The time dynamics of flagellar and ciliary beating is often neglected in theories of microswimmers, with the most common models prescribing a time-constant actuation of the surrounding fluid. By explicitly introducing a metachronal wave, coarse-grained to a sinusoidal surface slip velocity, we show that a spatial resonance between the metachronal wave and the corrugation of a confining cylindrical channel enables a ciliate to swim even when it cannot move forward in a bulk fluid. Using lubrication theory, we reduce the problem to the Adler equation that reveals an oscillatory and steady swimming regime. Interestingly, a ciliate can even reverse its swimming direction in a corrugated channel compared to the bulk fluid.

Energy correlators have recently attracted significant attention in the study of heavy ion collisions due to their potential to robustly connect experimental measurements with an underlying quantum field theoretic description. While theoretical studies have so far primarily focused on the simplest two-point correlator, mapping out the dynamics of the quark-gluon plasma (QGP) will require developing a theoretical understanding of multipoint energy correlators. In this Letter, we present a systematic theoretical study of multipoint energy correlators for jets fragmenting in a dense quark-gluon plasma, accounting for both the medium’s perturbative modification to the jet and its hydrodynamical backreaction. We consider both the scaling behavior of projected correlators, as well as the shape dependent three-point correlator, highlighting how both provide insight into interactions with the QGP. We discuss the parametric dependence of modifications on the medium scales, opening new opportunities to experimentally separate jet modifications from the medium response. Our results open the door to a systematic exploration of multipoint energy correlators in heavy ion collisions.

We present the observation of three semiforbidden transitions in singly ionized ytterbium from the metastable ${}^2{\mathrm{F}}_{7/2}^o$ state. Owing to the long lifetimes of both the upper and lower states involved, these transitions are narrow and complement those already frequently used in this atom for quantum information and searches for new physics. We report the absolute frequencies of these electric quadrupole transitions, their isotope shifts, hyperfine structure, and measurements of the quadrupole transition moments. We find that the spontaneous lifetimes of these excited states are limited by slow magnetic dipole emission to lower-lying, odd-parity states, the lowest of which is accessible by laser excitation from ${{}^2\mathrm{F}}_{7/2}^o$ and is an attractive candidate for hosting a long-lived qubit.

We performed de Haas–van Alphen (dHvA) oscillation measurements and band-structure calculations for ${\text{YNi}}_2{\mathrm{B}}_2\mathrm{C}$. Our improved band structure successfully explained the origins of the large dHvA frequencies $\beta$ and $\zeta$, which were inexplicable in previous works. By comparing experimental effective masses with band masses, we determined the electron-phonon coupling for each orbit. The results showed a clear Fermi-surface-sheet dependence of the electron-phonon coupling strength, especially highlighting that the coupling for the band-28 sheet is very weak, almost absent for the orbit with $B\parallel c$. This finding is consistent with previous observations of dHvA oscillations from this orbit in the mixed state down to very low fields. Amid growing interest in high-temperature superconductivity driven by electron-phonon coupling in hydrides under high pressure, this Letter provides foundational data pivotal to precisely understanding electron-phonon coupling.

Kinetic uncertainty relations (KURs) set fundamental limits on the precision of nonequilibrium transport by bounding the signal-to-noise ratio of currents in terms of the dynamical activity, a quantity that counts exchange events between a system and its reservoirs. This framework is well established in the weak-coupling regime, where transport occurs via well-defined, particlelike tunneling processes. At strong coupling, however, quantum coherence challenges both the validity of standard KURs and the notion of activity itself. In this Letter, we introduce a generalized definition of dynamical activity valid at arbitrary system-reservoir coupling, and show that it leads to a breakdown of standard KURs at strong coupling. Building on this result, we derive and prove a novel uncertainty relation, denoted quantum KUR (QKUR), which provides a genuine quantum extension of KUR, accounting for intrinsic quantum coherent contributions of the generalized activity. We demonstrate that the generalized activity reduces to the standard master-equation definition in the weak-coupling regime for generic systems of $N$ coupled quantum dots described by a quadratic Hamiltonian, and analyze the resulting QKUR bound in paradigmatic quantum-coherent mesoscopic devices, including single- and double-quantum dot systems and a quantum point contact.

Active polymers are ubiquitous in nature, and often kicked by persistent noises that break detailed balance. In order to capture the out-of-equilibrium dynamics of such active polymers, we propose a simple yet reliable analytical framework based on a compounding formula. Connecting polymeric dynamics to the isolated monomeric behavior via the notion of tension propagation, the formula allows us to clarify rich scaling scenarios alongside corresponding intuitive physical pictures. We demonstrate distinctive transient and steady-state scalings due to the non-Markovian nature of the active noise. Aside from a paradigmatic example of an active Rouse polymer, we expect the framework to be applicable to wide variety of spatially extended systems, including more general polymers (crumpled globule, semiflexible polymers, etc.), fluctuation of growing interfaces, and an array of particles in single-file configuration.

