An internal symmetry in a lattice model is said to be onsiteable if it can be disentangled into an on-site action by introducing ancillas and conjugating with a finite-depth circuit. A standard lore holds that onsiteability is equivalent to being anomaly-free, which is indeed valid for finite 0-form symmetries in $(1+1)\mathrm{D}$. However, for higher-form symmetries, these notions become inequivalent: a symmetry may be on site while still anomalous. In this Letter, we clarify the conditions for onsiteability of higher-form symmetries by proposing an equivalence between onsiteability and the possibility of higher gauging. For a finite 1-form symmetry in $(2+1)\mathrm{D}$, we show that the symmetry is onsiteable if and only if its ‘t Hooft anomaly satisfies a specific algebraic condition that ensures the symmetry can be 1-gauged. We further demonstrate that onsiteable 1-form symmetry in $(2+1)\mathrm{D}$ can always be brought into transversal Pauli operators by ancillas and circuit conjugation. In generic dimensions, we derive necessary conditions for onsiteability using lattice ‘t Hooft anomaly of higher-form symmetry, and conjecture a general equivalence between onsiteability and possibility of higher gauging on lattices. We also identify new “lattice anomalies” intrinsic to higher-form symmetry of lattice models, obstructing on-site realization of symmetry beyond the possibility of higher gauging in continuum.

A mechanism for electrically tunable $\mathcal{P}\mathcal{T}$-symmetric magnonic lasing and antilasing is proposed along with a device consisting of a current-biased region in a magnetically ordered planar waveguide. Within the bias area, several heavy-metal wires carrying dc charge currents are periodically attached to the waveguide, generating spatially periodic spin-orbit torques that produce electrically modulated magnon gain and loss. We demonstrate that despite the nonlinear magnon dispersion, this decorated waveguide can emit a strong, single frequency magnon mode at the Bragg point (lasing) and also absorb at the same frequency phase-matched incoming coherent magnons (antilasing). In contrast to spin torque oscillators with multimode excitations driven solely by gain, the $\mathcal{P}\mathcal{T}$-symmetric gain-loss balance stabilizes a single magnon mode operation. The underlying physics is captured by an analytical model and validated with full material and device-specific numerical simulations. We further show that the magnonic laser absorber can be electrically tuned and implemented in ring geometries and for antiferromagnetic ordering. These results establish an experimentally realistic platform where a single element functions simultaneously as a magnon laser and absorber, opening opportunities for reconfigurable non-Hermitian magnonics and integrated magnon signal processing.

We present a fully Gaussian and experimentally feasible scheme for the simultaneous estimation of the four real parameters that characterize a two-channel optical network. The scheme utilizes a two-mode squeezed probe and balanced homodyne detection at both output ports, for which we derive the complete classical Fisher information matrix analytically. Our scheme achieves the Heisenberg-scaling sensitivity for all four parameters simultaneously, enabling full multiparameter characterization of the two-channel interferometric network. We further show, by maximum-likelihood estimation, that the corresponding multiparameter Cramér-Rao bounds are saturated with a modest number of experimental repetitions and for low photon number. The scheme establishes a practical route to Heisenberg-scaling multiparameter Gaussian metrology for a two-channel network, with direct relevance to calibration and sensing in integrated photonics and distributed quantum-enhanced measurement architectures.

We report on the control and characterization of the isomer population of ions inside superfluid helium nanodroplets, using two-color operation of a dual-oscillator infrared free-electron laser. The timing of both lasers is highly synchronized and their frequencies (or “colors”) can be tuned independently over a wide range. Interaction of the singly deuterated proton-bound dimer of dihydrogen phosphate and formate inside helium nanodroplets with both colors enables the control over its isomer population and the recording of—one-color hidden—infrared spectra of individual isomers.

Laser cooling and trapping of atomic matter waves in optical potentials has enabled rapid progress in quantum science, particularly when combined with Rydberg excitation of the atoms to induce long-range interactions. Here, we propose the local manipulation and spatiotemporal sculpting of the electronic matter wave of a Rydberg atom by a laser field focused so that its beam width is smaller than the Rydberg electron orbit. We compute the electronic eigenstates in the presence of a sharply focused Gaussian laser beam, and find strong Rydberg state mixing leading to large kilo-Debye dipole moments. These can be modulated with high bandwidth controlled by the local tweezer intensity. Oscillations in the position-dependent level shifts, analogous to the potential wells allowing ultralong-range Rydberg molecules to form, provide opportunities for eccentric radial trapping of the Rydberg electron via ponderomotive forces acting on suborbital length scales.

Critical points (CPs) in ferroelectrics are known for their association with giant dielectric and electromechanical responses, yet their structural origin, especially in nonrelaxor systems, remains unclear. We combine in situ biasing-heating transmission electron microscopy with first-principles-based simulations to map polarization disorder across the electric-field-temperature ($E$, $T$) phase diagram of single-crystal ${\mathrm{BaTiO}}_3$ (BTO). Near-CP conditions, Fourier-space analysis of high-resolution images shows diffuse broadening at the (001) point, suggesting randomized Ti off centering and local lattice distortion. Simulation reproduces and extends these trends: selected piezoelectric and dielectric coefficients peak along the ferroelectric phase boundary and its Widom-line continuation, while probability-density functions for unit cell dipoles broaden (higher disorder) near the CP and then narrow with increasing field (field-aligned ordering). This unified evidence identifies a disorder-driven enhancement of piezoelectricity in BTO near the CP and explains its decline in the supercritical regime. The results clarify the microscopic origin of the response maximum and suggest a practical route: tuning the disorder-order balance to maximize piezoelectric and other functional properties.

