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Shuang Zhang

Publications and source records attributed to Shuang Zhang.

At least 19 recordsLinked to original sources
arXiv2026

Scale-free wave localization at topological multicriticality

Spatial wave localization at boundaries is conventionally restricted to exponential decay. Here, we observe a scale-free boundary mode exhibiting anomalous polynomial decay, highlighted by strictly linear spatial envelopes, driven by topological multicriticality in acoustic metamaterials. We establish a universal geometric bulk-boundary correspondence rooted in singularity theory by mapping n-th order topological multicriticality onto Arnold An catastrophe. We prove that defectiveness in the spatial transfer matrix enforces a (n-1)-th power spatial decay of boundary modes. At a topological tri-critical point, the singularity of winding function manifests as an A2 fold catastrophe. This dictates a strictly linear spatial decay, marking a sharp departure from the conventional exponential scaling paradigm. Using acoustic metamaterial platforms tuned to a tricritical point, we experimentally demonstrate this linear decay envelope in 1D, and further generalize it to two-dimensional systems to realize scale-free corner modes with simultaneous linear decay along orthogonal directions. While existing critical topology frameworks rely on entanglement spectra to diagnose mode existence in gapless regimes, our work bridges catastrophe theory with topological matter at multicriticalities, advancing the field from abstract mode identification to deterministic real-space wavefunction engineering.

physics.optics↗
arXiv2026

Single-Mode Laser Arrays with Size-Invariant Loss Discrimination

In conventional coupled oscillator lattices and laser arrays, expanding the active volume inevitably causes spectral crowding and degrades spatial uniformity, posing a long-standing barrier to high-power single-mode operation. We uncover a dissipative selection mechanism in sparse star networks that decouples modal selectivity from lattice size constraints. By engineering dissipative auxiliary couplings between a central hub and N peripheral resonators, the system establishes an exact star-Laplacian symmetry. This enforces a target eigenstate that is immune to all lossy channels while maintaining equal amplitude across all main nodes. All competing eigenstates break this symmetry, driving the auxiliary loss and opening a persistent, size-independent modal loss gap that prevents multi-mode competition. Realistic microring simulations validate the robustness of this dark-state isolation under electromagnetic dispersion and mechanism extension to arbitrary arrays is allowed when meets the system's exceptional point. By exploiting graph topology to bypass multi-mode competition, this work establishes a general route toward scalable high-power single-supermode laser arrays and robust state selection in coupled non-Hermitian systems.

physics.optics↗
arXiv2026

Spectral window engineering for temporal leakage of synthetic gain waveform

Arbitrary waveform generation enables precise engineering of optical fields. As an alternative, the synthetic wave approach has been proposed to generate virtual-gain waveforms for loss compensation. However, the achievable synthetic gain is severely limited by the finite spectral bandwidth available in realistic experiments. This imposes a rectangular spectral window, causing abrupt spectral truncation and inducing severe temporal leakage in the time domain synthetic response. Here, we introduce spectral window engineering to fundamentally resolve this limitation. By employing smooth-edged spectral filters, such as the Hann and Blackman windows, temporal leakage is pushed deeply into the late-time regime, yielding a significantly extended effective lifetime and reduced residual damping. Using a coupled plasmonic resonator platform, we experimentally validate that our windowed approach suppresses residual damping by more than a factor of two compared to the standard rectangular baseline. Our findings establish a practical and robust spectral filtering strategy to realize high efficiency synthetic gain, with promising prospects for nanodetection and advanced spectroscopy.

physics.optics↗
arXiv2026

Constraining three-nucleon forces in nuclear lattice effective field theory

We study short-range three-nucleon forces (3NFs) in nuclear lattice effective field theory with a chiral two-nucleon interaction at N${}^3$LO. The one-pion-exchange ($c_D$) and contact ($c_E$) terms of the leading 3NF are decomposed into locally and non-locally smeared components and supplemented by partial-wave-resolved pair contacts coupled to the density of a third nucleon. We determine their coefficients from nuclear binding energies for nuclei in the mass range from $A=3$ to $A=40$ and neutron--alpha finite-volume energies. This allows to work out the minimal three-nucleon force that can be used for future precision studies in NLEFT.

