It is found that a small distortion caused by magnetostriction and a structural phase transition caused by Jahn-Teller distortion are continuously connected in ${\mathrm{Co}}_{1-x}{\mathrm{Fe}}_x{\mathrm{V}}_2{\mathrm{O}}_4$ under variation of $x$. Spin-orbit coupling in Jahn-Teller-active ${\mathrm{Fe}}^{2+}$ ions gives rise to this novel correlation between spins, orbitals, and the lattice distortion in this series of compounds.

Altermagnets, a new frontier for spintronics, represent a distinct magnet class with nonrelativistic splitting of both electronic and chiral magnon bands, yet experimental verification of their unique magnon dynamics remains scarce. In this Letter, inelastic neutron scattering experiments on $\alpha \text{−}{\text{Fe}}_2{\mathrm{O}}_3$ reveal a clear magnon band splitting about 3 meV at $\sim 100\mathrm{meV}$. We trace the origin of this splitting to the alternating exchange interactions between the 13th nearest neighbors, as supported by first-principles calculations, and confirm that the magnons have chiral splits by theoretical modeling. This definitive characterization of chiral magnons in hematite provides the fundamental insight needed to design and control spin transport in novel spintronic applications.

Partial information decomposition (PID) is a principled and flexible method to unveil complex high-order interactions in multiunit network systems. Though being defined exclusively for random variables, PID is ubiquitously applied to multivariate time series taken as realizations of random processes with temporal statistical structure. Here, to overcome the incomplete and sometimes misleading depiction of high-order effects by PID schemes applied to dynamic networks, we introduce the framework of “partial information rate decomposition (PIRD).” PIRD is first formalized applying lattice theory to decompose the information shared dynamically between a target random process and a set of source processes, and then implemented for Gaussian processes through a spectral expansion of information rates. The PIRD framework is validated in simulated network systems and demonstrated in the practical analysis of time series from large-scale climate oscillations.

While many living biological media combine both viscous and elastic properties, most theoretical studies employ either purely fluid or solidlike descriptions. We here use a unified framework for active films on substrates capable of describing a range of viscoelastic behavior to explore the interplay between activity and rheology. The core of the study is a comprehensive state diagram showing a rich world of spatiotemporal dynamic states. Our results demonstrate the potential of tunable rheology to realize modes of controlled active transport on the microscale.

Collective actuation in active solids—the spontaneous coherent excitation of a few vibrational modes—emerges from feedback between structural deformations and the orientation of active forces. It is an excellent candidate as a basic mechanism for oscillatory dynamics and regulation in dense living systems, and better control over its onset would open new avenues in the life sciences. Combining model experiments, simulations, and theory, we study the dynamics of such an active solid in the presence of an external field that polarizes the active forces. The experiments reveal a novel oscillatory regime absent at zero field. The theoretical analysis of a single agent demonstrates that the small field oscillations and the large field ones can be mapped onto the bounded and unbounded phase dynamics of a nonlinear pendulum. In the many-agents case, the transition to collective actuation is promoted at low field, leading to a reentrant transition.

Neutrino self-interactions beyond the standard model have profound implications in astrophysics and cosmology. In this Letter, we study an uncharted scenario in which one of the three neutrino species has a mass smaller than the temperature of the cosmic neutrino background. This results in a relativistic component that significantly broadens the absorption feature on the astrophysical neutrino spectra, in contrast to the sharply peaked absorption expected in the extensively studied scenarios assuming a fully nonrelativistic cosmic neutrino background. By solving the Boltzmann equations for neutrino absorption and regeneration, we demonstrate that this mechanism provides novel sensitivity to sub-keV mediator masses, well below the traditional $\sim 1–100\mathrm{MeV}$ range. Future observations of the diffuse supernova neutrino background with Hyper-Kamiokande could probe coupling strengths down to $g\sim {10}^{-8}$, surpassing existing constraints by orders of magnitude. These findings open new directions for discoveries and offer crucial insights into the interplay between neutrinos and the dark sector.

Smashing nuclei at ultrarelativistic speeds and analyzing the momentum distribution of outgoing debris provides a powerful method to probe the many-body properties of the incoming nuclear ground states. Within a perturbative description of initial-state fluctuations in the quark-gluon plasma, we express the measurement of anisotropic flow in ultracentral heavy-ion collisions as the quantum-mechanical average of a specific set of operators measuring the harmonic structure of the two-body azimuthal correlations among nucleons in the colliding states. These observables shed a new light on spatial correlations in atomic nuclei while enabling us to test the complementary pictures of nuclear structure delivered by low- and high-energy experiments on the basis of state-of-the-art theoretical approaches rooted in quantum chromodynamics.

