Projective measurement onto arbitrary superposition of weak coherent state bases

Shuro Izumi*, Masahiro Takeoka, Kentaro Wakui, Mikio Fujiwara, Kazuhiro Ema, Masahide Sasaki

*Corresponding author for this work

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Abstract

One of the peculiar features in quantum mechanics is that a superposition of macroscopically distinct states can exist. In optical system, this is highlighted by a superposition of coherent states (SCS), i.e. a superposition of classical states. Recently this highly nontrivial quantum state and its variant have been demonstrated experimentally. Here we demonstrate the superposition of coherent states in quantum measurement which is also a key concept in quantum mechanics. More precisely, we propose and implement a projection measurement onto an arbitrary superposition of two weak coherent states in optical system. The measurement operators are reconstructed experimentally by a novel quantum detector tomography protocol. Our device is realized by combining the displacement operation and photon counting, well established technologies, and thus has implications in various optical quantum information processing applications.
Original languageEnglish
Article number2999
JournalScientific Reports
Volume8
Issue number1
Number of pages8
ISSN2045-2322
DOIs
Publication statusPublished - 2018

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