The production of identified hadrons in semi-inclusive deep-inelastic scattering (SIDIS) is sensitive to parton distribution functions and hadron fragmentation functions. Neutrino-induced SIDIS processes probe combinations of these functions differently from their charged-lepton-induced counterparts. We compute charged pion production in (anti)neutrino-induced SIDIS up to second order in perturbative QCD and compare our predictions to precise legacy fixed-target data. We demonstrate the high sensitivity of these data on the parametrization of the fragmentation functions and discuss future SIDIS probes at the LHC Forward Physics Facility.

We predict a gyroscopic effect that can be demonstrated with Rydberg atoms following the dynamics of a Kepler Hamiltonian with an additional uniaxial anisotropy induced by optical ponderomotive force. This effect is analogous to the rotation of the Foucault pendulum in response to the Earth’s rotation. We argue that in Rydberg states with a large principal quantum number a similar geometric angle can be generated by mechanical rotations of an atomic-optical setup on timescales between $1\mathrm{\mu }\mathrm{s}$ and 1 ms.

Non-Hermitian bulk-boundary correspondence, a central principle in non-Hermitian topological physics, is deeply rooted in symmetry. In particular, preserved chiral symmetry is one of the key ingredients, which plays a pivotal role in determining non-Hermitian topology. Nevertheless, chiral symmetry breaking in non-Hermitian systems substantially reshapes spectral and edge-state behavior. The corresponding fundamentally important bulk-boundary correspondence thus needs to be drastically reconstructed. However, it has so far eluded experimental efforts. Here, we theoretically predict and experimentally demonstrate the bulk-boundary correspondence of a one-dimensional (1D) non-Hermitian system with chiral symmetry breaking in discrete-time nonchiral nonunitary quantum walks of single photons. Through constructing a domain-wall configuration, we experimentally observe the photon localization at the interface of a domain-wall structure, clearly indicating the presence of the topological edge mode. The appearance of that matches excellently with the prediction of our newly introduced nonchiral non-Bloch topological invariants pair. Our Letter thus builds the non-Hermitian bulk-boundary correspondence for studying topological physics in non-chiral non-Hermitian systems.

The breakup of a capillary jet into drops is believed to be governed by initial disturbances on the surface of the jet that grow exponentially. The disturbances are often assumed to be due to external sources of noise, to turbulence, or to imperfections of the nozzle. Here we demonstrate that the initial disturbances observed across a wide range of conditions are quantitatively consistent with thermal capillary waves, where the initiating disturbances must be of the order of an angstrom, suggesting that thermal noise can act as a primary driver of jet breakup under typical experimental conditions. Our experiments with a wide range of nozzles show no significant variation in breakup length linked to nozzle type, shape, or inner roughness. By systematically varying the jet diameter and velocity and the fluid properties, we validate our thermal disturbance model over 4 orders of magnitude in jet length, and 7 orders of magnitude when previous molecular dynamics simulations and stochastic hydrodynamics calculations of nanojets are included.

Inspired by recent experimental observations of a harmonically excited elastic foil hovering near a wall while supporting substantial weight, we develop a theoretical framework that describes the underlying physical effects. Using elastohydrodynamic lubrication theory, we quantify how the dynamic deformation of the soft foil couples to the viscous fluid flow in the intervening gap. Our analysis shows that the soft foil rectifies the reversible forcing, breaking time-reversal symmetry; the spatial distribution of the forcing determines whether the sheet is attracted to or repelled from the wall. A simple scaling law predicts the time-averaged equilibrium hovering height and the maximum weight the sheet can sustain before detaching. Numerical simulations of the governing equation corroborate our theoretical predictions, are in qualitative agreement with experiments, and might explain the behavior of organisms while providing design principles for soft robotics.

Turbulence serves as a catalyst for rapid bubble dispersion, increasing the residence time of bubbles in the ocean and shaping the crucial process of mass transfer during air-sea interactions. In this Letter, we experimentally investigate the pair dispersion of bubbles in turbulence. Our findings highlight two key differences: initially, bubbles are preferentially drawn toward each other when in close proximity, which slows down their dispersion. As bubbles are driven further apart, they enter a superdiffusive regime where the Richardson constant is governed by two competing mechanisms: larger bubbles gain more kinetic energy due to biased sampling, yet simultaneously exhibit increased misalignment between their relative velocity and separation vector due to the inertia of bubbles, which limits the effectiveness of that energy in driving dispersion. These effects, absent in the tracer limit, offset each other, yielding a reduced yet size-independent Richardson constant. A model is then developed to predict this alignment behavior and the Richardson constant, providing a framework for the dispersion and transport of buoyant particles in turbulent flows.

