TY - JOUR
T1 - Reversal of the weak measurement of a quantum state in a superconducting phase qubit
AU - Katz, Nadav
AU - Neeley, Matthew
AU - Ansmann, M.
AU - Bialczak, Radoslaw C.
AU - Hofheinz, M.
AU - Lucero, Erik
AU - O'Connell, A.
AU - Wang, H.
AU - Cleland, A. N.
AU - Martinis, John M.
AU - Korotkov, Alexander N.
PY - 2008/11/10
Y1 - 2008/11/10
N2 - 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 nonunitary transformation of the qubit state. However, by adding a rotation and a second partial measurement with the same strength, we erase the extracted information, 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.
AB - 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 nonunitary transformation of the qubit state. However, by adding a rotation and a second partial measurement with the same strength, we erase the extracted information, 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.
UR - http://www.scopus.com/inward/record.url?scp=56249131431&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.101.200401
DO - 10.1103/PhysRevLett.101.200401
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AN - SCOPUS:56249131431
SN - 0031-9007
VL - 101
JO - Physical Review Letters
JF - Physical Review Letters
IS - 20
M1 - 200401
ER -