nucl-th↗
arXiv2026

Metasurface quantum graphs for polarization-independent certified randomness

Quantum random number generators are crucial for information security, yet existing implementations are hindered by bulky optics, device imperfections, and state alignment constraints. Here, using a compact metasurface platform, we achieve polarization-independent certified randomness by establishing a quantitative quantum graph framework. By mapping multi-channel nanophotonic responses onto graph vertices, we assign metasurface measurements an operational information-theoretic meaning, directly connecting weighted graph degrees to conditional min-entropy estimation. The resulting graph-certified measurements yield robust private randomness even under entanglement-based attacks without complex optics. Experimentally, we fabricate 4- and 6-channel dielectric metasurfaces to implement high-dimensional positive operator-valued measure graphs, successfully certifying randomness with heralded single photons and Poissonian light. By integrating complex quantum measurements into a single passive layer, our metasurface quantum graphs provide a scalable route for integrated quantum technologies.

quant-ph↗
arXiv2026

Universal Drude Weights in One-dimensional Repulsive Fermi Gas

Building on the Bethe ansatz and generalized hydrodynamics, we rigorously establish universal relations between Drude weights governing charge, spin, and energy transport and thermodynamic properties for the one-dimensional repulsive two-component continuum Fermi gas - the paradigmatic integrable Yang-Gaudin model. We analytically derive thermodynamic expressions for charge Drude weights: $D_{nn}$, $D_{nm}$, $D_{ne}$ (responses of particle, magnetization and energy currents to a chemical potential gradient) equal the particle density, magnetization, and temperature times entropy density, respectively. These relations constitute a hallmark of ballistic transport, and can be generalized to other 1D continuum integrable systems. Furthermore, we investigate spin Drude weight ($D_{mm}$, $D_{me}$) at zero and low temperatures. They characterize the magnetization and energy current responses to a magnetic field gradient, revealing an essential spin-charge coupling feature in quantum transport. We find that the Drude weights $D_{nm}$, $D_{mm}$, and $D_{me}$ across the $μ\text{-}H$ plane remarkably map out the zero-temperature phase boundary. This work fills a critical gap in the understanding of transport within integrable quantum gases and furnishes a direct theoretical foundation for future ultracold-atom experiments.

cond-mat.quant-gas↗
arXiv2026

Pseudospin Hall Transport Induced by Berry Curvature

Pseudospin-1 Dirac systems exhibit unique physics distinct from conventional Dirac cones, such as flat-band crossings and non-Abelian characteristics, yet their topological transport properties have remained largely untapped in passive, time-reversal-invariant settings. Here we uncover an in-plane polarity of the Berry-curvature texture in a pseudospin-1 Dirac Hamiltonian, a previously unexplored geometric degree of freedom encoded in the sign-resolved distribution of Berry curvature despite zero net Berry flux, and reveal a new mechanics where Berry curvature induce pseudospin Hall behaviors in a system. We show that the oriented coupling between this momentum-space polarity and a real-space mass gradient governs a geometric selection rule that dictates the emergence of gapless pseudospin Hall modes. By engineering the intracell couplings of a four-site planar lattice, we independently program the Berry-curvature polarity and the spatial mass gradient without altering the host lattice symmetry. Acoustic experiments directly confirm this directional selection rule: reversing the mass gradient closes or reopens the dispersive gap, while pseudospin-selective source excitation launches counterpropagating pseudospin branches along arbitrary prescribed axes. Our work establishes quantum geometric polarity as a versatile tool for reconfigurable wave routing, sensing, and high-capacity quantum applications.

cond-mat.mes-hall↗
arXiv2026

Room-temperature polariton supersolids

Exploring exotic quantum phases of matter at room temperature represents a frontier challenge in modern physics. The supersolid phase, uniquely merging crystalline order with frictionless superfluid flow, stands among the most intriguing macroscopic quantum phenomena. However, all previous demonstrations of supersolidity, whether in ultracold atomic gases or III-V semiconductor-based polariton systems, have been strictly confined to cryogenic temperatures. Here, we report the observation of room-temperature supersolids in photonic-crystal polariton condensates. By integrating a room-temperature-stable perovskite semiconductor with a dispersion-engineered photonic-crystal waveguide, we create a polariton condensate with multi-mode dispersion landscapes and pronounced parametric nonlinearities. Above a critical condensation density, the interacting condensates spontaneously break continuous translational symmetry, creating a non-rigid supersolid phase that simultaneously exhibits emergent crystalline order and global quantum coherence. This work establishes a room-temperature platform for investigating quantum hydrodynamics and developing coherent quantum simulation devices.

