We present how entanglement between a spatially separated pair of color centers can be created by letting them weakly interact with the quantum fluctuations of a nonequilibrium magnetic environment. To this end, we consider two coupled ferromagnets, one in the ground state and one in an inverted state with respect to an applied magnetic field. The resulting energetic instability leads to a quantum spin current in the vacuum state that is sustained by the creation of magnon-antimagnon pairs at the interface. We show that these quantum fluctuations imprint a steady-state entanglement onto the two dipole-coupled color centers through nonlocal dissipation. We derive conditions for establishing a maximally entangled Bell state. This entanglement is absent in thermal equilibrium.

We report experiments using magnetic resonance force microscopy to investigate the dynamics of magnetic vortices in submicrometer CoFeB disks grown on a piezoelectric substrate. We compare the vortex gyration excited inductively by microwave magnetic fields and through magnetoelastic coupling via surface acoustic waves (SAWs). Based on the device geometry and modeling performed, we find that the dominant mechanism for SAW-driven excitation is through lattice rotations, which generate an effective field localized at the vortex core. This contrasts with the magnetoelastic strains typically assumed in similar experiments. Moreover, we demonstrate that this magnetorotation torque can be tuned by applying a perpendicular magnetic field. Unlike spin wave excitations, nontrivial spin textures, such as vortices, effectively couple to magnetorotation torques, making them valuable probes for studying such phenomena.

Long-range entanglement is an important quantum resource, particularly for topological orders and quantum error correction. In reality, preparing long-range entangled states requires a deep unitary circuit, which poses significant experimental challenges. A promising avenue is offered by replacing some quantum resources with local operations and classical communication (LOCC). With these classical components, one can communicate outcomes of midcircuit measurements in distant subsystems, substantially reducing circuit depth in many important cases. However, to prepare general long-range entangled states, finding LOCC-assisted circuits of a short depth remains an open question. Here, to address this challenge, we propose a quantum-classical hybrid algorithm to find optimal LOCC protocols for preparing ground states of given Hamiltonians. In our algorithm, we introduce an efficient way to estimate parameter gradients and use such gradients for variational optimization. Theoretically, we establish the conditions for the absence of barren plateaus, ensuring trainability at a large system size. Numerically, the algorithm accurately solves the ground state of long-range entangled models, such as the perturbed Greenberger–Horne–Zeilinger state and surface code. Our results demonstrate the advantage of our method over conventional unitary variational circuits: the practical advantage in the accuracy of estimated ground-state energy and the theoretical advantage in creating long-range entanglement.

In quantum-enhanced astronomical imaging, multiple distant apertures work together by utilizing quantum resources distributed from a central server. Our findings suggest that preprocessing the stellar light received by all telescopes can improve imaging performance without increasing resource consumption. The preprocessing leverages weak quantum measurements and modifies random-party entanglement distillation protocols from quantum information science. Intuitively, this approach allows us to collapse the stellar light that is originally coherent between all telescopes to one pair of telescopes with probability arbitrarily close to one. The central server can then distribute entanglement solely to the pair of telescopes receiving a photon, thereby enhancing the efficiency of resource utilization. We discuss two types of resources that benefit from this preprocessing: shared entanglement and a shared reference frame.

We present the results from the first axionlike particle search conducted using a dish antenna. The experiment was conducted at room temperature and sensitive to axionlike particles in the $44–52\mathrm{\mu }\mathrm{eV}$ range (10.7–12.5 GHz). The novel dish antenna geometry was proposed by the BREAD Collaboration and previously used to conduct a dark photon search in the same mass range. To allow for axionlike particle sensitivity, the BREAD dish antenna was placed in a 3.9 T solenoid magnet at Argonne National Laboratory. In the presence of a magnetic field, axionlike dark matter converts to photons at the conductive surface of the reflector. The signal is focused onto a custom coaxial horn antenna and read out with a low-noise radio-frequency receiver. No evidence of axionlike dark matter was observed in this mass range and we place the most stringent laboratory constraints on the axion-photon coupling strength, $g_{a\gamma \gamma }$, in this mass range at 90% confidence.

Quantum fluctuations in QCD influence nucleon structure and interactions, with pion production serving as a key probe of chiral dynamics. In this Letter, we present a lattice QCD calculation of multipole amplitudes at threshold, related to both pion electroproduction and weak production from a nucleon, using two gauge ensembles near the physical pion mass. We develop a technique for spin projection and construct multiple operators for analyzing the generalized eigenvalue problem in both the nucleon-pion system in the center-of-mass frame and the nucleon system with nonzero momentum. The numerical lattice results are then compared with those extracted from experimental data and predicted by low-energy theorems incorporating one-loop corrections.