Scattering between dark matter (DM) and protons leads to suppressed small-scale fluctuations, with implications for a variety of cosmological observables. In this Letter, we search for evidence of DM-proton scattering with an interaction cross section $\sigma ={\sigma }_0(v/c{)}^n$ for $n=0$, 2 and 4, corresponding, e.g., to velocity-independent contact interactions from heavy mediators, velocity-dependent pseudoscalar-mediated scattering, and higher-order dipole interactions, respectively, using high-redshift ($z\sim 4–10$) ultraviolet galaxy luminosity functions (UVLFs) observed by the Hubble Space Telescope (HST). We employ an adjusted implementation of gallumi combined with the modified Boltzmann solver class dmeff that accounts for interacting DM, and incorporate UVLF data from both blank and lensed HST fields, alongside Planck CMB data and the Pantheon supernova catalog in a Bayesian analysis framework to set constraints on ${\sigma }_0$. Our results show that including lensed UVLF data, which probe fainter galaxies than the blank HST fields and thus smaller scales, leads to a substantial improvement in the constraints on ${\sigma }_0$ for $n>0$, surpassing existing bounds from Milky Way (MW) satellite abundance and CMB anisotropies. For $m_{\chi }=1\mathrm{MeV}$, for example, we set the upper bounds at $1.1\times {10}^{-25}{\mathrm{cm}}^2$ for $n=2$ and $2.1\times {10}^{-22}{\mathrm{cm}}^2$ for $n=4$. For $n=0$, our bound is within an order of magnitude of those from the Lyman-$\alpha$ forest and MW satellites.

The James Webb Space Telescope (JWST) has discovered bright galaxies at high redshifts ($z\approx 10–14$) and various galaxy candidates extending to even higher redshifts ($z\approx 15–30$). Many astrophysical and beyond the Standard Model physics scenarios have been proposed to explain these observations. We investigate, for the first time, the implications of dark matter (DM) scattering with baryons (protons and electrons) in light of the JWST UV luminosity function (UVLF) observations. These interactions suppress structure formation on galactic scales, which may have an observable effect on the UVLF measurements at high redshifts. Using a recent galaxy formation model designed to explain high-redshift observations, we obtain strong upper limits on DM-baryon scattering cross sections and explore new regions of the parameter space. For DM-proton scattering with cross section $\propto v^{-2}$ velocity dependence, we obtain the strongest limit for DM masses of $\sim 1–500\mathrm{MeV}$. For other cases that we study (DM-proton scattering cross section $\propto v^0,v^{-4}$ and DM-electron scattering cross section $\propto v^0,v^{-2},v^{-4}$), our limits are competitive with those obtained from other cosmological observables. Our Letter highlights the potential of JWST observations as a novel and powerful probe of nongravitational interactions of DM.

Quantum state readout with minimal resources is crucial for scalable quantum information processing. As a leading platform, neutral atom arrays rely on fluorescence readout, requiring short-exposure schemes to mitigate heating and atom loss. However, a fundamental challenge arises in the single-photon regime where severe overlap in state distributions causes conventional threshold discrimination to fail. Here, we report a neural-network-assisted Bayesian inference method for fluorescence readout in neutral atom arrays. We introduce a weakly anchored Bayesian scheme that requires calibration of only one state, addressing asymmetric calibration challenges common across quantum platforms. Acceleration via a permutation-invariant neural network, yields a 100-fold speedup by compressing Bayesian inference into a single forward pass. The approach achieves relative readout fidelity above 99% and 98% for histogram overlaps of 61% and 72%, respectively, enabling reliable extraction of Rabi oscillations and Ramsey interference—results unattainable with conventional threshold-based methods.

Dissipation, originating from intrinsic material absorption or leakage to the environment, is usually considered detrimental to wave transport. Here, we experimentally demonstrate a counterintuitive phenomenon where transport is enhanced by deliberately introduced dissipation in phononic crystal. The key to this phenomenon lies in the fact that a nonuniform dissipation texture reshapes both the real and imaginary parts of the classical wave dispersion, thereby closing the hybridization gap between two counterpropagating modes and thus enhancing transport. We experimentally verify this finding on a valley phononic crystal with two closely positioned valley kink state channels. When dissipation is added to one of the channels, it is observed that the hybridization gap is reduced and the sound decay in the other channel becomes smaller. Our results reveal the power of dissipation in controlling wave transport, and the proposed scheme is ready to be generalized to various wave devices where crosstalks occur.

