We consider the scenario of excitons in a semiconductor bilayer that are strongly coupled to cavity photons, leading to the formation of dipolar exciton polaritons (dipolaritons). Using a realistic pseudopotential for the dipolar interactions, we exactly determine the scattering between dipolaritons, accounting for the hybridization between interlayer and intralayer excitons. Similar to conventional nondipolar polaritons, we find that the light-matter coupling enhances the interactions between dipolaritons by forcing excitons to scatter at energies that would otherwise be forbidden in ordinary exciton-exciton collisions. However, we show that this light enhancement is larger for long-range dipolar interactions than for short-range intralayer interactions, and is sensitive to the (nonuniform) dielectric environment of the bilayer. Crucially, we find that the largest dipolariton interactions are achieved for transition-metal dichalcogenide bilayers in vacuum. Our results thus reveal the optimal dipolariton setup for realizing strong photon correlations.

We investigate the entanglement properties of the Quantum Six-Vertex Model on a cylinder, focusing on the Shannon-Rényi entropy in the limit of Rényi order $n=\infty$. This entropy, calculated from the ground state amplitudes of the equivalent XXZ spin-1/2 chain, allows us to determine the Renyi entanglement entropy of the corresponding Rokhsar-Kivelson wave functions, which describe the ground states of certain conformal quantum critical points. Our analysis reveals a logarithmic correction to the expected entanglement scaling when the system size is odd. This anomaly arises from the geometric frustration of spin configurations imposed by periodic boundary conditions on odd-sized chains. We demonstrate that the scaling prefactor of this logarithmic term is directly related to the compactification radius of the low-energy bosonic field theory description or, equivalently, the Luttinger parameter. Thus, this correction directly probes the underlying Conformal Field Theory describing the critical point. Our findings highlight the crucial role of system size parity in determining this model's entanglement properties and offer insights into the interplay between geometry, frustration, and criticality.

Motivated by recent advancements in the Josephson diode effect and unconventional $p$-wave magnets (UPMs), we investigate the supercurrent in UPM/superconductor Josephson junctions by the Green's function method. The simultaneous presence of an out-of-plane Zeeman field and Rashba spin-orbit coupling within the UPM breaks the conventional current-phase relation $I\left(\phi \right)=-I(-\phi )$, yielding a Josephson diode effect with high rectification efficiency. The diode polarity and efficiency exhibit systematic oscillations as functions of the Néel vector orientation and strength, as well as Rashba spin-orbit coupling. We identify the conditions necessary for the emergence of the Josephson diode effect through symmetry analysis. Furthermore, the current-phase relation and the Josephson diode effect are sensitive to the orientation of the Néel vector, offering an alternative scheme for its electrical detection. These findings enhance the understanding of the Josephson diode effect in UPM-based Josephson devices and provide a novel detection method for the Néel vector in UPMs.

Starting from the purely microscopic model, we go beyond conventional mean-field theory and develop a self-consistent microscopic thermodynamic framework for disordered 2D superconductors. It incorporates the fermionic Bogoliubov quasiparticles, bosonic Nambu-Goldstone (NG) quantum and thermal phase fluctuations in the presence of long-range Coulomb interactions, and topological Berezinskii-Kosterlitz-Thouless (BKT) vortex-antivortex fluctuations on an equal footing, to self-consistently treat the superconducting gap and superfluid density. This unified phase-fluctuating description naturally recovers the previously known limiting results: the superconducting gap in the 2D limit can remain robust against long-wavelength NG phase fluctuations at $T=0^{+}$ due to Coulomb-induced regularization, while the gradual proliferation of BKT fluctuations as the system approaches criticality drives a separation between the global superconducting transition temperature $T_c$ and the gap-closing temperature $T^{*}$. In contrast to mean-field theory, which predicts 2D superconductivity to be independent of carrier density and nonmagnetic disorder (Anderson theorem), the incorporation of phase fluctuations generates a density- and disorder-dependent zero-point gap $\mathrm{\Delta }\left(0\right)$ and consequently $T_c$ and $T^{*}$. Remarkably, applications to bilayer ${\mathrm{MoS}}_2$ [Nat. Nanotechnol. 14, 1123 (2019)] and disordered ${\mathrm{InO}}_x$ thin films [Nat. Phys. 21, 104 (2025)] quantitatively reproduce key experimental observations in excellent agreement. The framework offers a useful theoretical tool for understanding phase-fluctuation-dominated superconductivity.

