Parametric amplifier for Bell measurement in continuous-variable quantum state teleportation

Abstract

A parametric amplifier is in essence a linear four-port device, which couples and linearly mixes two inputs before amplifying and sending them to two output ports. Here we show that for quadrature-phase amplitudes, a parametric amplifier can replace beam splitters to play the role of the mixer. We apply this idea to a continuous-variable quantum state teleportation scheme in which a parametric amplifier replaces a beam splitter in the Bell measurement. We show that this scheme is loss tolerant in the Bell measurement process and thus demonstrate the advantage of the parametric amplifier over the beam splitter in the applications in quantum measurement.