Polar skyrmions in ferroelectric superlattices are nanoscale topological polarization textures typically regarded as weakly coupled objects confined to individual layers, with a role secondary to that of the underlying symmetry-breaking order parameter. Here, using large-scale phase-field simulations of ferroelectric superlattices, we uncover a hidden thermal crossover deep inside the ferroelectric phase, where polar skyrmions evolve from an uncorrelated, layer-resolved state into an interlayer-correlated ensemble. This crossover occurs without additional symmetry breaking or a new order parameter, but produces a pronounced broad peak in the dielectric susceptibility. The anomaly originates from the competition between correlation-enhanced response, associated with the growth of interlayer skyrmion correlations, and polarization-induced stiffness, which suppresses dielectric fluctuations at low temperature. Under ac driving, the peak shifts with frequency, resembling relaxor ferroelectrics despite the absence of quenched disorder or polar nanoregions. Our results establish a disorder-free route to relaxorlike dielectric response and identify topological defect correlations as an organizing principle for thermodynamic anomalies, providing a mechanism distinct from conventional critical behavior associated with symmetry breaking and divergent order-parameter fluctuations.

Spin textures are ubiquitous in antiferromagnets, yet their consequences for altermagnets remain largely unexplored. We show that smooth spatial variations of the Néel order act on itinerant electrons as emergent gauge fields that couple to the altermagnetic sublattice-odd channel. For a coplanar spin helix, this channel generates two responses that vanish when it is removed: a momentum-resolved sublattice-odd spectral structure and a net interband linear dichroism whose principal axes are controlled by the helix wave vector, so the optical response can be steered by the magnetic texture. The dichroism exhibits two distinct regimes separated by a crossover: at low frequencies the absorption axis is locked to the crystal axes, while at high frequencies it tracks the helix. Anisotropic dc transport provides a complementary quantitative signature, and all signatures are robust to weak intrinsic spin-orbit coupling. Our results identify polarization-resolved optics and sublattice-sensitive spectroscopy as direct probes of textured altermagnetic states and suggest a route to direction-selective electronic and optical functionality in altermagnets.

A Floquet ladder lattice (FLL) is created by introducing ultrastrong temporal modulation into a gain-embedded cavity magnonics platform. In contrast to conventional atomic lattices, the FLL is a synthetic polariton lattice manifested in the frequency dimension, embodying light-matter interaction, temporal diffraction, and gain-driven nonequilibrium dynamics. Distinct lattice phenomena—including bistability-enabled exfoliation, edge singularities, compact edge localization, and Floquet band gaps—are experimentally observed and theoretically analyzed. Benefiting from its highly flexible lattice architecture, the FLL enables a superior microwave frequency comb with on-demand engineering capabilities.

Rydberg excitons in two-dimensional semiconductors provide sensitive and nondestructive probes of physics in proximal sample layers that host correlated electronic states. In particular, electron or hole doping of the sample layer is heralded by a strong frequency shift and loss of transition strength of 2s excitons in the sensor layer. In analogy to the attractive polaron observed near the 1s exciton, this redshifted resonance, which we term Rydberg attractive polaron (RAP), has been attributed to the formation of a bound state of a 2s exciton and a remote electron. Through a theoretical analysis of exciton-electron scattering, we show that the nature of the RAP and its underlying trion can only be explained by electron-mediated hybridization of 2s, 2p, and interlayer excitons, endowing the RAP a different structure than the 1s attractive polaron. We anticipate that this new understanding will ensure a more accurate assessment of the signatures of correlated electrons in two-dimensional materials.

The classical SIR model, assuming constant viral traits, represents the cornerstone model for computing key indicators during epidemic outbreaks, such as the expected peak of infections or the impact of control policies. Viral evolution has been reported to challenge the physics of the SIR model, changing the nature of the epidemic transitions or the early-time dynamics of outbreaks. Here we consider a minimal extension of the SIR model, allowing infectiousness to evolve, to explore how the latter mechanism affects the two aforementioned indicators. We show that evolution induces a nonmonotonic behavior of the epidemic peak with the basic reproduction number and undermines the impact of control policies, as lifting interventions too early can lead to worse epidemic scenarios than no action. We derive analytical expressions for the critical mutation rate and intervention time governing this behavior and identify a strong asymmetry between control strategies: while shortening the infectious period hinders transmission without suppressing the evolution of viral infectiousness, lowering transmission both reduces cases and slows down this evolution.