cond-mat.quant-gas↗
arXiv2026

Fast-BEV++: Fast by Algorithm, Deployable by Design

The advancement of vision-only BEV (Bird's-Eye-View) perception is hindered by the fundamental trade-off between perception accuracy and deployment efficiency. We introduce Fast-BEV++, resolving this tension through two principles: Fast by Algorithm and Deployable by Design. By decomposing view transformation into a hardware-oriented Index-Gather-Reshape pipeline, Fast-BEV++ eliminates custom kernels while achieving no less than 3 times speedup over baseline methods. Empirically, Fast-BEV++ establishes a new state-of-the-art accuracy-speed trade-off on nuScenes, achieving 0.488 NDS while sustaining real-time inference at over 134 FPS. In particular, depth supervision yields consistent and tangible performance gains, maintaining the highest accuracy among comparable methods. The decomposed architecture enables seamless real-time deployment on production-level platforms, eliminating hardware constraints without loss of efficiency. Code and models are released on the linked project page.

cs.CV↗
arXiv2026

Interference-engineered shortcut to perfect state transfer

Achieving fast, high-fidelity state transfer is fundamental to scalable integrated photonics and quantum information processing. While adiabatic evolution provides inherent robustness against control and fabrication imperfections, its requirement for slow driving leads to impractically long propagation distances in photonic circuits. Existing acceleration strategies, such as shortcuts to adiabaticity (STA), can dramatically shorten evolution times but generally rely on non-native auxiliary couplings or delicate Hamiltonian engineering that are difficult to implement in practice. Here we introduce evolution-pause synthesis (EPS), an interference engineered shortcut protocol that achieves fast, near-perfect state transfer strictly within the native system Hamiltonian. It achieves this by treating transient excitations as coherent resources and canceling their accumulated amplitudes via strategically interleaved pauses. By decoupling relative dynamical phase accumulation from parameter variations, EPS steers open transition trajectories into a closed loop in complex amplitude space, enabling perfect state transfer without auxiliary fields or complex parameter detours. We demonstrate this mechanism in Landau-Zener dynamics and extend it to a multilevel STIRAP process, achieving an 11.8-fold acceleration over the adiabatic baseline. Further, we experimentally validate EPS on a silicon photonic platform, realizing high-fidelity state transfer in a $16\,μ\mathrm{m}$ footprint, a nearly tenfold reduction in device length compared with a $150\,μ\mathrm{m}$ adiabatic reference. EPS offers a general hardware-compatible framework for fast, practical coherent control across wave and quantum platforms.

physics.optics↗
arXiv2026

Imaginary Gauge Fields for One-Way Transparency and Absorption in a Passive Metasurface

Electromagnetic nonreciprocity enables waves to respond differently when their propagation direction is reversed, forming the basis of isolation, directional routing, and asymmetric energy control. A central challenge is to achieve high transmission in one direction while inducing strong absorption in the opposite direction within a single passive element, as passive material dissipation typically attenuates both propagation channels equally. Here we demonstrate that an imaginary artificial gauge field can redistribute net dissipation between opposite directions in a passive structure. By synthesizing a moving-type magnetoelectric response from gyromagnetic elements and subwavelength metallic resonators, we realize a polarization-independent metasurface in which the forward wave weakly excites the dissipative resonance through destructive current interference, whereas the backward wave strongly activates the same lossy mode through constructive interference. The fabricated metasurface transmits more than 80% of the incident power from one side while absorbing more than 80% from the opposite side, with low reflection from both directions. Near-field mapping of the surface electric field provides direct real-space evidence of this gauge-controlled, direction-dependent charge accumulation and dissipation. This work establishes imaginary gauge fields as a powerful route for engineering dissipative landscapes in open wave systems and opens a pathway toward compact, passive, reflectionless isolators and nonreciprocal absorbers.

physics.optics↗
arXiv2026

Plasma-state metasurfaces for ultra-intensive field manipulation

High-power lasers offer ultrahigh intensities for plasma interactions, but they lack advanced techniques to control the properties of the fields, because no optical elements could withstand their high intensities. The vibrant field of metasurfaces has transformed modern optics by enabling unprecedented control over light at subwavelength through deliberate design. However, metasurfaces have traditionally been limited to solid-state materials and low light intensities. Extending the sophisticated capabilities of metasurfaces from solids into the plasma realm would open new horizons for high-field science. Here, we experimentally demonstrate plasma-state metasurfaces (PSMs) through the photonic spin Hall effect and stable-propagating vortex beam generation irradiated by intense light. Time-resolved pump-probe measurements reveal that the functionality of PSMs can persist for several picoseconds, making them suitable for controlling ultra-intense femtosecond lasers, even in state-of-the-art multi-petawatt systems. Harnessing the powerful toolkit of metasurfaces, this approach holds the promise to revolutionize our ability to manipulate the amplitude, phase, polarization, and wavefront of high-power lasers during their pulse duration. It also opens new possibilities for innovative applications in laser-plasma interactions such as compact particle acceleration and novel radiation sources.

