ELFT HÍRADÓ

[Kiss Tamás <tkiss AT szfki.hu>]

SZFI Szeminárium

2014. július 10, csütörtök, 10:00:00


Bernád J. Zsolt

TU Darmstadt, Németország, vendéglátó: Kiss Tamás



Entangling remote material qubits by photon exchange

The realization of a quantum repeater capable of creating entanglement
between qubits over large distances still represents a major quantum
technological challenge. In this context the pioneering proposal of
van Loock et al. [1] of a hybrid quantum repeater in which continuous
variables of the electromagnetic field exchange quantum information
with spatially separated material qubits offers interesting
perspectives for preparing highly entangled material qubit pairs over
large distances. In this talk I present several extensions to the
proposal of van Loock et al. [1]. First, it is demonstrated that
resonant interaction between the material qubits and the photons
results in higher fidelity Bell-states between the two spatially
separated material qubits than the off-resonant interaction case
considered so far by [1]. A model for the optical fiber, i.e, the
quantum channel, is introduced and the effects originating from loss
are discussed. The material qubits are usually implemented as trapped
ions or atoms. Therefore, effects of center-of-mass motion are also
presented. Studying the dynamics of the center-of-mass motion in the
Lamb-Dicke regime, destructive effects on the generation of
high-fidelity Bell-states with a certain success probability are
shown. In order to overcome this hurdle, I present a dynamical
decoupling scheme performed locally on the material qubits, which can
suppress center-of-mass motion induced decoherence.

[1] P. van Loock, T.D. Ladd, K. Sanaka, F. Yamagouchi, K. Nemoto, W.
J. Munro, and Y. Yamamoto, Phys. Rev. Lett. 96, 240501 (2006).





I. épület, Tanácsterem



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