We compute the shear viscosity, thermal conductivity, and spin diffusivity of a Fermi gas with short-range interactions in the Fermi liquid regime of the normal phase, that is, at temperatures $T$ much lower than the Fermi temperature $T_{\mathrm{F}}$ and larger than the superfluid critical temperature $T_c$. In line with recent advances in the precision of cold atom experiments, we provide exact results up to the second order in the interaction strength. We extend the Landau-Salpeter equation to compute the collision amplitude beyond the forward-scattering limit, covering all collisions on the Fermi surface. We treat the collision kernel exactly, leading to significant corrections beyond relaxation-time or variational approximations. The transport coefficients, as functions of the $s$ wave scattering length $a$ and Fermi wave number $k_{\mathrm{F}}$, follow $(1+\gamma k_{\mathrm{F}}a)/a^2$ up to corrections of order $O(a^0)$, with a positive coefficient $\gamma$ for the viscosity and negative one for the thermal conductivity and spin diffusivity.

Quantum-enhanced interferometers have been widely used in single-parameter precision measurement, and multiparameter precision measurement is the building block of numerous sensing and imaging applications. However, it remains challenging to realize high-sensitivity multiparameter sensing without increasing power, which is crucial for biological science. Here, we propose and demonstrate a deterministic quantum-enhanced interferometer, where high-sensitivity multiparameter sensing is realized by effectively squeezing noises and amplifying signals. Key technologies are essential to the results, including the parallel and sequential use of squeezed states inside the interferometer. Notably, in the quantum-enhanced three-arm interferometer, not only joint but also individual values of three signals are simultaneously measured with a signal-to-noise ratio of more than $10.37\pm 0.13\mathrm{dB}$ compared with that of the conventional interferometer under the same phase-sensing power. These advances constitute a critical step toward observing multiple elusive signals and give rise to a wide range of sensing and imaging applications.

The optical responses of solids are typically understood to be local in space. Whether locality holds for the optical response of a macroscopic quantum system has, however, been largely unexplored. Here, we use multidimensional coherent spectroscopy at the optical diffraction limit to demonstrate nonlocal optical nonlinearities in a semiconductor microcavity. These nonlocal optical responses are both coherent and quantum in nature, deriving from the macroscopic length scale of confined exciton-polariton wave functions.

We introduce a data-driven approach to learn generalized collision operators from molecular dynamics. Unlike conventional models (e.g., Landau), the present operator takes a symmetry-breaking form that depends not only on the relative velocity but also on the average velocity of the collision pair, capturing heterogeneous energy transfer arising from collective interactions with the environment. Numerical results show that preserving this overlooked anisotropy is crucial for predicting plasma kinetics and transport coefficients in the moderate coupling regime, where the Landau model fails.

We derive the asymptotic forms of the Green’s function at the open edges of general non-Hermitian band systems in all dimensions in the longtime limit, using a modified saddle point approximation and the analytic continuation of the momentum. The edge dynamics is determined by the “dominant saddle point,” a complex momentum which, contrary to previous conjectures, may lie outside the generalized Brillouin zone. From this result, we obtain the effective edge Hamiltonians that evidently, as demonstrated by extensive numerical simulations, characterize the dynamics on the edges and can be probed in real-time experiments or spectroscopies.

Strong light-matter interactions can create nonequilibrium materials with on-demand novel functionalities. For periodically driven solids, the Floquet-Bloch theory provides the natural states to characterize the physical properties of these laser-dressed systems. However, signatures of such Floquet states are needed, as common experimental conditions, such as pulsed laser excitation and dissipative many-body dynamics, can disrupt their formation and survival. Here, we identify a tell-tale signature of Floquet states in the linear optical response of laser-dressed solids that remains prominent even in the presence of the strong spectral congestion of bulk matter. To do so, we introduce a computationally efficient strategy based on the Floquet formalism to finally capture the full frequency dependence in the optical response properties of realistic laser-dressed crystals, and use it investigate the Floquet engineering in a first-principle model for ZnO of full dimensionality. The computations reveal intense, spectrally isolated, laser-controllable, absorption and stimulated emission features at midinfrared energies present for a wide range of laser-driving conditions that arise due to the hybridization of the Floquet states. As such, these spectral features open a purely optical pathway to investigate the birth and survival of Floquet states in crystals while avoiding the experimental challenges of fully reconstructing the band structure of laser-dressed materials.

