Future mHz gravitational wave interferometers will precisely probe massive black hole environments, such as accretion disks, cold dark matter overdensities, and clouds of ultralight bosons, as long as we can accurately model the dephasing they induce on the waveform of extreme mass-ratio inspirals (EMRIs). Most existing models rely on extrapolations from Newtonian results to model the interaction of the small black hole in an EMRI system with the environment surrounding the massive black hole. Here, we present a fully relativistic formalism to model such interaction with collisionless environments, focusing on the case of cold dark matter overdensities, like "spikes" and "mounds." We implement our new formalism in the fastemriwaveforms framework, and show that the resulting waveforms are significantly different from those based on a Newtonian treatment of environmental effects. Our results indicate that a fully relativistic treatment is essential to capture the environmental dephasing of gravitational wave signals from EMRIs accurately.

We report on a search for axion dark matter in the frequency range near 5.9 GHz, conducted using the haloscope technique. The experiment employed an 8-cell microwave resonator designed to extend the accessible frequency range by a multifold factor relative to conventional single-cell configurations, while maintaining a large detection volume. To enhance sensitivity, a flux-driven Josephson parametric amplifier operating near the quantum noise limit was utilized, together with a sideband-summing method that coherently combines mirrored spectral components generated by the Josephson parametric amplifier. Data were acquired over the frequency range 5.83-5.94 GHz. With no statistically significant excess observed, we exclude axion-photon couplings g_{aγγ} down to 1.2×10^{-14}  GeV^{-1} at a 90% confidence level. The achieved sensitivity approaches the Kim-Shifman-Vainshtein-Zakharov benchmark prediction, setting the most stringent limits to date in this range.

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.

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.

Optical tweezers are widely used as a highly sensitive tool to measure forces on micron-scale particles. One such application is the measurement of the electric charge of a particle, which can be done with high precision in liquids, air, or vacuum. We experimentally investigate how the trapping laser itself can electrically charge such a particle, in our case a ∼1  μm SiO_{2} sphere in air. We model the charging mechanism as a two-photon process which reproduces the experimental data with high fidelity.

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 explore a general mechanism that allows (1+1)d CFTs to have interesting interface conformal manifolds even in the absence of any continuous internal symmetry or supersymmetry. This is made possible by the breaking of an enhanced continuous symmetry-which is generically noninvertible-arising in the folded theory. We provide several examples and showcase the power of the symmetry-based approach by computing the evolution of the reflection coefficient along the defect conformal manifold. We also discuss higher-dimensional generalizations and we comment on no-go theorems.

Optical frequency combs and their spectra of evenly spaced discrete laser lines are essential to modern time and frequency metrology. Recent advances in integrated photonic waveguides enable efficient nonlinear broadening of an initially narrowband frequency comb to multi-octave bandwidth. Here, we study the nonlinear dynamics in the generation of such ultrabroadband spectra where different harmonics of the comb can overlap. We show that a set of interleaved combs with different offset frequencies extending across the entire spectrum can emerge, which can be arranged into a practically evenly spaced ultrabroadband frequency comb when the initial comb is offset-free.

We uncover a striking connection between conformal blocks and fractional calculus. By employing a modified form of half derivatives, we derive explicitly the exact form of the three-dimensional conformal block, expressed as the product of two hypergeometric _{4}F_{3} functions. This result provides a rigorous proof of Hogervorst's formula, conjectured nearly a decade ago. Furthermore, we demonstrate its implications for the conformal bootstrap, potentially leading to new analytical techniques and numerical tools that deepen our understanding of conformal field theory.

We investigate automated in situ optimization of the potential landscape in a quantum point contact device, using a 3×3 gate array patterned atop the constriction. Optimization is performed using the covariance matrix adaptation evolutionary strategy, for which we introduce a metric for how "steplike" the conductance is as the channel becomes constricted. We first perform the optimization of the gate voltages in a tight-binding simulation and show how such in situ tuning can be used to mitigate a random disorder potential. The optimization is then performed in a physical device in experiment, where we also observe a marked improvement in the quantization of the conductance resulting from the optimization procedure.

