We investigate the transition rates of a centripetally accelerated atom inside a high-quality cavity and show that they can be extensively tuned by adjusting the cavity resonance and the rotation frequency. Crucially, while inertial atoms cannot be excited in vacuum, rotation induces spontaneous excitation via the circular Unruh effect, with the cavity serving only as an amplifier. Using experimentally feasible parameters, we demonstrate that, in one scenario, the excitation rate can reach $\sim {10}^7{\mathrm{s}}^{-1}$ while emission remains negligible, enabling substantial population inversion. In another scenario, both excitation and emission can simultaneously attain $\sim {10}^7{\mathrm{s}}^{-1}$, corresponding to millions of transitions per second for a single atom. These findings highlight a powerful method for manipulating atomic transition rates for quantum applications and open a promising route toward experimental verification of the circular Unruh effect with state-of-the-art quantum technologies.

We propose a coherent optical population transfer of weakly bound field-linked (FL) tetratomic molecules (tetramers) to deeper FL bound states using stimulated Raman adiabatic passage. We consider static-electric-field shielded polar alkali-metal diatomic molecules and corresponding FL tetramers in their ${\mathrm{X}}^1{\mathrm{\Sigma }}^{+}+{\mathrm{X}}^1{\mathrm{\Sigma }}^{+}$ ground electronic state. We show that the excited metastable ${\mathrm{X}}^1{\mathrm{\Sigma }}^{+}+{\mathrm{b}}^3\mathrm{\Pi }$ electronic manifold supports FL tetramers in a broader range of electric fields with collisional shielding extended to zero field. We calculate the Franck-Condon factors between the ground and excited FL tetramers and show that they are highly tunable with the electric field. We also predict photoassociation of ground-state shielded molecules to the excited FL states in free-bound optical transitions. We propose proof-of-principle experiments to implement stimulated Raman adiabatic passage and photoassociation using FL tetramers, paving the way for the formation of deeply bound ultracold polyatomic molecules.

We introduce coherent matrix phase-space distributions. These use conservation laws and symmetries to improve the accuracy and speed of quantum phase-space representations. As an example, this is applied to the validation of low-loss Gaussian boson sampling (GBS) quantum computational advantage experiments, where classical generation of the random photon-number counts is exponentially hard. Large improvements in sampling errors are demonstrated compared to previous methods. Matrix phase-space representations also provide a large numerical speedup due to their (at worst) quadratic scaling, compared to other methods for validating total count probabilities of large-scale, low-loss GBS networks.

We propose a molecular optomechanical platform to generate robust entanglement among bosonic modes—photons, phonons, and plasmons—under ambient conditions. The system integrates a high-Q whispering-gallery-mode (WGM) optical resonator with a plasmonic nanocavity formed by a metallic nanoparticle and a single molecule. This hybrid architecture offers two critical advantages over stand-alone plasmonic systems: (i) efficient redirection of Stokes photons from the lossy plasmonic mode into the long-lived WGM resonator and (ii) suppression of molecular absorption and sustaining vibrational ground states via plasmon-WGM interactions. These features enable entanglement to redistribute from the fragile plasmon-phonon bipartition to a robust photon-phonon bipartition in the blue-detuned regime, yielding robust stationary entanglement resilient to environmental noise. Remarkably, the achieved entanglement surpasses the theoretical bound for conventional two-mode squeezing in certain parameter regimes. Our scheme establishes a universal approach to safeguard entanglement in open quantum systems and opens avenues for noise-resilient quantum information technologies.

Surface acoustic wave (SAW) devices are key components of classical communication systems and recently studied for quantum information processing. We here propose and study a hybrid quantum system composed of skyrmion qubit and a SAW cavity, which supports multiple long-lived phononic modes. The system allows for strong coupling between single skyrmion qubit and single phonon of different modes. By manipulating the qubit through a static magnetic field and a time-dependent modulation magnetic field, we further study the interaction between skyrmion qubit and individual phononic modes, phonon-phonon interaction, and qubit-qubit interaction, all operating in strong-coupling regime. The controllability of nanoscale skyrmion qubit and the dense phononic modes of single SAW cavity make our system have promising applications in large-scale chips for quantum communication and computing.

We study at the laboratory scale the rupture of thin floating sheets made of a brittle material under a wave-induced mechanical forcing. We show that the rupture occurs where the curvature is maximum and the breakup threshold strongly depends on the wave properties. We observe that the critical stress for fracture depends on the forcing wavelength. Hence our observations are incompatible with a critical stress criterion for fracture. Instead, our measurements can be rationalized as an energy criterion: a fracture propagates when the material surface energy is lower than the released elastic energy, which depends on the forcing geometry. In light of these findings, it may be worthwhile to revisit current numerical models of sea ice fracture by ocean waves.

