Optimal quantum circuits for general phase estimation.

Journal article

We address the problem of estimating the phase phi given N copies of the phase-rotation gate uphi. We consider, for the first time, the optimization of the general case where the circuit consists of an arbitrary input state, followed by any arrangement of the N phase rotations interspersed with arbitrary quantum operations, and ending with a general measurement. Using the polynomial method, we show that, in all cases where the measure of quality of the estimate phi for phi depends only on the difference phi-phi, the optimal scheme has a very simple fixed form. This implies that an optimal general phase estimation procedure can be found by just optimizing the amplitudes of the initial state.

Authors: van Dam, W; D'Ariano, G; Ekert, A; Macchiavello, C; Mosca, M

• Publication status: Published
• Journal: Physical Review Letters
• Volume: 98
• Issue: 9
• Pages: 090501
• Publication date: 2007-03-01
• DOI: 10.1103/physrevlett.98.090501
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English