Protecting quantum information with entanglement and noisy optical modes

Abstract

We incorporate active and passive quantum error-correcting techniques to protect a set of optical information modes of a continuous-variable quantum information system. Our method uses ancilla modes, entangled modes, and gauge modes (modes in a mixed state) to help correct errors on a set of information modes. A linear-optical encoding circuit consisting of offline squeezers, passive optical devices, feedforward control, conditional modulation, and homodyne measurements performs the encoding. The result is that we extend the entanglement-assisted operator stabilizer formalism for discrete variables to continuous-variable quantum information processing.Keywords Operator quantum error correction · Stabilizer formalism · Entanglement-assisted quantum error correction · Continuous variables · Linear-optical quantum computation PACS 03.67.-a · 03.67.Hk · 42.50.Dv

Entanglement-assisted quantum convolutional coding

“…Several references provide a review of this technique and generalizations of the basic theory to block [39] and convolutional [38] entanglement distillation protocols, continuous-variable codes [40], and entanglement-assisted operator codes for discrete-variable [13,14] and continuous-variable systems [41].…”

“…The entanglement-assisted stabilizer formalism is a significant extension of the standard stabilizer formalism that incorporates shared entanglement as a resource for encoding [21,22]. Several references provide a review of this technique and generalizations of the basic theory to block [39] and convolutional [38] entanglement distillation protocols, continuous-variable codes [40], and entanglement-assisted operator codes for discrete-variable [13,14] and continuous-variable systems [41].…”