Perturbative guiding center theory adequately describes the slow drift motion of charged particles in the strongly magnetized regime characteristic of thermal particle populations in various magnetic fusion devices. However, it breaks down for particles with large-enough energy. We report on a data-driven method for learning a nonperturbative guiding center model from full-orbit particle simulation data. We show the data-driven model significantly outperforms traditional asymptotic theory in magnetization regimes appropriate for fusion-born $\alpha$ particles in stellarators, thus opening the door to nonperturbative guiding center calculations.

We present in situ x-ray diffraction and velocity measurements of ${\mathrm{Fe}}_2{\mathrm{O}}_3$ under laser shock compression at pressures between 38–122 GPa. None of the high-pressure phases reported by static compression studies were observed. Instead, we observed an isostructural phase transition from $\alpha \text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$ to a new ${\alpha }^{\prime }\text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$ phase at a pressure of 50–62 GPa. The ${\alpha }^{\prime }\text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$ phase differs from $\alpha \text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$ by an 11% volume drop and a different unit cell compressibility. We further observed a two-wave structure in the velocity profile, which can be related to an intermediate regime where both $\alpha$ and ${\alpha }^{\prime }$ phases coexist. Density functional theory calculations with a Hubbard parameter indicate that the observed unit cell volume drop can be associated with a spin transition following a magnetic collapse.

By designing carbon nanotube based nanochannels and exploiting the recent developed thermomechanical nanomolding technique, we reveal that the interface diffusion and boundary slip mechanisms play a key role in metal nanoforming. The former dominates the matter transport at the atomic scale and is significantly affected by surface defects, while the latter is closely related to the flow units at the continuum scale, and more sensitive to the apparent interfacial adhesion work than atomic scale defects. In particular, the excellent lubrication of graphitic materials maintained at high temperatures and in air is uncovered from the defect-insensitive boundary slip mechanism. Our findings not only clarify the fundamental physical processes behind metal nanoforming, but also provide new insights into nanofriction and lubrication.

Emergent phenomena arising from nontrivial band structures based on topology and symmetry have been attracting keen interest in contemporary condensed-matter physics. Materials such as SnTe and PbTe are one such example, which demonstrate a topological phase transition while showing ferroelectric instability derived from their rock-salt structure. The ferroelectricity can lift the valley degeneracy, enabling the emergence of the $Z_2$ topological insulator phase, although its observation in transport phenomena remains elusive. Here, we report magnetotransport properties of ferroelectric (Sn, Pb)Te thin films with finely controlled Fermi levels via In doping. We identified the ferroelectric topological insulator phase from the observations of the quantum Hall states with filling factors of $\nu =1$, 2, and 3 with both spin- and valley-degeneracy lifting. The electronic states are two-dimensional, indicating the ferroelectricity-induced topological surface states with a single Dirac cone. The finding of the new topological state with ferroelectricity will further expand the field of topological physics and advance the development of functional properties, such as topological nonlinear photonics and nonreciprocal transport with memory effect.

We propose adiabatic pumping of orbital magnetization driven by coherent spin precession, which enables rectification by converting periodic oscillations into a static signal. The orbital magnetization originates from the adiabatic evolution of valence electrons with a topological bulk contribution expressed as a Chern-Simons form. When the precession cone angle of spin $\mathit{S}$ is small, the resulting magnetization is proportional to $\mathit{S}\times \dot{\mathit{S}}$ and contributes to the magnon Zeeman effect, the energy shift induced by a magnetic field. With a large cone angle, the magnetization can reach its natural unit, $e/T$, in an antiferromagnetic topological insulator with $e$ as the elementary charge and $T$ as the precession period. This significant magnetization is related to the global properties of the electronic geometric phases in the parameter space spanned by $\mathit{S}$ and momentum $\mathit{k}$. When the pumped magnetization is inhomogeneous, induced by spin textures or electronic topological phase domains, a dissipationless charge current is also pumped. At last, we discuss the boundary contributions from the spin-driving edge states, which are intricately linked to the gauge-dependent quantum uncertainty of the Chern-Simons form.

