Nonlocal memory effects allow perfect teleportation with mixed states

Abstract

One of the most striking consequences of quantum physics is quantum teleportation – the possibility to transfer quantum states over arbitrary distances. Since its theoretical introduction, teleportation has been demonstrated experimentally up to the distance of 143 km. In the original proposal two parties share a maximally entangled quantum state acting as a resource for the teleportation task. If, however, the state is influenced by decoherence, perfect teleportation can no longer be accomplished. Therefore, one of the current major challenges in accomplishing teleportation over long distances is to overcome the limitations imposed by decoherence and the subsequent mixedness of the resource state. Here we show that, in the presence of nonlocal memory effects, perfect quantum teleportation can be achieved even with mixed photon polarisation states. Our results imply that memory effects can be exploited in harnessing noisy quantum systems for quantum communication and that non-Markovianity is a resource for quantum information tasks.

Characterizing non-Markovianity via quantum interferometric power

“…Non-Markovianity is a ubiquitous feature of quantum dynamical maps, and is nowadays recognized as a resource for certain applications of quantum technology, such as metrology, cryptography, and communication [15][16][17][18]. The role of nonMarkovianity in enhancing the robustness of quantum correlations in systems exposed to noisy environments has been studied by means of various quantitative approaches [6,25,28].…”

“…[10]) to the system, a fact which has interesting ramifications from the perspective of quantum information theory [11]. For example, non-Markovian processes have been shown to preserve entanglement [12] in many-body [13] and biomolecular [14] systems, and have been exploited in quantum key distribution [15], enhancing precision in quantum metrology [16], and implementing certain quantum information protocols [17,18]. Non-Markovianity also plays a detrimental role in quantum Darwinism, thus impeding the emergence of classical objectivity from a quantum world [19].…”

“…[1]), there is considerable interest in characterizing and quantifying non-Markovian dynamics and investigating possible applications in scalable quantum technologies [15][16][17][18] that are robust against environment-induced decoherence [13] or phenomena such as entanglement sudden death [21]. Although the concept of non-Markovianity is well established in the classical realm [22], its quantum extension is often riddled with inconsistency and subtle variations.…”

Non-Markovian dynamics in two-qubit dephasing channels with an application to superdense coding

“…Further, first theoretical proposals for exploiting non-Markovianity for quantum information processing and metrology exist [6,20,21]. However, many questions related to the proper quantification of non-Markovianity [10][11][12][13][14][15] and to the exploitation of memory effects as a quantum resource still remain elusive.…”

“…The conventional wisdom is that the noise is harmful for all quantum protocols and isolation from the surroundings is necessary for harnessing the quantum properties. However, recent work has shown, how adding even more noise to the system can actually be beneficial in certain cases [5][6][7][8][9]. Quantum information protocols, such as entanglement swapping, distillation, quantum teleportation, and quantum key distribution have been shown to benefit from correlated noise, when non-Markovian features are present.…”