Pal, A;
Rashba, EI;
Halperin, BI;
(2015)
Exact CNOT gates with a single nonlocal rotation for quantum-dot qubits.
Physical Review B
, 92
(12)
, Article 125409. 10.1103/physrevb.92.125409.
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Abstract
We investigate capacitively-coupled exchange-only two-qubit quantum gates based on quantum dots. For exchange-only coded qubits electron spin S and its projection Sz are exact quantum numbers. Capacitive coupling between qubits, as distinct from interqubit exchange, preserves these quantum numbers. We prove, both analytically and numerically, that conservation of the spins of individual qubits has a dramatic effect on the performance of two-qubit gates. By varying the level splittings of individual qubits, Ja and Jb, and the interqubit coupling time, t, we can find an infinite number of triples (Ja ,Jb,t) for which the two-qubit entanglement, in combination with appropriate single-qubit rotations, can produce an exact CNOT gate. This statement is true for practically arbitrary magnitude and form of capacitive interqubit coupling. Our findings promise a large decrease in the number of nonlocal (two-qubit) operations in quantum circuits.
| Type: | Article |
|---|---|
| Title: | Exact CNOT gates with a single nonlocal rotation for quantum-dot qubits |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/physrevb.92.125409 |
| Publisher version: | https://doi.org/10.1103/PhysRevB.92.125409 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10084466 |
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