Dissipative Kerr solitons in optical microresonators offer unparalleled platforms for ultralow-noise, high-repetition rate frequency comb generation with a compact form and driven by a continuous-wave laser. However, despite their attractive properties suited for practical applications, fundamental limitations regarding their output power and conversion efficiency still remain crucial problems that must be overcome. Here we discover unexplored operation regimes of Kerr soliton microcombs yielding high power and a picosecond pulse width by exploiting the strong mode interaction in birefringent crystalline microresonators. We demonstrate experimentally single-soliton microcombs with average powers of up to 24 and 38 mW as well as an improved conversion efficiency with a double-digit percentage and a microwave soliton repetition rate as low as 15.5 GHz. The observations are in agreement with numerical analyses based on the Lugiato-Lefever equation. The presented results not only facilitate novel applications and an architecture based on microresonator frequency combs, but also contribute to a further understanding of soliton physics.

Combination of optical spectroscopy and in situ high-temperature–high-pressure techniques, were employed to investigate the melting curve and map out the location of methane’s solid phases up to 45 GPa and 1100 K. The experiments yield two distinct diagrams, one that demonstrates the kinetic phase transformations and the other presenting the equilibrium states usually reached with time. Raman spectroscopy demonstrates that the appearance and transitions between the higher pressure phases (VII, VIII, and IX) are strongly dependent on the pressure-temperature-time path. Combined visual observations and Raman spectroscopy indicate that the melting curve of methane extends to significantly higher temperatures than previously reported, e.g., $\sim 1000\mathrm{K}$ at 15 GPa. The study also suggests that some inconsistencies in the earlier melting data could be attributed to photochemical dissociation and/or a reaction induced by high-intensity light sources.

Metamaterials are a promising platform for a range of applications, from shock absorption to mechanical computing. These functionalities typically rely on floppy modes or mechanically frustrated loops, both of which are difficult to design. In particular, how to design multiple modes or loops with target deformations remains an open problem. We introduce a combinatorial approach that allows to create an arbitrarily large number of floppy modes and frustrated loops. The design freedom of the mode shapes enables to easily introduce kinematic incompatibility to turn them into frustrated loops. We demonstrate that floppy modes can be sequentially buckled by using a specific instance of elastoplastic buckling. We utilize our combinatorial floppy chains and frustrated loops to achieve matrix-vector multiplication in materia. Our findings bring about new principles for the design and use of floppiness and frustration in soft matter and metamaterials.

Anisotropic flow and radial flow are two key probes of the expansion dynamics and properties of the quark-gluon plasma (QGP). While anisotropic flow has been extensively studied, radial flow, which governs the system’s radial expansion, has received less attention. Notably, direct experimental evidence for the global and collective nature of radial flow fluctuations has been lacking. This Letter presents the first measurement of transverse momentum ($p_{\mathrm{T}}$) dependence of radial flow fluctuations ($v_0(p_{\mathrm{T}})$) over $0.5<p_{\mathrm{T}}<10\mathrm{GeV}$ and demonstrates its collective nature using a two-particle correlation method in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$. The data reveal three key features supporting the collective nature of radial flow: long-range correlation in pseudorapidity, factorization in $p_{\mathrm{T}}$, and centrality-independent shape in $p_{\mathrm{T}}$. The comparison with a hydrodynamic model demonstrates the sensitivity of $v_0(p_{\mathrm{T}})$ to bulk viscosity, a crucial transport property of the QGP. These findings establish a new, powerful tool for probing collective dynamics and properties of the QGP.

This Letter presents measurements of long-range transverse-momentum correlations using a new observable, $v_0(p_{\mathrm{T}})$, serving as a probe of event-by-event radial-flow fluctuations, the underlying radial expansion, and the medium’s properties in heavy-ion collisions. Results are reported for inclusive charged particles, pions, kaons, and protons across various centrality intervals in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$, recorded by the ALICE detector. A pseudorapidity-gap technique, similar to that used in anisotropic-flow studies, is employed to suppress short-range correlations. At low $p_{\mathrm{T}}$, a characteristic mass ordering consistent with hydrodynamic collective flow is observed. At higher $p_{\mathrm{T}}$ ($>3\mathrm{GeV}/c$), protons exhibit larger $v_0(p_{\mathrm{T}})$ than pions and kaons, in agreement with expectations from quark-recombination models. Comparisons to viscous hydrodynamic calculations with varying bulk viscosity and equation of state demonstrate the sensitivity of the $v_0(p_{\mathrm{T}})$ observable to these key medium properties. The findings establish $v_0(p_{\mathrm{T}})$ as a valuable addition to the set of observables used in Bayesian analyses for extracting the transport properties and constraining the equation of state of strongly interacting matter, while also helping to systematically explore its sensitivity and impact within such global studies.

