Scalable two- and four-qubit parity measurement with a threshold photon counter

Luke C.G. Govia, Emily J. Pritchett, B. L.T. Plourde, Maxim G. Vavilov, R. McDermott, Frank K. Wilhelm

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Parity measurement is a central tool for many quantum information processing tasks. In this work, we propose a method to directly measure two- and four-qubit parity with low overhead in hardware and software while remaining robust to experimental imperfections. Our scheme relies on dispersive qubit-cavity coupling and photon counting that is sensitive only to intensity; both ingredients are widely realized in many different quantum computing modalities. For a leading technology in quantum computing, superconducting integrated circuits, we analyze the measurement contrast and the back action of the scheme and show that this measurement comes close enough to an ideal parity measurement to be applicable to quantum error correction.

Original languageEnglish (US)
Article number022335
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number2
StatePublished - Aug 14 2015

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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