Quasiparticle interference (QPI) obtained from scanning tunneling microscopy (STM) is a powerful method to help extract the pairing symmetry of unconventional superconductors. We examine the general properties of QPI on surfaces of spin-triplet superconductors. It is shown how the multicomponent nature of the spin-triplet $\overrightarrow{d}$-vector and the general existence of topological surface states in triplet condensates both offer important differences from QPI on spin-singlet superconductors. We then turn to a microscopic model relevant for the spin-triplet candidate ${\mathrm{UTe}}_2$ and compare the computed QPI with recent STM measurements. We conclude that the two candidate pairing instabilities $B_{2u}$ and $B_{3u}$ exhibit distinct features in the QPI intensity which allows for distinguishing them using the experimental data. Characteristic features of the emergent topological surface states protected by chiral symmetry in general, and by mirror symmetries in the case of ${\mathrm{UTe}}_2$, provide further unique signatures to help pinpoint the pairing symmetry channel of this material.

When contacting solids slide against each other, friction typically increases as material stiffness decreases due to the resulting increase in real contact area. However, varying trends have been observed, influenced by wear, surface geometry, tribochemistry, and environmental factors. To disentangle these effects, we construct a microscale structural superlubric system composed of graphite slider and graphene substrate, featuring wearless, fully contacted, atomically smooth, and chemically stable interfaces. The normal stiffness is tuned using few-layer graphene with different thicknesses. Experiments show that, for the system with a clean interface, friction remains constant across substrates with varying stiffness. By contrast, a positive stiffness dependence of friction is observed in third body-rich interfaces. A comprehensive framework is provided, clarifying fundamentally how friction and its stiffness dependence originate from the configuration transition of third body molecules and symmetry of the stiffness for the two contacting surfaces, corroborated by molecular dynamics simulations.

Measurements fundamentally alter the evolution of a quantum system by disturbing its state, which can either freeze its dynamics (quantum Zeno effect, ZE) or accelerate transitions (anti-Zeno effect, AZE). While these effects are well established for ordinary quantum states, their impact on topological states—renowned for their robustness against disorder—has remained unexplored. Here we explore this interplay in a classical wave analog of quantum dynamics, demonstrating both theoretically and experimentally that topological boundary states can be controlled by quantumlike measurements implemented in spatially modulated acoustic waveguides. By introducing controlled perturbations, we emulate repeated measurements and reveal how they freeze or accelerate boundary-state tunneling. Using a geometric framework based on the quantum metric, we identify the general conditions for ZE and AZE, and further uncover a new tunneling mechanism enabled by varying measurement strength. These results establish quantumlike measurement as a versatile tool for manipulating topological states and wave propagation, with broad relevance to photonic, elastic, and quantum systems.

We study the electromagnetic (EM) response of the excitonic insulator phase of a time-reversal (TR) invariant Weyl semimetal (WSM). At low temperatures, the system develops two exciton condensates. The condensates are related to each other by TR symmetry and weakly coupled by a Josephson tunneling term. The latter leads to the formation of the Leggett mode [Number-phase fluctuations in two-band superconductors, Prog. Theor. Phys. 36, 901 (1966).] with a small gap. Our main finding is that the Leggett mode couples to the EM fields as a massive dynamical axion. This is a consequence of the chiral anomaly and the chiral magnetic effect in the parent WSM. Because of the small axion mass, its coupling to EM fields results in a giant anisotropic polarizability and birefringence in the presence of a static magnetic field. The photon-axion hybridization produces a polariton resonance near the axion gap.

Chiral phonons are desirable for applications in spintronics but their generation and control remains a challenge. Here we demonstrate the emergence of truly chiral phonons from selective magnon-phonon coupling in inversion-symmetric magnetic systems. Considering bcc Fe as an example, we quantitatively calculate hybridized magnon-phonon quasiparticle states across the entire Brillouin zone utilizing first-principles calculations. Our findings challenge conventional magnetoelastic interpretations and reveal finite zero-point phonon angular momentum and strong anomalous thermal Hall responses linked to finite (spin) Berry curvatures. Our results further establish that the existence of chiral phonons, particularly along high-symmetry directions, is common in many magnetic materials, offering promising avenues for novel spintronic and phononic devices.

Ferroelectric polarization can be harnessed to record binary data in a nonvolatile manner, where the electric field switching of polarization offers a possibility for an energy-efficient data writing process. The detection of ferroelectric polarization—associated with the data readout process—is achievable in ferroelectric or multiferroic tunnel junctions. In single-phase multiferroics, it is anticipated that ferroelectric polarization may be detected by measuring anomalous Hall conductivity (AHC) or nonlinear Drude conductivity (NDC) that is intrinsically hosted by the material and is ferroelectrically switchable. Yet, selection rules for the identification of such multiferroics are lacking. Here, we use a group-theory-based approach to established a theory on ferroelectrically switchable AHC and NDC in multiferroics. We further work with polar magnetic point groups (MPGs) and provide a symmetry classification of these MPGs with respect to ferroelectrically switchable AHC or NDC. We identify various multiferroic materials (including multiferroic altermagnets) that exhibit the aforementioned intriguing AHC or NDC, and confirm by first-principles simulations that ${\mathrm{YMnO}}_3$ and ${\mathrm{LuFeO}}_3$ showcase ferroelectrically switchable NDC and AHC, respectively. Our Letter opens a door for developing multiferroic memory devices based on AHC or NDC transport phenomena.

