Optimal quantum operations at zero energy cost
Quantum technologies are developing powerful tools to generate and manipulate coherent superpositions of different energy levels. Envisaging a new generation of energy-efficient quantum devices, here we explore how coherence can be manipulated without exchanging energy with the surrounding environme...
| Main Authors: | , |
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| Format: | Journal article |
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American Physical Society
2017
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| _version_ | 1826286982925385728 |
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| author | Chiribella, G Yang, Y |
| author_facet | Chiribella, G Yang, Y |
| author_sort | Chiribella, G |
| collection | OXFORD |
| description | Quantum technologies are developing powerful tools to generate and manipulate coherent superpositions of different energy levels. Envisaging a new generation of energy-efficient quantum devices, here we explore how coherence can be manipulated without exchanging energy with the surrounding environment. We start from the task of converting a coherent superposition of energy eigenstates into another. We identify the optimal energy-preserving operations, both in the deterministic and in the probabilistic scenario. We then design a recursive protocol, wherein a branching sequence of energy-preserving filters increases the probability of success while reaching maximum fidelity at each iteration. Building on the recursive protocol, we construct efficient approximations of the optimal fidelity-probability trade-off, by taking coherent superpositions of the different branches generated by probabilistic filtering. The benefits of this construction are illustrated in applications to quantum metrology, quantum cloning, coherent state amplification, and ancilla-driven computation. Finally, we extend our results to transitions where the input state is generally mixed and we apply our findings to the task of purifying quantum coherence. |
| first_indexed | 2024-03-07T01:51:47Z |
| format | Journal article |
| id | oxford-uuid:9a564af5-4e0c-4dee-9147-9236b1a66325 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:51:47Z |
| publishDate | 2017 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | oxford-uuid:9a564af5-4e0c-4dee-9147-9236b1a663252022-03-27T00:20:39ZOptimal quantum operations at zero energy costJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:9a564af5-4e0c-4dee-9147-9236b1a66325Symplectic Elements at OxfordAmerican Physical Society2017Chiribella, GYang, YQuantum technologies are developing powerful tools to generate and manipulate coherent superpositions of different energy levels. Envisaging a new generation of energy-efficient quantum devices, here we explore how coherence can be manipulated without exchanging energy with the surrounding environment. We start from the task of converting a coherent superposition of energy eigenstates into another. We identify the optimal energy-preserving operations, both in the deterministic and in the probabilistic scenario. We then design a recursive protocol, wherein a branching sequence of energy-preserving filters increases the probability of success while reaching maximum fidelity at each iteration. Building on the recursive protocol, we construct efficient approximations of the optimal fidelity-probability trade-off, by taking coherent superpositions of the different branches generated by probabilistic filtering. The benefits of this construction are illustrated in applications to quantum metrology, quantum cloning, coherent state amplification, and ancilla-driven computation. Finally, we extend our results to transitions where the input state is generally mixed and we apply our findings to the task of purifying quantum coherence. |
| spellingShingle | Chiribella, G Yang, Y Optimal quantum operations at zero energy cost |
| title | Optimal quantum operations at zero energy cost |
| title_full | Optimal quantum operations at zero energy cost |
| title_fullStr | Optimal quantum operations at zero energy cost |
| title_full_unstemmed | Optimal quantum operations at zero energy cost |
| title_short | Optimal quantum operations at zero energy cost |
| title_sort | optimal quantum operations at zero energy cost |
| work_keys_str_mv | AT chiribellag optimalquantumoperationsatzeroenergycost AT yangy optimalquantumoperationsatzeroenergycost |