SciPost Submission Page
Competition of light- and phonon-dressing in microwave-dressed Bose polarons
by Georgios M. Koutentakis, Simeon I. Mistakidis, Fabian Grusdt, Hossein R. Sadeghpour, Peter Schmelcher
Submission summary
| Authors (as registered SciPost users): | Fabian Grusdt · Georgios M. Koutentakis |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2504.03411v1 (pdf) |
| Date submitted: | April 8, 2025, 10:50 p.m. |
| Submitted by: | Koutentakis, Georgios M. |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
We theoretically investigate the stationary properties of a spin-1/2 impurity immersed in a one-dimensional confined Bose gas. In particular, we consider coherently coupled spin states with an external field, where only one spin component interacts with the bath, enabling light dressing of the impurity and spin-dependent bath-impurity interactions. Through detailed comparisons with ab-initio many-body simulations, we demonstrate that the composite system is accurately described by a simplified effective Hamiltonian. The latter builds upon previously developed effective potential approaches in the absence of light dressing. It can be used to extract the impurity energy, residue, effective mass, and anharmonicity induced by the phononic dressing. Light-dressing is shown to increase the polaron residue, undressing the impurity from phononic excitations because of strong spin coupling. For strong repulsions-previously shown to trigger dynamical Bose polaron decay (a phenomenon called temporal orthogonality catastrophe), it is explained that strong light-dressing stabilizes a repulsive polaron-dressed state. Our results establish the effective Hamiltonian framework as a powerful tool for exploring strongly interacting polaronic systems and corroborating forthcoming experimental realizations.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Current status:
Reports on this Submission
Strengths
- Comprehensive theoretical analysis using different methods
- Interesting problem
Weaknesses
- Very long paper and sometimes confusing (or erroneous) notation
- Unclear what the main results and why they are interesting
Report
The topic of the manuscript is timely and interesting since there is presently a significant research activity exploring the physics of mobile impurities in a quantum degenerate environment. Before the paper is published, I however request the authors to consider the points below.
Requested changes
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Is it really correct to speak about polarons in 1D? The existence of quasiparticles in 1D is not obvious. For instance, in arXiv:2504.17558 it was shown that a mobile impurity in a Fermi gas has zero quasiparticle residue. I presume the same holds for an impurity in a Bose gas? I suggest the authors discuss this in the manuscript.
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In Fig. 1, the case of zero Rabi coupling is labeled as a solid black line. However, I think the line is dashed.
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I don't understand the formula for the residue Z given in the fourth line of page 8. Doesn't this formula give zero?
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The authors in general find very small deviations between the exact numerical calculations and the approximate theories. It would make the paper more interesting and suitable for SciPost, if the authors explore if this holds also for stronger impurity-boson interactions - especially on the attractive side where there is no phase separation. In particular, the authors state on page 14 that the effective Hamiltonian is accurate for g_BI<g_BB. Is this obvious for large and negative g_IB?
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On page 18, the authors state that detunings \Delta<-3\omega_B are suitable for studying the repulsive polaron. This probably depends on the value of g_IB. Should the condition involve the polaron energy instead?
Recommendation
Publish (meets expectations and criteria for this Journal)
Report #1 by Arturo Camacho Guardian (Referee 1) on 2025-5-18 (Invited Report)
Strengths
- Solid theoretical framework which has extensively been used by the authors.
- Timely problem and interesting problem.
- Exhaustive study of their model.
Weaknesses
- Some aspects of the presentation can be improved.
- Not entirely clear what is the "theoretical/numerical " novelty of this study.
Report
The topic of the manuscript is timely, the methodology robust, the results interesting and overall the manuscript is well-written. Before giving my final recommendations please find below my requested changes and questions.
Requested changes
- Some figures are quite crowded and difficult to interpret. For instance, in Fig. 1(a) and (b), it is hard to distinguish the differences between the plots, understand the role of N=2, and determine whether impurity-impurity interactions are present. The arrows in Fig. 1(b) are not particularly useful and add to the confusion.
- Perhaps I missed something, but one of the main conclusions seems to be that the residue increases with light-dressing. However, I couldn't find a figure that clearly demonstrates this. In fact, most of the results show a residue close to 1, so I struggle to understand how the impurity is dressed at all. (see next point)
- I also found the notation somewhat confusing, particularly in Section 3. My understanding is that the system can be described by a simple two-level model consisting of the non-interacting impurity state and the polaron state (in the limit of vanishing light-matter coupling). These two states then couple to the light field and hybridize. If this is correct, why is the residue not simply given by Eq. (7)? 4.My main concern relates to the novelty and significance of the results, which connects to the previous comment. It appears that the light-matter coupling can be described by a simple two-level system, and that, in the explored regime, no particularly intriguing phenomena emerge. From what I understand, the main observable effect comes from Fig. 1(d), where there is a “drop” in S from 0.5 to 0.492—this seems rather small. Could the authors comment on the physical relevance of such a small difference? Is it experimentally observable? Also, did the use of the ML-MCTDHX method require any non-trivial extensions for this study?
- On page 13, the authors refer to the 1/k^4 scaling related to Tan’s contact to support their claims. I don’t fully understand this argument. As far as I know (though I may be mistaken), this scaling is a high-energy feature usually captured only with non-perturbative methods. While I agree that ML-MCTDHX is an ab initio approach, it is unclear to me how it could include the relevant two-body physics (e.g., Feshbach resonance physics) necessary to reproduce the 1/k^4 scaling. Minor comments: On page 2, second paragraph: it reads quasiparticletheories — a space is missing. On page 2, the authors cite Refs. [69–82] as related to their previous work. Since this manuscript builds on those studies, could the authors clarify the relevance of each reference for the present work? They begin to do this on page 3, but the discussion could be made more explicit.
Recommendation
Publish (easily meets expectations and criteria for this Journal; among top 50%)