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Optimal photonic indistinguishability tests in multimode networks
摘要： Particle indistinguishability is at the heart of quantum statistics that regulates fundamental phenomena such as the electronic band structure of solids, Bose-Einstein condensation and superconductivity. Moreover, it is necessary in practical applications such as linear optical quantum computation and simulation, in particular for Boson Sampling devices. It is thus crucial to develop tools to certify genuine multiphoton interference between multiple sources. Our approach employs the total variation distance to find those transformations that minimize the error probability in discriminating the behaviors of distinguishable and indistinguishable photons. In particular, we show that so-called Sylvester interferometers are near-optimal for this task. By using Bayesian tests and inference, we numerically show that Sylvester transformations largely outperform most Haar-random unitaries in terms of sample size required. Furthermore, we experimentally demonstrate the efficacy of the transformation using an efficient 3D integrated circuits in the single- and multiple-source cases. We then discuss the extension of this approach to a larger number of photons and modes. These results open the way to the application of Sylvester interferometers for optimal assessment of multiphoton interference experiments.
关键词： Sylvester interferometers,Particle indistinguishability,Quantum statistics,Optical quantum computation,Multiphoton interference experiments,Bayesian tests,Quantum simulation
更新于2025-09-23 15:23:52
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Efficient Orthogonal Control of Tunnel Couplings in a Quantum Dot Array
摘要： Electrostatically-defined semiconductor quantum dot arrays offer a promising platform for quantum computation and quantum simulation. However, crosstalk of gate voltages to dot potentials and interdot tunnel couplings complicates the tuning of the device parameters. To date, crosstalk to the dot potentials is routinely and efficiently compensated using so-called virtual gates, which are specific linear combinations of physical gate voltages. However, due to exponential dependence of tunnel couplings on gate voltages, crosstalk to the tunnel barriers is currently compensated through a slow iterative process. In this work, we show that the crosstalk on tunnel barriers can be efficiently characterized and compensated for, using the fact that the same exponential dependence applies to all gates. We demonstrate efficient calibration of crosstalk in a quadruple quantum dot array and define a set of virtual barrier gates, with which we show orthogonal control of all interdot tunnel couplings. Our method marks a key step forward in the scalability of the tuning process of large-scale quantum dot arrays.
关键词： quantum simulation,quantum dot arrays,tunnel couplings,quantum computation,crosstalk compensation
更新于2025-09-23 15:21:01
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Effective many-body Hamiltonians of qubit-photon bound states
摘要： Quantum emitters (QEs) coupled to structured baths can localize multiple photons around them and form qubit-photon bound states. In the Markovian or weak coupling regime, the interaction of QEs through these single-photon bound states is known to lead to effective many-body QE Hamiltonians with tuneable but yet perturbative interactions. In this work we study the emergence of such models in the non-Markovian or strong coupling regime in different excitation subspaces. The effective models for the non-Markovian regime with up to three excitations are characterized using analytical methods, uncovering the existence of doublons or triplon states. Furthermore, we provide numerical results for systems with multiple excitations and demonstrate the emergence of polariton models with optically tuneable interactions, whose many-body ground state exhibits a super?uid-Mott insulator transition.
关键词： long-range interactions,quantum simulation,quantum optics
更新于2025-09-23 15:21:01
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The Integration of Photonic Crystal Waveguides with Atom Arrays in Optical Tweezers
摘要： Integrating nanophotonics and cold atoms has drawn increasing interest in recent years due to diverse applications in quantum information science and the exploration of quantum many-body physics. For example, dispersion-engineered photonic crystal waveguides (PCWs) permit not only stable trapping and probing of ultracold neutral atoms via interactions with guided-mode light, but also the possibility to explore the physics of strong, photon-mediated interactions between atoms, as well as atom-mediated interactions between photons. While diverse theoretical opportunities involving atoms and photons in 1D and 2D nanophotonic lattices have been analyzed, a grand challenge remains the experimental integration of PCWs with ultracold atoms. Here, an advanced apparatus that overcomes several significant barriers to current experimental progress is described, with the goal of achieving strong quantum interactions of light and matter by way of single-atom tweezer arrays strongly coupled to photons in 1D and 2D PCWs. Principal technical advances relate to efficient free-space coupling of light to and from guided modes of PCWs, silicate bonding of silicon chips within small glass vacuum cells, and deterministic, mechanical delivery of single-atom tweezer arrays to the near fields of photonic crystal waveguides.
关键词： atoms and nanophotonics,quantum simulation,quantum dielectrics,quantum information science
更新于2025-09-23 15:19:57
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Laser Trapping of Circular Rydberg Atoms
摘要： Rydberg atoms are remarkable tools for quantum simulation and computation. They are the focus of an intense experimental activity, mainly based on low-angular-momentum Rydberg states. Unfortunately, atomic motion and levels lifetime limit the experimental timescale to about 100 μs. Here, we demonstrate two-dimensional laser trapping of long-lived circular Rydberg states for up to 10 ms. Our method is very general and opens many opportunities for quantum technologies with Rydberg atoms. The 10 ms trapping time corresponds to thousands of interaction cycles in a circular-state-based quantum simulator. It is also promising for quantum metrology and quantum information with Rydberg atoms, by bringing atom-field interaction times into unprecedented regimes.
