%0 Journal Article
%J Physical Review A
%D 2010
%T Adiabatic preparation of many-body states in optical lattices
%A Anders S. Sorensen
%A Ehud Altman
%A Michael Gullans
%A J. V. Porto
%A Mikhail D. Lukin
%A Eugene Demler
%X We analyze a technique for the preparation of low entropy many body states of atoms in optical lattices based on adiabatic passage. In particular, we show that this method allows preparation of strongly correlated states as stable highest energy states of Hamiltonians that have trivial ground states. As an example, we analyze the generation of antiferromagnetically ordered states by adiabatic change of a staggered field acting on the spins of bosonic atoms with ferromagnetic interactions.
%B Physical Review A
%V 81
%8 2010/6/22
%G eng
%U http://arxiv.org/abs/0906.2567v3
%N 6
%! Phys. Rev. A
%R 10.1103/PhysRevA.81.061603
%0 Journal Article
%J Physical Review A
%D 2010
%T Fast Entanglement Distribution with Atomic Ensembles and Fluorescent Detection
%A Jonatan B. Brask
%A Liang Jiang
%A Alexey V. Gorshkov
%A Vladan Vuletic
%A Anders S. Sorensen
%A Mikhail D. Lukin
%X Quantum repeaters based on atomic ensemble quantum memories are promising candidates for achieving scalable distribution of entanglement over long distances. Recently, important experimental progress has been made towards their implementation. However, the entanglement rates and scalability of current approaches are limited by relatively low retrieval and single-photon detector efficiencies. We propose a scheme, which makes use of fluorescent detection of stored excitations to significantly increase the efficiency of connection and hence the rate. Practical performance and possible experimental realizations of the new protocol are discussed.
%B Physical Review A
%V 81
%8 2010/2/12
%G eng
%U http://arxiv.org/abs/0907.3839v2
%N 2
%! Phys. Rev. A
%R 10.1103/PhysRevA.81.020303
%0 Journal Article
%J Physical Review A
%D 2008
%T Photon storage in Lambda-type optically dense atomic media. IV. Optimal control using gradient ascent
%A Alexey V. Gorshkov
%A Tommaso Calarco
%A Mikhail D. Lukin
%A Anders S. Sorensen
%X We use the numerical gradient ascent method from optimal control theory to extend efficient photon storage in Lambda-type media to previously inaccessible regimes and to provide simple intuitive explanations for our optimization techniques. In particular, by using gradient ascent to shape classical control pulses used to mediate photon storage, we open up the possibility of high efficiency photon storage in the non-adiabatic limit, in which analytical solutions to the equations of motion do not exist. This control shaping technique enables an order-of-magnitude increase in the bandwidth of the memory. We also demonstrate that the often discussed connection between time reversal and optimality in photon storage follows naturally from gradient ascent. Finally, we discuss the optimization of controlled reversible inhomogeneous broadening.
%B Physical Review A
%V 77
%8 2008/4/4
%G eng
%U http://arxiv.org/abs/0710.2698v2
%N 4
%! Phys. Rev. A
%R 10.1103/PhysRevA.77.043806
%0 Journal Article
%J Physical Review Letters
%D 2007
%T Optimal control of light pulse storage and retrieval
%A Irina Novikova
%A Alexey V. Gorshkov
%A David F. Phillips
%A Anders S. Sorensen
%A Mikhail D. Lukin
%A Ronald L. Walsworth
%X We demonstrate experimentally a procedure to obtain the maximum efficiency for the storage and retrieval of light pulses in atomic media. The procedure uses time reversal to obtain optimal input signal pulse-shapes. Experimental results in warm Rb vapor are in good agreement with theoretical predictions and demonstrate a substantial improvement of efficiency. This optimization procedure is applicable to a wide range of systems.
