Using state-of-the-art rare-event sampling simulations, we precisely characterize the nucleation of liquid droplets from a supersaturated Lennard-Jones gas and uncover a key physical feature: critical clusters nucleate with a density that differs substantially from that of the macroscopic equilibrium liquid. Our atomistic simulations also reveal a nonclassical nucleation pathway showing simultaneous growth and densification in liquid condensation. We then exploit these insights to develop a two-variable nucleation theory, in which the cluster density is allowed to vary. Our accessible model based on the capillary approximation is able to quantitatively retrieve the numerical results in nucleation rate and critical cluster properties over a large range of supersaturation. Remarkably, the two-variable model successfully captures the observed nucleation pathway. The effectiveness of this integrated numerical and theoretical framework demonstrates that the cluster density is a decisive variable in nucleation, highlighting the limitations of the single-variable description while offering a robust foundation for its refinement.

We present a randomized dynamical decoupling (DD) protocol that can substantially improve the performance of any given deterministic DD scheme for suppressing coherent noise by using no more than two additional pulses. Our construction is implemented by probabilistically applying sequences of pulses, which, when combined, effectively eliminate the error terms that scale linearly with the system-environment coupling strength. As a result, we show that a randomized protocol using a few pulses can outperform deterministic DD protocols that require considerably more pulses. Furthermore, we prove that the randomized protocol provides an improvement compared to deterministic DD sequences that aim to reduce the error in the system’s Hilbert space, such as Uhrig DD, which had been previously regarded to be optimal. To rigorously evaluate the performance, we introduce new analytical methods suitable for analyzing higher-order DD protocols that might be of independent interest. We also present numerical simulations confirming the significant advantage of using randomized protocols compared to widely used deterministic protocols.

We introduce a new positive geometry, the associahedral grid, which provides a geometric realization of the inverse string theory Kawai–Lewellen–Tye kernel. It captures the full ${\alpha }^{\prime }$ dependence of stringified amplitudes for biadjoint scalar ${\varphi }^3$ theory, pions in the nonlinear sigma model (NLSM), and their mixed $\varphi /\pi$ amplitudes, reducing to the corresponding field theory amplitudes in the ${\alpha }^{\prime }\to 0$ limit. Our results demonstrate how positive geometries can be utilized beyond rational functions to capture stringy features of amplitudes, such as an infinite resonance structure. The kinematic $\delta$ shift, recently proposed to relate field theory $\mathrm{Tr}({\varphi }^3)$ and NLSM pion amplitudes, naturally emerges as the leading contribution to the stringy geometry. We show how the connection between $\mathrm{Tr}({\varphi }^3)$ and NLSM can be geometrized using the associahedral grid.

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, $H\to c\overline{c}$, produced in association with a top quark-antiquark pair ($t\overline{t}H$) is presented. The search is performed with data from proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. Advanced machine learning techniques are employed for jet flavor identification and event classification. The Higgs boson decay to a bottom quark-antiquark pair is measured simultaneously and the observed $t\overline{t}H(H\to b\overline{b})$ event rate relative to the standard model expectation is ${0.91}_{-0.22}^{+0.26}$. The observed (expected) upper limit on the product of production cross section and branching fraction $\sigma (t\overline{t}H)\mathcal{B}(H\to c\overline{c})$ is 0.11 (0.13) pb at 95% confidence level, corresponding to 7.8 (8.7) times the standard model prediction. When combined with the previous search for $H\to c\overline{c}$ via associated production with a $W$ or $Z$ boson, the observed (expected) 95% confidence interval on the Higgs-charm Yukawa coupling modifier, ${\kappa }_c$, is $|{\kappa }_c|<3.5$ (2.7), the most stringent constraint to date.

Interactions between MHD-scale tearing modes (TMs) and ion-gyroradius-scale trapped-electron modes (TEMs) in a fusion plasma are simulated with global gyrokinetics, using a consistent set of fixed equilibrium profiles. Unstable core TMs nonlinearly couple and transfer energy to smaller-scale stable TMs near the edge, where TEMs are present. Magnetic stochasticity from these edge TMs erodes TEM-generated zonal flows near the edge rational surfaces, leading to strongly increased electrostatic flux. This interaction of macro- and microscale modes suggests it may be possible to control microturbulence through current-profile modifications.

