Undoing a weak quantum measurement of a solid-state qubit
Undoing a weak quantum measurement of a solid-state qubit
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DOI：
10.1103/physrevlett.97.166805
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发表时间：
2006-10-20
影响因子：
8.6
通讯作者：
Jordan, Andrew N.
中科院分区：
文献类型：
--
作者：
Korotkov, Alexander N.;Jordan, Andrew N.
我们提出了一个实验，证明了一个固态量子比特的弱连续测量的撤销，使任何未知的初始状态被完全恢复。由于量子测量的非幺正性质，撤销过程只有有限的成功概率，尽管它伴随着一个明确的实验指示，表明撤销是否成功。成功的概率随着测量强度的增加而降低，对于传统的投影测量达到零。测量撤销（“量子撤销”）可以被解释为一种量子擦除器，其中从第一次测量获得的信息被第二次测量擦除，这是撤销过程的重要部分。实验可以使用量子点（电荷）或超导（相位）量子比特来实现。
We propose an experiment which demonstrates the undoing of a weak continuous measurement of a solid-state qubit, so that any unknown initial state is fully restored. The undoing procedure has only a finite probability of success because of the nonunitary nature of quantum measurement, though it is accompanied by a clear experimental indication of whether or not the undoing has been successful. The probability of success decreases with increasing strength of the measurement, reaching zero for a traditional projective measurement. Measurement undoing ("quantum undemolition") may be interpreted as a kind of quantum eraser, in which the information obtained from the first measurement is erased by the second measurement, which is an essential part of the undoing procedure. The experiment can be realized using quantum dot (charge) or superconducting (phase) qubits.