Experimental quantum teleportation of propagating microwaves

Abstract

Experimental microwave teleportation brings quantum local area networks within reach by exceeding the no-cloning limit.

Perspectives of microwave quantum key distribution in open-air

“…In experiments, JPAs operating in the GHz regime were shown to reach noise levels on the order of 0.1 added noise photons in the phase-sensitive regime [17]. Presently, the noise performance of JPAs is limited by fabrication imperfections, pump-induced noise [30,31], or higher-order nonlinearities [32]. The displacement operation required by our CV-QKD protocol can be experimentally realized by applying strong coherent drive tones to cryogenic directional couplers [26].…”

Propagating Quantum Microwaves: Towards Applications in Communication and Sensing

“…Interestingly, even devices with only three signal connectors were shown to have a fourth internal port there. 50:50 beam splitters are used to create superpositions or path entanglement between two microwave beams [30], in microwave interferometers [31], for dualpath tomography [32,33], and in the feedforward mechanism of quantum teleportation [15]. In these experiments, often commercial conducting devices (i.e.…”

“…The corresponding microwave device is commonly called a directional coupler and, again, exists in low-loss normal-conducting commercial [36], and laboratory-made superconducting [35] variants. Since its demonstration for propagating microwaves [36], displacement is being routinely used in the feedforward mechanism of microwave continuous-variable quantum communication protocols [15,37].…”

“…In Ref. [15] these are realized using two phase-sensitive amplifiers together with two hybrid rings, and a directional coupler. Bell measurements are required in most implementations of CVs quantum teleportation, as well as in situations where one needs to guarantee a loophole-free Bell test scenario.…”

Broadband continuous variable entanglement generation using Kerr-free Josephson metamaterial

“…The generation of quantum resources -most notably quantum entanglement -is an essential task for the new emerging industry employing quantum technologies. While entanglement in discrete variable represents the standard approach for quantum computing, continuous variable (CV) entanglement between microwave photons is a cornerstone for more robust quantum computing [1][2][3], sensing [4,5], and communication [6][7][8] schemes. However, despite extensive technical developments over the past decades, the generation of continuous-variable entanglement lacks efficiency in the microwave range.…”