Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity
Operator controllability refers to the ability to implement an arbitrary unitary in SU(N) and is a prerequisite for universal quantum computing. Controllability tests can be used in the design of quantum devices to reduce the number of external controls. Their practical use is hampered, however, by...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
2023-12-01
|
| Series: | Quantum |
| Online Access: | https://quantum-journal.org/papers/q-2023-12-21-1214/pdf/ |
| _version_ | 1797383245602488320 |
|---|---|
| author | Fernando Gago-Encinas Tobias Hartung Daniel M. Reich Karl Jansen Christiane P. Koch |
| author_facet | Fernando Gago-Encinas Tobias Hartung Daniel M. Reich Karl Jansen Christiane P. Koch |
| author_sort | Fernando Gago-Encinas |
| collection | DOAJ |
| description | Operator controllability refers to the ability to implement an arbitrary unitary in SU(N) and is a prerequisite for universal quantum computing. Controllability tests can be used in the design of quantum devices to reduce the number of external controls. Their practical use is hampered, however, by the exponential scaling of their numerical effort with the number of qubits. Here, we devise a hybrid quantum-classical algorithm based on a parametrized quantum circuit. We show that controllability is linked to the number of independent parameters, which can be obtained by dimensional expressivity analysis. We exemplify the application of the algorithm to qubit arrays with nearest-neighbour couplings and local controls. Our work provides a systematic approach to the resource-efficient design of quantum chips. |
| first_indexed | 2024-03-08T21:18:09Z |
| format | Article |
| id | doaj.art-34018d94ba72492a9301f019baef03cc |
| institution | Directory Open Access Journal |
| issn | 2521-327X |
| language | English |
| last_indexed | 2024-03-08T21:18:09Z |
| publishDate | 2023-12-01 |
| publisher | Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften |
| record_format | Article |
| series | Quantum |
| spelling | doaj.art-34018d94ba72492a9301f019baef03cc2023-12-21T12:35:05ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2023-12-017121410.22331/q-2023-12-21-121410.22331/q-2023-12-21-1214Determining the ability for universal quantum computing: Testing controllability via dimensional expressivityFernando Gago-EncinasTobias HartungDaniel M. ReichKarl JansenChristiane P. KochOperator controllability refers to the ability to implement an arbitrary unitary in SU(N) and is a prerequisite for universal quantum computing. Controllability tests can be used in the design of quantum devices to reduce the number of external controls. Their practical use is hampered, however, by the exponential scaling of their numerical effort with the number of qubits. Here, we devise a hybrid quantum-classical algorithm based on a parametrized quantum circuit. We show that controllability is linked to the number of independent parameters, which can be obtained by dimensional expressivity analysis. We exemplify the application of the algorithm to qubit arrays with nearest-neighbour couplings and local controls. Our work provides a systematic approach to the resource-efficient design of quantum chips.https://quantum-journal.org/papers/q-2023-12-21-1214/pdf/ |
| spellingShingle | Fernando Gago-Encinas Tobias Hartung Daniel M. Reich Karl Jansen Christiane P. Koch Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity Quantum |
| title | Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity |
| title_full | Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity |
| title_fullStr | Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity |
| title_full_unstemmed | Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity |
| title_short | Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity |
| title_sort | determining the ability for universal quantum computing testing controllability via dimensional expressivity |
| url | https://quantum-journal.org/papers/q-2023-12-21-1214/pdf/ |
| work_keys_str_mv | AT fernandogagoencinas determiningtheabilityforuniversalquantumcomputingtestingcontrollabilityviadimensionalexpressivity AT tobiashartung determiningtheabilityforuniversalquantumcomputingtestingcontrollabilityviadimensionalexpressivity AT danielmreich determiningtheabilityforuniversalquantumcomputingtestingcontrollabilityviadimensionalexpressivity AT karljansen determiningtheabilityforuniversalquantumcomputingtestingcontrollabilityviadimensionalexpressivity AT christianepkoch determiningtheabilityforuniversalquantumcomputingtestingcontrollabilityviadimensionalexpressivity |