Recent work has highlighted the remarkable properties of quantum turbulence in superfluid helium II, consisting of a disordered tangle of quantized vortex lines which interact with each other and reconnect when they collide. According to Landau’s two-fluid theory, these vortex lines move in a surrounding of thermal excitations called the normal fluid. Until now, the normal fluid has often been considered a passive background which simply provides the vortex lines with a mechanism for dissipating their kinetic energy into heat. Using a model which fully takes into account the two-way interaction between the vortex lines and the normal fluid, here we show numerically that each vortex line creates a macroscopic wake in the normal fluid that can be larger than the average distance between vortex lines; this is surprising, given the microscopic size of the superfluid vortex cores which induce these wakes. We show that in heat transfer experiments, the flow of the normal fluid can therefore be described as the superposition of an imposed uniform flow and wakes generated by the vortex lines, leading to nonclassical statistics of the normal fluid velocity. We also argue that this first evidence of independent fluid structures in the thermal excitations postulated by Landau may be at the root of recent, unaccounted for, experimental findings.

Kagome materials offer a versatile platform for exploring correlated and topological quantum states, where Van Hove singularities (VHSs) play a pivotal role in driving electronic instabilities, exhibiting distinct behaviors depending on electron filling and interaction settings. In the recently discovered kagome superconductors $A{\mathrm{V}}_3{\mathrm{Sb}}_5$ ($A=\mathrm{K}$, Rb, Cs), unconventional charge density wave order, superconductivity, and electronic chirality emerge, yet the nature of VHSs near the Fermi level ($E_{\mathrm{F}}$) and their connection to these exotic orders remain elusive. Here, using high-resolution polarization-dependent angle-resolved photoemission spectroscopy, we uncover a universal electronic structure across $A{\mathrm{V}}_3{\mathrm{Sb}}_5$ that is distinct from density-functional theory predictions that show noticeable discrepancies. We identify multiple common sublattice-pure VHSs near $E_{\mathrm{F}}$, arising from strong $\mathrm{V}\text{−}d/\mathrm{Sb}\text{−}p$ hybridization, which significantly promote bond-order fluctuations and likely drive the observed charge density wave order. These findings provide direct spectroscopic evidence for hybridization-driven VHS formation in kagome metals and establish a unified framework for understanding the intertwined electronic instabilities in $A{\mathrm{V}}_3{\mathrm{Sb}}_5$.

We present a general theory to treat periodic solids with quantum-chemistry methods. It relies on two main developments: (1) the modeling of a solid as a Clifford torus, which is a torus that is both periodic and flat, and (2) the introduction of a periodic Gaussian basis set that is compatible with the topology of the Clifford torus. We illustrate our approach by calculating the ground-state energy of a periodic chain of hydrogen atoms within both Hartree-Fock and coupled cluster theory. We demonstrate that our approach yields the correct ground-state energy in the thermodynamic limit by comparing it to the ground-state energy of a ring of hydrogen atoms in the same limit. Since equivalent ring-like calculations for three-dimensional solids are impossible, our approach is an excellent alternative to perform quantum-chemistry calculations of solids. Our Clifford formalism can be seamlessly combined with current implementations of quantum-chemistry methods designed for atoms and molecules to make them applicable to solids.

Electronic stripe-nematic phases are fascinating, strongly correlated states characterized by spontaneous rotational symmetry breaking. In the quantum Hall regime, such phases typically emerge at half-filled, high-orbital-index ($N\ge 2$) Landau levels (LLs) where the short-range Coulomb interaction is softened by the nodes of electron wave functions. In the lowest ($N=0$) LLs, these phases are not expected. Instead, composite fermion (CF) liquids and fractional quantum Hall states, which are well explained in the picture of weakly interacting CF quasiparticles, are favored. Here, we report the observation of an unexpected stripe-nematic phase in the lowest LL at filling factor $\nu =5/8$ in ultra-high-quality GaAs two-dimensional hole systems, evinced by a pronounced in-plane transport anisotropy. Remarkably, $\nu =5/8$ can be mapped to a half-filled, high-index CF LL ($N_{\mathrm{CF}}=2$), analogous to the $N=2$ hole LL. Our finding signals a novel stripe-nematic phase of CFs driven by the residual long-range interaction among these emergent quasiparticles. This phase is surprisingly robust, surviving up to $\sim 100\mathrm{mK}$. Its absence in electron-type systems suggests that severe LL mixing stemming from the large hole effective mass and nonlinear LL fan diagram plays a crucial role in modifying the CF-CF interaction.

We report two light-induced orbital magnetization effects in quantum Hall (QH) fluids, stemming from their transverse response. The first is a purely transverse contribution to the inverse Faraday effect (IFE), where circularly polarized light induces a dc magnetization by stirring the charged fluid. This contribution dominates the IFE in the QH regime. The second is the orbital inverse Cotton-Mouton effect (ICME), in which linearly polarized light generates a dc magnetization. Since the applied field in the ICME does not break time-reversal symmetry, the induced magnetization directly probes the chiral orbital response of the fluid at the driving frequency. We estimate that the resulting magnetization lies in the range of 0.5–10 Bohr magnetons per charge carrier in materials such as graphene and transition-metal dichalcogenides (TMDs) in the QH regime. Finally, we show that the induced magnetization is accompanied by a local correction to the static particle density, enabling optical quantum printing of density profiles into the QH fluid.