We analyze the correlation between the energy, momentum, and spatial entanglement produced by two luminal jets in the massive Schwinger model. Using tensor network methods, we show that for m/g>1/π, in the vicinity of the strong- to weak-coupling transition, a nearly perfect and chargeless effective fluid behavior appears around the midrapidity region with a universal energy-pressure relationship. The evolution of energy and pressure is strongly correlated with the rise of the spatial entanglement entropy, indicating a key role of quantum dynamics. Some of these observations may be used to analyze high multiplicity jet fragmentation events, energy-energy and energy-charge correlators at current collider energies.

Deep thermalization refers to the emergence of Haar-like randomness from quantum systems upon partial measurements. As a generalization of quantum thermalization, it is often associated with high complexity and entanglement. Here, we introduce computational deep thermalization and construct the fastest possible dynamics exhibiting it at infinite effective temperature. Our circuit dynamics produce quantum states with low entanglement in polylogarithmic depth that are indistinguishable from Haar random states to any computationally bounded observer. Importantly, the observer is allowed to request many copies of the same residual state obtained from partial projective measurements on the state-this condition is beyond the standard settings of quantum pseudorandomness but natural for deep thermalization. In cryptographic terms, these states are pseudorandom and pseudoentangled, and crucially, they retain these properties under local measurements. Our results demonstrate a new form of computational thermalization in which thermal-like behavior arises from structured quantum states endowed with cryptographic properties instead of from highly unstructured ensembles. The low resource complexity of preparing these states suggests scalable simulations of deep thermalization using quantum computers. Our Letter also motivates the study of computational quantum pseudorandomness beyond BQP observers.

We explore the dynamics of two-dimensional Rydberg atom arrays coupled to a single-mode optical cavity, employing nonequilibrium diagrammatic techniques to capture nonlinearities and fluctuations beyond mean-field theory. We discover a novel prethermalization regime driven by the interplay between short-range Rydberg interactions and long-range photon-mediated interactions. In this regime, matter and light equilibrate at distinct-and in some cases opposite-effective temperatures, resembling the original concept of prethermalization from particle physics. Our results establish strongly correlated AMO platforms as tools to investigate fundamental questions in statistical mechanics, including quantum thermalization in higher-dimensional systems.

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 d[over →]-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 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 UTe_{2}, provide further unique signatures to help pinpoint the pairing symmetry channel of this material.

Quantum computation offers significant potential for accelerating the simulation of molecules and materials through algorithms such as quantum phase estimation (QPE). However, the expected speedup in ground-state energy estimation depends critically on the ability to efficiently prepare an initial state with high overlap with the true ground state. For strongly correlated molecules such as iron-sulfur clusters, this overlap is demonstrated to decay exponentially with system size. To alleviate this problem, we introduce an efficient classical algorithm to find entanglement-minimized orbitals (EMOs) and their orderings using spin-adapted low-bond-dimension matrix product states (MPS). The EMO basis yields a more compact ground-state representation, significantly easing initial state preparation for challenging systems. Our algorithm improves initial state overlap by nearly an order of magnitude over prior orbital optimization approaches for an iron-sulfur cluster with four irons, and is scalable to larger systems with many unpaired electrons, including the P-cluster and FeMo-cofactor in nitrogenase with eight transition metal centers. For these systems, we achieve substantial enhancements on initial state overlap by factors of O(10^{2}) and O(10^{5}), respectively, compared to results obtained using localized orbitals. Our results show that initial state preparation for these challenging systems requires far fewer resources than prior estimates suggested.

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.

