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Unbounded entanglement production via a dissipative impurity
by Vincenzo Alba
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Submission summary
| Authors (as registered SciPost users): | Vincenzo Alba |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2104.10921v2 (pdf) |
| Date submitted: | 2021-05-14 09:31 |
| Submitted by: | Alba, Vincenzo |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
We investigate the entanglement dynamics in a free-fermion chain initially prepared in a Fermi sea and subjected to localized losses (dissipative impurity). We derive a formula describing the dynamics of the entanglement entropies in the hydrodynamic limit of long times and large intervals. The result depends only on the absorption coefficient of the effective delta potential describing the impurity in the hydrodynamic limit. Genuine dissipation-induced entanglement is certified by the linear growth of the logarithmic negativity. Finally, in the quantum Zeno regime at strong dissipation the entanglement growth is arrested (Zeno entanglement death).
Current status:
Reports on this Submission
Anonymous Report 2 on 2021-7-7 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2104.10921v2, delivered 2021-07-07, doi: 10.21468/SciPost.Report.3199
Report
The paper presents results on entanglement dynamics of a one dimensional chain of fermions with a single dissipative impurity. The problem is thoroughly studied from both numerical and analytical perspectives. The paper is well-organized, clearly written and extensively referenced. The results are of modest interest as the problem exhibits different regimes of entanglement dynamics with a simple physical picture. As a result, I recommend the paper for publication. To strengthen the results, I recommend the author adds additional discussion of the experimental realizations and probes of this phenomena in cold atom or solid-state systems.
Anonymous Report 1 on 2021-6-13 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2104.10921v2, delivered 2021-06-13, doi: 10.21468/SciPost.Report.3057
Strengths
1- Excellent presentation that makes the paper accessible to non-experts.
2- Results help to improve understanding of dissipative systems and potentially open new avenues in the study of entanglement properties.
Weaknesses
1- Some overlap with their previous work, arXiv:2103.05671.
2- No immediate experimental relevance due to focus on quantities that are only useful for theory work.
Report
In this work, the author considers entanglement production by a single dissipative impurity in one-dimensional noninteracting systems. The dissipation is modeled by the Lindblad equation, and information about entanglement and the logarithmic negativity is extracted from the covariance matrix, i.e, two-point fermionic correlators. In the hydrodynamic limit, i.e., at long times and large distances, and starting from the filled Fermi Sea, the author finds that the entanglement entropy increases linearly at short times before saturating to a value that satisfies the volume law. Comparing this behavior to the logarithmic negativity, the author concludes that a certain extent of the entanglement production does not originate from "genuine" entanglement production, but from classical correlations between the two considered subsystems, a result of the system being in a mixed state due to dissipation.
The manuscript is scientifically sound, well-written, and well-structured. The results are presented in a clear and comprehensive way and shine light onto the role of entanglement in dissipative systems. I have only a few remarks the author should consider prior to publication:
1. As motivated in the introduction, the author chose the single-impurity setup as a minimal model to study the effects of dissipation in many-body systems. However, the considered system is noninteracting. I would welcome a comment if the author has an intuition about the effect of interactions.
2. Are there any experimental observables linked to the findings of this paper? While the von-Neumann entropy is notoriously difficult to measure experimentally, I am wondering if there are indirect measures sensitive to the production of entanglement, especially observables that distinguish between "genuine" entanglement and classical entanglement.
3. Related to the former point: The author might want to comment on the distinction between the genuine quantum and classical entanglement.
4. Some of the results overlap with the author's previous work, Ref. [44]. For example, Fig. 2 is already contained in Ref. [44] and the expressions for the covariance matrix are the same. The paper would benefit from disentangling the new contributions from previous work.
Since the paper links entanglement production to dissipation in quantum systems, it has the potential to open a new pathway in the study of entanglement properties of dissipative systems. It is thus suited for publication in SciPost once the author considers above comments.
Requested changes
1- The author should make the distinction between quantum and classical entanglement more transparent (cf. point 3. in the report).
2- It should be more clear which results have already been presented in Ref. [44] and which results are new (cf. point 4. in the report).