We develop a framework for extracting nonpolynomial analytic functions of density matrices in randomized measurement experiments by a method of analytical continuation. A central advantage of this approach, dubbed stabilized analytic continuation (SAC), is its robustness to statistical noise arising from finite repetitions of a quantum experiment, making it well suited to realistic quantum hardware. As a demonstration, we use SAC to estimate the von Neumann entanglement entropy of a numerically simulated quenched Néel state from Rényi entropies estimated via the randomized measurement protocol. We then apply the method to experimental Rényi data from a trapped-ion quantum simulator experiment, extracting subsystem von Neumann entropies at different evolution times. Finally, we briefly note that the SAC framework is readily generalizable to obtain other nonlinear diagnostics, such as the logarithmic negativity and Rényi relative entropies.

Thermal behavior in subsystems of closed quantum systems is commonly attributed to dynamical chaos, quantum ergodicity, canonical typicality, or the eigenstate thermalization hypothesis, suggesting a fundamentally statistical origin of thermalization. Here, we propose a potential alternative mechanism in which thermal structures emerge deterministically from symmetry considerations alone, without recourse to statistical arguments. We prove a finite de Finetti–type theorem for quantum states invariant under energy-preserving unitaries, establishing that the reduced marginals of any such invariant $N$-qudit state are close (both in trace distance and relative entropy) to convex mixtures of thermal product states, with explicit error bounds vanishing as $N\to \infty$. We further present an example of Lindblad dynamics whose longtime limit is invariant under energy-preserving unitaries, providing a dynamical realization of the desired symmetry class. These results imply that invariance under energy-preserving unitaries suffices as a sole fundamental, deterministic principle to enforce thermal structures.

We characterize the causal structure of coherence transport in open bosonic systems using a two-tooth quantum comb. We show that, by mapping sequential interactions between a structured bosonic absorber and a long-lived coherent probe onto a process-tensor description, the probe functions as a temporal interferometer for environmental two-time correlations. We derive closed-form expressions for a nonmonotonic memory response arising from a competition between instantaneous thermal responsivity and the delay-dependent evolution of absorber correlations. By tuning the intertooth delay, the comb can enhance or suppress the net temperature imprint, providing direct access to population correlators and enabling discrimination of spectrally structured non-Markovian fluctuations from effective thermal noise. The protocol provides an explicit bosonic implementation of two-time thermal-correlation sensing, complementary to prior studies of memory effects in noisy quantum metrology.

We demonstrate an interspecies entangling Rydberg gate between rubidium (Rb) and cesium (Cs) atoms with fidelity $\mathcal{F}=0.975\pm 0.002$. The two-species atom array enables in-place quantum nondemolition (QND) qubit measurements which are a key capability for quantum error correction. We demonstrate this functionality with multiatom error syndrome measurements achieving QND measurement fidelities of ${\mathcal{F}}_{\mathrm{QND}}=0.933(12)$ and 0.865(17) for two- and three-qubit plaquettes, respectively.

Quantum metrology harnesses quantum entanglement to improve measurement precision beyond the standard quantum limit. Although nonlinear interaction is essential for generating entanglement, during signal accumulation, it becomes detrimental and therefore must be suppressed. To address this challenge, we propose an alternating in-phase and quadrature modulation (AIQM) scheme, designed to operate under a fixed nonlinear interaction. During signal accumulation, our time-interleaved approach sequentially applies the in-phase and quadrature driving fields, thereby eliminating the effects of nonlinear interaction. Our AIQM scheme achieves better metrological performance than conventional schemes, particularly under strong nonlinear interaction and prolonged signal accumulation, with pronounced robustness against parameter variations. Furthermore, we propose a full-stage AIQM protocol in which the one-axis twisting interaction remains fixed throughout the procedure. This protocol exhibits significantly better metrological performance than the protocol without AIQM, and demonstrates strong robustness against detection noise. By selectively eliminating and utilizing nonlinear interactions via AIQM, our work enables high-precision and high-accuracy entanglement-enhanced measurement without requiring active control of the nonlinear interaction for realistic quantum sensing and many-body metrology.

