Reversal of the weak measurement of a quantum state in a superconducting phase qubit

Nadav Katz; Matthew Neeley; M. Ansmann; Radoslaw C. Bialczak; M. Hofheinz; Erik Lucero; A. O'Connell; H. Wang; A. N. Cleland; John M. Martinis; Alexander N. Korotkov

doi:10.1103/PhysRevLett.101.200401

Reversal of the weak measurement of a quantum state in a superconducting phase qubit

Nadav Katz^*, Matthew Neeley, M. Ansmann, Radoslaw C. Bialczak, M. Hofheinz, Erik Lucero, A. O'Connell, H. Wang, A. N. Cleland, John M. Martinis, Alexander N. Korotkov

^*Corresponding author for this work

Racah Institute of Physics

Research output: Contribution to journal › Article › peer-review

222 Scopus citations

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 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.

Original language	American English
Article number	200401
Journal	Physical Review Letters
Volume	101
Issue number	20
DOIs	https://doi.org/10.1103/PhysRevLett.101.200401
State	Published - 10 Nov 2008

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title = "Reversal of the weak measurement of a quantum state in a superconducting phase qubit",

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 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.",

author = "Nadav Katz and Matthew Neeley and M. Ansmann and Bialczak, {Radoslaw C.} and M. Hofheinz and Erik Lucero and A. O'Connell and H. Wang and Cleland, {A. N.} and Martinis, {John M.} and Korotkov, {Alexander N.}",

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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.

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U2 - 10.1103/PhysRevLett.101.200401

DO - 10.1103/PhysRevLett.101.200401

M3 - Article

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SN - 0031-9007

VL - 101

JO - Physical Review Letters

JF - Physical Review Letters

IS - 20

M1 - 200401

ER -

Reversal of the weak measurement of a quantum state in a superconducting phase qubit

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