We observe the interlayer $A_{1s}^I$, $A_{2s}^I$, and $B_{1s}^I$ excitons in bilayer ${\mathrm{WSe}}_2$ under applied electric fields using reflectance contrast spectroscopy. Remarkably, these interlayer excitons remain optically bright despite being well separated from symmetry-matched intralayer excitons—a regime where conventional two-level coupling models fail unless unphysically large coupling strengths are assumed. To uncover the origin of this brightening, we perform density functional theory (DFT) calculations and find that the applied electric field distorts the valence-band Bloch states, driving the hole wave function from one layer to the other. This field-driven interlayer hole transfer imparts intralayer character to the interlayer excitons, thereby enhancing their oscillator strength without requiring hybridization with bright intralayer states. Simulations confirm that this mechanism accounts for the major contribution to the observed brightness, with excitonic hybridization playing only a minor role. Our results identify interlayer hole transfer as a key mechanism for brightening interlayer excitons in bilayer transition metal dichalcogenides, especially when inter- and intralayer excitons are energetically well separated.

We characterize monitored quantum dynamics in a solvable model exhibiting a phase transition between a measurement apparatus and a scrambler. We show that approximate decoherent histories emerge in both phases with respect to a coarse-grained extensive observable. However, the apparatus phase, where quantum Darwinism emerges, is distinguished by the nonergodicity of the histories and their correlation with the measured qubit, which selects an ensemble of preferred pointer states. Our results demonstrate a clear distinction between two notions of classicality, decoherent histories, and environment-induced decoherence.

The amplification of magnetic fields is crucial for understanding the observed magnetization of stars and galaxies. Turbulent dynamo is the primary mechanism responsible for that but the understanding of its action in a collapsing environment is still rudimentary and relies on limited numerical experiments. We develop an analytical framework and perform numerical simulations to investigate the behavior of small-scale and large-scale dynamos in a collapsing turbulent cloud. This approach is also applicable to expanding environments and facilitates the application of standard dynamo theory to evolving systems. Using a supercomoving formulation of the magnetohydrodynamic equations, we demonstrate that dynamo action in a collapsing background leads to a superexponential growth of magnetic fields in time, significantly faster than the exponential growth seen in stationary turbulence. The enhancement is mainly due to the increasing eddy turnover rate during the collapse, which boosts the instantaneous growth rate of the dynamo. We also show that the scaling of final saturated magnetic field strength with density robustly exceeds the expectation from considerations of pure flux-freezing. Apart from establishing a formal framework for studying magnetic field evolution in collapsing (or expanding) turbulent plasmas, these findings suggest that during star and galaxy formation magnetic fields can become dynamically relevant much earlier than previously thought.

The photoelectric feedback processes leading to growth of relativistic runaway electron avalanches are believed to be responsible for extreme fluxes of $\gamma$ rays produced from very compact regions of space with dimensions on the order of a hundred meters in association with lightning activity in the Earth’s natural environment [V. P. Pasko et al., Photoelectric effect in air explains lightning initiation and terrestrial $\gamma$ ray flashes, J. Geophys. Res. 130, e2025JD043897 (2025)]. Here, we demonstrate for the first time that the same photoelectric feedback discharges can be realized on centimeter scales in common solid state dielectric materials, like quartz, acrylic, and bismuth germanate. These discharges can serve as new sources of high energy x-ray radiation.

We report pressure-induced superconductivity in the spinel ${\text{CuIr}}_2{\mathrm{S}}_4$ with a transition temperature ($T_{\mathrm{c}}$) reaching 18.2 K, establishing a new record for this class of materials and surpassing the decades-old limit of 13.7 K. Our electrical transport and synchrotron x-ray diffraction studies up to 224 GPa reveal the emergence of two distinct superconducting phases from a charge-ordered insulating state. The first phase (SC-I) appears around 18 GPa, and forms a dome-shaped superconducting region in which the resistivity exhibits a pronounced, field- and current-sensitive drop without reaching strict zero above our base temperature. Above 111.8 GPa, a second, lower-$T_{\mathrm{c}}$ phase (SC-II) emerges and coexists with SC-I over a broad pressure range, and SC-II ultimately develops a true zero-resistance state above 122.2 GPa. These superconducting phases are intimately linked to a cascade of structural transitions that systematically distort the frustrated pyrochlore lattice of Ir atoms. Our results expand the potential for superconductivity in spinels and demonstrate a pathway to high-$T_{\mathrm{c}}$ pairing directly from a correlated insulating state driven by lattice tuning.