When embedded in superfluid helium nanodroplets, the dopant molecule exhibits either localization or delocalization behaviors that are critically determined by the spatial spread of its wave function, which in turn are influenced by the confining potential of the nanodroplets. Here, we examine the spatial extent of a molecule's wave function with respect to the size of the nanodroplet by diagnosing the angular nodal structures in the photoelectron momentum distributions (PMDs). We find that, for the lightest H_{2} molecules or heavier D_{2} and O_{2} molecules, with extents of wave function distributions comparable to or smaller than the nanodroplet size, the emitted electrons undergo either minimal or significant scattering with the liquid helium surroundings, leading to either preserved or blurred nodal structures in the PMDs. These observations reveal the underlying delocalization or localization of a molecule within the nanodroplet, which is governed by its wave functions as determined by the confining potential of the droplet. Our findings provide insight into the quantum solvation dynamics of light impurities in nanoscale and confined systems.

There are many exotic thermodynamic processes that are hard to study in nature. Here, we synthesize a structured environment to explore the extremes of thermodynamics. We present an engine running at extreme temperatures of above ten Megakelvin. Our underdamped engine is realised by electrically levitating and controlling a charged microparticle in vacuum. Giant fluctuations are observed in the engine's heat exchange with the environment, while its efficiency shows stochastic events where more work is performed by the engine than heat consumed. Moreover, the nonuniformity of the synthetic environment leads to the particle experiencing position dependent diffusion, a critical phenomenon in microscale biological processes. We theoretically account for the effects of multiplicative noise and find excellent agreement with the observed behavior.

The concept of flux in quantum physics is connected to many intriguing phenomena such as the Aharonov-Bohm effect and Hofstadter butterfly. Particularly, flux in lattices with certain symmetries gives rise to many unprecedented phases of matter. Here, we report the experimental realization of two-dimensional photonic crystals featuring diverse synthetic π-flux patterns, achieved through harnessing the higher-orbital degree of freedom within confined-Mie-resonance photonic crystals. As a proof of concept, we fabricate two types of π-flux photonic crystals, and show that novel topological phases can emerge with peculiar optical effects, including a topological edge state with 4π-period phase evolution, as well as two pairs of topological states which are localized at opposite boundaries but related by a nonlocal twist. These signatures characterize unambiguously a photonic Möbius insulator [an insulator with topological edge states with a 4π-periodic sideband junction (like a Möbius ring)] and a momentum-space-nonsymmorphic symmetry characterized insulator, which remain experimentally unexplored to date. Our Letter opens the frontiers to explore the underlying physics between synthetic π-flux and photonic crystals.

We report the observation of transverse intensity fluctuations-spikes-in synchrotron radiation from a single undulator cell at the European XFEL after monochromatization. Autocorrelation analysis of the recorded events confirms that these fluctuations originate from the partial transverse coherence of the radiation. By calculating the second-order autocorrelation function, we determined the averaged transverse slice size of the electron beam along the SASE1 undulator. The measurements were performed with 5.49 keV x-ray photons using a commissioning silicon monochromator with (111) Bragg reflection and an x-ray imager. This technique enables undulator cell-by-cell diagnostics of the transverse electron beam size at free-electron laser facilities.

The variation of absorption coefficient with the direction of light propagation in a solid is called nonreciprocal directional dichroism (NDD). In polar magnets with polarization P and magnetization M, NDD depends on the direction of P×M; its magnitude is expected to be controlled via a change in P×M by simultaneously applying electric and magnetic fields. Here, we show that the ultrafast control of NDD can be achieved using a strong terahertz pulse in an antipolar antiferromagnet, Bi_{2}CuO_{4}, in which no macroscopic polarization and magnetization appear. By measuring the dependence of the absorption changes on the incident directions of the terahertz pump and visible probe pulses, as well as on the phase of magnetic domains, the primary component of the NDD changes induced by the terahertz pulse is demonstrated to be proportional to the product of its orthogonal electric field E_{THz} and magnetic field B_{THz}. This is ascribed to the magnetoelectric effect modulation by the electromagnetic fields.