/pssb.202300576}},
doi = {{10.1002/pssb.202300576}},
year = {{2024}},
}