Chirality, a widely existing material property in nature that involves breaking the left-right symmetry, has had profound influence on various fields of natural sciences. Nonlinear responses, such as electronic magnetochiral anisotropy (eMChA), have been recognized as sensitive probes for the effects of symmetry breaking and nontrivial quantum geometries in solids. So far, observations of eMChA have primarily been limited to inversion-symmetry broken materials. Here, we report a remarkable chiral transport in centrosymmetric candidate topological superconductor $2\mathrm{M}\text{−}{\mathrm{WS}}_2$ flakes observed via second-harmonic generation under an out-of-plane magnetic field. More importantly, eMChA becomes significant around the crossover temperature $T_{\mathrm{FL}}\sim 25\mathrm{K}$ from the Fermi liquid (FL) to strange metal (SM) in the normal state, which interestingly echoes the anomalously large Nernst response at the same temperature in bulk $2\mathrm{M}\text{−}{\mathrm{WS}}_2$. These observations reveal a direct correspondence between the nonlinear response, Nernst response, and FL-SM transition in $2\mathrm{M}\text{−}{\mathrm{WS}}_2$. Theoretical analysis indicates that nontrivial quantum geometry is behind the simultaneous response of eMChA and Nernst effects in $2\mathrm{M}\text{−}{\mathrm{WS}}_2$ and the contribution from the orbital magnetic moment at the Fermi surface becomes significant during the FL-SM transition. Based on first-principles calculations, a thick-layer-sliding mechanism with minimal energy gain in $2\mathrm{M}\text{−}{\mathrm{WS}}_2$ provides one possibility for the generation of such nontrivial quantum geometry. The intertwined physics of the remarkable eMChA, Nernst response, and FL-SM transition make $2\mathrm{M}\text{−}{\mathrm{WS}}_2$ a rare quantum platform to study the chiral transport and unexplored phenomena in strange metals, which may shed light on one of the trans-century unresolved scientific issues with unconventional high-temperature superconductivity.

In flat-band systems with quenched kinetic energy, most of the conventional length scales related to the band dispersion become ineffectual. Although a few geometric length scales, such as the quantum metric length, can still be defined, because of their embedding dependence, i.e., the dependence on the choice of orbital positions used to construct the tight-binding model, they cannot serve as a universal length scale of the flat-band systems. Here, we introduce an embedding independent length scale ${\xi }_{\mathrm{flat}}$ of a flat band that is defined as the localization length of an in-gap state proximate to the flat band. Because ${\xi }_{\mathrm{flat}}$ is derived from the intrinsic localization of compact localized states, it is solely determined by the Hamiltonian and provides a robust foundation for embedding-independent observables. We show analytically that the superconducting coherence length in a flat-band superconductor is given by ${\xi }_{\mathrm{flat}}$ in the weak-coupling limit, thereby identifying ${\xi }_{\mathrm{flat}}$ as the relevant length scale for many-body phenomena. Numerical simulations on various lattice models confirm all theoretical predictions, including the correspondence between ${\xi }_{\mathrm{flat}}$ and the superconducting coherence length. Our results highlight ${\xi }_{\mathrm{flat}}$ as an intrinsic, embedding-independent length scale governing exponential localization associated with flat bands.

Altermagnetic materials have recently emerged as promising candidates for next-generation spintronic applications, characterized by the $\mathbf{k}$-dependent spin-splitted band structure and a simultaneous zero-net-magnetization. Among them, altermagnetic candidate CrSb has attracted considerable attention, owing to its $g$-wave spin splitting and high Néel temperature. In this Letter, we employed mechanical point-contact spectroscopy with superconducting Nb tips to probe the Andreev reflection on CrSb single crystals along three principal crystallographic orientations. The extracted momentum-dependent spin polarizations are approximately 73.4% for the (0001) plane, 67.9% for the ($\overline{1}\overline{1}20$) plane, and 61.9% for the ($10\overline{1}0$) plane, respectively, distinct from conventional antiferromagnets. Furthermore, conductance spectra from spatial linescans on the sample surface support the existence of altermagnetic domains with a characteristic size of 250–500 nm separated by domain walls with width about 250 nm. These results strongly support the momentum-dependent spin polarization in altermagnetic CrSb and establish Andreev reflection as a new paradigm to probe $\mathbf{k}$-dependent spin textures.

We introduce the concept of orbital altermagnetism, a symmetry-protected magnetic order of pure orbital degrees of freedom. It is characterized with ordered antiparallel orbital magnetic moments in real space but momentum-dependent orbital band splittings, analogous to spin altermagnetism. Using a minimal tight-binding model with complex hoppings in a square-kagome lattice, we show that such order inherently arises from staggered loop currents, producing a $d$-wave-like orbital-momentum locking. First-principles calculations show that orbital altermagnetism emerges independent of spin ordering in in-plane ferromagnets of ${\mathrm{CuBr}}_2$ and ${\mathrm{VS}}_2$, so that it can be unambiguously identified experimentally. On the other hand, it may also coexist with spin altermagnetism, such as in monolayer MoO and CrO. The orbital altermagnetism offers an alternative platform for symmetry-driven magnetotransport and orbital-based spintronics, as exemplified by large nonlinear current-induced orbital magnetization.