Generation of large-amplitude coherent-state superposition via ancilla-assisted photon subtraction.
We propose and demonstrate a novel method to generate a large-amplitude coherent-state superposition (CSS) via ancilla-assisted photon subtraction. The ancillary mode induces quantum interference of indistinguishable processes in an extended space, widening the controllability of quantum superposition at the conditional output. We demonstrate this by a simple time-separated two-photon subtraction from continuous wave squeezed light. We observe the largest CSS of traveling light ever reported without correcting any imperfections, which will enable various quantum information applications with CSS states.
Takahashi
Hiroki
H
National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795, Japan.
Wakui
Kentaro
K
Suzuki
Shigenari
S
Takeoka
Masahiro
M
Hayasaka
Kazuhiro
K
Furusawa
Akira
A
Sasaki
Masahide
M