Cryptography using two-mode quantum mechanically squeezed optical pulses

Madison Durrance, Zach Galberd, Abbey Savage +2 more

Pascal Neveu, J Clarke, M R Vanner +1 more

Abstract We propose a protocol how to generate and verify bipartite Gaussian entanglement between two mechanical modes coupled to a single optical cavity, by means of short optical pulses and measurement. Our protocol requires neither the resolved sideband regime, nor low thermal phonon occupancy, and allows the generation and verification of quantum entanglement in less than a mechanical period of motion. Entanglement is generated via effective two-mode mechanical squeezing through conditioning position measurements. We study the robustness of entanglement to experimental deviations in mechanical frequencies and optomechanical coupling rates.

Mark C. Kuzyk, Hailin Wang

A pulsed scheme for generating two-mode squeezed light via the coupling of two optical modes to a mechanical oscillator in an optomechanical system is proposed. The scheme can be robust against thermal mechanical motion.

Eleni Diamanti

Alberto M. Marino, Carlos R. Stroud

T. Eberle, Vitus Händchen, R. Schnabel

Abstract: Continuous variable entanglement is a fundamental resource for many quantum information tasks. Important protocols like superac-tivation of zero-capacity channels and finite-size quantum cryptography that provides security against most general attacks, require about 10 dB two-mode squeezing. Additionally, stable phase control mechanisms are necessary but are difficult to achieve because the total amount of optical loss to the entangled beams needs to be small. Here, we experimentally demonstrate a control scheme for two-mode squeezed vacuum states at the telecommunication wavelength of 1550 nm. Our states exhibited an Einstein-Podolsky-Rosen covariance product of 0.0309 ± 0.0002, where 1 is the critical value, and a Duan inseparability value of 0.360±0.001, where 4 is the critical value. The latter corresponds to 10.45 ± 0.01dB which reflects the average non-classical noise suppression of the two squeezed vacuum states used to generate the entanglement. With the results of this