Scientific Reports (Nov 2021)

Proposal for a destructive controlled phase gate using linear optics

  • S. U. Shringarpure,
  • J. D. Franson

DOI
https://doi.org/10.1038/s41598-021-01384-2
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 8

Abstract

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Abstract Knill, Laflamme, and Milburn showed that linear optics techniques could be used to implement a nonlinear sign gate. They also showed that two of their nonlinear sign gates could be combined to implement a controlled-phase gate, which has a number of practical applications. Here we describe an alternative implementation of a controlled-phase gate for a single-rail target qubit that only requires the use of a single nonlinear sign gate. This gives a much higher average probability of success when the required ancilla photons are generated using heralding techniques. This implementation of a controlled-phase gate destroys the control qubit, which is acceptable in a number of applications where the control qubit would have been destroyed in any event, such as in a postselection process.