physics.plasm-ph↗
arXiv2026

Full Uncertainty Quantification of Sign-Problem-Free Quantum Monte Carlo Methods and Nuclear Lattice Effective Field Theory Benchmarks

Sign-problem-free quantum Monte Carlo (QMC) methods provide one of the few polynomial-scaling routes to controlled, nonperturbative benchmarks of medium-mass and heavy nuclei. We present a detailed uncertainty analysis of the recently developed sign-problem-free spin-orbit lattice action LAT-OPT1 and use it to benchmark nuclear lattice effective field theory (NLEFT). We quantify various systematic uncertainties, finding that the cumulative many-body computational uncertainty in ground-state energies of doubly magic nuclei up to $^{100}$Sn is well below the percent level. In response to recent criticism of NLEFT benchmarks, we also revisit the relation between lattice transfer matrices, lattice Hamiltonians, Hartree--Fock variational bounds, finite-box and thermodynamic-limit calculations, and the continuum-limit behavior of regulated lattice interactions. We identify several conceptual and technical errors in the analysis of Ref.~\cite{Rothman2026_NuLattice}. These include (i) the comparison of inequivalent lattice transfer-matrix and lattice-Hamiltonian calculations, (ii) an inconsistent determination of correlation energies from comparisons of Hartree--Fock and full ground-state calculations with different boundary conditions, (iii) the attribution of nuclear saturation to lattice artifacts rather than to nonlocal smearing of interactions, a mechanism that can be demonstrated in continuous space, and (iv) an incorrect renormalization of short-range two-body interactions in the continuum limit. When the same regulated lattice theory, renormalization prescription, and finite-volume boundary conditions are used consistently and analyzed properly, the reported discrepancies and concerns about the corresponding published NLEFT results are resolved.

nucl-th↗
arXiv2026

EdgeFM: Efficient Edge Inference for Vision-Language Models

Vision-language models (VLMs) have demonstrated strong applicability in edge industrial applications, yet their deployment remains severely constrained by requirements for deterministic low latency and stable execution under resource limitations. Existing frameworks either rely on bloated general-purpose designs or force developers into opaque, hardware-specific closed-source ecosystems, leading to hardware lock-in limitation and poor cross-platform adaptability. Observing that modern AI agents can efficiently search and tune configurations to generate highly optimized low-level kernels for standard LLM operators, we propose EdgeFM, a lightweight, agent-driven VLM/LLM inference framework tailored for cross-platform industrial edge deployment. EdgeFM removes non-essential features to reduce single-request latency, and encapsulates agent-tuned kernel optimizations as a modular library of reusable skills. By allowing direct invocation of these skills rather than waiting for closed-source implementations, it effectively closes the performance gap long dominated by proprietary toolchains. The framework natively supports mainstream platforms including x86 and NVIDIA Orin SoCs, and represents the first end-to-end VLA deployment on the domestic Horizon Journey platform, enhancing cross-platform portability. In most cases, it yields clearly better inference performance than conventional vendor-specific toolchains, achieving up to 1.49 times speedup over TensorRT-Edge-LLM on the NVIDIA Orin platform. Experimental results show that EdgeFM delivers favorable end-to-end inference performance, providing an open-source, production-grade solution for diverse edge industrial scenarios.

cs.CV↗
arXiv2026

Nuclear charge radii of aluminium isotopes at the proton drip line

Understanding the evolution of nuclear size away from stability remains a central challenge in nuclear physics. In neutron-deficient systems, charge radii can be highly sensitive to the interplay between strong and electromagnetic interactions, and the effects of weak binding, giving rise to exotic nuclear phenomena. However, experimental data on these systems has been limited by short lifetimes and low production rates. Here we report the first laser-spectroscopy measurements of nuclear charge radii along the neutron-deficient aluminium isotopic chain, from $^{25}$Al to the proton-drip-line nucleus $^{22}$Al, using the {Resonance Ionization Spectroscopy Experiment} (RISE) at the {Facility for Rare Isotope Beams} (FRIB). Our measurements reveal a step-like increase in charge radius toward the drip line, with similar radii for $^{22,\,23}$Al. A comparison of our results with those of their mirror partners reveals an almost identical correlation with the calculated proton skins and is consistent with the systematic trend of well-bound nuclei. These results offer insight for understanding the evolution of nuclear size at the proton dripline and place important constraints on modern nuclear theory. They also demonstrate the unique combined capabilities of RISE and FRIB to probe the structures of previously inaccessible nuclei at the limits of existence.

