- 标题
- 摘要
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- 实验方案
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Field-squeeze operators via coherent population trapping
摘要： We present a scheme to generate unitarily two-mode and four-mode ?eld squeezing in optical cavities with the near-resonantly dressed three-level atoms in the (cid:2) con?guration. The dressing ?elds open two coherent population trapping (CPT) windows, within which the atoms stay predominantly in the dark state and yield strong nonlinearities for both the dressing ?elds themselves and the other applied ?elds. The two-mode squeeze operator is separated from degrees of freedom of atoms in a common CPT window, and the multimode squeeze operator is segregated in different CPT windows. The resulting two-mode and multimode interaction strengths are at least one order higher than in the previous dispersive schemes, where all ?elds are far off resonant with the atoms. The present near-resonant scheme is robust to spontaneous emission since atoms are nearly trapped in a long-lived superposition state.
关键词： field squeezing,coherent population trapping,optical cavities,quantum optics,three-level atoms
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - On the Transfer of Quantum-Optic Pair Sources Realized on SOI Photonics to Electronic Wafers
摘要： A micro-ring assisted photon-pair engine for CWDM and DWDM emission is implemented on silicon-on-insulator technology. Coincidences in pair emission show a 95% visibility for the photonic die. Just a small degradation is observed after wafer-level transfer to a BiCMOS electronics wafer in the 1550-nm region.
关键词： Photon pair source,3D Integration,Silicon photonics,Quantum optics
更新于2025-09-23 15:22:29
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Majorization preservation of Gaussian bosonic channels
摘要： It is shown that phase-insensitive Gaussian bosonic channels are majorization-preserving over the set of passive states of the harmonic oscillator. This means that comparable passive states under majorization are transformed into equally comparable passive states by any phase-insensitive Gaussian bosonic channel. Our proof relies on a new preorder relation called Fock-majorization, which coincides with regular majorization for passive states but also induces another order relation in terms of mean boson number, thereby connecting the concepts of energy and disorder of a quantum state. The consequences of majorization preservation are discussed in the context of the broadcast communication capacity of Gaussian bosonic channels. Because most of our results are independent of the speci?c nature of the system under investigation, they could be generalized to other quantum systems and Hamiltonians, providing a new tool that may prove useful in quantum information theory and especially quantum thermodynamics.
关键词： quantum channels,majorization theory,passive states,gaussian bosonic channels,quantum optics
更新于2025-09-23 15:21:21
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Cooling atomic ions with visible and infra-red light
摘要： We demonstrate the ability to load, cool and detect singly charged calcium ions in a surface electrode trap using only visible and infrared lasers for the trapped-ion control. As opposed to the standard methods of cooling using dipole-allowed transitions, we combine power broadening of a quadrupole transition at 729 nm with quenching of the upper level using a dipole allowed transition at 854 nm. By observing the resulting 393 nm ?uorescence we are able to perform background-free detection of the ion. We show that this system can be used to smoothly transition between the Doppler cooling and sideband cooling regimes, and verify theoretical predictions throughout this range. We achieve scattering rates which reliably allow recooling after collision events and allow ions to be loaded from a thermal atomic beam. This work is compatible with recent advances in optical waveguides, and thus opens a path in current technologies for large-scale quantum information processing. In situations where dielectric materials are placed close to trapped ions, it carries the additional advantage of using wavelengths which do not lead to signi?cant charging, which should facilitate high rate optical interfaces between remotely held ions.
关键词： trapped ions,laser cooling,quantum optics
更新于2025-09-23 15:21:21
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Topological Quantum Optics Using Atomlike Emitter Arrays Coupled to Photonic Crystals
摘要： We propose an experimentally feasible nanophotonic platform for exploring many-body physics in topological quantum optics. Our system is composed of a two-dimensional lattice of nonlinear quantum emitters with optical transitions embedded in a photonic crystal slab. The emitters interact through the guided modes of the photonic crystal, and a uniform magnetic field gives rise to large topological band gaps, robust edge states, and a nearly flat band with a nonzero Chern number. The presence of a topologically nontrivial nearly flat band paves the way for the realization of fractional quantum Hall states and fractional topological insulators in a topological quantum optical setting.
