Robustness of Spin-Chain State-Transfer Schemes

Stolze, Joachim; Álvarez, Gonzalo; Osenda, Omar; Zwick, Analia

doi:10.1007/978-3-642-39937-4_5

Cited by 12 publications

(19 citation statements)

References 144 publications

(176 reference statements)

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“…In this figure, the horizontal dash-lines correspond to α 2 = const, while the solid lines correspond to α 1 = const. Emphasize that it is not necessary to work with the whole domain (10) of control parameters because the parameters from the first sub-domain (27) cover the whole creatable space, as is shown in Fig.4a, where some particular values of the control parameters are indicated. Therewith the map (23) is one-to-one map for this sub-domain.…”

Section: B Ekert Chainmentioning

confidence: 99%

“…The parameters from the second sub-domain (28) are mapped into the same region in Fig.4a (therewith, the parameter α 1 increases from Thus, the subregion in Fig.4b is covered four times by the parameters from the all four sub-domains (27)(28)(29)(30) and consequently the states from this sub-region are simpler creatable than others. This subregion correspond to the relatively small values of Q R .…”

Section: B Ekert Chainmentioning

confidence: 99%

“…In Figs.5a-b and 6a-b, we depict map (23) corresponding to sub-domain (27) of the control-parameter space, this is almost the one-to-one map. We see that the map in this case can be viewed as a deformation of the Ekert case shown in Fig.4a.…”

Section: B Ekert Chainmentioning

confidence: 99%

“…So, the classical channel as an additional part of the "communication line" is not needed. Next, the high probability state transfer [26][27][28][29][30][31][32][33][34][35] was proposed, which is much simpler realizable in comparison with the perfect state transfer. Besides, instead of transferring the sender's state itself, we may try to create another state-of-interest directly related with the sender's state (but different from it) [1,2,[23][24][25].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Remote control of quantum correlations in a two-qubit receiver by a three-qubit sender

Doronin¹,

Zenchuk²

2016

Theor Math Phys

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We study the problem of remote control of quantum correlations (discord) in a sub-system of two qubits (receiver) via the parameters of the initial state of another sub-system of three qubits (sender) connected with the receiver by the inhomogeneous spin-1/2 chain. We propose two parameters characterizing the creatable correlations. The first one is the discord between the receiver and the rest of spin-1/2 chain, it concerns the mutual correlations between these two subsystems. The second parameter is the discord between the two nodes of the receiver and describes the correlations inside of the receiver. We study the dependence of these two discords on the inhomogeneity degree of spin chain.

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Section: B Ekert Chainmentioning

confidence: 99%

Section: B Ekert Chainmentioning

confidence: 99%

Section: B Ekert Chainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Remote control of quantum correlations in a two-qubit receiver by a three-qubit sender

Doronin¹,

Zenchuk²

2016

Theor Math Phys

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“…Successive eigenvectors (as ordered by energy) are alternatingly even and odd under spatial reflection. This property makes perfect state transfer possible if the ε ν are commensurate (see, for example, [14] for details). A prominent example [15] is given by J i = i(N − i), leading to an equidistant ladder of ε ν values.…”

mentioning

confidence: 99%

Transferring entangled states through spin chains by boundary-state multiplets

Lorenz

Stolze

2014

Phys. Rev. A

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Quantum spin chains may be used to transfer quantum states between elements of a quantum information processing device. A scheme discovered recently [1] was shown to have favorable transfer properties for single-qubit states even in the presence of built-in static disorder caused by manufacturing errors. We extend that scheme in a way suggested already in [1] and study the transfer of the four Bell states which form a maximally entangled basis in the two-qubit Hilbert space. We show that perfect transfer of all four Bell states separately and of arbitrary linear combinations may be achieved for chains with hundreds of spins. For simplicity we restrict ourselves to systems without disorder.PACS numbers: 03.67. Hk, 75.10.Pq, 75.40.Gb Quantum information processing [2] relies on a number of key elements of technology, among them quantum bits and quantum gates. Since any quantum computer will contain a large number of different quantum gates and registers, information must be transferred between these elements of the computer. One possibility for that information transfer is offered by quantum spin chains, linear arrays of suitably coupled qubits. Research on quantum information transfer by spin chains started roughly a decade ago [3] and quickly developed into an active field with many contributors (see, for example, the reviews in [4]). However, most of the research up to now has focused on the transfer of single-qubit states, although the handling of entangled multi-qubit states is of primary importance in all known algorithms of quantum information processing. In this Brief Report we show how a natural extension of a single-qubit state transfer protocol [1] can be used to achieve high-fidelity transmission of arbitrary pure two-qubit states along spin chains with up to hundreds of sites.Spin chains for quantum information transfer mostly fall into one of two classes distinguished by the degree of "engineering", or fine-tuning, of the nearest-neighbor couplings along the chain. Perfect state transfer (PST) may be achieved if all transition frequencies generated by the spin chain Hamiltonian are commensurate and hence the time evolution of arbitrary initial states becomes periodic. In combination with spatial symmetry this enables perfect "mirroring" of initial states located at one end of the chain [5][6][7][8][9]. To achieve this goal, all nearest-neighbor couplings must be tuned to specific values, hence this class of chains may be called "fully engineered". A much simpler route to good (but not perfect) state transfer is opened by modifying only the boundary couplings affecting the very first and last spins of the chain, respectively, leaving all other couplings at one and the same value [10][11][12]. In the limit of weak boundary couplings the system then possesses nearly degenerate (symmetric and antisymmetric) eigenstates concentrated on the boundary spins and the dynamics of these states may be exploited for the transfer of quantum information. That class of systems may be called boundarydominated or op...

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Evaluation of the performance of two state-transfer Hamiltonians in the presence of static disorder

Pavlis

Nikolopoulos

Lambropoulos

2016

Quantum Inf Process

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We analyse the performance of two quantum-state-transfer Hamiltonians in the presence of diagonal and off-diagonal disorder, and in terms of different measures. The first Hamiltonian pertains to a fully-engineered chain and the second to a chain with modified boundary couplings. The task is to find which Hamiltonian is the most robust to given levels of disorder and irrespective of the input state. In this respect, it is shown that the performance of the two protocols are approximately equivalent.

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Robustness of Spin-Chain State-Transfer Schemes

Cited by 12 publications

References 144 publications

Remote control of quantum correlations in a two-qubit receiver by a three-qubit sender

Remote control of quantum correlations in a two-qubit receiver by a three-qubit sender

Transferring entangled states through spin chains by boundary-state multiplets

Evaluation of the performance of two state-transfer Hamiltonians in the presence of static disorder

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