In ultrafast experiments on superconductors, a pump laser pulse often heats up the electronic system and suppresses the density of superfluid electrons. Subsequently, the electrons undergo a cooling process because of electron-phonon thermalization so that the superfluid density recovers in time. We study the nonequilibrium electromagnetic response of the system in this cooling process. We show that if a supercurrent is initiated by a probe electric field pulse, an intriguing phenomenon of ‘‘supercurrent growth’’ occurs, meaning that the net current grows in time with the increasing superfluid density. Using the Boltzmann kinetic equation, we uncover its microscopic origin as the momentum-relaxing scattering of Bogoliubov quasiparticles by impurities and phonons, in stark contrast to the widely accepted intuition that impurities always attenuate currents. We further show that supercurrent growth has important experimental manifestations, including the ultrafast Meissner effect and an optical reflectivity exceeding unity.

The mechanical behavior of semiconductors is critical to the reliability of microelectronic, power, photonic, and sensing devices, notably under multiphysical stimuli, e.g., light illumination and stress. Zinc sulfide (ZnS), a prototype II–VI semiconductor, exhibits a positive photoplastic effect, with an increased strength and reduced plastic deformability under light illumination. Yet, the atomistic mechanisms behind such light-induced mechanical modulation remain not well understood. In this study, we perform molecular dynamics simulations with machine-learned force fields to investigate the deformation behavior of ZnS nanopillars under both dark and illuminated conditions. Three representative crystallographic orientations ([001], $\left[1\overline{1}0\right]$, [111]) are considered to understand the plastic anisotropy in it. Our simulation results reveal that phase transformation, rather than dislocation glide, dominates the plastic flow in ZnS under deformation along [001] direction. In contrast, the shear banding-induced brittle failure occurs when ZnS is compressed along two other directions ($\left[1\overline{1}0\right]$ and [111]). Under light illumination, the yield stress of ZnS increases by at least 4.2% across all the three orientations, but with different mechanisms underlying them. In detail, when the sample is compressed along [001] direction, the strength enhancement arises primarily because photoexcited charge carriers delay the phase transformation. Instead, when the sample is deformed along $\left[1\overline{1}0\right]$ and [111] directions, the yielding strength is enhanced because illumination suppresses shear localization and delays failure initiation in the brittle failure orientations. This work provides atomistic insight into how illumination modulates the plastic flow in ZnS under deformation.

Compared to its ferromagnetic (FM) counterpart, the Griffiths singularity arising from antiferromagnetic (AF) rare regions remains much less explored. Here, we investigate this rare-region effect in Fe-doped perovskite manganites ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}{\mathrm{Mn}}_{1-y}{\mathrm{Fe}}_y{\mathrm{O}}_3$ (LSMFO). We observe that Fe doping suppresses the long-range FM order and induces a metal-to-insulator transition at a percolation threshold $y_c^{\mathrm{MI}}\simeq 0.18$, dual to the insulator-to-metal transition at $x_c^{\mathrm{IM}}\simeq 0.175$ in ${\mathrm{La}}_{1-x}{\mathrm{Sr}}_x{\mathrm{MnO}}_3$ (LSMO). Extending this percolation duality, we find corroborating evidence for a dual AF Griffiths phase in LSMFO, with a percolation threshold $y_c^{\mathrm{AG}}$ closely mirroring that of the FM Griffiths phase in LSMO $(x_c^{\mathrm{FG}}\simeq 0.07)$. Furthermore, we demonstrate that strong disorder and frustration, mediated by the Griffiths rare regions, destabilize both long-range FM and AF correlations, culminating in a low-temperature spin glass state for $y\ge 0.18$. Our work thus establishes a unified perspective for understanding rare-region effects in systems involving competing FM and AF exchange interactions.