关键词： Chern number,quantum emitters,fractional quantum Hall states,photonic crystals,topological quantum optics
更新于2025-09-23 15:21:01
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Discrimination of entangled photon pair from classical photons by de Broglie wavelength
摘要： Quantum optics largely relies on the fundamental concept that the diffraction and interference patterns of a multi-partite state are determined by its de Broglie wavelength. in this paper we show that this is still true for a mixed state with one sub-system being in a classical coherent state and one being in entangled state. We demonstrate the quantum-classical light discrimination using de Broglie wavelength for the states with all classical parameters being the same.
关键词： entangled photons,de Broglie wavelength,quantum optics,classical photons,quantum-classical discrimination
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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functions
摘要： We propose a quantum optical device to experimentally realize quantum processes, which perform the regularization of the—in general highly singular—Glauber–Sudarshan P functions of arbitrary quantum states before their application and/or measurement. This allows us to produce a broad class of nonclassical states with regular P functions, also called nonclassicality quasiprobabilities. For this purpose, the input states are combined on highly transmissive beam splitters with specific Gaussian or non-Gaussian classical states. We study both balanced and unbalanced homodyne detections for the direct sampling of the output states of the implemented processes, which requires no further regularization or state-reconstruction. By numerical simulations we demonstrate the feasibility of our approach and we outline the generalization to multimode light.
关键词： quantum processes,Glauber–Sudarshan P functions,homodyne detection,nonclassical states,quantum optics
更新于2025-09-23 15:21:01
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Laser spectroscopy of pionic helium atoms
摘要： Charged pions are the lightest and longest-lived mesons. Mesonic atoms are formed when an orbital electron in an atom is replaced by a negatively charged meson. Laser spectroscopy of these atoms should permit the mass and other properties of the meson to be determined with high precision and could place upper limits on exotic forces involving mesons (as has been done in other experiments on antiprotons). Determining the mass of the π? meson in particular could help to place direct experimental constraints on the mass of the muon antineutrino. However, laser excitations of mesonic atoms have not been previously achieved because of the small number of atoms that can be synthesized and their typically short (less than one picosecond) lifetimes against absorption of the mesons into the nuclei. Metastable pionic helium (π4He+) is a hypothetical three-body atom composed of a helium-4 nucleus, an electron and a π? occupying a Rydberg state of large principal (n ≈ 16) and orbital angular momentum (l ≈ n ? 1) quantum numbers. The π4He+ atom is predicted to have an anomalously long nanosecond-scale lifetime, which could allow laser spectroscopy to be carried out. Its atomic structure is unique owing to the absence of hyperfine interactions between the spin-0 π? and the 4He nucleus. Here we synthesize π4He+ in a superfluid-helium target and excite the transition (n, l) = (17, 16) → (17, 15) of the π?-occupied π4He+ orbital at a near-infrared resonance frequency of 183,760 gigahertz. The laser initiates electromagnetic cascade processes that end with the nucleus absorbing the π? and undergoing fission. The detection of emerging neutron, proton and deuteron fragments signals the laser-induced resonance in the atom, thereby confirming the presence of π4He+. This work enables the use of the experimental techniques of quantum optics to study a meson.
关键词： pionic helium atoms,Laser spectroscopy,mesons,quantum optics
更新于2025-09-23 15:21:01
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Wehrl entropy based quantification of nonclassicality for single mode quantum optical states
摘要： Nonclassical states of a quantized light are described in terms of Glauber-Sudarshan P distribution which is not a genuine classical probability distribution. Despite several attempts, defining a uniform measure of nonclassicality (NC) for the single mode quantum states of light is yet an open task. In our previous work [Phys. Rev. A 95, 012330 (2017)] we have shown that the existing well-known measures fail to quantify the NC of single mode states that are generated under multiple NC-inducing operations. In this paper, we propose a new quantification of NC for the single mode quantum states as the difference between the total Wehrl entropy of the state and the maximum Wehrl entropy arising due to its classical characteristics. The classical reference state is chosen at the same randomness, given by the von-Neumann entropy, as the state itself. We further suggest operational interpretation of the proposed measure in terms of phase-space sampling entropy as well as potential to generate entanglement, in the case of pure states. We obtain analytic expressions of NC for pure states and Gaussian mixed states. We show that, along with the states generated under single NC-inducing operations, also for the broader class of states that are generated under multiple NC-inducing operations, our quantification enumerates the NC consistently. However, the evaluation of NC for the non-Gaussian mixed states is subject to extensive numerical computation that lies beyond the scope of the current work. We finally conclude with certain open questions.
关键词： Wehrl Entropy,Quantumness,Phase Space Distributions,Quantum Optics,Nonclassicality
更新于2025-09-23 15:21:01