The $2{{}^3\mathrm{S}}_1\to 2{}^3{\mathrm{P}}_2$ interval (${\nu }_2$) in positronium has been measured using a phase-variation separated oscillatory fields technique. A beam of positronium atoms in the $2{}^3{\mathrm{S}}_1$ state was passed through two spatially separated coherent microwave fields tuned close to the ${\nu }_2$ resonance frequency ($8626.71\pm 0.08\mathrm{MHz}$), and the surviving beam fraction was recorded as a function of the relative phase between the fields. The resonance frequency was obtained from the frequency dependence of the phase of the interference signal without scanning over the full spectral line shape of the transition. We obtain ${\nu }_2=8626.39\pm 1.17_{\mathrm{stat}}\pm 0.80_{\mathrm{sys}}\mathrm{MHz}$, which is in agreement with QED theory.

We experimentally demonstrate that the rotation of molecules embedded in helium nanodroplets can be controlled with an optical centrifuge, allowing for the study of molecular dynamics inside the strongly interacting many-body environment of superfluid helium at variable levels of rotational excitation. By doping the droplets with dimers of nitric oxide, $(\mathrm{NO}{)}_2$, and measuring the degree of their centrifuge-induced alignment as a function of time, we show both the forced in-field rotation of molecules in a continuous range of frequencies, as well as the field-free resonant rotation with a long nanosecond-scale decay. The ability to control and monitor the rotational dynamics of molecular rotors inside the superfluid medium may shed new light on superfluidity and the interaction of superfluids with defects at the atomic level.

We numerically construct asymptotically global ${\mathrm{AdS}}_3\times {\mathrm{S}}^3\times {\mathrm{T}}^4$ black holes in type IIB supergravity, with ${\mathbb{R}}_t\times \mathrm{SO}(2)\times \mathrm{SO}(3)\times \mathrm{U}(1{)}^4$ symmetry, localized on the ${\mathrm{S}}^3$ and translationally invariant along the torus. These solutions, with horizons whose spatial cross sections have ${\mathrm{S}}^4\times {\mathrm{T}}^4$ topology, dominate the microcanonical ensemble at low energies. At higher energies, a first-order phase transition occurs to $\mathrm{BTZ}\times {\mathrm{S}}^3\times {\mathrm{T}}^4$ black holes—possessing ${\mathbb{R}}_t\times \mathrm{SO}(2)\times \mathrm{SO}(4)\times \mathrm{U}(1{)}^4$ symmetry and ${\mathrm{S}}^1\times {\mathrm{S}}^3\times {\mathrm{T}}^4$ horizon topology. By the AdS/CFT correspondence, this transition reflects the spontaneous breaking of the SO(4) $R$ symmetry of the $D1\text{−}D5$ ${\mathrm{CFT}}_2$ to SO(3). We also compute the expectation value of the scalar operator with lowest conformal dimension in the low-energy phase. Our SO(3)-localized black holes—together with the $\mathrm{U}(1{)}^2$-localized solutions of Bena et al. [J. High Energy Phys. 10 (2025) 165.]—point to a rich landscape of novel black holes that may approach the ${\mathrm{CFT}}_2$ “sparseness bootstrap condition,” and shed light on how macroscopic entanglement in thermal phases encodes microscopic structure via internal directions.

We provide evidence that three-party entanglement signals in holography obey a relation that is not satisfied by generalized Greenberger-Horne-Zeilinger (GHZ) states. Using proposed holographic duals for these entanglement signals, we provide a geometric argument establishing this relation. This is the first known inequality on the structure of pure three-party holographic states, and shows that time-symmetric holographic states can never have purely GHZ-like entanglement. We also discuss similar relations for four parties.

Developments in ultrastable lasers have fueled remarkable advances in optical frequency metrology and quantum science. A key ingredient in further improving laser frequency stability is the use of low-noise mirror materials such as AlGaAs crystalline coatings. However, excess noise observed with these coatings limits the performance of cryogenic silicon cavities with AlGaAs mirrors to similar levels achieved with conventional dielectric coatings. With a new pair of crystalline coated mirrors in a 6-cm-long cryogenic silicon cavity operated at 17 K, we demonstrate a clear advantage of crystalline coatings over dielectric coatings. The achieved fractional frequency stability of $2.5\times {10}^{-17}$ at 10 s is four times better than expected for dielectric mirrors and corresponds to more than a tenfold reduction in the coating mechanical loss factor. We also combine two silicon cavities to demonstrate optical frequency averaging for enhanced stability. In addition, we present a long-term frequency drift record of four cryogenic silicon cavities measured over several years. These results open up realistic prospects for cavity-stabilized lasers with ${10}^{-18}$ fractional stability, as well as an all-optical timescale with continuously operating optical local oscillators.