Understanding how elemental variations influence defect cluster formation is a longstanding challenge in materials science. By combining defect rates-based long-time dynamics with molecular dynamics and irradiation experiments, we identify a distinct, cluster-mediated mechanism—governed by element-specific interactions—as the dominant driver of vacancy cluster evolution into voids or stacking-fault tetrahedra in irradiated complex concentrated alloys, specifically NiCoCr, ${\mathrm{Fe}}_{50}{\mathrm{Mn}}_{30}{\mathrm{Co}}_{10}{\mathrm{Cr}}_{10}$, and Ni at elevated temperatures. Unlike conventional models that focus on point defect behaviors, the proposed mechanism highlights a critical two-step process—vacancy-tetrahedron formation and annihilation—that governs the bifurcation of vacancy clusters. Ni and Co promote void formation by favoring annihilation over formation, leading to $\mathrm{Ni}/\mathrm{Co}$ segregation, whereas larger atoms such as Cr, Fe, and Mn resist annihilation, thus favoring stacking-fault tetrahedra formation. These findings offer new insights into how local chemical environments influence defect evolution and provide strategies for tailoring materials to perform better under extreme conditions.

The superionic state is a phase of matter in which liquidlike ionic mobility coexists with a solid crystalline lattice. Recently identified in Earth’s inner core (IC), this state has attracted considerable attention for its unique kinetic behavior and geophysical implications. However, the ab initio phase diagram describing the equilibrium between the superionic phase and the liquid solution under core conditions remains largely unexplored. Here, we present a thermodynamic approach to compute the Gibbs free energy and construct the ab initio superionic-liquid phase diagram for the ${\mathrm{Fe}}_{1\text{−}x}{\mathrm{O}}_x$ system under IC conditions. We find that oxygen forms superionic states in both hcp and bcc Fe phases, with a pronounced influence on cooperative diffusion of iron in the bcc lattice. The stability fields of these superionic phases are sensitive to oxygen stoichiometry. The presence of superionic states leads to a higher oxygen concentration in the IC than previously estimated. Our Letter establishes a framework for investigating superionic-liquid equilibria under extreme conditions.

Charge density waves (CDWs) involve coupled amplitude and phase degrees of freedom, but direct access to local amplitude correlations remains experimentally challenging. Here, we report cryogenic four-dimensional scanning transmission electron microscopy measurements of CDW ordering in a $2\mathrm{H}\text{−}{\mathrm{NbSe}}_2$ flake of 24 nm thickness, enabled by liquid-helium-based cooling. By mapping the spatial distribution of CDW superlattice intensities at nanometer-scale resolution and analyzing their autocorrelations, we extract the temperature-dependent correlation length associated with the local amplitude of the CDW order parameter, independent of global phase coherence. Our results reveal that a finite local CDW amplitude is already established well above the transition temperature. When the system is cooled below the transition temperature down to 20 K, the correlation length extends to nearly 110 nm, and the local CDW amplitude is found to strongly anticorrelate with the local strain field.

The recent topological classification of non-Hermitian “Hamiltonians” is usually interpreted in terms of pure quantum states that decay or grow with time. However, many-body systems with loss and gain are typically better described by mixed-state open quantum dynamics, which only correspond to pure-state non-Hermitian dynamics upon a postselection of measurement outcomes. Since postselection becomes exponentially costly with particle number, we here investigate to what extent the most important example of non-Hermitian topology can survive without it: the non-Hermitian skin effect and its relationship to a bulk winding number in one spatial dimension. After defining the winding number of the Lindbladian superoperator for a quadratic fermion system, we systematically relate it to the winding number of the associated postselected non-Hermitian Hamiltonian. We prove that the two winding numbers are equal (opposite) in the absence of gain (loss), and provide a physical explanation for this relationship. When both loss and gain are present, the Lindbladian winding number typically remains quantized and non-zero, though it can change sign at a phase transition separating the loss and gain-dominated regimes. This transition, which leads to a reversal of the Lindbladian skin effect localization, is rendered invisible by postselection. We also identify a case where removing postselection induces a skin effect from otherwise topologically trivial non-Hermitian dynamics.

Energy-efficient fast switching of spin orientations or textures is a core issue of spintronics, which is highly demanded but remains challenging. Different from the mainstream routes based on spin-transfer torque or spin-orbit torque, here we propose another mechanism coined as magnetoelectric torque to switch the magnetization in polar magnetic bilayers via pure electric field. In some magnetic van der Waals bilayers, when the electrostatic energy of polarization can compensate the interlayer magnetic coupling, a magnetoelectric torque is generated to fastly flip spins within a few picoseconds, which is demonstrated by combining the first-principles calculations, analytic model, as well as atomistic simulations. Such a magnetoelectric torque doesn’t rely on the spin-orbit coupling and is generally active in polar magnetic homostructures and heterostructures. Our work provides an alternative route to switch magnetization in nanoscale, which may benefit the energy-saving and fast-response spintronic devices.