Long-range interactions are ubiquitous in nature, where they are mediated by diffusive fields at the cellular scale or by visual cues for groups of animals. Short-range forces, which are paradigmatic in physics, can thus often be neglected when modeling the collective behaviors of biological systems induced by mediated interactions. However, when self-organization leads to the emergence of dense phases, we show that excluded-volume interactions play an important and versatile role. We consider assemblies of active particles that undergo either condensation or phase separation due to motility regulation and show that short-range repulsive forces can induce opposite effects. When motility regulation triggers an absorbing phase transition, such as a chemotactic collapse, repulsive forces oppose the formation of condensates and stabilize instead the coexistence between finite-density phases. In contrast, when motility regulation induces liquid-gas coexistence, repulsive forces can, counterintuitively, lead to a significant increase in the liquid density.

Ergotropy, the maximum work extractable from a quantum system, is a central resource in quantum physics. Computing ergotropy is well established when the system state is fully known, but its estimation under partial information remains an open problem. Here we introduce a general certification framework that lower bounds ergotropy using only the expectation values of a limited set of arbitrary observables. The method naturally applies in the finite-statistics regime, yielding confidence-certified bounds that explicitly incorporate shot noise. We benchmark our approach on both synthetic data and experimental measurements from an IBM quantum processor. This establishes a robust and experimentally accessible tool for certifying extractable work in realistic quantum settings.

Spontaneous symmetry breaking is one of the central organizing principles in physics. Time crystals have emerged as an exotic phase of matter, spontaneously breaking the time translational symmetry, and are mainly categorized as discrete or continuous. While these distinct types of time crystals have been extensively explored as stand-alone systems, intriguing effects can arise from their mutual interaction. Here, we demonstrate that a time-independent coupled system of discrete and continuous time crystals induces a simultaneous twofold temporal symmetry breaking, resulting in a hierarchical time crystal phase. Interestingly, one of the subsystems breaks a discrete temporal symmetry that is absent from the time-independent Liouvillian generating the dynamics, but instead emerges dynamically, giving rise to a convoluted nonequilibrium phase. We demonstrate that hierarchical time crystals are robust, emerging for fundamentally different coupling schemes and persisting across wide ranges of system parameters.

Proposed quantum advantage in electronic structure has so far required significant fine-tuning to find problems where classical heuristics fail. We describe how to obtain robust quantum speedups for correlated electronic structure and dynamics precisely in the regime where widely used classical heuristics are most successful.

We propose a definition of asymptotically flat spacetimes that is consistent with both null infinities and compatible with known properties of gravitational scattering, incoming and outgoing radiation, and interactions with matter. For this class of spacetimes, we prove three antipodal matching conditions at spatial infinity: one for the so-called dual mass aspect, one for the leading tail of the shear, and one that nontrivially relates the peeling properties of the spacetime at both null infinities to the leading tail and mass aspect at spatial infinity. Furthermore, we reformulate these identities as conservation and flux balance laws defined on the boundary hyperboloid at spatial infinity.

We report the first complete next-to-leading order QCD calculation for processes involving fully charm-tetraquark states, revealing that the renormalization constant of the color-singlet four charm quark operator is exactly unity at this order. We have investigated the possible quark configurations of the fully charm tetraquarks and expanded their states in the color symmetry-antisymmetry basis. By applying the transverse momentum dependent factorization formalism, large logarithms induced by soft and collinear gluon radiations are resummed to all orders in the expansion of the strong interaction coupling at the accuracy of next-to-leading logarithm. By combining LHCb data on the total cross section of the exotic hadron $X(6900)$ and CMS measurements of its spin parity, we extracted its nonperturbative but universal long-distance matrix element. The rapidity and transverse momentum distributions of the $X(6900)$ and its spin-zero partners are also predicted, which await further experimental verification.

Fluctuations of integrated currents have attracted considerable interest over the past decades in the context of statistical mechanics. Recently, anomalous current fluctuations, characterized by the M-Wright function, were obtained exactly in a classical automaton [Ž. Krajnik et al., Phys. Rev. Lett. 128, 160601 (2022)], and previous studies have shown that this anomalous behavior can arise in a variety of classical systems. Despite the rapidly growing interest in such anomalous behaviors, which capture a universal aspect of one-dimensional many-body transport, the exact derivation of the M-Wright function in quantum many-body systems has remained elusive. In this Letter, we present the first exact microscopic derivation of the M-Wright function in quantum many-body dynamics by analyzing the integrated spin current in a one-dimensional Fermi-Hubbard model with infinitely strong repulsive interactions. Our results lay the groundwork for exploring anomalous integrated currents in a broad class of quantum many-body systems.

