Improving fidelity of quantum cloning via the Dzyaloshinskii-Moriya interaction in a spin network

Abstract

We investigate the effect of the Dzyaloshinskii-Moriya (DM) interaction on the fidelity of the 1 → M phasecovariant cloning machine (PCCM) in a spin star network. The results of numerical calculation show that the DM interaction can further improve the cloning fidelity to reach the optimal value. Furthermore, the physical mechanism is investigated by analyzing the effect of the DM interaction on the populations of the qubits. It is shown that the DM interaction leads to the populations of states |1 |S(M,k + 1) and |1 |S(M,k) [or |0 |S(M,k) and |0 |S(M,k − 1) ] simultaneously reaching the maximum or minimum value periodically, where the first ket |i (i ∈ 0,1) in |i |S(M,k) denotes the state of central spin with |0 and |1 representing the spin-up and spin-down states, respectively, while the second ket |S(M,k) denotes the state of outer spins with M being the total number of outer spins and k the number of up spins. At these extreme overlapping points of two states, the fidelity of quantum cloning can reach optimal value. Finally the forms of these two different 1 → M optimal cloning transformations are presented.

Quantum cloning machines and their implementation in physical systems

“…Analogously, in Refs. [110] and [111], the quantum cloning process is greatly simplified, benefitting from characteristics of the physical system. Of course, each scheme has the advantages of the adopted platform.…”

“…On one hand, designers have tried to build scalable QCMs. [68,69,110,111] On the other hand, the designers have tried to build general QCMs that can implement several types of quantum cloning processes. [74][75][76]88,89,105] As is well known, the scalability of QCM is tied to the conservation of quantum information and quantum state estimation, so a general QCM has some advantages for being used in quantum communication and computation processes.…”

Quantum simulation of the central spin model with a Rydberg atom and polar molecules in optical tweezers

“…In that case the model is commonly applied to analyze the decoherence of the qubit caused by its coupling to a disordered environment. Alternately, central spin models can be used to represent networks of qubits connected in a "spin star" topology [25][26][27][28][29][30][31][32], which have been analyzed for applications such as secure remote quantum computation [33], qubit state transfer [34,35], approximate quantum state cloning [36], implementing quantum algorithms [37], or generating entangled states for use in quantum communication [38].…”

Dynamical pairwise entanglement and two-point correlations in the three-ligand spin-star structure

“…Also due to their strong non-Markovian behavior, spin-star networks are an excellent models to study the decoherence of a single nitrogenvacancy (NV) center coupled to a bath of nuclear spins in diamond [62,63]. In addition, spin-star networks have been considered from quantum entanglement and quantum cloning point of view [64,65,66,67]. Moreover, the dynamical behavior of the entanglement between two non-interacting qubits in a bath of spin star structure has been considered in Ref.…”