We introduce a generative modeling framework for thermodynamic computing, in which structured data are synthesized from noise by the natural time evolution of a physical system governed by Langevin dynamics. While conventional diffusion models use neural networks to perform denoising, here the information needed to generate structure from noise is encoded by the dynamics of a thermodynamic system. Training proceeds by maximizing the probability with which the computer generates the reverse of a noising trajectory, which ensures that the computer generates data with minimal heat emission. We demonstrate this framework within a digital simulation of a thermodynamic computer. If realized in analog hardware, such a system would function as a generative model that produces structured samples without the need for artificially injected noise or active control of denoising.

Multistability—the coexistence of multiple stable states—is a cornerstone of nonlinear dynamical systems, governing their equilibrium, tunability, and emergent complexity. Recently, the concept of hidden multistability, where certain stable states evade detection via conventional continuous parameter sweeping, has garnered increasing attention due to its elusive nature and promising applications. In this Letter, we present the first experimental observation of hidden multistability using a programmable acoustic coupled-cavity platform that integrates competing self-focusing and self-defocusing Kerr nonlinearities. Beyond established bistability, we demonstrate semihidden and fully hidden tristabilities by precisely programming system parameters. Crucially, the hidden stable states, typically inaccessible via the traditional protocol, are unambiguously revealed and dynamically controlled through pulsed excitation, enabling flexible transitions between distinct types of stable states. These experimental findings not only offer new insights into the fundamental physics of emerging hidden multistability, but also unlock new avenues for applications in information storage, information encryption, and safety precaution, where multistate dynamics could enable advanced control techniques.

We theoretically proposed and experimentally demonstrated that a nonlinear acoustic dimer system with amplitude-dependent and sign-reversible coupling exhibits unprecedented control over multistability and state selection. The engineered inter-resonator coupling $\kappa ={\kappa }_0+\alpha |{\psi }_1{|}^2$ yields a quintic steady-state response with at most three dynamically stable states: low (LS), intermediate (IS), and high (HS). Monotonic sweeps produce asymmetric hysteresis—$\mathrm{LS}\to \mathrm{HS}$ on upsweep, but $\mathrm{HS}\to \mathrm{IS}\to \mathrm{LS}$ on downsweep—leaving a linearly stable yet dynamically inaccessible IS under conventional driving. Basin-of-attraction analysis shows that nonlinear coupling reshapes the phase-space geometry, creating barriers that isolate the IS. Leveraging this insight, we developed a simple up-down-up adiabatic protocol that achieves full and selective access to all stable states, including the otherwise transparent IS. Mapping versus drive frequency and damping reveals transitions from separated bistable loops to a unified tristable regime. These results, to our knowledge, provide the first experimental realization of nonlinear-coupling-governed multistability and a versatile route to programmable multistate control.

We present an experimental study of molecular alignment echoes driven by ultrashort structured light fields carrying orbital angular momentum (OAM). By combining two time-delayed pump pulses with spatially varying polarization, we produce a molecular “$q$ plate” in a gaseous ${\mathrm{CO}}_2$ sample that can be rephased in a controllable manner. This approach enables the storage of OAM information within the rotational coherences of molecules and its retrieval at adjustable times. The concept is validated using vortex beams of various topological charges $\ell =\pm 1$, 2. These results extend the mechanism of molecular alignment echoes to vector light fields and establish a new route for optical processing of ultrashort OAM pulses, advancing molecular-based quantum interfaces for structured light.

We demonstrate the general failure of the famous concept of tight binding and mode hybridization underlying modern theories of coupled open resonators. Despite sophisticated examples in the literature illustrating these theories, they fail to describe planar systems. This includes even the simplest case of two dielectric slabs placed next to each other or separated by a distance, which is straightforward to verify analytically. We present a rigorous theory capable of calculating correctly the eigenmodes of arbitrary three-dimensional dispersive coupled resonators in terms of their individual modes, revealing proper mode hybridization and formation of bonding and antibonding supermodes. Planar optical resonators, such as coupled slabs and Bragg-mirror microcavities, are used for illustration since they allow reliable verification of the theory.

We introduce a combined density functional theory and nonequilibrium Green’s function framework to compute the capacitance of nanocapacitors and directly extract the dielectric response of a subnanometer dielectric under bias. We identify that at the nanoscale conventional capacitance evaluations based on stored charge per unit voltage suffer from an ill-posed partitioning of electrode and dielectric charge. This partitioning directly impacts the geometric definition of capacitance through the capacitor width, which in turn makes the evaluation of dielectric response uncertain. This ambiguous separation further induces spurious interfacial polarizability when analyzed via maximally localized Wannier functions. Focusing on crystalline ice, we develop a robust charge-separation protocol that yields unique capacitance-derived polarizability and dielectric constants, unequivocally demonstrating that confinement alters neither ice’s intrinsic electronic response nor its insensitivity to proton order. Our results lay the groundwork for rigorous interpretation of capacitor measurements in low-dimensional dielectric materials.

