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Vacuum-field-induced state mixing
by Diego Fernández de la Pradilla, Esteban Moreno, Johannes Feist
This is not the latest submitted version.
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Submission summary
| Authors (as registered SciPost users): | Johannes Feist · Diego Fernández de la Pradilla · Esteban Moreno |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202305_00002v2 (pdf) |
| Date submitted: | 2023-10-09 16:08 |
| Submitted by: | Fernández de la Pradilla, Diego |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
By engineering the electromagnetic vacuum field, the induced Casimir-Polder shift (also known as Lamb shift) and spontaneous emission rates of individual atomic levels can be controlled. When the strength of these effects becomes comparable to the energy difference between two previously uncoupled atomic states, an environment-induced interaction between these states appears after tracing over the environment. This interaction has been previously studied for degenerate levels and simple geometries involving infinite, perfectly conducting half-spaces or free space. Here, we generalize these studies by developing a convenient description that permits the analysis of these non-diagonal perturbations to the atomic Hamiltonian in terms of an accurate non-Hermitian Hamiltonian. Applying this theory to a hydrogen atom close to a dielectric nanoparticle, we show strong vacuum-field-induced state mixing that leads to drastic modifications in both the energies and decay rates compared to conventional diagonal perturbation theory. In particular, contrary to the expected Purcell enhancement, we find a surprising decrease of decay rates within a considerable range of atom-nanoparticle separations. Furthermore, we quantify the large degree of mixing of the unperturbed eigenstates due to the non-diagonal perturbation. Our work opens new quantum state manipulation possibilities in emitters with closely spaced energy levels.
Author comments upon resubmission
Please see below for a list of changes. The detailed replies to the referees have been posted in the first submission.
List of changes
- Improvement of explanations and inclusion of references suggested by the referees (more details in the replies).
- The Methods section has been restructured to include part of what was previously in the Appendix, to improve the clarity and exposition.
Current status:
Reports on this Submission
Report
The authors have convincingly replied to the points raised in the report.
Requested changes
Two points, extensively discussed in the reply letter by the authors, are missing in the manuscript : i) the comment on the fact that vacuum-induced interference in free space is negligible in the setting the authors consider ii) the reference to Buchheit et al, PRA (2016), to which the authors referenced in their reply letter when justifying the geometric mean.