We propose that excitons in moiré transition metal dichalcogenide bilayers offer a promising platform for investigating collective radiative properties. While some of these optical properties resemble those of cold atom arrays, moiré excitons extend to the deep subwavelength limit, beyond the reach of current optical lattice experiments. Remarkably, we show that the collective optical properties can be exploited to probe certain correlated electron states without requiring subwavelength spatial resolution. Specifically, we illustrate that the Wigner crystal states of electrons doped into these bilayers act as an emergent periodic potential for excitons. Moreover, the collective dissipative excitonic bands and their associated Berry curvature can reveal various charge orders that emerge at the corresponding electronic doping. Our Letter provides a promising pathway for future research on the interplay between collective effects and strong correlations involving moiré excitons.

Light-matter interaction has become one of the promising routes to manipulating various physical features of quantum materials in an ultrafast kinetics. In this Letter, we focus on the nonlinear optical effects of the spintronic behavior in antiferromagnetic (AFM) and altermagnetic (AM) systems with compensated magnetic moments, which has been extensively attractive for their potential applications. With vanishing net magnetic moments, one of the main concerns is how to distinguish and disentangle AFMs and AMs in experiments, as they usually behave similarly in many susceptibility measurements. To address this challenge, we propose that linearly polarized light could trigger contrasting nonequilibrium local spin torques in these systems, unraveling hidden light-induced spintronic behaviors. In general, one could achieve light-induced spin canting in AMs, but only Néel vector torques in AFMs. We scrutinize and enumerate their symmetry constraints of all 122 magnetic point groups. We also adopt low energy Hamiltonian models and first-principles calculations on two representative materials to illustrate our theory. Our work provides a new perspective for the design and optimization of spintronic devices.

We revisit the long-standing question of whether water molecules dissociate on the Ru(0001) surface through nanosecond-scale path-integral molecular dynamics simulations on a sizable supercell. This is made possible through the development of an efficient and reliable machine-learning potential with near first-principles accuracy, overcoming the limitations of previous ab initio studies. We show that the quantum delocalization associated with nuclear quantum effects enables rapid and frequent proton transfers between water molecules, thereby facilitating the water dissociation on Ru(0001). This work provides the direct theoretical evidence of water dissociation on Ru(0001), resolving the enduring issue in surface sciences and offering crucial atomistic insights into water-metal interfaces.

Shear induced frictional networks have been proposed to be responsible for the emergence of discontinuous shear thickening (DST) in complex fluids. However, little experimental evidence exists to support this model directly. Here, using x-ray photon correlation spectroscopy (XPCS), we show the existence of an intrinsic heterodyne feature during shear cessation, which originates from the relative motion of mobile particles against an aggregated or jammed network induced by shear thickening. Upon removing the shear, the shear stress dissipates rather quickly in a two-step fashion, whereas the heterogeneous particle dynamics persist much longer with the relative velocity decaying slowly with time as $t^{-1}$. More importantly, both continuous shear thickening (CST) and DST show similar heterodyne features, indicating the intrinsic mechanisms causing shear thickening are similar in nature.

We consider self-organization and memory formation in a mesoscopic model of an amorphous solid subject to a protocol of random shear confined to a strain range $\pm {ϵ}_{\max }$. We develop proper readout protocols to show that the response of the driven system self-organizes to retain a memory of the strain range, which can be subsequently retrieved. Our findings generalize previous results obtained upon oscillatory driving and suggest that self-organization and memory formation of disordered materials can emerge under more general conditions, such as a disordered system interacting with its fluctuating environment. Self-organization results in a correlation between the dynamics of the system and its environment, providing thereby an elementary mechanism for sensing. We conclude by discussing our results and their potential relevance for the adaptation of simple organisms lacking a brain to changing environments.

Biological surfaces, such as developing epithelial tissues, exhibit in-plane polar or nematic order and can be strongly curved. Recently, integer ($+1$) topological defects have been identified as morphogenetic hotspots in living systems. Yet, while $+1$ defects in active matter on flat surfaces are well understood, the general principles governing curved active defects remain unknown. Here, we study the dynamics of integer defects in an extensile or contractile polar fluid on two types of morphogenetically relevant substrates: (i) a cylinder terminated by a spherical cap, and (ii) a bump on an otherwise flat surface. Because the Frank elastic energy on a curved surface generically induces a coupling to deviatoric curvature, $\mathcal{D}$ (difference between squared principal curvatures), a $+1$ defect is induced on both surface types. We find that $\mathcal{D}$ leads to surprising effects including localization of orientation gradients and active flows, and particularly for contractility, to hysteresis and bistability between quiescent and flowing defect states.