Self-poisoning is ubiquitous in polymer crystallization but has so far manifested itself visibly only as minima in growth rate vs temperature in either monodisperse systems where, e.g., unstable folded chains obstruct crystallization of stable extended chains, or in periodically segmented chains where unstable stems with n-1 segments disturb deposition of stable stems with n segments. Here, we report a new type of self-poisoning found in poly(lactic acid), where a less stable crystal form (${\alpha }^{\prime }$) disturbs growth of the stable form ($\alpha$). While $\alpha$ requires strict up-down order of the polar chains, α’ does not, hence is kinetically favored. Unexpectedly, below the temperature of the growth rate minimum, the lamellar thickness increases rather than drops, as in all other reported cases of polymer crystallization with decreasing temperature. A growth rate equation model is developed, giving good match with experiments, but revealing an unexpectedly low fold surface free energy of ${\alpha }^{\prime }$ form. Delayed crystallization due to self-poisoning of $\alpha$ in practical fast-cooling processing not only gives the low-modulus ${\alpha }^{\prime }$ form, but also leads to an increased glassy amorphous fraction that results in embrittlement of the biofriendly poly(lactic acid) through physical aging.

Global gyrokinetic simulation of the ion temperature gradient mode shows that the radial electric field, $E_r$ well, upshifts the critical temperature gradient near the magnetic axis, in the weak but not in the strong magnetic shear ($s$) configuration. The geometric curvature effect almost cancels/doubles the $\mathit{E}\times \mathit{B}$ shear in the inner/outer half of the near-axis $E_r$ well, so that the $E_r$ well suppresses the modes in the outer region but does not in the inner region, where the weak-$s$ effect is necessary to suppress the modes. This new finding unravels the formation mechanism of the internal transport barrier in the weak central $s$ discharges.

Raman measurements performed on dense ${\mathrm{H}}_2$, ${\mathrm{D}}_2$ and ${\mathrm{H}}_2+{\mathrm{D}}_2$ in a wide pressure-temperature range reveal the presence of the $\mathrm{\Delta }J=0$ rotational excitation. In the gas/fluid state this excitation has zero Raman shift, but in the solid, the crystal field drives it away from the zero value, e.g., $\sim 75{\mathrm{cm}}^{-1}$ at around 50 GPa and 10 K for both isotopes and their mixture. In the case of deuterium, the $\mathrm{\Delta }J=0$ mode splits upon entering phase II suggesting a very complex molecular environment of the broken symmetry phase (BSP). In the fluid state and phases I and II the frequencies (energies) of the $\mathrm{\Delta }J=0$ transition for ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$ scale neither as rotational (by factor of 2) nor vibrational (by $\sqrt{2}$) modes and appear to be completely isotope independent. This independence on mass marks this transition as unique and a fundamentally different type of excitation from the commonly considered harmonic oscillator and quantum rotor.

The thermal conductivity of ice polymorphs constitutes a critical parameter in multidisciplinary research spanning cryobiology, atmospheric physics, and planetary science. However, the intricate structures and phonon dynamics pose significant challenges to understanding thermal transport in ice polymorphs across diverse phase diagrams. To bridge this knowledge gap, we combined deep learning potential with molecular dynamics simulations to investigate the thermal transport in ice polymorphs with ab initio accuracy across 150–400 K and ${10}^{-3}–10\mathrm{GPa}$. Pronounced anisotropic behaviors and nonmonotonic pressure dependence of thermal transport are demonstrated. Phonon dynamics analysis reveals the structure-phonon relationship and rich phonon behaviors, including nonuniformity-induced phonon hybridization, distortion-induced phonon softening, and disorder-induced phonon scatterings. Configurational local entropy quantification identifies the complexity of the hydrogen bond network as the governing factor in thermal transport variation. Our Letter provides fundamental insights into microscopic energy transport in complex hydrogen bond systems.

Surface plasmon polaritons (SPPs) can be understood as two-dimensional light confined to a conductor-dielectric interface via plasmonic excitations. While low-energy SPPs behave similarly to photons, higher-frequency SPPs resemble surface plasmons. Electrically generating midrange SPPs is particularly challenging because it requires compensating for momentum mismatch, a process conventionally achieved through inelastic electron transport in nanostructures. Here, we theoretically demonstrate that electrical SPP generation is possible by directly coupling electron-hole dipoles to the quantized SPP field across an insulating spacer without accompanying electron transport. This approach can be realized in plasmonic van der Waals heterostructures composed of strongly biased monolayer graphene as the emitter, few-layer hexagonal boron nitride as the spacer, and silver (or gold) as the plasmonic material. In this configuration, graphene’s remarkable ability to support a strongly nonequilibrium steady-state electron-hole population results in nonthermal, bias-tunable SPP emission that is uniform along the hBN/Ag interface, achieving a power conversion efficiency of up to 1% and a Purcell factor of up to 100. These findings pave the way for integrating photonic and electronic functionalities within a single two-dimensional heterostructure.