Quantum oscillations in electrical transport have long served as a powerful probe of fundamental Fermi surface physics. To date, however, such studies have been restricted to linear electrical transport. This letter presents the experimental observation of quantum oscillations in nonlinear electrical transport and, more importantly, demonstrates their ability to uncover key features of the Fermi surface that lie beyond the reach of linear-transport quantum-oscillation techniques. Using $\alpha \text{−}\mathrm{Sn}$, a topological Dirac semimetal known to support both linear and nonlinear transport, this study shows that quantum oscillations of nonlinear resistance are highly sensitive to both the geometry and spin texture of the Fermi contour—features to which linear counterparts are insensitive. Further, nonlinear-transport oscillations exhibit markedly distinct dependencies on magnetic field and temperature compared to their linear analogs. These findings establish nonlinear-transport quantum oscillations as a transformative tool for exploring Fermi surface physics, opening new avenues for revealing hidden Fermi surface properties in known materials and discovering new exotic electronic states and phases.

Anderson localization is anticipated to play a pivotal role in the manifestation of superconducting phases, optimal thermoelectric properties, and the quantum anomalous Hall effect. Dimensionality plays a central role in the physics of Anderson localization. Previous studies of localization in 2D conductors have relied on thin metallic films produced by vapor deposition, but challenges such as domain size effects, grain boundaries, and strain continue to complicate interpretation. Here, we overcome these challenges by investigating localization physics in ${\mathrm{Pd}}_5{\mathrm{AlI}}_2$, a van der Waals metal that can be exfoliated to the 2D limit. Using scanning tunneling spectroscopy, we demonstrate Anderson localization of electrons in monolayer ${\mathrm{Pd}}_5{\mathrm{AlI}}_2$ from the presence of a Coulomb gap at the Fermi level and a unique density of state distribution characteristic of wave function localization. Moreover, we show evidence of phonon localization in ${\mathrm{Pd}}_5{\mathrm{AlI}}_2$ from the layer-dependent broadening and softening of phonon modes. These signatures of electron and phonon localization, absent in multilayer samples, provide spectroscopic evidence for the theoretical predictions that localization is enhanced at reduced dimensionality.

Atmospheric rivers (ARs) are essential components of the global hydrological cycle, with profound implications for water resources, extreme weather events, and climate dynamics. Yet, the statistical organization and underlying physical mechanisms of AR intensity and evolution remain poorly understood. Here we apply methods from statistical physics to analyze the full life cycle of ARs and identify universal signatures of self-organized criticality. We demonstrate that AR morphology exhibits nontrivial fractal geometry, while AR event sizes—quantified via integrated water vapor transport—follow robust power-law distributions, displaying finite-size scaling. To interpret these emergent behaviors, we develop a moisture avalanche model that reproduces the observed scaling laws and links them to threshold-driven moisture transport and precipitation dissipation. These scaling properties persist under warming scenarios, suggesting that ARs operate near a critical state as emergent, self-regulating systems. Concurrently, we observe a systematic poleward migration and intensification of ARs, driven by thermodynamic amplification and dynamical reorganization. Our findings establish a statistical physics framework for ARs, connecting critical phenomena to the spatiotemporal structure of extreme events in a warming climate.

Lattice vibrations can carry angular momentum and magnetic moments under broken inversion or time-reversal symmetry, forming so-called chiral phonons. While such excitations have been explored in nonmagnetic systems via optical probes, their direct detection in magnetic materials and coupling to spin excitations remain largely unexplored. Here, using neutron spectroscopy, sensitive to both nuclear and magnetic scattering, we reveal the magnetic signature of chiral phonons in ferrimagnetic ${\mathrm{Fe}}_{1.75}{\mathrm{Zn}}_{0.25}{\mathrm{Mo}}_3{\mathrm{O}}_8$ with Curie temperature $T_{\mathrm{C}}\sim 49\mathrm{K}$. Below $T_{\mathrm{C}}$, we observe enhanced magnetic scattering of phonons at small momenta, arising from strong magnon-phonon coupling. In addition, out-of-plane intensity modulation, phonon mode splitting, and field-induced Zeeman shifts are observed, all closely associated with the ferrimagnetic order. These features vanish above $T_{\mathrm{C}}$, where phonon spectra are dominated by nuclear scattering. These observations demonstrate the existence of chiral phonons carrying substantial magnetic moments that directly contribute to magnetic scattering, and establish neutron spectroscopy as a powerful, momentum-resolved probe of their magnetic character.

