01740nas a2200145 4500008004100000245008100041210006900122260001400191520125300205100003001458700002401488700002301512700002201535856003701557 2023 eng d00aFeasibility of a trapped atom interferometer with accelerating optical traps0 aFeasibility of a trapped atom interferometer with accelerating o c8/23/20233 a

In order to increase the measured phase of an atom interferometer and improve its sensitivity, researchers attempt to increase the enclosed space-time area using two methods: creating larger separations between the interferometer arms and having longer evolution times. However, increasing the evolution time reduces the bandwidth that can be sampled, whereas decreasing the evolution time worsens the sensitivity. In this paper, we attempt to address this by proposing a setup for high-bandwidth applications, with improved overall sensitivity. This is realized by accelerating and holding the atoms using optical dipole traps. We find that accelerations of up to 103-105 m/s2 can be achieved using acousto-optic deflectors (AODs) to move the traps. By comparing the sensitivity of our approach to acceleration as a baseline to traditional atom interferometry, we find a substantial improvement to the state of the art. In the limit of appropriate beam and optics stabilization, sensitivities approaching 10−14 (m/s2)/Hz−−−√ may be achievable at 1 Hz, while detection at 1 kHz with a sensitivity an order of magnitude better than traditional free-fall atom interferometers is possible with today's systems.

1 aPremawardhana, Gayathrini1 aKunjummen, Jonathan1 aSubhankar, Sarthak1 aTaylor, Jacob, M. uhttps://arxiv.org/abs/2308.1224601880nas a2200169 4500008004100000022001400041245006100055210006100116260001400177490000600191520140600197100001901603700001301622700001901635700001901654856003701673 2021 eng d a2691-339900aFaster Digital Quantum Simulation by Symmetry Protection0 aFaster Digital Quantum Simulation by Symmetry Protection c2/14/20210 v23 a

Simulating the dynamics of quantum systems is an important application of quantum computers and has seen a variety of implementations on current hardware. We show that by introducing quantum gates implementing unitary transformations generated by the symmetries of the system, one can induce destructive interference between the errors from different steps of the simulation, effectively giving faster quantum simulation by symmetry protection. We derive rigorous bounds on the error of a symmetry-protected simulation algorithm and identify conditions for optimal symmetry protection. In particular, when the symmetry transformations are chosen as powers of a unitary, the error of the algorithm is approximately projected to the so-called quantum Zeno subspaces. We prove a bound on this approximation error, exponentially improving a recent result of Burgarth, Facchi, Gramegna, and Pascazio. We apply our technique to the simulations of the XXZ Heisenberg interactions with local disorder and the Schwinger model in quantum field theory. For both systems, our algorithm can reduce the simulation error by several orders of magnitude over the unprotected simulation. Finally, we provide numerical evidence suggesting that our technique can also protect simulation against other types of coherent, temporally correlated errors, such as the 1/f noise commonly found in solid-state experiments.

1 aTran, Minh, C.1 aSu, Yuan1 aCarney, Daniel1 aTaylor, J., M. uhttps://arxiv.org/abs/2006.1624804684nas a2200145 4500008004100000245004500041210004500086260001500131520426900146100001804415700002304433700002604456700001904482856003704501 2016 eng d00aFigures of merit for quantum transducers0 aFigures of merit for quantum transducers c2016/10/043 a

Recent technical advances have sparked renewed interest in physical systems that couple simultaneously to different parts of the electromagnetic spectrum, thus enabling transduction of signals between vastly different frequencies at the level of single photons. Such hybrid systems have demonstrated frequency conversion of classical signals and have the potential of enabling quantum state transfer, e.g., between superconducting circuits and traveling optical signals. This Letter describes a simple approach for the theoretical characterization of performance for quantum transducers. Given that, in practice, one cannot attain ideal one-to-one quantum conversion, we will explore how well the transducer performs in various scenarios ranging from classical signal detection to applications for quantum information processing. While the performance of the transducer depends on the particular application in which it enters, we show that the performance can be characterized by defining two simple parameters: the signal transfer efficiency η and the added noise N.