Metals typically have multiple Fermi-surface sheets, and when they enter the superconducting state, some electrons on these sheets may remain uncondensed, or their superconducting pairs can be rapidly destroyed by a magnetic field. Detecting uncondensed electrons within the superconducting state provides key information about the underlying electronic structure; however, this task remains a significant experimental challenge. Here we demonstrate quantum oscillations from the uncondensed electrons in the heavy-fermion superconductor ${\text{CeCoIn}}_5$, observed through thermal conductivity measurements with a magnetic field rotating within the tetragonal $a\text{−}b$ plane. We detect a fine structure in thermal conductivity characterized by multiple small resonances (oscillations) in a rotating magnetic field. Remarkably, the phase of these resonances shifted by as much as $\pi$ for a field above 9.7 T where spin-density wave (SDW) order emerges and coexists with superconductivity. This approximate $\pi$-phase shift in resonance can be naturally interpreted as a Berry-phase evolution associated with an SDW-induced reconstruction of the uncondensed Fermi surface, within the superconducting state. Our work strongly supports the existence of uncondensed electrons in the superconducting state of ${\text{CeCoIn}}_5$, thus resolving a long-standing debate on this issue.

Exceptional points in non-Hermitian photonics provide singular responses for topological light-field control. Yet, converting such singular responses into coupled control over multiple optical degrees of freedom remains a central challenge. Here, based on a plasmonic non-Hermitian metasurface described by a reflection Jones matrix, we theoretically and experimentally reveal the parameter-space topology associated with zero-eigenvalue exceptional points. In this regime, zero-eigenvalue degeneracy preserves the singular topological features of non-Hermitian systems while elevating controllability from scalar phase modulation to coupled control of both phase and polarization, manifested as vectorial phase singularities. As a proof of concept, we implemented precise local structural tuning in a plasmonic non-Hermitian metasurface to achieve simultaneous alignment of reflection-coefficient zeros across multiple polarization channels and observed the radial collapse of scaled eigenstates on the Bloch sphere. Based on such vectorial phase singularities, we experimentally synthesized polarization-phase composite vortices, opening new avenues for high-dimensional light-field manipulation, vector holography, and topological photonic device design.

Layered van der Waals (vdW) magnetic semiconductors open a new avenue for exploring intertwined excitonic and magnetic phenomena. Here, we investigate this interplay in the vdW antiferromagnet ${\mathrm{MnPS}}_3$, uncovering an exceptionally long exciton lifetime ($\sim 100\mathrm{\mu }\mathrm{s}$) below the Néel temperature ($T_N$). We demonstrate that the exciton lifetime is primarily governed by phonon-assisted nonradiative recombination and thus exhibits a strong temperature dependence. In contrast, the exciton radiative recombination shows a distinct temperature dependence that is sensitive to magnetic order. Below $T_N$, the temperature dependence of the radiative recombination rate is consistent with a magnon-assisted emission pathway, while above $T_N$ it reflects the combined effects of short-range spin correlations and phonons. These findings not only establish ${\mathrm{MnPS}}_3$ as a compelling candidate for excitonic devices due to its long lifetime and correlation with magnetic orders but also provide crucial insights into the interplay between excitons, spins, and lattices in vdW magnetic semiconductors.

Accumulation at boundaries represents a widely observed phenomenon in active systems with implications for microbial ecology and engineering applications. To rationalize the underlying physics, we study the first-passage properties and spatial distributions of an active Brownian particle (ABP) in a channel. Leveraging Siegmund duality, we establish a direct mapping between the propagators of ABPs with absorbing and hard-wall boundary conditions, yielding analytical results in both problems. We analyze the system across low and high activity regimes—quantifying persistent motion relative to diffusion—and show that active motion, together with a favorable initial orientation, typically lowers the mean first-passage time relative to passive diffusion. Notably, the full time-dependent propagator between hard walls approaches a wall-accumulated stationary state, given by the derivative of the splitting probability as a consequence of Siegmund duality.