Routing quantum information in spin chains

Paganelli, Simone; Lorenzo, Salvatore; Apollaro, Tony J. G.; Plastina, Francesco; Giorgi, Gian Luca

doi:10.1103/physreva.87.062309

Cited by 84 publications

(79 citation statements)

References 39 publications

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“…[2,3] (see also [32]). By adding in local defects, either in form of magnetic fields or coupling strengths, it is possible to carry out high-fidelity quantum-state transfer (it takes place by effectively reducing the operating Hilbert space) [4,6,7,10,11,33], routing protocols [34][35][36], and to control and enhance entanglement distribution [13,14]. Also, it has been shown that gapped dimerized models plays a major role in establishing long-distance communication [6,17,19,21,27,33].…”

Section: Introductionmentioning

confidence: 99%

Disorder-assisted distribution of entanglement in XY spin chains

et al. 2017

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We study the creation and distribution of entanglement in disordered XY -type spin-1/2 chains for the paradigmatic case of a single flipped spin prepared on a fully polarized background. The local magnetic field is set to follow a disordered long-range-correlated sequence with power-law spectrum. Depending on the degree of correlations of the disorder, a set of extended modes emerge in the middle of the band yielding an interplay between localization and delocalization. As a consequence, a rich variety of entanglement distribution patterns arises, which we evaluate here through the concurrence between two spins. We show that, even in the presence of disorder, the entanglement wave can be pushed to spread out reaching distant sites and also enhance pairwise entanglement between the initial site and the rest of the chain. We also study the propagation of an initial maximallyentangled state through the chain and show that correlated disorder improves the transmission quite significantly when compared with the uncorrelated counterpart. Our work contributes in designing solid-state devices for quantum information processing in the realistic setting of correlated static disorder.

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Section: Introductionmentioning

confidence: 99%

Disorder-assisted distribution of entanglement in XY spin chains

et al. 2017

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“…[5] for an implementation with a cavity array). Protocols based on time-dependent couplings [6,7], fully engineered interactions [8][9][10], and ballistic transfer [11][12][13][14][15][16], Rabi-like oscillations [17][18][19][20][21][22][23][24][25][26][27][28][29], just to name a few, have been shown to achieve high fidelity 1-QST, in addition to some additional tasks like routing of the quantum information to an on-demand location on a spin graph [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Transfer of arbitrary two-qubit states via a spin chain

et al. 2015

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We investigate the fidelity of the quantum state transfer (QST) of two qubits by means of an arbitrary spin-1 2 network, on a lattice of any dimensionality. Under the assumptions that the network Hamiltonian preserves the magnetization and that a fully polarized initial state is taken for the lattice, we obtain a general formula for the average fidelity of the two qubits QST, linking it to the one-and two-particle transfer amplitudes of the spin excitations among the sites of the lattice. We then apply this formalism to a 1D spin chain with XX-Heisenberg type nearest-neighbour interactions adopting a protocol that is a generalization of the single qubit one proposed in Paganelli et al. [Phys. Rev. A 87, 062309 (2013)]. We find that a high-quality two qubit QST can be achieved provided one can control the local fields at sites near the sender and receiver. Under such conditions, we obtain an almost perfect transfer in a time that scales either linearly or, depending on the spin number, quadratically with the length of the chain.

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“…This result can be understood by considering that both weak coupling and strong potential offsets lead to an effective decoupling of the extreme sites from the rest of the chain [31]. The condition for the decoupling to be effective can be obtained, within a perturbation-theory approach, by assuming that the two eigenvalues close to B 1 = B N are only slightly modified by the presence of the channel.…”

Section: Resultsmentioning

confidence: 99%

Quantum state transfer in the presence of nonhomogeneous external potentials

Giorgi

Busch

2013

Phys. Rev. A

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Type of publicationArticle (peer-reviewed) Heisenberg-type spin models in the limit of a low number of excitations are useful tools to study basic mechanisms in strongly correlated and magnetic systems. Many of these mechanisms can be experimentally tested using ultracold atoms. Here, we discuss the implementation of a quantum state transfer protocol in a tight-binding chain in the presence of an inhomogeneous external potential. We show that it can be used to extend the parameter range in which high-fidelity state transfer can be achieved beyond the well established weak-coupling regime. Among the class of mirror-reflecting potentials that allow for high fidelity quantum state transfer, the harmonic case is especially relevant because it allows us to formulate a proposal for the experimental implementation of the protocol in the context of optical lattices.

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Routing quantum information in spin chains

Cited by 84 publications

References 39 publications

Disorder-assisted distribution of entanglement in XY spin chains

Disorder-assisted distribution of entanglement in XY spin chains

Transfer of arbitrary two-qubit states via a spin chain

Quantum state transfer in the presence of nonhomogeneous external potentials

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