Non-ambiguity quantum teleportation protocol

Mario Mastriani
2019 unpublished
Teleportation is the most important and impactful tool in the arsenal of quantum communications with a particular projection on quantum internet. We propose a non-ambiguity alternative to the original teleportation protocol, which completely eliminates the classical-disambiguation-channel used by the original version. Experimental evidence on a quantum platform, via IBM cloud, is provided to demonstrate its performance. Introduction.-Since the publication of the famous paper of Bennett et al
more » ... of Bennett et al [1] , quantum teleportation has gained a central position in the world of quantum communications [2], for all that it represents and implies. This protocol consists of the following steps: (i) the generation and distribution of an entangled pair, in order to build a quantum channel between Alice and Bob. (ii) Alice receives the qubit to be teleported, which when interacting with one of the elements of the entangled pair gives rise to an ambiguous state, that is, a sum in which the original state is involved in four ways at once. (iii) Alice must make a measurement on that state, whose result is absolutely random. This measurement eliminates ambiguity, entanglement and also the original state, otherwise the No-Cloning Theorem [3] would be violated with each teleportation, which we know does not happen under any point of view. (iv) Alice transmits to Bob the result of the detection process via a classical channel, subject to the restrictions of the Einstein-Podolsky-Rosen (EPR) paradox [4] , and therefore of the Special Relativity [5] , which states that nothing can travel faster than light, implying that teleportation as a whole cannot be a process of instant transmission of useful information at all. (v) Bob applies a unit transformation based on the classical bits sent by Alice in order to reconstruct the teleported state. The distribution of the entangled pair from which each teleportation process is inaugurated is also carried out through a classical channel, usually using optical-fiber [6]. This procedure requires repeaters every approximately 50 km due to the optical properties of the fiber, for example: the absorption, the refractive index, and the reduced speed to which the entangled element travels (2/3 of speed of light in vacuum) which would make all teleportation efforts impossible over long distances by land without the use of quantum repeaters [7] . In some cases [8] , an optical link based on a canontelescope pair is used, which does not require repeaters, as long as the eye contact between both elements is maintained. Teleportation uses two classical channels: the first one for the distribution of the entangled pair, and the second one between Alice and Bob to be used in the transmission of the measurement result made by Alice. Consequently, the elimination of this second channel, which represents the central idea of this work, does not imply in the least that the new teleportation protocol is instantaneous as a whole and thus collides with the Special Relativity [5], given that there is still the first classical channel for the distribution of the entangled pair, which gives rise to the quantum channel. Based on what has been said so far, a question automatically arises: what is the impact of the second classical channel in the context of quantum communications? We will answer it with an example. If we use a quantum key distribution (QKD) protocol based on entanglement [9], we will have several channels at once: a first classical channel for the distribution of the entangled pair, which generates the quantum channel on which the public key will be teleported, the quantum channel generated as a result of the previous step, a second classical channel through which Alice transmits to Bob the result of her measurement, and a third classical channel on which the ciphered text travels, and which is encrypted by means of the teleported public key. If this architecture was intervened by a hacker, he would not be able to obtain the key that is teleported through the quantum channel, due to the fact that this channel is inaccessible to him, since an entanglement link is an intrinsically monogamous mean [10] , that is, no third party can intervene without an initial consent of Alice and Bob, or what is the same, if at the time of the generation and distribution of the entangled elements no
doi:10.13140/rg.2.2.34412.51844/3 fatcat:e5czz7yarvdflfugta6yliaepi