Uncollapsing of a quantum state in a superconducting phase qubit
Quantum Physics
2015-05-13 v1 Superconductivity
Abstract
We demonstrate in a superconducting qubit the conditional recovery ("uncollapsing") of a quantum state after a partial-collapse measurement. A weak measurement extracts information and results in a non-unitary transformation of the qubit state. However, by adding a rotation and a second partial measurement with the same strength, we erase the extracted information, effectively canceling the effect of both measurements. The fidelity of the state recovery is measured using quantum process tomography and found to be above 70% for partial-collapse strength less than 0.6.
Cite
@article{arxiv.0806.3547,
title = {Uncollapsing of a quantum state in a superconducting phase qubit},
author = {Nadav Katz and Matthew Neeley and M. Ansmann and Radoslaw C. Bialczak and M. Hofheinz and Erik Lucero and A. O'Connell and H. Wang and A. N. Cleland and John M. Martinis and Alexander N. Korotkov},
journal= {arXiv preprint arXiv:0806.3547},
year = {2015}
}
Comments
4 pages, 4 figures