Nonreciprocal propagation of energy and information is fundamental to a wide range of quantum technology applications. In this work, we explore the quantum many-body dynamics of a qubit ensemble coupled to a shared bath that mediates coherent and dissipative interqubit interactions with both symmetric and antisymmetric components. We find that the interplay between antisymmetric (symmetric) coherent and symmetric (antisymmetric) dissipative interactions results in nonreciprocal couplings, which, in turn, generate a spatially asymmetric emission pattern. We demonstrate that this pattern arises from nonreciprocal interactions coupling different quantum many-body states within a specific excitation manifold. Focusing on solid-state baths, we show that their lack of time-reversal and inversion symmetry is a key ingredient for generating nonreciprocal dynamics in the qubit ensemble. With the plethora of quantum materials that exhibit this symmetry breaking at equilibrium, our approach paves the way for realizing cooperative nonreciprocal transport in qubit ensembles without requiring time-modulated external drives or complex engineering. Using an ensemble of nitrogen-vacancy (NV) centers coupled to a generic noncentrosymmetric ferromagnetic bath as a concrete example, we demonstrate that our predictions can be tested in near-future experiments. Additionally, we find that the spatial asymmetry in the relaxation dynamics increases with the size of the qubit ensemble and persists over longer interqubit distances than the signatures of super- and subradiant collective relaxation dynamics. As the spatial asymmetry in the relaxation dynamics of the qubit ensemble is a direct probe of symmetry breaking in the solid-state bath, our work also opens the door to developing model-agnostic quantum sensing schemes capable of detecting bath properties invisible to current state-of-the-art protocols, which operate solid-state defects as single-qubit sensors.

Recently, (101)-oriented $\mathrm{Ru}{\mathrm{O}}_2$ films have been intensively studied because of their ability to generate a spin current with out-of-plane polarization, enabling field-free switching of perpendicular magnetization. This unconventional spin current has typically been attributed to the altermagnetic spin splitting effect in $\mathrm{Ru}{\mathrm{O}}_2$. In this study, we investigate the spin-charge interconversion in $\mathrm{Ru}{\mathrm{O}}_2\left(101\right)$ films through the spin Seebeck effect and spin-orbit torque induced magnetization switching measurements. By comparing the reciprocal relations in $\mathrm{Ru}{\mathrm{O}}_2\left(101\right)$ and the conventional heavy metal Pt, we find that the out-of-plane polarized spin current generated in our $\mathrm{Ru}{\mathrm{O}}_2\left(101\right)$ film is dominated by the anisotropic spin Hall effect. Our work not only enriches the understanding of spin transport in $\mathrm{Ru}{\mathrm{O}}_2$ but also establishes a straightforward and effective approach for distinguishing the altermagnetic spin splitting effect and spin Hall effect.

We study the Ising model with competing ferromagnetic nearest- and antiferromagnetic next-nearest-neighbor interactions of strengths $J_1>0$ and $J_2<0$, respectively, on the honeycomb lattice. For $J_2>-J_1/4$ it has a ferromagnetic ground state, and previous work has shown that at least for $J_2\gtrsim -0.2J_1$ the transition is in the Ising universality class. For even lower $J_2$ some indicators pointing towards a first-order transition were reported. By utilizing population annealing Monte Carlo simulations together with a rejection-free and adaptive update, we can equilibrate systems with $J_2$ as low as $-0.23J_1$. By means of a finite-size scaling analysis we show that the system undergoes a second-order phase transition within the Ising universality class at least down to $J_2=-0.23J_1$ and, most likely, for all $J_2>-J_1/4$. As we show here, there exist very long-lived metastable states in this system explaining the first-order like behavior seen in only partially equilibrated systems.

We develop a linear response theory for the dynamical proximity effect in topological superconductor/ferromagnetic insulator (TS/FI) hybrids. Our approach integrates the nonequilibrium quasiclassical Keldysh-Usadel formalism for the TS with the Landau-Lifshitz-Gilbert equation for the FI's magnetization dynamics. This framework reveals a proximity-induced coupling between magnons and superconducting collective modes. Crucially, we find that spin-momentum locking in the TS surface state drives a hybridization between magnons and the superconducting Nambu-Goldstone (phase) mode, giving rise to composite magnon–Nambu-Goldstone excitations. We analyze the coupling strength's dependence on key parameters both analytically and numerically. In contrast, we demonstrate that the Higgs (amplitude) mode does not couple to magnons at linear order and is thus excluded from the hybrid excitation spectrum. The hybridization between magnons and the superconducting phase mode provides a mechanism for the interconversion of spin signals and the spinless signals carried by collective superconducting excitations, thereby giving impetus to the development of superconducting spintronics.