A single massive Dirac surface band is predicted to exhibit a half-quantized Hall conductance, a hallmark of the $C=1/2$ parity anomaly state in quantum field theory. Experimental signatures of the $C=1/2$ parity anomaly state have been observed in semimagnetic topological insulator (TI) bilayers, yet whether it supports a half-quantized chiral edge current remains elusive. Here, we observe a robust half-quantized Hall conductance plateau in a molecular beam epitaxy grown asymmetric magnetic TI trilayer under specific in plane magnetic field regimes, corresponding to the $C=1/2$ parity anomaly state. Within this state, both nonlocal and nonreciprocal transport signals are greatly enhanced, which we identify as direct evidence for a half-quantized chiral edge current localized at the boundary of the top gapped surface. Our numerical simulations demonstrate that this half-quantized chiral edge channel is the essential carrier of the observed half-quantized Hall conductance plateau. The half-quantized chiral edge channel emerges from the collective behavior of multiple metallic modes of massless Dirac electrons and is fundamentally distinct from the fully quantized chiral edge channel in the $C=1$ quantum anomalous Hall state. Our results provide experimental evidence for the half-quantized chiral edge transport in a $C=1/2$ parity anomaly state. This Letter establishes asymmetric magnetic TI trilayers as a platform for probing single Dirac fermion physics and paves the way to explore a series of exciting phenomena in the $C=1/2$ parity anomaly state, including the topological magnetoelectric effect and quantized magneto-optical response.

Magnets have recently emerged as promising candidates for quantum computing, particularly using topologically-protected nanoscale spin textures. While the quantum dynamics of such spin textures has been theoretically studied, direct experimental evidence of their nonclassical behavior remains an open challenge. To address this, we propose to employ Brillouin light scattering (BLS) as a method to probe the quantum nature of skyrmions in frustrated magnets. We show that, for a specific geometry, classical skyrmions produce symmetric sidebands in the BLS spectrum, whereas quantum skyrmions exhibit a distinct asymmetry arising from vacuum fluctuations of their rotation. By studying the photon-skyrmion interaction, we calculate the BLS spectrum using a quantum master equation and show that sideband asymmetry serves as a robust witness of energy level quantization. We find that this asymmetry is pronounced at low temperatures, and can be controlled by input laser power. These findings establish a concrete protocol for the optical detection of nonclassical features in spin textures, paving the way for exploring their role in quantum applications.

Organic-inorganic hybrid perovskites with giant piezoelectric responses, exemplified by ${\mathrm{TMCM}\text{−}\mathrm{CdCl}}_3$, represent a promising platform for flexible and environmentally friendly electromechanical materials. However, the microscopic origin of such exceptional performance in this weakly polar system has remained elusive. Here, using deep-learning-assisted large-scale molecular dynamics simulations, we resolve this paradox by reproducing a giant piezoelectric coefficient of $\approx 211\mathrm{pC}/\mathrm{N}$ and demonstrating that it arises from the collective contribution of multiple intrinsic components, particularly the shear component $d_{15}$. This effect does not stem from conventional polarization rotation or phase switching, but instead originates from stochastic 120° in-plane rotational hopping of a small fraction of organic cations. This discrete hopping mechanism is governed by the local ${\mathrm{C}}_3$-symmetric halogen-bonding network between the host framework and the guest cation. The Arrhenius-type temperature dependence of $d_{15}$ further confirms the role of thermally activated dipole hopping. This Letter provides a clear pathway to enhance piezoelectric performance of hybrid materials through rational engineering of host-guest interactions.

We demonstrate that the Bondi-van der Burg-Metzner-Sachs (BMS) evolution equations for the mass and angular momentum aspects in asymptotically flat Einstein gravity follow from local Carroll, Weyl, and diffeomorphism invariance at the null conformal boundary, upon providing a minimalistic holographic dictionary as the sole input from the bulk. This result is a significant step in the quest for a flat-space holographic correspondence and offers a geometric implementation of the radiative degrees of freedom that source the boundary theory in the presence of bulk gravitational waves.

The concept of using photoelectron interferometry in short laser fields to probe electron dynamics and target structures was introduced more than two decades ago. However, the quality of experimental data has remained insufficient for quantitative analysis, largely due to the instability of few-cycle Ti:sapphire laser pulses—the current workhorse of short pulses. Here, we report the first systematic strong-field ionization experiments performed with industrial-grade, carrier-envelope-phase stabilized, near-single-cycle Yb lasers. By measuring photoelectron momentum distributions in the direct-ionization regime, we show that single-cycle cosine-shaped pulses can separate and enhance both spider-leg and fishbone holographic structures. The spider-leg structure enables extraction of the electron scattering phase from the Ar atomic potential—information typically accessible through attosecond metrology—while the fishbone structure reveals the orbital-parity contrast between Ar atoms and nitrogen molecules. Our measurements are quantitatively reproduced by both semiclassical Herman-Kluk-propagator and ab initio simulations, paving the way for precision studies of electron-molecule scattering with widely accessible industrial-grade lasers.

