We perform time-domain evolutions of the ergoregion instability on a horizonless spinning ultracompact spacetime in scalar theories with potential-type and derivative self-interactions mimicking the nonlinear structure of the Einstein equations. We find that the instability saturates by triggering a weakly turbulent direct cascade, which transfers energy from the most unstable and large-scale modes to small scales. The cascade’s nonlinear timescales of each mode are orders of magnitude shorter than the corresponding linear e-folding times. Through this mechanism, the counterrotating stable light ring is filled with a spectrum of higher-order azimuthal modes forming a ringlike shape. Thereby we demonstrate that turbulent processes are likely also important during the fully gravitational saturation of the instability, leaving imprints in the gravitational wave emission.

We report the first experimental observation of subgap transport in ferromagnetic insulator–superconductor–insulator–superconductor junctions realized in $\mathrm{EuS}/\mathrm{Al}/\mathrm{AlOx}/\mathrm{Al}$ vertical stacks. Differential conductance measurements reveal multiple Andreev reflection peaks, with odd-order peaks split by the spin-splitting induced in the superconductor adjacent to EuS, while even-order peaks remain unaffected. Combining experiments with quasiclassical transport modeling, we extract the spin-splitting and an approximate distribution of transmission channels, finding that roughly a hundred highly transmitting ($\tau >0.3$) channels will dominate transport. The observation of a Josephson current further confirms strong superconducting coupling through these channels. Our results demonstrate that a single spin-split superconductor is sufficient to observe the even-odd multiple Andreev reflection effect. Our work establishes EuS/Al junctions as a versatile platform to study subgap transport, Josephson coupling, and spin-polarized superconducting phenomena.

Transverse thermophotovoltaics has been conceptually proposed as a paradigm distinct from conventional junction-based photovoltaics, but has so far lacked a theoretical foundation. In this Letter, we establish a microscopic formalism of this effect in which a transverse electric current emerges in a two-dimensional metal sheet via nonreciprocal surface plasmon polaritons driven by near-field thermal radiation. This theoretical formalism incorporates the electron-photon interaction by integrating electronic transition factor governed by energy-momentum conservation, the photon flux factor encoding the nonreciprocal surface modes, and their directional coupling. Our approach quantitatively confirms the plasmon-drag mechanism and reveals the role of impurity scattering. This Letter provides a rigorous theoretical foundation for transverse thermophotovoltaic devices and opens avenues for active nanoscale thermal energy conversion.

We develop a method for studying chemical oscillators in the presence of phase separation. Specifically, we define a dynamics at phase equilibrium by imposing timescale separation between slow reactions and fast diffusion. We show that colocalization of components can alter oscillator frequency and amplitude, and that it determines the stability of oscillations and fixed points. Although our method applies to general reaction networks with phase separation, we illustrate it on a concrete example of a three-component oscillator (“rock-paper-scissors” model) with two-phase coexistence. The analysis is validated with a spatial model, where relaxing the timescale separation between reactions and diffusion leads to waves of phase equilibria at mesoscopic scales.

Structure most frequently constrains material behavior, resulting in the coupling between structural and dynamical properties. Using numerical simulations, we show that single-particle elasticity can cause the breakdown of this coupling, enabling liquidlike dynamics within crystalline configurations. Our findings reveal that the elastic heterogeneity of the many-particle system is key to this behavior, allowing the transition from a disordered to an ordered structure, where particles remain mobile; the resultant ordered material is thus characterized by the presence of rearrangements, a characteristic feature of the liquid state. Our findings clearly identify elasticity as a definitive aspect for achieving the decoupling of structure and dynamics.