This Letter extends a recent IceCube sterile neutrino search to include unstable sterile neutrinos within the context of a model termed $3+1+\mathrm{Decay}$, which expands upon the $3+1$ model by introducing sterile neutrino decay to invisible particles with coupling constant $g^2$. The model is attractive since it reduces tension between oscillation experiments within the global fits and with constraints that come from cosmological observables. The analysis uses 10.7 years of up-going muon neutrino data with energy 500 GeV to 100 TeV and with improved reconstruction and modeling of systematics. The best-fit point is found to be $g^2=0$, ${\sin }^2(2{\theta }_{24})=0.16$, and $\mathrm{\Delta }{m}_{41}^2=3.5{\mathrm{eV}}^2$, in agreement with the recent $3+1$ sterile neutrino search. Values of $g^2\ge \pi$ are excluded at 95% confidence level. This result substantially limits decay parameter space indicated by recent global fits, disfavoring the decay scenario.

We propose the use of several unconventional materials as detectors for dark matter with mass beneath the MeV scale. These include the transition-metal dichalcogenide ${\mathrm{TiSe}}_2$ hosting a low-energy plasmon in the charge-density-wave phase, ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ containing a low-energy acoustic demon mode, and hole-doped diamond with tunable optical and acoustic plasmon frequencies. We perform first-principles density functional theory computations of their loss functions at nonvanishing momenta and establish their reach into light dark matter parameter space. We show that due to intense low-energy plasmon modes—of different microscopic origin in each—the reach of detectors based on these materials could surpass existing proposals by several orders of magnitude for both dark matter scattering and absorption on electrons. The anisotropic response of these materials, which enables directional detection, renders them exceptionally strong detector candidates, motivating the design and fabrication of future devices.

We report results from searches for new physics models through electron recoils using data collected by the LUX-ZEPLIN experiment during its first two science runs, with a total exposure of $4.2\mathrm{tonne}\text{−}\mathrm{years}$. The observed data are consistent with a background-only hypothesis. Constraints are derived for electromagnetic interactions of solar neutrinos, solar axionlike particles (ALPs), mirror dark matter, and the absorption of bosonic dark matter candidates. The inverse Primakoff process for ${}^{57}\mathrm{Fe}$ deexcitation solar ALPs is considered for the first time. These results represent the most stringent constraints to date on keV-scale Primakoff and ${}^{57}\mathrm{Fe}$ solar ALPs, bosonic dark matter, mirror dark matter, and neutrino millicharge, while remaining competitive for the other signal models investigated.

We determine the complete three-loop QCD soft anomalous dimension for multileg amplitudes involving a single massive colored particle and any number of massless ones. This is achieved by applying a novel strategy based on a light-cone expansion of correlators of semi-infinite Wilson lines using the method of regions. The resulting region integrals depend exclusively on rescaling-invariant ratios that remain finite in the limit. We evaluate these integrals using differential equation techniques. The result is written in terms of uniform weight five generalized polylogarithms of a 12-letter alphabet in three variables, and is compatible with the massless limit as well as with two- and three-particle collinear factorization.

The ground state of the three-proton emitter ${}^{17}\mathrm{Na}$ has been identified. Energy correlations between the protons and the ${}^{14}\mathrm{O}$ residue indicate that its decay is sequential initiated by the emission of a single proton to the ground state of ${}^{16}\mathrm{Ne}$ followed by simultaneous emission of two protons to the ground state of ${}^{14}\mathrm{O}$, and the derived total decay energy is 4.45(3) MeV. The angular distribution of the proton from the first step indicates that this emission is $d$-wave and only consistent with a spin parity of $5/2^{+}$. This assignment is consistent with state-of-the-art Gamow shell-model calculations. As the ground state of ${}^{17}\mathrm{C}$ is $3/2^{+}$, the assigned spin parity of its mirror ${}^{17}\mathrm{Na}$ indicates that the pair presents a new case of ground-state mirror symmetry violation (GMSV). Unlike other GMSV cases, which arise solely from either a Coulomb induced shift or deformation effects, the ${}^{17}\mathrm{Na}/{}^{17}\mathrm{C}$ case is generated by differences in the many-body correlations.