Nuclear spins’ dipolar order is created under magic angle spinning through the first-order process made possible by simultaneous implementation of dipolar recoupling and adiabatic demagnetization in a reference frame reached out through nested transformations, first from the laboratory frame into the rotating frame, and then into the spin coordinate system nutating inside its parent frame. In such a nutating frame, both the static and resonantly rotating radio-frequency (rf) fields are invisible, and the reintroduced dipolar interaction provides a secular eigenstate on which dipolar order develops with assist of an additional portion of rf field designed to implement adiabatic demagnetization in the nutating frame.

Many swimming bacteria naturally inhabit confined environments, yet how confinement influences their swimming behaviors remains unclear. Here, we combine experiments, continuum modeling, and particle-based simulations to investigate near-surface bacterial swimming in dilute suspensions under varying confinement. Confinement reduces near-surface accumulation and facilitates bacterial escape. These effects are quantitatively captured by models incorporating the force quadrupole, a higher-order hydrodynamic singularity, that generates a rotational flow reorienting bacteria away from surfaces. Under strong confinement, bacterial trajectories straighten due to the balancing torques exerted by opposing surfaces. These findings highlight the role of hydrodynamic quadrupole interactions in near-surface bacterial motility, with implications for microbial ecology, infection control, and industrial applications.

Thermodynamic uncertainty relations (TURs) are a set of inequalities expressing a fundamental trade-off between precision and dissipation in nonequilibrium classical and quantum thermodynamic processes. TURs show that achieving low fluctuations in a thermodynamic quantity (e.g., heat or work) requires a minimum entropy production, with profound implications for the efficiency of biological and artificial thermodynamic processes. The accurate evaluation of TURs is a necessary requirement to quantify the fluctuation and dissipation entailed by a thermodynamic process, and ultimately to optimize the performance of quantum devices, whose operation is fundamentally a quantum thermodynamic process. Here, we simulate TURs in a transverse-field Ising model subjected to a time-dependent driving protocol, using quantum and classical computers in concert. Varying the duration and strength of the drive as well as the system size, we verify the validity of TURs, identify quantum signatures in the work statistics within the linear response regime, and observe TUR saturation in the high-temperature limit.

We theoretically study the influence of frequency uncertainties on the operation of a Kerr-cat qubit. As the mean photon number increases, Kerr-cat qubits provide an increasing level of protection against phase errors induced by unknown frequency shifts during idling and $X$ rotations. However, realizing rotations about the other principal axes (e.g., $Y$ and $Z$ axes) while preserving robustness is nontrivial. To address this challenge, we propose a universal set of gate schemes which circumvents the trade-off between protection and controllability in Kerr-cat qubits and retains robustness to unknown frequency shifts to at least first order. Assuming an effective Kerr oscillator model, we theoretically and numerically analyze the robustness of elementary gates on Kerr-cat qubits, with special focus on gates along nontrivial rotation axes. An appealing application of this qubit design would include tunable superconducting platforms, where the induced protection against frequency noise would allow for a more flexible choice of operating point and thus the potential mitigation of the impact of spurious two-level systems.

We show that a simple coupling between dark energy and dark matter can simultaneously address two distinct hints at new physics coming from cosmological observations. The first is the recent evidence from the DESI project and supernovae observations that the dark energy equation of state $w$ is evolving over cosmic time from an earlier value that is $<-1$ to a present-day value $>-1$. The second observation is the so-called $S_8$ tension, describing the suppression of the growth of matter overdensities compared to that expected in the $\mathrm{\Lambda }\mathrm{CDM}$ model. We propose a stable, technically natural particle physics implementation of this idea, in which dark matter consists of dark baryons in a strongly coupled hidden sector, and the dark energy field is the associated dark axion. The time variation of the dark matter mass results in an effective dark energy equation of state that exhibits a phantom crossing behavior consistent with recent results. It also results in a slight delay in matter-radiation equality, which suppresses the overall growth of density perturbations.