A key advantage of quantum metrology is the ability to surpass the standard quantum limit (SQL) for measurement precision through the use of nonclassical states. However, there is typically little to no improvement in precision with the use of nonclassical states for measurements whose duration exceeds the decoherence time of the underlying quantum states. Measurements aimed at the ultimate possible precision are thus performed almost exclusively with classical states and, therefore, are constrained by the SQL. Here, we demonstrate that by using the phenomenon of subharmonic excitation, in combination with a recently demonstrated technique of Raman excitation of a harmonic oscillator, the frequency of an electric field can be measured at a resolution below the SQL of the corresponding linear generator. With this method we measure a radio-frequency electrical signal with a fractional frequency uncertainty of $0.56\mathrm{Hz}/80\mathrm{MHz}=7\times {10}^{-9}$, which to our knowledge is the most precise frequency measurement of a radio-frequency electrical signal using a quantum harmonic oscillator. Because the input states can be classical, the coherence time is not degraded by the enhanced decoherence typically associated with nonclassical states, thereby improving the ultimate achievable precision. While we demonstrate this technique using motional Raman subharmonic excitation of a single ${}^{40}{\mathrm{Ca}}^{+}$ ion through engineered Floquet states, this technique is expected to be extendable to other platforms, such as NV centers, solid-state qubits, and neutral atoms, where it can provide metrological gain for sensing across the radio frequency, microwave, and optical domains.

QCD axions would be copiously produced in the protoneutron star formed in a core-collapse supernova (SN). After escaping, they would convert into gamma rays in the Galactic magnetic field and, as recently shown, in that of the progenitor star itself. Here, we show that Type Ibc SNe—whose progenitors have lost their hydrogen or even helium envelopes—are the optimal targets for this search. The stripped progenitors are much more compact, and they show larger magnetic fields than both red and blue supergiants, the progenitors of Type IIP/L SNe. If the next galactic SN is of Type Ibc, Fermi-LAT or a similar gamma-ray satellite might be able to discover the QCD axion down to masses as small as $m_a\simeq {10}^{-4}\mathrm{eV}$ (Peccei-Quinn scale $f_a\simeq {10}^{11}\mathrm{GeV}$).

We demonstrate the emergence of novel topological phases in quantum Hall-superconductor hybrid structures driven by Landau-level mixing and spin-orbit coupling. For a narrow superconducting stripe atop a two-dimensional electron gas, hybridization of chiral Andreev edge states yields a rich phase diagram, including the unexpected realization of the long-sought $p$-wave superconducting state at even filling factors, thus allowing its detection at lower fields. These phases feature quantized nonlocal conductance from electron cotunneling at filling factor $\nu =1$, coexisting with quantized crossed Andreev reflection at $\nu =2$ leading to the appearance of a neutral mode. Numerical simulations and effective modeling reveal how spin-orbit coupling and geometry control these transitions, enabling realistic routes to engineer topology in proximized quantum Hall devices.

Local measurements can radically reshape patterns of many-body entanglement, especially in long-range entangled quantum-critical states. Yet, analytical results addressing the effects of measurements on many-body states remain scarce, and measurements are often approximated as forcing specific measurement outcomes. We study measurement-induced entanglement (MIE) in Tomonaga-Luttinger liquids, a broad family of $1+1\mathrm{D}$ quantum critical states described at low energies by compact free boson conformal field theories. Using a replica trick to address the randomness of the measurement outcomes, we compute exactly the entanglement induced by measuring the local charge operator for Tomonaga-Luttinger liquids, in very good agreement with matrix-product state calculations. We show that the MIE for physical quantum measurements is fundamentally different from the entanglement induced by forcing measurement outcomes, and has a natural interpretation in terms of Born averaging over conformally invariant boundary conditions.

Programmable neutral atom arrays show great promise for fault-tolerant quantum computing. A dominant physical error on this platform is qubit leakage and loss, notably decay errors from the Rydberg state during two-qubit gates. Such leakage events are particularly detrimental as they propagate, generating correlated errors that severely degrade the effective error distance of quantum error correction codes. Here, we present a novel approach to address Rydberg decay errors leveraging measurement-based quantum computation. Our scheme strategically exploits the inherent geometric structure of topological cluster states and only uses final leakage detection information to locate propagated errors originating from Rydberg decay. This eliminates the need for complex and atom-species-specific midcircuit leakage detection, offering broader applicability, e.g., to the well-established Rb atom platform. We demonstrate a high error threshold of 3.65% per cz gate for pure Rydberg decay and achieve a favorable error distance $d_e\approx d$. Our method compares favorably with state-of-the-art erasure conversion protocols in the subthreshold performance, offering comparable or marginally larger logical error rates while significantly reducing experimental overhead.

