State transfer in intrinsic decoherence spin channels

Hu, Ming‐Liang; Lian, Han‐li

doi:10.1140/epjd/e2009-00220-8

Cited by 49 publications

(32 citation statements)

References 46 publications

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“…Limiting our discussion to chains of length N = 3 and N = 5 as likely candidates for a first experimental demonstration (and also for numerical tractability) has allowed us to obtain insight into important characteristics of such a protocol in the presence of realistic noise. Our conclusions will be equally relevant for longer chains, which are known to be even more susceptible to decoherence [37][38][39]. We have shown that directly meeting quantum error correction thresholds remains infeasible even if all spins possessed the exceptional coherence time of NV − centers.…”

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confidence: 74%

Practicality of Spin Chain Wiring in Diamond Quantum Technologies

et al. 2013

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Coupled spin chains are promising candidates for 'wiring up' qubits in solid-state quantum computing (QC). In particular, two nitrogen-vacancy centers in diamond can be connected by a chain of implanted nitrogen impurities; when driven by a suitable global fields the chain can potentially enable quantum state transfer at room temperature. However, our detailed analysis of error effects suggests that foreseeable systems may fall far short of the fidelities required for QC. Fortunately the chain can function in the more modest role as a mediator of noisy entanglement, enabling QC provided that we use subsequent purification. For instance, a chain of 5 spins with inter-spin distances of 10 nm has finite entangling power as long as the T2 time of the spins exceeds 0.55 ms. Moreover we show that re-purposing the chain this way can remove the restriction to nearest-neighbor interactions, so eliminating the need for complicated dynamical decoupling sequences.Spin chains with nearest neighbor XY coupling mediate coherent interactions between distant spin qubits with fixed locations, and can thus serve as channels to transfer quantum information [1][2][3]. An important application would be to interconnect distant sub-registers of parallel parts in a scalable, solid-state quantum computer [4], e.g. in a diamond-based architecture at room temperature [5]. With an observed roomtemperature coherence time of 1.8 ms [6], the electron spin of individual nitrogen-vacancy (NV − ) defects in diamond is a promising candidate for a qubit [7]: Initialisation, coherent manipulation and measurement with nanoscale resolution (∼ 150 nm) have already been experimentally demonstrated using optical techniques under ambient conditions [8]. In addition, the long-lived 15 N nuclear spin (I = 1/2) associated with each NV − center can act as a local, coherent memory, accessible via the hyperfine coupling [9, 10]. A universal set of quantum operations between the nuclear memory spin and the processing electronic spin qubit within each NV − center is available with microwave and radio-frequency pulses [11][12][13]. Two NV − centers with only a small separation (r 10 nm) may be entangled through direct electron spin dipole-dipole coupling as long as a T 2 time on the order of milliseconds can be maintained [14]. However, individual addressability of the NV − center qubits demands larger separations of several tens or hundreds of nanometers [8], and the direct interaction becomes too weak.A recent proposal [15] suggested a chain of N implanted nitrogen impurities (each with a "dark" electronic spin-1/2) as a coherent quantum channel to transfer quantum states between distant NV − centers at room-temperature (see Fig. 1a). Here, the electron spins of the NV − centers and the nitrogen impurities interact with each other through nearest-neighbor dipoledipole coupling [16, 17]. Importantly, the scheme does not require individual control of the chain spins, instead relying on global resonant driving fields to turn the effective Hamiltonian into an XY exc...

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confidence: 74%

Practicality of Spin Chain Wiring in Diamond Quantum Technologies

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“…1 During the last decade, special attention has been paid for describing QST in spin networks. [2][3][4][5][6][7][8][9][10][11][12][13][14] Indeed, spin based communication protocols are one of the best candidates for scalable computing for two main reasons. 15 First, spin excitations delocalize in lattices owing to the interactions that naturally arise between neighboring sites.…”

Section: Introductionmentioning

confidence: 99%

Exciton localization-delocalization transition in an extended dendrimer

Pouthier

2013

The Journal of Chemical Physics

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Exciton-mediated quantum state transfer between the periphery and the core of an extended dendrimer is investigated numerically. By mapping the dynamics onto that of a linear chain, it is shown that a localization-delocalization transition arises for a critical value of the generation number G(c) ≈ 5. This transition originates in the quantum interferences experienced by the excitonic wave due to the multiple scatterings that arise each time the wave tunnels from one generation to another. These results suggest that only small-size dendrimers could be used for designing an efficient quantum communication protocol.

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“…Moreover, as a natural candidate for implementing quantum information processing tasks such as quantum state transfer [43][44][45], the spin model remains people's research focus for many years. Recently, quantum discord in various spin models have been studied by a number of authors [46][47][48][49][50][51][52][53][54][55][56].…”

Section: Introductionmentioning

confidence: 99%