Ferroelectric domain walls play a fundamental role in the functionality of ferroelectric materials. As ferroelectric domain walls are mostly charge neutral to minimize electrostatic energy, the recently observed intrinsically stable charged 180° domain wall in a Bi monolayer opens uncharted research territory. In this Letter, we utilized deep potential molecular dynamics (DeePMD) simulations to investigate the finite-temperature dynamics of domain walls in the Bi monolayer. We discovered unique intertwined topological domain structures formed by two domain pairs (created by the charged 180° domain walls) separated by conventional 90° domain walls. These topological domain wall structures exhibit complex reaction dynamics when subjected to mechanical loading. They retain their structural topology up to a tensile strain of 4.70%. Beyond this strain, they begin to merge, cross, and ultimately transform into an identical counterpart, rotated by 90°. At strain exceeding 9%, the topological structure disintegrates into parallel charged 180° domain walls. Our findings provide unprecedented insights into the topological structures of charged 180° domain walls, laying the groundwork for further investigations and potential applications in electronic devices.

Photoisomeric azobenzene derivatives with distinguished conductance in trans and cis states have gained extensive attention for their potential application in fabricating light-controlled electronic switches, which, however, faces great challenges due to the quenching effect once they are coupled to the electrode. Here, two kinds of azobenzene derivatives (TATA-TMA and TATA-TA) were synthesized by tethering a large TATA base, which increases the intermolecular distance and facilitates conformational changes, and by incorporating decoupling group into the molecular skeleton to insulate the azobenzene functional cores from electrode interactions. It is demonstrated that the conductance switch ratios of the synthesized molecules are enhanced by one order of magnitude. Interestingly, TATA-TMA and TATA-TA, although they have the same azobenzene core and TATA base, exhibit opposite conductance evolution trends during the photoisomerization process. Further elucidation of the underlying mechanism offers a logical routine for designing high-performance photoresponsive systems with controllable switching direction.

We show how dynamic heterogeneities (DHs), a hallmark of glass-forming materials, depend on chain flexibility and chain length in polymers. For highly flexible polymers, a relatively large number of monomers ($N_c\sim 500$) undergo correlated motion at the glass transition temperature ($T_g$), independent of molecular weight ($M$). In contrast, less flexible polymers show a complex $N_c(M)$ behavior divided into three regimes, consistent with observations in both $T_g(M)$ and chain conformational structure. For short oligomers ($\lesssim 2$ Kuhn steps), a transition from mainly intermolecular correlations and $N_c\sim 200$ to strongly intramolecular correlations and $N_c<50$ (roughly the molecular size) is observed; for longer chains, $N_c$ increases weakly, before saturating. For poly(methyl methacrylate), a remarkable similarity is found between $N_c(M)$ and the $M$-dependent ratio of the activation barriers of the structural ($\alpha$) and secondary ($\beta$) relaxations; we present evidence that this relationship is a general feature of glass-forming polymers. Our results suggest a direct link between the DH length scale and the number of $\beta$ relaxation events jointly activated to facilitate the $\alpha$ relaxation.

Deciding which sets of quantum measurements allow a simultaneous readout is a central problem in quantum measurement theory. The problem is relevant not only from the foundational perspective, but also has direct applications in quantum correlation problems fueled by incompatible measurements. Although central, only a few analytical criteria exist for deciding the incompatibility of general sets of measurements. This Letter approaches the problem through functions defined on the Boolean hypercube and their Fourier transformations. We show that this reformulation of the problem leads to a complete geometric characterization of joint measurability of any finite set of unbiased binary qubit measurements and gives a necessary condition for the biased case. We discuss our results in the realm of quantum steering, where they translate into a family of steering inequalities. When certain unbiasedness conditions are fulfilled, these criteria are tight, hence fully characterizing the steering problem when the trusted party holds a qubit, and the untrusted party performs any finite number of binary measurements. We further discuss how our results point towards a second-order cone programming approach to measurement incompatibility and compare this to the predominantly used semi-definite programming-based techniques. We use our approach to falsify an existing conjecture on measurement incompatibility of special sets of measurements.

We propose a method to cool a thermal photonic state in a cavity by passing electrons through it. Electrons are coherently split into two paths, with one path traversing the cavity, becoming entangled with its photonic state. A sequence of such entanglement interactions can achieve cooling of the cavity, e.g., a twofold reduction in thermal photon number with a 25% postselection probability. This “which-path” based approach extends to other qubit-oscillator systems, such as phonons in crystals or optomechanical resonators, offering a general framework for quantum oscillator cooling.