Nonreciprocal Synchronization of Active Quantum Spins
Active agents are capable of exerting nonreciprocal forces upon one another. For instance, one agent, say A, may attract another agent B while B repels A. These antagonistic nonreciprocal interactions have been extensively studied in classical systems, revealing a wealth of exciting phenomena such a...
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| Format: | Article |
| Language: | English |
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American Physical Society
2025-01-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.15.011010 |
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| _version_ | 1832592142577434624 |
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| author | Tobias Nadolny Christoph Bruder Matteo Brunelli |
| author_facet | Tobias Nadolny Christoph Bruder Matteo Brunelli |
| author_sort | Tobias Nadolny |
| collection | DOAJ |
| description | Active agents are capable of exerting nonreciprocal forces upon one another. For instance, one agent, say A, may attract another agent B while B repels A. These antagonistic nonreciprocal interactions have been extensively studied in classical systems, revealing a wealth of exciting phenomena such as novel phase transitions and traveling-wave states. Whether these phenomena can originate in quantum many-body systems is an open issue, and proposals for their realization are lacking. In this work, we present a model of two species of quantum spins that interact in an antagonistic nonreciprocal way of the attraction-repulsion type. We propose an implementation based on two atomic ensembles coupled via chiral waveguides featuring both braided and nonbraided geometries. The spins are active due to the presence of local gain, which allows them to synchronize. In the thermodynamic limit, we show that nonreciprocal interactions result in a nonreciprocal phase transition to time-crystalline traveling-wave states, associated with spontaneous breaking of parity-time symmetry. We establish how this symmetry emerges from the microscopic quantum model. For a finite number of spins, signatures of the time-crystal phase can still be identified by inspecting equal-time or two-time correlation functions. Remarkably, continuous monitoring of the output field of the waveguides induces a quantum traveling-wave state: a time-crystalline state of a finite-size quantum system, in which parity-time symmetry is spontaneously broken. Our work lays the foundation to explore nonreciprocal interactions in active quantum matter. |
| format | Article |
| id | doaj-art-4dafc8e6b02442a2bce5caae22a0f070 |
| institution | Kabale University |
| issn | 2160-3308 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj-art-4dafc8e6b02442a2bce5caae22a0f0702025-01-21T15:05:16ZengAmerican Physical SocietyPhysical Review X2160-33082025-01-0115101101010.1103/PhysRevX.15.011010Nonreciprocal Synchronization of Active Quantum SpinsTobias NadolnyChristoph BruderMatteo BrunelliActive agents are capable of exerting nonreciprocal forces upon one another. For instance, one agent, say A, may attract another agent B while B repels A. These antagonistic nonreciprocal interactions have been extensively studied in classical systems, revealing a wealth of exciting phenomena such as novel phase transitions and traveling-wave states. Whether these phenomena can originate in quantum many-body systems is an open issue, and proposals for their realization are lacking. In this work, we present a model of two species of quantum spins that interact in an antagonistic nonreciprocal way of the attraction-repulsion type. We propose an implementation based on two atomic ensembles coupled via chiral waveguides featuring both braided and nonbraided geometries. The spins are active due to the presence of local gain, which allows them to synchronize. In the thermodynamic limit, we show that nonreciprocal interactions result in a nonreciprocal phase transition to time-crystalline traveling-wave states, associated with spontaneous breaking of parity-time symmetry. We establish how this symmetry emerges from the microscopic quantum model. For a finite number of spins, signatures of the time-crystal phase can still be identified by inspecting equal-time or two-time correlation functions. Remarkably, continuous monitoring of the output field of the waveguides induces a quantum traveling-wave state: a time-crystalline state of a finite-size quantum system, in which parity-time symmetry is spontaneously broken. Our work lays the foundation to explore nonreciprocal interactions in active quantum matter.http://doi.org/10.1103/PhysRevX.15.011010 |
| spellingShingle | Tobias Nadolny Christoph Bruder Matteo Brunelli Nonreciprocal Synchronization of Active Quantum Spins Physical Review X |
| title | Nonreciprocal Synchronization of Active Quantum Spins |
| title_full | Nonreciprocal Synchronization of Active Quantum Spins |
| title_fullStr | Nonreciprocal Synchronization of Active Quantum Spins |
| title_full_unstemmed | Nonreciprocal Synchronization of Active Quantum Spins |
| title_short | Nonreciprocal Synchronization of Active Quantum Spins |
| title_sort | nonreciprocal synchronization of active quantum spins |
| url | http://doi.org/10.1103/PhysRevX.15.011010 |
| work_keys_str_mv | AT tobiasnadolny nonreciprocalsynchronizationofactivequantumspins AT christophbruder nonreciprocalsynchronizationofactivequantumspins AT matteobrunelli nonreciprocalsynchronizationofactivequantumspins |