%B Physical Review Letters
%V 98
%8 2007/6/15
%G eng
%U http://arxiv.org/abs/quant-ph/0702266v1
%N 24
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.98.243602
%0 Journal Article
%J Physical Review A
%D 2007
%T Photon storage in Lambda-type optically dense atomic media. I. Cavity model
%A Alexey V. Gorshkov
%A Axel Andre
%A Mikhail D. Lukin
%A Anders S. Sorensen
%X In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)], we used a universal physical picture to optimize and demonstrate equivalence between a wide range of techniques for storage and retrieval of photon wave packets in Lambda-type atomic media in free space, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo-based techniques. In the present paper, we perform the same analysis for the cavity model. In particular, we show that the retrieval efficiency is equal to C/(1+C) independent of the retrieval technique, where C is the cooperativity parameter. We also derive the optimal strategy for storage and, in particular, demonstrate that at any detuning one can store, with the optimal efficiency of C/(1+C), any smooth input mode satisfying T C gamma >> 1 and a certain class of resonant input modes satisfying T C gamma ~ 1, where T is the duration of the input mode and 2 gamma is the transition linewidth. In the two subsequent papers of the series, we present the full analysis of the free-space model and discuss the effects of inhomogeneous broadening on photon storage.
%B Physical Review A
%V 76
%8 2007/9/7
%G eng
%U http://arxiv.org/abs/quant-ph/0612082v2
%N 3
%! Phys. Rev. A
%R 10.1103/PhysRevA.76.033804
%0 Journal Article
%J Physical Review A
%D 2007
%T Photon storage in Lambda-type optically dense atomic media. II. Free-space model
%A Alexey V. Gorshkov
%A Axel Andre
%A Mikhail D. Lukin
%A Anders S. Sorensen
%X In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)], we presented a universal physical picture for describing a wide range of techniques for storage and retrieval of photon wave packets in Lambda-type atomic media in free space, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo based techniques. This universal picture produced an optimal control strategy for photon storage and retrieval applicable to all approaches and yielded identical maximum efficiencies for all of them. In the present paper, we present the full details of this analysis as well some of its extensions, including the discussion of the effects of non-degeneracy of the two lower levels of the Lambda system. The analysis in the present paper is based on the intuition obtained from the study of photon storage in the cavity model in the preceding paper [Gorshkov et al., Phys. Rev. A 76, 033804 (2007)].
%B Physical Review A
%V 76
%8 2007/9/7
%G eng
%U http://arxiv.org/abs/quant-ph/0612083v2
%N 3
%! Phys. Rev. A
%R 10.1103/PhysRevA.76.033805
%0 Journal Article
%J Physical Review A
%D 2007
%T Photon storage in Lambda-type optically dense atomic media. III. Effects of inhomogeneous broadening
%A Alexey V. Gorshkov
%A Axel Andre
%A Mikhail D. Lukin
%A Anders S. Sorensen
%X In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)] and in the two preceding papers [Gorshkov et al., Phys. Rev. A 76, 033804 (2007); 76, 033805 (2007)], we used a universal physical picture to optimize and demonstrate equivalence between a wide range of techniques for storage and retrieval of photon wave packets in homogeneously broadened Lambda-type atomic media, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo-based techniques. In the present paper, we generalize this treatment to include inhomogeneous broadening. In particular, we consider the case of Doppler-broadened atoms and assume that there is a negligible difference between the Doppler shifts of the two optical transitions. In this situation, we show that, at high enough optical depth, all atoms contribute coherently to the storage process as if the medium were homogeneously broadened. We also discuss the effects of inhomogeneous broadening in solid state samples. In this context, we discuss the advantages and limitations of reversing the inhomogeneous broadening during the storage time, as well as suggest a way for achieving high efficiencies with a nonreversible inhomogeneous profile.
%B Physical Review A
%V 76
%8 2007/9/7
%G eng
%U http://arxiv.org/abs/quant-ph/0612084v2
%N 3
%! Phys. Rev. A
%R 10.1103/PhysRevA.76.033806
%0 Journal Article
%J Physical Review Letters
%D 2007
%T Universal Approach to Optimal Photon Storage in Atomic Media
%A Alexey V. Gorshkov
%A Axel Andre
%A Michael Fleischhauer
%A Anders S. Sorensen
%A Mikhail D. Lukin
%X We present a universal physical picture for describing storage and retrieval of photon wave packets in a Lambda-type atomic medium. This physical picture encompasses a variety of different approaches to pulse storage ranging from adiabatic reduction of the photon group velocity and pulse-propagation control via off-resonant Raman fields to photon-echo based techniques. Furthermore, we derive an optimal control strategy for storage and retrieval of a photon wave packet of any given shape. All these approaches, when optimized, yield identical maximum efficiencies, which only depend on the optical depth of the medium.
%B Physical Review Letters
%V 98
%8 2007/3/19
%G eng
%U http://arxiv.org/abs/quant-ph/0604037v3
%N 12
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.98.123601