The origin of the strange metallic behavior observed in a wide range of quantum materials is an open challenge to condensed matter physics. Historically, strange metals were uniquely associated with antiferromagnetic quantum critical points (QCPs), but a new generation of materials reveals their association with uniform order parameters, such as ferromagnetism, valley, or nematic order, suggesting a deeper common denominator. At a QCP, order parameter fluctuations are characterized by the dynamical critical exponent $z$, which quantifies the space-time scaling asymmetry. Here, we report the observation of a divergence in the Grüneisen ratio at the QCP of the strange-metal ferromagnet ${\mathrm{CeRh}}_6{\mathrm{Ge}}_4$ with a dynamical critical exponent $z=3$, signaling that the underlying quantum singularity involves a conserved degree of freedom. Yet the magnetization of this easy-plane ferromagnet is not conserved. We argue that the $z=3$ strange criticality requires a description beyond the Landau paradigm, proposing a link with the gauge modes of the small-to-large Fermi surface transition and the associated gauge charge of the delocalizing heavy electrons.

We report the first global extraction of generalized parton distributions, GUMP 1.0, by combining deeply virtual Compton scattering and $\rho$-meson production data from Jefferson Lab and the Hadron-Electron Ring Accelerator with global fits of parton distribution functions, charge form factors, and lattice quantum chromodynamics simulations. Using a conformal moment space parametrization, we achieve a unified description across low- and high-$x$ regions at next to leading order accuracy in perturbative corrections. The results provide state-of-the-art generalized parton distributions consistent with almost all known facts, enabling three-dimensional nucleon imaging in impact parameter space and, at the same time, establishing a benchmark for future theoretical and experimental studies of the nucleon structure.

Exceptional rings are sets of non-Hermitian singularities stemming from Dirac points. We study them theoretically and experimentally in an atomic vapor cell. We demonstrate the formation of an exceptional ring in a photonic honeycomb lattice by showing a transition between conical diffraction and non-Hermitian broadening of a beam in real space. We further predict and demonstrate an original non-Hermitian effect: the transverse non-Hermitian drift. It is similar to the anomalous Hall effect, but it occurs in reciprocal space, and its description requires a biorthogonal quantum metric. The non-Hermitian drift can be used for applications in beam steering.

Superconductivity has been observed in twisted ${\mathrm{MoTe}}_2$ within the anomalous Hall metal parent state [Xu et al., arXiv:2504.06972.]. Key signatures—including a fully spin and valley-polarized normal state, anomalous Hall resistivity hysteresis, superconducting phase adjacent to the fractional Chern insulating state, and a narrow superconducting dome at zero gating field—collectively indicate chiral superconductivity driven by intravalley pairing of electrons. Within the Kohn-Luttinger mechanism, we compute the superconducting phase diagram via random phase approximation, incorporating Coulomb repulsion in a realistic continuum model. Our results identify a dominant intravalley pairing with a narrow superconducting dome of $p+ip$ type at zero gating field. This chiral phase contrasts sharply with the much weaker time-reversal-symmetric intervalley pairing at finite gating field. Our Letter highlights the role of band topology in achieving topological superconductivity and reveals the chiral and topological nature of the superconductivity observed in twisted ${\mathrm{MoTe}}_2$.

In the two-dimensional limit, the interplay between Néel order and band topology in van der Waals topological antiferromagnets can give rise to novel quantum phenomena in the quantum anomalous Hall state. However, because of the absence of net magnetization in antiferromagnets, probing the energetically degenerate Néel orders has long remained a significant challenge. In this Letter, we demonstrate deterministic control over the Néel orders in ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ thin flakes through surface anisotropy engineering enabled by the ${\mathrm{AlO}}_x$ capping layer. By tuning the surface anisotropy, we uncover parity-dependent symmetry breaking states that manifest as distinct odd-even boundary architectures, including 180° domain walls or continuous spin structures. Comparative studies between ${\mathrm{AlO}}_x$-capped and pristine odd-layer ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ flakes using domain-resolved magnetic force microscopy reveal pronounced differences in coercivity and magnetization-reversal dynamics. Notably, an unconventional giant exchange bias, which arises from perpendicular magnetic anisotropy, has been discovered. Our findings establish a pathway for manipulating Néel order through surface modification in topological antiferromagnets.