Optimal Manipulations with Qubits: Universal NOT Gate
| dc.creator | Buzek, V. | |
| dc.creator | Hillery, M. | |
| dc.creator | Werner, R. | |
| dc.date | 1999-01-17 | |
| dc.date.accessioned | 2026-07-07T06:16:05Z | |
| dc.date.available | 2026-07-07T06:16:05Z | |
| dc.description | It is not a problem to complement a classical bit, i.e. to change the value of a bit, a 0 to a 1 and vice versa. This is accomplished by a NOT gate. Complementing a qubit in an unknown state, however, is another matter. We show that this operation cannot be done perfectly. We define the Universal-NOT (U-NOT) gate which out of N identically prepared pure input qubits generates M output qubits in a state which is as close as possible to the perfect complement. This gate can be realized by classical estimation and subsequent re-preparation of complements of the estimated state. Its fidelity is therefore equal to the fidelity F= (N+1)/(N+2) of optimal estimation, and does not depend on the required number of outputs. We also show that when some additional a priori information about the state of input qubit is available, than the fidelity of the quantum NOT gate can be much better than the fidelity of estimation. | |
| dc.description | 4 pages, revtex | |
| dc.identifier | https://arxiv.org/abs/quant-ph/9901053 | |
| dc.identifier | http://arxiv.org/abs/quant-ph/9901053 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/93953 | |
| dc.subject | Quantum Physics | |
| dc.title | Optimal Manipulations with Qubits: Universal NOT Gate | |
| dc.type | text |