nucl-ex↗
arXiv2026

Non-Hermitian reshaping of high-order Landau modes

When charged particles are subjected to strong magnetic fields, they form discrete energy levels known as Landau levels. The Landau levels consist of a series of degenerate states of Landau modes, making them a promising platform for large-capacity information processing. However, to date, exploiting the high-order Landau modes and control their spatial distributions has remained elusive. Here, we propose to construct magnetic fields, electric fields, and imaginary momentum simultaneously to reshape high-order Landau modes in non-Hermitian systems. By building a non-Hermitian electric circuit platform, we experimentally realize pseudomagnetic fields via inhomogeneous coupling and pseudoelectric fields via a gradient on-site potential, while simultaneously introducing an imaginary momentum via non-reciprocal coupling. We directly observe multi-frequency single-peak localization of high-order Landau modes. Our work provides a universal method for manipulating high-order Landau modes and exploring applications in nonHermitian systems, such as frequency multiplexing and wave packet reshaping.

physics.optics↗
arXiv2026

Multi-neutron correlations in light nuclei via ab-initio lattice simulations

The quest to understand multi-neutron systems has a long history, and recent experimental efforts aim to probe candidate four-neutron configurations in neutron-rich light nuclei such as ${}^8$He and ${}^7$H via quasi-free knockout reactions. However, the ground-state energies of the hydrogen isotopes ${}^6$H and ${}^7$H are not yet well constrained, with substantial discrepancies across experimental analyses and theoretical predictions. Using ab initio nuclear lattice effective field theory with an ensemble of 282 chiral two- and three-nucleon forces, we perform a Bayesian uncertainty-quantified analysis of the ground-state energies of ${}^6$H and ${}^7$H. The marginal posteriors suggest single-neutron separation energy $S_n({}^{7}\mathrm{H})=0.35^{+0.32}_{-0.32}$ MeV, which kinematically disfavors sequential decay via ${}^{6}\mathrm{H}+n$ and thereby makes multi-neutron emission channels comparatively more relevant. Intrinsic densities indicate triton- and $α$-like clusters in ${}^7$H and ${}^8$He, respectively. By computing two-body and reduced four-body correlation functions, we find that the valence neutrons in the surface region of these systems form compact dineutrons that predominantly organize into approximately symmetric dineutron-dineutron configurations, with only a small but non-negligible fraction assembling into more compact tetraneutron-like substructures. In ${}^7$H, these components account for roughly 95\% and 5\% of the sampled four-neutron configurations, respectively, and ${}^8$He exhibits a similar hierarchy. For these configurations, we also extract the corresponding spatial and angular correlation patterns among the nucleons. These results provide nuclear-structure insights into the debate surrounding four-neutron clusters and complement ongoing experimental searches for tetraneutron signatures in light nuclei.

nucl-th↗
arXiv2026

Universal Quantized Berry-Dipole Flat Bands

Perfectly flat bands with nontrivial quantum geometry have emerged as a frontier for exotic topological phenomena and superconductors. Here, we unveil a universal family of quantized Berry-dipole flat bands in chiral-symmetric (2n+1)-band systems, where the central perfectly flat band carries a Berry-dipole moment d=n, with n an arbitrary integer, while preserving zero Chern number. We construct explicit lattice models to showcase three topological phenomena characterized by the Berry-dipole moment: a flat-band returning pump featuring bidirectional, soliton-like displacement of Wannier centers by exactly n unit cells per half cycle, a dipolar Haldane phase diagram arising from the competition between time-reversal and parity symmetries, and n pairs of bulk helical zero modes whose existence depends on the orientation of pseudomagnetic field. Our findings establish a universal framework for the topology beyond Chern class in perfectly flat bands and provide a tunable platform for exploring quantum geometry and interaction-driven phases.

cond-mat.mes-hall↗