Certifying quantum teleportation experimentally

Neng-Fei Gong, Tie-Jun Wang

Xiao‐Min Hu, Chao Zhang, Chengjie Zhang +5 more

How to properly certify the quantum function of a quantum process (device) is one of the key problems in quantum information science, particularly, for a function beyond its classical counterpart. To properly verify quantum teleportation is a critical task because of its fundamental roles in quantum communication and quantum computation. Here, we experimentally certified nonclassical quantum teleportation with one setting by the random teleportation robustness introduced by [Phys. Rev. Lett. 119, 110501 (2017)]. Our results show that the random teleportation robustness is experimentally convenient and powerful for verifying nonclassical teleportation and entanglement.

Dik Bouwmeester, Jian-Wei Pan, Klaus Mattle +3 more

Stefano Pirandola, Jens Eisert, Christian Weedbrook +2 more

Gonzalo Carvacho, Francesco Andreoli, Luca Santodonato +6 more

Quantum teleportation establishes a correspondence between an entangled state shared by two separate parties that can communicate classically and the presence of a quantum channel connecting the two parties. The standard benchmark for quantum teleportation, based on the average fidelity between the input and output states, indicates that some entangled states do not lead to channels which can be certified to be quantum. It was recently shown that if one considers a finer-grained witness, then all entangled states can be certified to produce a nonclassical teleportation channel. Here we experimentally demonstrate a complete characterization of a new family of such witnesses, of the type proposed in Phys. Rev. Lett. 119, 110501 (2017)PRLTAO0031-900710.1103/PhysRevLett.119.110501 under different conditions of noise. We report nonclassical teleportation using quantum states that cannot achieve average fidelity of teleportation above the classical limit. We further use the violation of these witnesses to estimate the negativity of the shared state. Our results have fundamental implications in quantum information protocols and may also lead to new applications and quality certification of quantum technologies.

Daniel Cavalcanti, Paul Skrzypczyk, Ivan Šupić

Quantum teleportation, the process by which Alice can transfer an unknown quantum state to Bob by using preshared entanglement and classical communication, is one of the cornerstones of quantum information. The standard benchmark for certifying quantum teleportation consists in surpassing the maximum average fidelity between the teleported and the target states that can be achieved classically. According to this figure of merit, not all entangled states are useful for teleportation. Here we propose a new benchmark that uses the full information available in a teleportation experiment and prove that all entangled states can implement a quantum channel which cannot be reproduced classically. We introduce the idea of nonclassical teleportation witness to certify if a teleportation experiment is genuinely quantum and discuss how to quantify this phenomenon. Our work provides new techniques for studying teleportation that can be immediately applied to certify the quality of quantum technologies.