It is common knowledge that black holes necessarily contain a region where general relativity breaks down, due to the inevitable formation of either a curvature singularity or a Cauchy horizon. In this Letter we challenge this view by analyzing a charged spherically symmetric black hole formed through gravitational collapse and evaporating via Hawking radiation. We show that the electromagnetic repulsion and the violation of energy conditions due to the presence of Hawking radiation can be sufficient to avoid the formation of both a singularity and a Cauchy horizon. We argue that a similar mechanism may apply to astrophysical black holes in which the role of the electric charge is replaced by the angular momentum.

Anomalous Hall crystals (AHCs) are exotic phases of matter that simultaneously break continuous translation symmetry and exhibit the quantum anomalous Hall effect. AHCs have recently been proposed to explain the observation of an integer quantum anomalous Hall phase in a multilayer graphene system. Despite intense theoretical and experimental interest, little is known about the mechanical properties of AHCs. We study the elastic properties of AHCs first by using a continuum model with quadratic dispersion and uniform Berry curvature. We find using time-dependent Hartree-Fock that the stiffness of the AHC is an order of magnitude smaller than that of the WC, which we attribute to the finite Chern number of the AHC preventing exponential localization of the charge density. By modifying the dispersion relation to include a local minimum modeled after that of rhombohedral pentalayer graphene (R5G), we find that deformations away from the triangular lattice minimize the AHC’s kinetic energy, which overwhelms the small stiffness and triggers a mechanical instability. Using a microscopic model of R5G, we observe a similar mechanical instability over an experimentally relevant parameter regime. We conclude that the topologically limited stiffness of AHCs makes them susceptible to mechanical instabilities, an important consideration when interpreting experiments in terms of AHCs.

Interlayer excitons (IXs) in transition metal dichalcogenide moiré heterobilayers offer a versatile platform for exploring strongly correlated quantum phases. Despite recent progress in probing excitonic properties, the thermalization dynamics of IXs, particularly within moiré superlattices, remain poorly understood due to their intrinsic weak oscillator strength. Here, we investigate how IXs are thermalized in both R- and H-stacked ${\mathrm{WSe}}_2/{\mathrm{WS}}_2$ heterobilayers using a moiré-resolved ultrafast spectroscopy that probes intralayer exciton states with distinct atomic registry and spatial localization. We resolve the formation and cooling kinetics of IXs, revealing that thermalization proceeds via phonon-mediated scattering on a timescale of $\sim 15\mathrm{ps}$. Our results highlight the role of exciton localization and site-specific interactions in governing IX dynamics and establish a spatially sensitive approach to exciton spectroscopy beyond the conventional momentum-space framework.

We compute three-loop corrections to the three-point form factor of the operator $\mathrm{tr}({\varphi }^2)$ in $\mathcal{N}=4$ supersymmetric Yang-Mills theory. In particular, our result is valid beyond the leading-color limit and will consequently be an important input towards extending the amplitude-bootstrap program beyond the leading-color approximation. We find that our analytic formulae are strikingly compact expressions in terms of integer linear combinations of generalized polylogarithms of weight six.

We present the first lattice QCD determination of the electromagnetic form factors of the exotic tetraquark $T_{bb}(bb\overline{u}\overline{d})$ with quantum numbers $I(J^P)=0(1^{+})$. The extracted form factors encode information about its internal structure, including the charge distribution and the magnetic dipole moments, determined separately for the light and heavy quarks. Our results provide evidence in favor of it being a bound state consisting of a compact heavy diquark $[bb]$ in a color-antitriplet with spin one and a light antidiquark $[\overline{u}\overline{d}]$ in a color-triplet with spin zero. The charge radius of $T_{bb}$ is found to be significantly smaller than the combined charge radii of $B$ and $B^{*}$ mesons. These two comprise the lowest-lying threshold $B{B}^{*}$ in the channel that we are considering, and their electric charge form factors are also determined. The computations were performed on a single ensemble, generated by the Coordinated Lattice Simulations effort, with $N_f=2+1$ dynamical quarks and a lattice spacing of approximately $a\approx 0.064\mathrm{fm}$ at the pion mass $m_{\pi }\approx 290\mathrm{MeV}$.