Combining geometrical frustration and one-dimensional magnetism boosts quantum fluctuations and leads to unusual states of quantum matter. We report the magnetic behavior of a well-separated $S=\frac{5}{2}$ sawtooth spin chain compound ${\mathrm{CaFe}}_2\mathrm{O}{\left({\mathrm{PO}}_4\right)}_2$ (CFPO). Magnetic susceptibility, heat capacity, and ${}^{31}\mathrm{P}$ nuclear magnetic resonance measurements show evidence of strong magnetic frustration in the compound. Despite a relatively large antiferromagnetic Curie-Weiss temperature of about $-1073\mathrm{K}$, the compound exhibits multiple magnetic transitions at low temperatures at 15.5, 10.4, and 7.8 K, respectively, with a frustration parameter $\left(\mathit{f}\approx |{\theta }_{\text{CW}}|/T_{\text{N}}\right)$ about 70. The Knight shift shows a broad maximum around 70 K for P1 and P2 sites. The spin-lattice relaxation rate $1/T_1$ follows temperature-independent behavior well above the long-range order (LRO). First-principles calculations capture the strong antiferromagnetic interactions in this quasi-one-dimensional sawtooth lattice, providing a microscopic explanation for the experimentally observed frustration, low dimensionality, and the onset of LRO at low temperatures. Our results indicate that CFPO exhibits the presence of short-range correlations and persistent spin dynamics characteristics above the LRO, which probably stem from the $S=\frac{5}{2}$ sawtooth spin chain model.

The precise role of electron-phonon $\left(e\text{−}\mathrm{ph}\right)$ coupling in graphene and related materials on a honeycomb lattice is not yet fully understood, despite extensive research on these systems. Here, we perform sign-problem-free determinant quantum Monte Carlo simulations of the optical Su-Schrieffer-Heeger (oSSH)-Hubbard model on the honeycomb lattice, focusing on the parameters relevant to graphene. Performing finite-size scaling analyzes, we obtain the model's ground-state phase diagram, which includes the semi-metal (SM), Kekulé valence bond solid (KVBS), and antiferromagnetic (AFM) phases, as well as indications of a small KVBS/AFM coexistence region. We find that a weak to moderate Hubbard repulsion, tuned toward the SM-AFM critical value in the pure honeycomb Hubbard model, enhances KVBS correlations and can even stabilize the KVBS phase. Estimating the effective parameters for graphene places it in the SM region of the phase diagram, but near the SM-KVBS phase boundary. Notably, we predict that increasing either the on-site Hubbard repulsion or the $e\text{−}\mathrm{ph}$ coupling strength drives graphene toward the KVBS phase rather than the AFM phase, highlighting a synergistic effect that can be exploited to further control the remarkable properties of graphene and related materials.

We analyze the validity of the Cutler-Mott relations outside the Landau Fermi-liquid concept. We consider a two-site charge Kondo circuit as a paradigmatic example of a system possessing both Fermi- and non-Fermi- liquid properties. It is shown that the generalized Cutler-Mott-like relations derived in the paper hold in both operating regimes of the charge Kondo quantum circuit, describing a smooth crossover between low- and high-temperature regimes. We discuss the applicability of the generalized Cutler-Mott relations for computing a figure of merit for the non-Fermi-liquid quantum simulators.

The heavy-fermion superconductor ${\mathrm{CeRh}}_2{\mathrm{As}}_2$ exhibits a nonsuperconducting phase transition that precedes the emergence of superconductivity. The nature of the corresponding order parameter remains under debate, with competing proposals involving magnetic dipoles or electric quadrupoles. We derive the momentum-dependent multipolar susceptibilities and effective interactions among the localized $4f$ electrons, based on the framework of density functional theory combined with dynamical mean-field theory. Magnetic fluctuations within the crystalline-electric-field (CEF) ground-state doublet are dominated by $\mathit{q}=(1/2,1/2,0)$, corresponding to a two-dimensional checkerboard configuration of the magnetic moment $M_z$ along the $c$ axis. Hybridization between the CEF ground-state and the first-excited doublet gives rise to leading magnetic octupole fluctuations of $z(x^2-y^2)$ symmetry, followed by electric quadrupole fluctuations of $x^2-y^2$ and $\{yz,zx\}$ symmetries. By taking into account the anisotropic magnetic-field dependence of the transition temperature $T_0$, we conclude that an antiferromagnetic order of $M_z$ at $\mathit{q}=(1/2,1/2,0)$ is consistent with the experiments, owing to the enhancement of $T_0$ caused by fluctuations of the field-induced quadrupole of $\{yz,zx\}$ type under an in-plane magnetic field.

