From AI-assisted art creation to large language model (LLM)-powered ChatGPT, AI-generated contents and services are becoming a transforming force. It calls for the telecom industry to embrace the prospects of AIGC ser...
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A key method to produce trapped and laser-cooled molecules is the magneto-optical trap (MOT), which is conventionally created using light red detuned from an optical transition. In this work, we report a MOT for CaF m...
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A key method to produce trapped and laser-cooled molecules is the magneto-optical trap (MOT), which is conventionally created using light red detuned from an optical transition. In this work, we report a MOT for CaF molecules created using blue-detuned light. The blue-detuned MOT (BDM) achieves temperatures well below the Doppler limit and provides the highest densities and phase-space densities reported to date in CaF MOTs. Our results suggest that BDMs are likely achievable in many relatively light molecules including polyatomic ones, but our measurements suggest that BDMs will be challenging to realize in substantially heavier molecules due to sub-mK trap depths. In addition to record temperatures and densities, we find that the BDM substantially simplifies and enhances the loading of molecules into optical tweezer arrays, which are a promising platform for quantum simulation and quantum information processing. Notably, the BDM reduces molecular number requirements ninefold compared to a conventional red-detuned MOT, while not requiring additional hardware. Our work therefore substantially simplifies preparing large-scale molecular tweezer arrays, which are a novel platform for simulation of quantum many-body dynamics and quantum information processing with molecular qubits.
The competition between scrambling and projective measurements can lead to measurement-induced entanglement phase transitions (MIPT). In this work, we show that the universality class of the MIPT can be drastically al...
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The competition between scrambling and projective measurements can lead to measurement-induced entanglement phase transitions (MIPT). In this work, we show that the universality class of the MIPT can be drastically altered when the system has a diffusing conserved density. As a numerical tractable model of this, we study a 1+1d random Clifford circuit locally monitored by classically diffusing particles (“measurers”). The resulting diffusive correlations in the measurement density are a relevant perturbation to the usual space-time random MIPT critical point, producing a new universality class for this phase transition. We find “Griffiths-like” effects due to rare space-time regions where, e.g., the diffusive measurers have a low or high density, but these are considerably weaker than the Griffiths effects that occur with quenched randomness that produce rare spatial regions with infinite lifetime.
Metamaterial absorbers have sparked widespread interest due to their remarkable electromagnetic properties, which enable a wide range of applications in light absorption and manipulation. This study introduces a new t...
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Slowing down light in on-chip photonic devices strongly enhances the light-matter interaction, but typically also leads to increased backscattering and small-bandwidth operation. It was shown recently that, if one mod...
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Slowing down light in on-chip photonic devices strongly enhances the light-matter interaction, but typically also leads to increased backscattering and small-bandwidth operation. It was shown recently that, if one modifies the edge termination of a photonic Chern insulator such that the edge mode wraps many times around the Brillouin zone, light can be slowed to arbitrarily low group velocity over a large bandwidth, without being subject to backscattering. Here we study the robustness of these in-gap slow light modes against fabrication disorder, finding that disorder on scales significantly larger than the minigaps between edge bands is tolerable. We identify the mechanism for wavepacket breakup as disorder-induced velocity renormalization and calculate the associated breakup time.
Unmanned Aerial Vehicles(UAVs)will be essential to support mission-critical applications of Ultra Reliable Low Latency Communication(URLLC)in futuristic Sixth-Generation(6G)***,several security vulnerabilities and att...
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Unmanned Aerial Vehicles(UAVs)will be essential to support mission-critical applications of Ultra Reliable Low Latency Communication(URLLC)in futuristic Sixth-Generation(6G)***,several security vulnerabilities and attacks have plagued previous generations of communication systems;thus,physical layer security,especially against eavesdroppers,is vital,especially for upcoming 6G *** this regard,UAVs have appeared as a winning candidate to mitigate security *** this paper,we leverage UAVs to propose two *** first method utilizes a UAV as Decode-and-Forward(DF)relay,whereas the second method utilizes a UAV as a jammer to mitigate eavesdropping attacks for URLLC between transmitter and receiver ***,we present a low-complexity algorithm that outlines the two aforementioned methods of mitigating interception,*** secrecy rate,and we compare them with the benchmark null method in which there is a direct communication link between transmitter and receiver without the UAV DF ***,simulation results show the effectiveness of such methods by improving the secrecy rate and its dependency on UAV height,blocklength,decoding error probability and transmitter-receiver separation ***,we recommend the best method to enhance the secrecy rate in the presence of an eavesdropper based on our simulations.
