Mixed-state learnability transitions in monitored noisy quantum dynamics
Fuente:
arXiv
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866914335614304256 |
|---|---|
| author | Singh, Hansveer Vasseur, Romain Potter, Andrew C. Gopalakrishnan, Sarang |
| author_facet | Singh, Hansveer Vasseur, Romain Potter, Andrew C. Gopalakrishnan, Sarang |
| contents | We consider learnability transitions in monitored quantum systems that undergo noisy evolution, subject to a global strong symmetry -- i.e., in addition to the measuring apparatus, the system can interact with an unobserved environment, but does not exchange charge with it. As in the pure-state setting, we find two information-theoretic phases -- a sharp (fuzzy) phase in which an eavesdropper can rapidly (slowly) learn the symmetry charge. However, because the dynamics is noisy, both phases can be simulated efficiently using tensor networks. Indeed, even when the true dynamics is unitary, introducing noise by hand allows an eavesdropper to efficiently learn the symmetry charge from local measurements, as we demonstrate. We identify the fuzzy phase in this setting as a mixed-state phase that exhibits spontaneous strong-to-weak symmetry breaking. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_10308 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Mixed-state learnability transitions in monitored noisy quantum dynamics Singh, Hansveer Vasseur, Romain Potter, Andrew C. Gopalakrishnan, Sarang Quantum Physics Statistical Mechanics We consider learnability transitions in monitored quantum systems that undergo noisy evolution, subject to a global strong symmetry -- i.e., in addition to the measuring apparatus, the system can interact with an unobserved environment, but does not exchange charge with it. As in the pure-state setting, we find two information-theoretic phases -- a sharp (fuzzy) phase in which an eavesdropper can rapidly (slowly) learn the symmetry charge. However, because the dynamics is noisy, both phases can be simulated efficiently using tensor networks. Indeed, even when the true dynamics is unitary, introducing noise by hand allows an eavesdropper to efficiently learn the symmetry charge from local measurements, as we demonstrate. We identify the fuzzy phase in this setting as a mixed-state phase that exhibits spontaneous strong-to-weak symmetry breaking. |
| title | Mixed-state learnability transitions in monitored noisy quantum dynamics |
| topic | Quantum Physics Statistical Mechanics |
| url | https://arxiv.org/abs/2503.10308 |