关键词： circular Rydberg states,quantum computation,Rydberg atoms,quantum simulation,laser trapping
更新于2025-09-23 15:19:57
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Controlled Phase Gate Protocol for Neutral Atoms via Off-Resonant Modulated Driving
摘要： Neutral-atom arrays serve as an ideal platform to study quantum simulation and quantum logic gates, where intense efforts have been devoted to improving the fidelity of two-qubit gates. We report our recent findings in constructing a different type of two-qubit controlled phase gate protocol with neutral atoms enabled by the Rydberg blockade, which aims at both robustness and high fidelity. It relies upon a modulated driving pulse with a specially tailored smooth waveform to gain appropriate phase accumulations for quantum gates. The major features include finishing a gate operation within a single pulse, not necessarily requiring individual site addressing, not being sensitive to the exact value of the blockade shift, and suppressing the population leakage error and rotation error. Building upon this progress, we further develop an upgrade in the form of dual-pulse off-resonant modulated driving with the major distinct feature of Doppler insensitivity, in order to address the challenge to the fidelity of two-qubit gates caused by residual thermal motion of the cold atoms. In principle, the gate fidelity remains reasonably high over a relatively significant velocity range of the qubit atoms. Moreover, we anticipate that this will inspire future improvements in gate protocols for other types of qubit platforms, and the strategies used here may find applications in the area of quantum optimal control.
关键词： Doppler insensitivity,controlled phase gate,quantum logic gates,neutral-atom arrays,Rydberg blockade,quantum simulation
更新于2025-09-23 15:19:57
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A new ultra-scaled graphene nanoribbon junctionless tunneling field-effect transistor: proposal, quantum simulation, and analysis
摘要： In this paper, a new ultrascaled junctionless graphene nanoribbon tunnel field-effect transistor (JL GNRTFET) is proposed through a computational study. The quantum simulation approach is based on the resolution of the Schr?dinger equation using the mode space non-equilibrium Green’s function formalism coupled self-consistently with a Poisson equation in the ballistic limit. The proposed nanodevice is endowed with ungated region between the auxiliary and control gates as well as with a laterally graded channel doping in order to improve the switching performance of the ultrascaled junctionless GNRTFET. The performance assessment has included the IDS–VGS transfer characteristics, subthreshold swing, current ratio, intrinsic delay, and power-delay product. It has been found that the proposed ultrascaled junctionless GNR tunneling FET can provide improved switching performance than its conventional counterpart. The proposed strategy can be applied to improve similar ultrascaled junctionless tunneling field-effect transistors for the future digital electronics, where the high-performance and the aggressive downscaling should be in agreement.
关键词： Junctionless,Graphene nanoribbon (GNR),Tunneling field-effect transistor (TFET),Switching,Quantum simulation,Tunneling
更新于2025-09-11 14:15:04
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Approximating vibronic spectroscopy with imperfect quantum optics
摘要： We study the impact of experimental imperfections on a recently proposed protocol for performing quantum simulations of vibronic spectroscopy. Specifically, we propose a method for quantifying the impact of these imperfections, optimizing an experiment to account for them, and benchmarking the results against a classical simulation method. We illustrate our findings using a proof of principle experimental simulation of part of the vibronic spectrum of tropolone. Our findings will inform the design of future experiments aiming to simulate the spectra of large molecules beyond the reach of current classical computers.
关键词： quantum optics,boson sampling,squeezed light,quantum simulation,vibronic spectroscopy,quantum chemistry
更新于2025-09-10 09:29:36
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An approach to spin-resolved molecular gas microscopy
摘要： Ultracold polar molecules are an ideal platform for studying many-body physics with long-range dipolar interactions. Experiments in this field have progressed enormously, and several groups are pursuing advanced apparatus for manipulation of molecules with electric fields as well as single-atom-resolved in situ detection. Such detection has become ubiquitous for atoms in optical lattices and tweezer arrays, but has yet to be demonstrated for ultracold polar molecules. Here we present a proposal for the implementation of site-resolved microscopy for polar molecules, and specifically discuss a technique for spin-resolved molecular detection. We use numerical simulation of spin dynamics of lattice-confined polar molecules to show how such a scheme would be of utility in a spin-diffusion experiment.
关键词： quantum gas microscopy,quantum simulation,ultracold molecules,single-molecule control,dipolar spin models,optical lattices
更新于2025-09-09 09:28:46
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Bohmian trajectory-bloch wave approach to dynamical simulation of electron diffraction in crystal
摘要： The Bohmian trajectory method is employed to study electron diffraction in crystalline materials. It provides a fresh understanding of the process of electron diffraction, including traveling channels of electrons and formation of diffraction patterns. By combining it with the Bloch wave method, the electron trajectories can be calculated more efficiently than the traditional wave-packet propagation algorithm. Meanwhile, we propose a momentum expectation approach which is a good approximation method with even higher computational efficiency. Both methods result in intuitive and accurate electron trajectories for the simulation of the electron backscatter diffraction (EBSD) pattern. Excellent agreement has been obtained between the simulated trajectory distributions and the experimental EBSD pattern from Mo (001) at 20 kV, where the Kikuchi patterns and higher order Laue zone rings are characterized.
关键词： quantum trajectories,electron diffraction,quantum simulation,Bohmian mechanics
更新于2025-09-09 09:28:46