We present a novel method for the suppression of laser intensity noise and pulse-to-pulse energy fluctuation, based on second-harmonic generation. This method is broadband, passive, has low complexity, and suppresses ...
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We present a novel method for the suppression of laser intensity noise and pulse-to-pulse energy fluctuation, based on second-harmonic generation. This method is broadband, passive, has low complexity, and suppresses noise uniformly over the noise spectrum. We theoretically model, analytically analyze, and numerically simulate this technique’s performance for cw and nanosecond pulse lasers with different pulse shapes. We demonstrate broadband relative intensity noise suppression of up to 48 dB, and pulse-to-pulse energy fluctuation suppression of up to 50 dB, and highlight the significance of these findings for extending atom trap storage time, e.g., for quantum information processing.
The ground states of interacting one-dimensional metals are generically Luttinger liquids. Luttinger-liquid theory is usually considered for translation invariant systems. The Luttinger-liquid description remains vali...
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The ground states of interacting one-dimensional metals are generically Luttinger liquids. Luttinger-liquid theory is usually considered for translation invariant systems. The Luttinger-liquid description remains valid for weak quasiperiodic modulations; however, as the quasiperiodic modulation gets increasingly strong, it is increasingly renormalized and eventually fails, as the system becomes localized. We explore how quasiperiodic modulation renormalizes the Luttinger parameter characterizing this emergent Luttinger liquid, using the renormalization of transmission coefficients across a barrier as a proxy that remains valid for general quasiperiodic modulation. We find, unexpectedly, that quasiperiodic modulation weakens the effects of short-range interactions, but enhances those of long-range interactions. We support the former finding with matrix-product numerics. We also discuss how interactions affect the localization phase boundary.
Performing analog computations with metastructures is an emerging wave-based paradigm for solving mathematical *** such devices,one major challenge is their reconfigurability,especially without the need for a priori m...
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Performing analog computations with metastructures is an emerging wave-based paradigm for solving mathematical *** such devices,one major challenge is their reconfigurability,especially without the need for a priori mathematical computations or computationally-intensive *** equation-solving capabilities are applied only to matrices with special spectral(eigenvalue)*** we report the theory and design of wave-based metastructures using tunable elements capable of solving integral/differential equations in a fully-reconfigurable *** consider two architectures:the Miller architecture,which requires the singular-value decomposition,and an alternative intuitive direct-complex-matrix(DCM)architecture introduced here,which does not require a priori mathematical *** examples,we demonstrate,using system-level simulation tools,the solutions of integral and differential *** then expand the matrix inverting capabilities of both architectures toward evaluating the generalized Moore-Penrose matrix ***,we provide evidence that metadevices can implement generalized matrix inversions and act as the basis for the gradient descent method for solutions to a wide variety of ***,a general upper bound of the solution convergence time reveals the rich potential that such metadevices can offer for stationary iterative schemes.
We define the entanglement entropy of free fermion quantum states in an arbitrary space-time slice of a discrete set of points and particularly investigate timelike (causal) slices. For one-dimensional lattice free fe...
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We define the entanglement entropy of free fermion quantum states in an arbitrary space-time slice of a discrete set of points and particularly investigate timelike (causal) slices. For one-dimensional lattice free fermions with an energy bandwidth E0, we calculate the time-direction entanglement entropy SA in a time-direction slice of a set of times tn=nτ (1≤n≤K) spanning a time length t on the same site. For zero-temperature ground states, we find that SA shows volume law when τ≫τ0=2π/E0; in contrast, SA∼13lnt when τ=τ0, and SA∼16lnt when τ<τ0, resembling the Calabrese-Cardy formula for one flavor of nonchiral and chiral fermion, respectively. For finite-temperature thermal states, the mutual information also saturates when τ<τ0. For noneigenstates, volume law in t and signatures of the Lieb-Robinson bound velocity can be observed in SA. For generic space-time slices with one point per site, the zero-temperature entanglement entropy shows a clear transition from area law to volume law when the slice varies from spacelike to timelike.
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