Gain maximization in a probabilistic entanglement protocol

Binayak S. Choudhury, Soumen Samanta

The protocols presented in this chapter are probabilistic teleportation protocols in which there are cases of failures with certain probabilities. Probabilistic teleportation schemes of various kinds have been discussed in works like [ 1 , 41 , 45 , 76 , 82 , 85 , 98 , 118 , 135 , 168 , 169 , 180 ]. Generally the quantum resources used in these protocols are not maximally entangled. This is one explanation for the probabilistic nature of these protocols. The justification of studying these protocols is that the generation and preservation of resources for these protocols are less difficult compared to that of those where maximally entangled states are used. Also, there is a class of resumable protocols in which the probabilistic teleportation process can be repeated in the case where the attempt fails in the first place [ 21 , 52 , 104 , 105 ].

Kenneth Goodenough, Stephanie Wehner, David Elkouss

Yuanbo Chen, Yoshihiko Hasegawa

Binayak Samadder Choudhury, Arpan Dhara

Qubits are realized as polarization state of photons or as superpositions of the spin states of electrons. In this paper we propose a scheme to probabilistically teleport an unknown arbitrary two-qubit state using a non-maximally entangled GHZ- like state and a non-maximally Bell state simultaneously as quantum channels. We also discuss the success probability of our scheme. We perform POVM in the protocol which is operationally advantageous. In our scheme we show that the non-maximal quantum resources perform better than maximal resources.

Linden, N, Adrian Kent, Serge Massar

Farzad Ghafari, Josephine Dias, Lynden K. Shalm +4 more

Entanglement distribution is crucial for quantum communication and cryptography but is hindered by channel loss and decoherence. Noiseless linear amplification (NLA) is a probabilistic protocol that supports noiseless amplification without violating the no-cloning theorem, aiding in tasks like entanglement distillation and enhanced metrology. The probabilistic nature of NLA and other quantum repeater elements creates a significant resource overhead, which depends on the success rate of each individual probabilistic step. We experimentally demonstrate a technique to increase NLA success probability while maintaining the amplification gain and the fidelity of the amplified state with a maximally entangled state. We show that symmetrically distributing loss before and after the amplification provides an improved scaling of the success rates of NLA. Our results are a critical step towards scalable quantum repeaters and enable efficient long-distance quantum communication