Temperature-controlled droplet shape transformations have been extensively studied, uncovering the mechanism of convex liquid polyhedron formation but failing to account for concave edges. Here, we reveal interfacially frozen metastable droplets with hexagram projections and concave edges. We combine macroscopic experiments, numerical simulations, and an analytical geometric model, elucidating the mechanism of these phenomena: previously unreported, mobile-fold nano-origami. Our findings open new avenues in self-assembly of complex faceted liquid and solid nanostructures for nanotechnology applications.

We report on the free decay of quasi-two-dimensional turbulence in superfluid ${}^4\mathrm{He}$ confined within nanofluidic channels. Using a pump-probe technique, we observe a complex decay of the vortex density $L(t)$ that deviates from a simple power law. The decay exhibits a universal fast transient, scaling as $L\propto t^{-2}$, followed by a slower nonuniversal regime that depends on the geometry and flow conditions. We demonstrate that this behavior is governed by the interplay between vortex pinning on the disordered topography of the channel walls and the mobilizing effect of the weak probe flow. A numerical model that treats pinning as a velocity-dependent effective mutual friction successfully reproduces the essential features of our experimental observations.

We report transport studies of hybrid Josephson junctions based on semiconducting InAs nanowires with fully overlapping epitaxial ferromagnetic insulator EuS and superconducting Al partial shells. Current-biased measurements reveal a hysteretic superconducting window with a sizable supercurrent near the coercive field of the ferromagnetic insulator, accompanied by multiple Andreev reflections. Tunneling spectroscopy shows a superconducting gap characterized by three peaks, which we attribute to tunneling between exchange-split superconductors. A theoretical model reproduces the observed features and indicates that spin mixing, driven by sizable spin-orbit coupling, is essential to their formation. Our results demonstrate proximity-induced superconductivity through a ferromagnetic insulator and establish a new platform for exploring spin-triplet pairing.

It seems self-evident that a density functional calculation should be normalized to the number of electrons in the system. We present multiple examples where the accuracy of the approximate energy is improved (sometimes greatly) by violating this basic principle. In one dimension, we explicitly derive the appropriate correction to the normalization. Beyond one dimension, Weyl asymptotics for energy levels yield these corrections for any cavity. We include examples with Coulomb potentials and the exchange energy of atoms to illustrate relevance to realistic calculations.

A thin-walled tubular superconductor develops a quantized fluxoid in the presence of an axial magnetic field. The fluxoid corresponds to the number of phase windings of the superconducting order parameter and is topological in nature. When the tube has a radius variation along the axial direction, forming a bottleneck structure between sections with different radius, a fluxoid mismatch can appear depending on the applied magnetic field. The bottleneck then becomes a topological boundary and is host to topologically protected solutions for the order parameter, dubbed fluxoid solitons, that are free to move around bottlenecks with cylindrical symmetry. Fluxoid solitons are a new type of vortex with nonquantized flux, loosely related to Pearl vortices in thin superconducting films, and fluxons in Corbino Josephson junctions. We characterize their properties as a function of system parameters using the self-consistent quasiclassical theory of diffusive superconductors. We consider both short bottleneck structures and long tapered tubes, where multiple trapped fluxoid solitons adopt elaborate arrangements dictated by their mutual repulsion.

In ordinary solids, nonlinear optical responses are typically studied in terms of unit-cell averages due to the ångström-scale lattice constants. In contrast, moiré superlattices, characterized by a large length scale, unlock an often-overlooked degree of freedom: intrasupercell spatial variations of local observables. Here, we formulate the second-order direct current (dc) charge response in a spatially resolved manner, showing that even uniform optical illumination can drive a static, spatially nonuniform charge redistribution within a supercell. This effect is ubiquitous and cannot be forbidden by any crystalline symmetries. Furthermore, we identify a dominant contribution arising from diverging analytical response coefficients, which leads to linear-in-time growth of the redistribution in the absence of relaxation. This growth is driven by the convergence or divergence of local dc photocurrents. Applying our theory to twisted bilayer ${\mathrm{MoTe}}_2$, we demonstrate strong, highly tunable charge modulation controlled by light intensity and frequency, opening a route to in situ, all-optical control of moiré-periodic electrostatic potentials. Our Letter underscores the importance of intracell degrees of freedom, which enable a qualitatively richer class of nonlinear optical responses in moiré superlattices.