Periodically driven quantum many-body systems exhibit a wide variety of exotic nonequilibrium phenomena and provide a promising pathway for quantum applications. A fundamental challenge for stabilizing and harnessing these highly entangled states of matter is system heating by energy absorption from the drive. Here, we propose and demonstrate a disorder-free mechanism, dubbed Fock space prethermalization (FSP), to suppress heating. This mechanism divides the Fock space network into linearly many sparse subnetworks, thereby prolonging the thermalization timescale even for initial states at high energy densities. Using 72 superconducting qubits, we observe an FSP-based time-crystalline order that persists over 120 cycles for generic initial Fock states. Further, we perform finite-size scaling analysis for domain wall (DW) and Fock space dynamics by varying system sizes, which reveals size-independent regimes for FSP-thermalization crossover and links the dynamical behaviors to the eigenstructure of the Floquet unitary. Our Letter establishes FSP as a robust mechanism for breaking ergodicity and paves the way for exploring novel nonequilibrium quantum matter and its applications.

We propose and demonstrate an experimental scheme to engineer thermal baths with independently tunable temperatures and dissipation rates for the motional modes of a trapped-ion system. This approach enables robust thermal-state preparation and quantum simulations of open-system dynamics in bosonic and spin-boson models at well-controlled finite temperatures. We benchmark our protocol by experimentally realizing out-of-equilibrium dynamics of a charge-transfer model at different temperatures. We observe that, when the process occurs at a higher temperature, the transfer rate spectrum broadens, with reduced rates at small donor-acceptor energy gaps and enhanced rates at large gaps. We then employ our scheme to study local-temperature effects in a two-mode vibrationally assisted exciton transfer system, where we observe thermally activated interference pathways for excitation transfer.

Small deviations from isotropy in the arrival directions of Galactic cosmic rays serve as a unique probe of the local magnetic environment. In this Letter, we report observations of medium-scale anisotropies at energies above 10 TeV using the LHAASO-KM2A array. Our analysis identifies four regions of excess and four regions of deficit, each spanning angular scales of approximately 10°. Crucially, we detect significant energy-dependent shifts in the centroids of two excess regions: Region B and the newly identified Region $\tilde{\mathrm{D}}$. We also characterize the energy evolution of the fractional relative intensity across both excess and deficit regions. These findings imply that the observed anisotropies are shaped by the specific realization of the local turbulent magnetic field within the cosmic ray scattering length. Such energy-dependent behaviors impose strict constraints on local turbulence models and cosmic ray propagation theories.

We report a search for the rare decay $B^{+}\to K^{+}{\tau }^{+}{\tau }^{-}$ using $1.2\times {10}^9\mathbf{\Upsilon }(4S)$ mesons produced near threshold in electron-positron collisions and collected by the Belle and Belle II experiments. We fully reconstruct the hadronic decay of one $B$ meson produced in the $\mathrm{\Upsilon }(4S)\to B^{+}{B}^{-}$ decay, and search for $B^{\pm }\to K^{\pm }{\tau }^{+}{\tau }^{-}$ candidates among the remaining collision products, reconstructing a charged kaon and leptonic decays of the $\tau$ leptons. We optimize the selection for best sensitivity and look for an excess over background at low values of the residual energy detected in the calorimeter after full event reconstruction. We observe no significant excess and set the limit $\mathcal{B}(B^{+}\to K^{+}{\tau }^{+}{\tau }^{-})<0.56\times {10}^{-3}$ at the 90% confidence level, improving on the only previous result by a factor of four.

The consistent matching of short-distance contributions and hadronic matrix elements is crucial for precise predictions of weak processes involving hadrons. In this Letter, we address this point for charged-current processes involving two pions—pion $\beta$ decay ${\pi }^{\pm }\to {\pi }^0{e}^{\pm }{\nu }_e$ and hadronic $\tau$ decays ${\tau }^{\pm }\to {\pi }^{\pm }{\pi }^0{\nu }_{\tau }$—whose decay rates depend on the so-called $\gamma W$ box correction. Using recent results from lattice QCD, we show how to formulate the matching beyond leading-logarithmic accuracy, in particular, how to cancel the dependence on the scheme choice for evanescent operators. As main results, we obtain a prediction for the decay rate of pion $\beta$ decay with theory uncertainties improved by a factor of 3, which renders theory uncertainties negligible for future determinations of $V_{ud}$ even beyond the reach of the PIONEER experiment, and an evaluation of isospin-breaking corrections to $\tau \to \pi \pi {\nu }_{\tau }$ with negligible uncertainty from the short-distance matching, as necessary for a future $\tau$-based determination of the hadronic-vacuum-polarization contribution to the anomalous magnetic moment of the muon.