1 aZeuthen, Emil1 aSchliesser, Albert1 aSørensen, Anders, S.1 aTaylor, J., M. uhttps://arxiv.org/abs/1610.0109901280nas a2200133 4500008004100000245005800041210005800099260001500157520087600172100001901048700001901067700002201086856003801108 2015 eng d00aFramework for learning agents in quantum environments0 aFramework for learning agents in quantum environments c2015/07/303 aIn this paper we provide a broad framework for describing learning agents in general quantum environments. We analyze the types of classically specified environments which allow for quantum enhancements in learning, by contrasting environments to quantum oracles. We show that whether or not quantum improvements are at all possible depends on the internal structure of the quantum environment. If the environments are constructed and the internal structure is appropriately chosen, or if the agent has limited capacities to influence the internal states of the environment, we show that improvements in learning times are possible in a broad range of scenarios. Such scenarios we call luck-favoring settings. The case of constructed environments is particularly relevant for the class of model-based learning agents, where our results imply a near-generic improvement. 1 aDunjko, Vedran1 aTaylor, J., M.1 aBriegel, Hans, J. uhttp://arxiv.org/abs/1507.08482v101274nas a2200181 4500008004100000245010400041210006900145260001500214300001200229490000800241520071300249100002100962700001500983700002100998700001901019700001701038856003701055 2015 eng d00aFrom membrane-in-the-middle to mirror-in-the-middle with a high-reflectivity sub-wavelength grating0 aFrom membraneinthemiddle to mirrorinthemiddle with a highreflect c2015/01/02 a81 - 880 v5273 aWe demonstrate a "membrane in the middle" optomechanical system using a silicon nitride membrane patterned as a subwavelength grating. The grating has a reflectivity of over 99.8%, effectively creating two sub-cavities, with free spectral ranges of 6 GHz, optically coupled via photon tunneling. Measurements of the transmission and reflection spectra show an avoided crossing where the two sub-cavities simultaneously come into resonance, with a frequency splitting of 54 MHz. We derive expressions for the lineshapes of the symmetric and antisymmetric modes at the avoided crossing, and infer the grating reflection, transmission, absorption, and scattering through comparison with the experimental data. 1 aStambaugh, Corey1 aXu, Haitan1 aKemiktarak, Utku1 aTaylor, J., M.1 aLawall, John uhttp://arxiv.org/abs/1407.1709v101407nas a2200157 4500008004100000245006700041210006700108260001400175490000700189520094200196100002201138700001701160700001901177700001601196856003701212 2011 eng d00aFast and robust quantum computation with ionic Wigner crystals0 aFast and robust quantum computation with ionic Wigner crystals c2011/4/150 v833 aWe present a detailed analysis of the modulated-carrier quantum phase gate implemented with Wigner crystals of ions confined in Penning traps. We elaborate on a recent scheme, proposed by two of the authors, to engineer two-body interactions between ions in such crystals. We analyze for the first time the situation in which the cyclotron (w_c) and the crystal rotation (w_r) frequencies do not fulfill the condition w_c=2w_r. It is shown that even in the presence of the magnetic field in the rotating frame the many-body (classical) Hamiltonian describing small oscillations from the ion equilibrium positions can be recast in canonical form. As a consequence, we are able to demonstrate that fast and robust two-qubit gates are achievable within the current experimental limitations. Moreover, we describe a realization of the state-dependent sign-changing dipole forces needed to realize the investigated quantum computing scheme. 1 aBaltrusch, J., D.1 aNegretti, A.1 aTaylor, J., M.1 aCalarco, T. uhttp://arxiv.org/abs/1011.5616v201388nas a2200145 4500008004100000245009200041210006900133260001300202490000700215520092500222100001401147700001901161700001801180856004401198 2007 eng d00aA fast and robust approach to long-distance quantum communication with atomic ensembles0 afast and robust approach to longdistance quantum communication w c2007/7/20 v763 aQuantum repeaters create long-distance entanglement between quantum systems while overcoming difficulties such as the attenuation of single photons in a fiber. Recently, an implementation of a repeater protocol based on single qubits in atomic ensembles and linear optics has been proposed [Nature 414, 413 (2001)]. Motivated by rapid experimental progress towards implementing that protocol, here we develop a more efficient scheme compatible with active purification of arbitrary errors. Using similar resources as the earlier protocol, our approach intrinsically purifies leakage out of the logical subspace and all errors within the logical subspace, leading to greatly improved performance in the presence of experimental inefficiencies. Our analysis indicates that our scheme could generate approximately one pair per 3 minutes over 1280 km distance with fidelity (F>78%) sufficient to violate Bell's inequality. 1 aJiang, L.1 aTaylor, J., M.1 aLukin, M., D. uhttp://arxiv.org/abs/quant-ph/0609236v301138nas a2200157 4500008004100000245007600041210006900117260001400186490000700200520065300207100001800860700001900878700002100897700001800918856004400936 2006 eng d00aFault-tolerant Quantum Communication with Minimal Physical Requirements0 aFaulttolerant Quantum Communication with Minimal Physical Requir c2006/2/230 v963 aWe describe a novel protocol for a quantum repeater which enables long distance quantum communication through realistic, lossy photonic channels. Contrary to previous proposals, our protocol incorporates active purification of arbitrary errors at each step of the protocol using only two qubits at each repeater station. Because of these minimal physical requirements, the present protocol can be realized in simple physical systems such as solid-state single photon emitters. As an example, we show how nitrogen vacancy color centers in diamond can be used to implement the protocol, using the nuclear and electronic spin to form the two qubits. 1 aChildress, L.1 aTaylor, J., M.1 aSorensen, A., S.1 aLukin, M., D. uhttp://arxiv.org/abs/quant-ph/0410123v301771nas a2200157 4500008004100000245012200041210006900163260001500232490000700247520123500254100002201489700001901511700002101530700001801551856004401569 2005 eng d00aFault-tolerant quantum repeaters with minimal physical resources, and implementations based on single photon emitters0 aFaulttolerant quantum repeaters with minimal physical resources  c2005/11/280 v723 aWe analyze a novel method that uses fixed, minimal physical resources to achieve generation and nested purification of quantum entanglement for quantum communication over arbitrarily long distances, and discuss its implementation using realistic photon emitters and photonic channels. In this method, we use single photon emitters with two internal degrees of freedom formed by an electron spin and a nuclear spin to build intermediate nodes in a quantum channel. State-selective fluorescence is used for probabilistic entanglement generation between electron spins in adjacent nodes. We analyze in detail several approaches which are applicable to realistic, homogeneously broadened single photon emitters. Furthermore, the coupled electron and nuclear spins can be used to efficiently implement entanglement swapping and purification. We show that these techniques can be combined to generate high-fidelity entanglement over arbitrarily long distances. We present a specific protocol that functions in polynomial time and tolerates percent-level errors in entanglement fidelity and local operations. The scheme has the lowest requirements on physical resources of any current scheme for fully fault-tolerant quantum repeaters. 1 aChildress, L., I.1 aTaylor, J., M.1 aSorensen, A., S.1 aLukin, M., D. uhttp://arxiv.org/abs/quant-ph/0502112v1