Many optical measurement techniques, such as light scattering from wavelength-scale particles or detecting motion of a surface with an optical lever, encode information in a complex radiation pattern. Extracting all available information is essential for many quantum-enhanced sensing protocols but is often impractical, as it requires multiple detection channels to spatially resolve the scattered signal. We present a new method to visualize how efficiently a measurement scheme captures the information available in the scattered light by mapping out the local contribution to the detection efficiency on the detector surface. We use this tool to experimentally optimize the measurement of the amplitude of motion of a mechanical resonator with a quadrant photodiode. We show that blocking sections of the photodetector enhances sensitivity, counterintuitively yielding a significant improvement in detecting higher-order mechanical modes in the system. We also show how our method can be applied to light scattering measurements of small particles.

We introduce crystal polaritons, hybrid excitations formed when the collective excitations of a periodic quantum-emitter array strongly couple to the resonant Bloch modes of a metasurface. This realizes a cavity-QED platform in which periodic light and periodic matter are treated on the same footing, allowing strong collective light-matter coupling in an extended, lossy, and dispersive nanophotonic structure. To describe this regime, we develop a reciprocal-space few-mode quantization based on macroscopic quantum electrodynamics, which maps the metasurface resonances seen by the emitter array onto a cavity-QED Hamiltonian at each in-plane momentum. We show that both plasmonic surface-lattice resonances and dielectric bound states in the continuum can enter the strong-coupling regime with a single emitter per unit cell. As a consequence of the resonant nonlinearities of the resulting crystal polaritons, the platform enables quantum light generation with efficiencies orders of magnitude higher than those achieved in conventional nonlinear metasurfaces.

We show theoretically that weak quantum fluctuations induced by a nonsymmetric electromagnetic environment may lead to a quantized transconductance of a multiterminal quantum contact rather than to a blockade of transport in the contact. The result suggests the possibility to realize quantum Hall phenomenology without its common ingredients and/or a topological quantum state.

Light-induced sliding ferroelectricity in two-dimensional van der Waals materials enables polarization control via relative layer motion. However, polarization switching occurs on the timescale of shear modes (tens of picoseconds) and requires very large fluences, potentially damaging the samples. Here, using constrained density functional theory and many-body real-time simulations, we demonstrate an ultrafast electronic reversal of the total out-of-plane polarization sign in the photoexcited state, without requiring interlayer sliding, in rhombohedrally stacked transition metal dichalcogenide bilayers. The polarization changes sign relative to its initial ground-state value at moderate fluences and within $\sim 200\mathrm{fs}$, about 50 times faster than the typical shear-mode period. The ultrafast switching is driven by a rearrangement of localized dipoles around the tungsten sites and can be probed by phase-sensitive transient second-harmonic generation measurements. We establish a novel general mechanism for electronic control of low-dimensional ferroelectrics common to all polar multilayers having type II band alignment. Our Letter has direct implications for ultrahigh-speed volatile optical memory operating on subpicosecond timescales.

Motivated by recent progress in moiré superlattices and spin-$1/2$ triangular-lattice antiferromagnets, we study how orbital magnetic flux and Zeeman coupling compete or cooperate in generating internal U(1) gauge flux in a triangular spin liquid. We show that orbital flux favors a chiral spin liquid with staggered internal flux, whereas Zeeman coupling destabilizes the spinon Fermi-pocket state toward a Landau-level state with spontaneous uniform internal flux and conical spin order. We demonstrate this mechanism in a spin-$1/2$ $J_1\text{−}{J}_2\text{−}{J}_{\chi }$ model and further identify thermal Hall and magnetic signatures that distinguish these regimes, with potential applications to moiré Hofstadter-Hubbard systems and triangular-lattice antiferromagnets.