Liquid marbles, droplets coated with a granular layer, are highly mobile as particles prevent capillary adhesion to the substrate. Yet their coating creates a static rolling friction, which we measure and model. Motion requires shear within the shell so that it is governed mainly by the grain density. This density controls yielding via a logistic function emerging as the particle network approaches percolation and increasing rapidly at close packing. More broadly, our system offers a simple platform for probing granular raft mechanics and measuring their effective surface tension.

Structural phase transition offers an effective means to modulate interfacial electronic states and accelerate electron transfer in water electrolysis. Here, we exploit a heat-induced monoclinic-to-tetragonal phase transition in ${\mathrm{VO}}_2$ to facilitate electron transfer at ${\mathrm{VO}}_2/{\mathrm{MO}}_{\mathrm{x}}{\mathrm{H}}_{\mathrm{y}}(\mathrm{M}=\mathrm{Co},\mathrm{Ni},\mathrm{Fe})$ heterojunction interfaces. The thermally triggered electronic restructuring lowers the Fermi level of ${\mathrm{VO}}_2$ relative to ${\mathrm{MO}}_{\mathrm{x}}{\mathrm{H}}_{\mathrm{y}}$, promoting the formation of high-valence active species. This significantly accelerates oxygen evolution reaction (OER) kinetics, driving a cascade of catalytic center activation and water oxidation. Our Letter establishes that coupling active catalysts with controllable phase transitions represents a viable strategy for synergistic heat-electricity activation in OER catalysis.

Accurate prediction of carrier mobility is critical for the discovery and design of next-generation electronic materials. Despite sustained progress, state-of-the-art ab initio methods remain limited by the approximate treatment of electron-phonon interactions at the density functional theory level. Here, we demonstrate that incorporating many-body $GW$ corrections to both the electronic band structure and electron-phonon couplings when solving the ab initio Boltzmann transport equation yields a mean absolute relative error of just 11% for electron mobilities across benchmark semiconductors, including Si, GaAs, GaP, diamond, and SiC. The common practice of neglecting $GW$ corrections to the electron-phonon interaction can lead to mobility errors exceeding 50%. The present findings highlight the importance of many-body $GW$ self-energy effects in carrier transport simulations and provides fundamental insights into how many-body electron-phonon interactions govern charge transport in crystalline solids.

We consider a family of generalized Rokhsar-Kivelson (RK) Hamiltonians, which are reverse-engineered to have an arbitrary edge-weighted superposition of dimer coverings as their exact ground state at the RK point. We focus on a quantum dimer model on the triangular lattice, with doubly periodic edge weights. For simplicity we consider a $2\times 1$ periodic model in which all weights are set to one except for a tunable horizontal edge weight labeled $\alpha$. We analytically show that the model exhibits a continuous quantum phase transition at $\alpha =3$, changing from a topological ${\mathbb{Z}}_2$ quantum spin liquid ($\alpha <3$) to a columnar ordered state ($\alpha >3$). The dimer-dimer correlator decays exponentially on both sides of the transition with the correlation length $\xi \propto 1/|\alpha -3|$ and as a power-law at criticality. The vison correlator exhibits an exponential decay in the spin liquid phase, but becomes a constant in the ordered phase, which we explain in terms of loop statistics of the double-dimer model. Using finite-size scaling of the vison correlator, we extract critical exponents consistent with the 2D Ising universality class. Additionally, we analytically show that the topological Rényi entropy of order $\infty$ (topological min-entropy) changes from log2 for the quantum spin liquid phase $\alpha <3$, to 0 for the ordered phase $\alpha >3$, thereby analytically confirming the topological nature of the phase transition.

Kardar-Parisi-Zhang (KPZ) scaling has been observed in discrete polariton lattices, enabled by engineered band structures that stabilize the condensate. Whether this universality extends to intrinsically continuous systems with natural noise regularization remains an open question. We propose and numerically demonstrate KPZ scaling in a continuous quasi-one-dimensional polariton condensate stabilized by optical confinement in the transversal direction. Large-scale simulations of the stochastic Gross-Pitaevskii equation, with experimentally relevant parameters, reveal temporal and spatial scaling exponents of the two-point phase correlation function, ${\beta }_C\approx 0.30(5)$ and ${\alpha }_C\approx 0.46(8)$, and Tracy-Widom one-point phase fluctuation statistics, yielding robust KPZ dynamics intrinsic to the continuous polariton fluid.