Southwest Quantum Information and Technology

A continuous-variable quantum repeater based on quantum scissors and switched mode-multiplexing

Presenting Author: Kaushik Seshadreesan, University of Arizona
Contributing Author(s): Hari Krovi Saikat Guha

Quantum repeaters are indispensable for high-rate, long-distance quantum communications. The vision of a future quantum internet strongly hinges on realizing quantum repeaters in practice. Numerous repeaters have been proposed for discrete-variable (DV) single-photon-based quantum communications. Continuous variable (CV) encodings over the quadrature degrees of freedom of the electromagnetic field mode offer an attractive alternative. For example, CV transmission systems are easier to integrate with existing optical telecom systems compared to their DV counterparts. Yet, repeaters for CV have remained elusive. We present a novel repeater scheme for entanglement distribution over a lossy bosonic channel based on CV entanglement sources that beats the direct transmission exponential rate-loss tradeoff. The repeater nodes consist of a) two-mode squeezed vacuum (TMSV) state sources for entanglement generation between adjacent nodes, b) the so-called quantum scissors operation to perform nondeterministic noiseless linear amplification of lossy TMSV states for entanglement distillation, c) a layer of switched mode-multiplexing inspired by second-generation DV repeaters—which is the key ingredient, apart from probabilistic entanglement purification that makes DV repeaters work, and d) a non-Gaussian entanglement swap operation to connect adjacent repeater nodes. We report our exact results on the rate-loss envelope achieved by the scheme.

Read this article online: https://arxiv.org/abs/1811.12393, https://journals.aps.org/pra/abstract/10.1103/PhysRevA.100.022315

(Session : from 5:00pm - 7:00pm)