Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity

Bibliographic Details
Title: Determining the ability for universal quantum computing: Testing controllability via dimensional expressivity
Authors: Gago-Encinas, Fernando, Hartung, Tobias, Reich, Daniel M., Jansen, Karl, Koch, Christiane P.
Source: Quantum 7, 1214 (2023)
Publication Year: 2023
Collection: Quantum Physics
Subject Terms: Quantum Physics
More Details: 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.
Comment: 20 pages, 9 figures, 2 tables, 2 algorithms
Document Type: Working Paper
DOI: 10.22331/q-2023-12-21-1214
Access URL: http://arxiv.org/abs/2308.00606
Accession Number: edsarx.2308.00606
Database: arXiv
More Details
DOI:10.22331/q-2023-12-21-1214