Motility-induced phase separation (MIPS) is a distinctive phenomenon in active matter that arises from its inherent nonequilibrium nature. Despite recent progress in understanding MIPS in dry active systems, it has been debated whether MIPS can be observed in wet systems in which fluid-mediated hydrodynamic interactions (HIs) are present. We use theory and large-scale active fast Stokesian dynamics simulations of the so-called squirmer model to show that collision-induced pusher force dipoles, which are present even for the simplest neutral squirmers (stealth swimmers), destroy MIPS when HIs are included. Both rotational and translational HIs independently suppress phase separation: rotation by shortening a swimmer’s persistence length (and thus reducing the swim pressure), and translation by a confinement-scale advective fluid flow. We further clarify that collisional dipoles between swimmers and boundaries can generate attractive flows that promote particle aggregation observed in some previous simulations and experiments. Finally, we show how to recover MIPS in fluidic environments by tuning the magnitude of the HIs through brushlike surface coatings on the active particles.

Hydrogen-rich lanthanum compounds show the highest known superconducting transition temperatures at high pressure. Despite the pivotal role of hydrogen within these systems, there has been no systematic exploration of how the composition and superconducting properties are intertwined. Our experimental and computational studies demonstrate that A15-type ${\mathrm{LaH}}_{5.75-x}$ hosts high-$T_c$ superconductivity ($T_c=98\mathrm{K}$ at 94 GPa) when available interstitial sites are fully occupied with hydrogen. Upon decompression, a site-selective hydrogen depopulation drives a superconductor-to-insulator transition with a threshold composition of ${\mathrm{LaH}}_5$. Strikingly, the A15 framework is experimentally retained from 120 to 4 GPa, with reversible pressure-dependent hydrogen content changes from ${\mathrm{LaH}}_{5.75}$ down to ${\mathrm{LaH}}_{3.25}$. Our results demonstrate the exceptional stability and tunability of the A15 framework, offering a unique platform to probe the interplay between composition, structure, and superconductivity in hydrogen-rich materials.

We report electric field-controlled modulation of the Fermi surface topology and explore its effects on the superconducting state in alternating-angle twisted quadrilayer graphene (TQG). The unique combination of flat and dispersive bands in TQG allows us to simultaneously tune the band structure through carrier density, $n$, and displacement field, $D$. From density-dependent Shubnikov–de Haas quantum oscillations and Hall measurements, we quantify the $D$-dependent bandwidth of the flat and dispersive bands and their hybridization. In the high $|D|$ regime, the increased bandwidth favors the single particle bands, which coincides exactly with the vanishing of the superconducting transition temperature $T_c$, showing that superconductivity in TQG is strongly bound to the symmetry-broken state. For a range of lower $|D|$ values, a Lifshitz transition occurs when the flat and dispersive band Fermi surfaces merge within the $\nu =+2$ symmetry-broken state. The superconducting state correspondingly shows an enhanced $T_c$, suggesting that the superconducting condensate is strongly dependent on the Fermi surface topology and density of states within this symmetry-broken state.

High-order anisotropic magnetoresistance (AMR) is observed up to the 18th harmonic in cubic Fe(001) thin films, overturning the long-standing paradigm that only two-fold and four-fold terms are symmetry-allowed. Using angle-resolved transport and Fourier analysis, we show that six-fold and higher-order terms are intrinsic, tunable by temperature and thickness, and predicted by crystal symmetry. Microscopically, the two-fold sign reversal arises from a crossover between weak and strong scattering regimes, while high-order terms emerge from the interplay of anisotropic Fermi velocity and relaxation time. Our results establish high-order AMR as a symmetry-prescribed property of cubic ferromagnets, providing critical benchmarks for spin-orbit transport theory and enabling new angular-sensitive spintronic functionalities.

We study clogging of cohesive particles in a two-dimensional hopper with experiments and simulations. The system consists of buoyant, monodisperse oil droplets in an aqueous solution, where the droplet size, buoyant force, cohesion, and hopper opening are varied. Stronger cohesion enhances clogging, a trend confirmed in simulations. Balancing buoyant and cohesive forces defines a cohesive length scale that collapses the data onto a master curve. Thus, under strong cohesion, we find that clogging is governed not by particle diameter, but by the cohesive length scale.