We extend the capabilities of correlation energy functionals based on the adiabatic-connection fluctuation-dissipation theorem by implementing the analytical atomic forces within the random phase approximation (RPA), in the context of plane waves and pseudopotentials. Forces are calculated at self-consistency through the optimized effective potential method and the Hellmann-Feynman theorem. In addition, non-self-consistent RPA forces, starting from the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation, are evaluated using density functional perturbation theory. In both cases, we find forces of excellent numerical quality. Furthermore, for most molecules and solids studied, self-consistency is found to have a negligible impact on the computed geometries and vibrational frequencies. The RPA is shown to systematically improve over PBE and, by including the exact-exchange kernel within RPA $+$ exchange (RPAx), through finite-difference total energy calculations, we obtain an accuracy comparable to advanced wave-function methods. Finally, we estimate the anharmonic shift and provide accurate theoretical references based on RPA and RPAx for the zone-center optical phonon of diamond, silicon, and germanium.

${\mathrm{Bi}}_2{\mathrm{WO}}_6$ is a representative $n$-type photocatalyst; however, a comprehensive understanding is required to enhance its electron carrier concentration $\left(n_{\mathrm{e}}\right)$. Considering intrinsic point defects, we calculate the formation energies, equilibrium Fermi-level positions, and defect/carrier concentrations of ${\mathrm{Bi}}_2{\mathrm{WO}}_6$ by hybrid functional calculations coupled with thermodynamic equilibrium simulations. Through formation energies calculation, we find that the $V_{\mathrm{O}}$ (oxygen vacancy), $V_{\mathrm{Bi}}$ (bismuth vacancy), and ${\mathrm{Bi}}_{\mathrm{W}}$ (bismuth occupies tungsten site) are the dominant intrinsic defects in ${\mathrm{Bi}}_2{\mathrm{WO}}_6$. The dopability results indicate that, unlike the ineffective doping of acceptor $\left(A^{-}\right)$, the donor $\left(D^{+}\right)$ doping can positively enhance the $n_{\mathrm{e}}$ under O-poor conditions; however, this requires a high experimental cost of strict temperature or oxygen partial pressure $\left(p_{\mathrm{O}2}\right)$. Inspiringly, the quench (from 923 to 300 K) strategy can address this issue. Using this strategy, (1) an optimal chemical potential region (OCPR) is obtained in which the $n_{\mathrm{e}}$ is higher, without recombination centers and significant compensation. This suggests that the experimental synthesis conditions should be in OCPR; (2) the $p_{\mathrm{O}2}$ of OCPR ranges from ${10}^{1.67}{p}^0\left(\approx 4.74\times {10}^6\mathrm{Pa}\right)$ to ${10}^{-10.53}{p}^0\left(\approx 3\times {10}^{-6}\mathrm{Pa}\right)$, which includes standard atmospheric pressure (1 atm) conditions. Interestingly, $n_{\mathrm{e}}$ can achieve approximately ${10}^{18}\mathrm{c}{\mathrm{m}}^{-3}$ in OCPR at 300 K and 1 atm, thus significantly reducing the experimental cost; and (3) the doubly positive $V_{\mathrm{O}}$ $\left(V_{\mathrm{O}}^{2+}\right)$ is a desirable donor defect consistent with the experiments, thus leading to $n_{\mathrm{e}}>{10}^{18}\mathrm{c}{\mathrm{m}}^{-3}$ in OCPR under O-poor conditions. Therefore, to obtain high $n_{\mathrm{e}}$ in ${\mathrm{Bi}}_2{\mathrm{WO}}_6$, the following strategies should be applied simultaneously: $D^{+}$ doping, quenching, and decreasing $p_{\mathrm{O}2}$, which is helpful for experimentally designing and synthesizing ${\mathrm{Bi}}_2{\mathrm{WO}}_6$.