Optimal State Estimation of Pure Qubits on Circles

• 来源期刊: 理论物理通讯(英文版)
• 年，卷（期）: 2008,（6）
• 页码范围: 1477-1482
• 页数: 6页
• 语种: 英文

摘要

We consider the problem of state estimation of qubits chosen from circles. It is shown that any qubit encoded in pairs chosen from a fixed circle parallel to the x-y equator with different phases contains the same information. We also investigate the problem of state estimation of qubits from three circles. The optimal estimation fidelity is derived.