We present the tightest cosmic microwave background (CMB) lensing constraints to date on the growth of structure by combining CMB lensing measurements from the Atacama Cosmology Telescope (ACT), the South Pole Telescope (SPT), and Planck. Each of these surveys individually provides lensing measurements with similarly high statistical power, achieving signal-to-noise ratios of approximately 40. The combined lensing band powers represent the most precise CMB lensing power spectrum measurement to date with a signal-to-noise ratio of 61 and an amplitude of $A_{\mathrm{lens}}^{\text{recon}}=1.025\pm 0.017$ with respect to the theory prediction from the best-fit CMB Planck-ACT cosmology. The band powers from all three lensing datasets, analyzed jointly, yield a 1.6% measurement of the parameter combination $S_8^{\mathrm{CMBL}}\equiv {\sigma }_8({\mathrm{\Omega }}_m/0.3{)}^{0.25}=0.825_{-0.013}^{+0.015}$. Including dark energy spectroscopic instrument baryon acoustic oscillation (BAO) data improves the constraint on the amplitude of matter fluctuations to ${\sigma }_8=0.829\pm 0.009$ (a 1.1% determination). When combining with uncalibrated supernovae from Pantheon+, we present a 4% sound-horizon-independent estimate of $H_0=66.4\pm 2.5\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$. The joint lensing constraints on structure growth and present-day Hubble rate are fully consistent with a $\mathrm{\Lambda }\mathrm{CDM}$ model fit to the primary CMB data from Planck and ACT. While the precise upper limit is sensitive to the choice of data and underlying model assumptions, when varying the neutrino mass sum within the $\mathrm{\Lambda }\mathrm{CDM}$ cosmological model, the combination of primary CMB, BAO, and CMB lensing drives the probable upper limit for the mass sum towards lower values, comparable to the minimum mass prior required by neutrino oscillation experiments.

Characterizing the anisotropic structure in noncollinear antiferromagnets is essential for antiferromagnetic spintronics. In this Letter, we provide a microscopic theory linking the anisotropy effects induced by the rigid-body rotation of spin order to spin-orbit coupling. Our method goes beyond the conventional magnetic group theory, offering a concise yet powerful tool to characterize diverse anisotropy effects in complex magnetic systems. Using the group representation theory of the spin group, we obtain a set of basis functions formed from tensor elements of spin-orbit vector—which originates from spin-orbit coupling and is tied to the rigid-body rotation of the spin order–to systematically describe the structure of anisotropy effects. As a concrete example, we apply our framework to coplanar antiferromagnets ${\mathrm{Mn}}_3\mathrm{Sn}$ and ${\mathrm{Mn}}_3\mathrm{Ir}$, demonstrating that the corresponding basis functions can well capture both the geometric and magnitude dependencies of the magnetic anisotropy energy and anomalous Hall conductivity. Finally, we discuss the generalization of our framework to broader classes of anisotropy phenomena in magnetic systems.

Conventional approaches to generating and distributing entangled quantum states usually rely on bulky traditional optical devices, posing significant challenges to system miniaturization and integration. Here we report an entanglement engineering scheme that utilizes quantum interference on a metasurface, combined with postselection, to generate and distribute multiple polarization-entangled photon pairs. Two unentangled identical photons, differing only in polarization, are incident on a multichannel metasurface where each channel supports a specific polarization transformation. The metasurface facilitates two-photon interference, generating postselected polarization-entangled states and forming a fully connected entanglement distribution among every two output channels. Experiments demonstrate the generation and distribution of four Bell states across 21 channel pairs, underscoring the potential of metasurfaces as compact, scalable entanglement sources for quantum networking.

Flow-mediated interactions between objects are important in sedimentation and collective locomotion. New phenomena arise in systems that are dominantly coupled by rotation, as relevant to active matter physics and biological and engineering contexts. Here we establish an experimental platform for studying fluid mechanical spin-coupling effects and map out how interactions depend on proximity, confinement, and flow state. The two-body problem of a driven rotor inducing spin of a passive rotor reveals a gearlike counterrotation mode but also surprising corotation modes that occur broadly across the parameter space. Streamline analysis and a mechanical model indicate distinct transitions between modes that arise geometrically at close range, topologically due to flow reconfiguration, and inertially with increasing Reynolds number. These findings provide ways to understand, control, and exploit hydrodynamic spin-spin interactions in applications.