We report the first demonstration of a minute-scale, edge-localized-mode-free high-confinement plasma regime compatible with divertor partial detachment and enhanced pedestal performance in a metal-wall tokamak, the Experimental Advanced Superconducting Tokamak. This regime is enabled by a newly identified mechanism: during divertor partial detachment, reduced ionization and enhanced pumping in a closed divertor lead to less cooling of the pedestal by recycling neutrals and seeding impurities, resulting in an increased pedestal temperature gradient, which excites high-frequency broadband turbulence. Gyrokinetic simulations identify the high-frequency broadband turbulence as a temperature-gradient-driven trapped electron mode (${\eta }_e$-TEM), which drives outward transport of particles and heat, thereby maintaining the edge-localized-mode-free state. This pedestal regime is particularly promising for the International Thermonuclear Experimental Reactor, where the anticipated lower density gradient, reduced $\mathrm{E}\times \mathrm{B}$ shear, and lower collisionality in the pedestal will further facilitate ${\eta }_e$-TEM excitation. The achieved integrated scenario with a detached divertor and turbulence-dominated pedestal thus offers a compelling solution for managing heat loads and metal impurity sources for long-pulse high-performance operation in future fusion reactors.

It is demonstrated that the peak toroidal impact phase of the post-disruption runaway electrons (REs) can be varied shot to shot by means of applied static nonaxisymmetric (3D) magnetic fields, or resonant magnetic perturbations (RMPs). In the experiments, high-current (500 kA), purged RE plateaus (i.e., low impurity postdisruption plasmas with current carried completely by REs) were terminated on the DIII-D tokamak center post. The global toroidal impact peak of the REs appears to be dominantly set by the toroidal phase of a wall-locked tearing mode, typically $(\mathit{m}/n)=(2/1)$, but sometimes $(\mathit{m}/n)=(3/2)$. In the absence of external RMP, the locked mode reliably locks close to a preferred toroidal phase $\varphi \simeq 75°$ probably set by intrinsic error fields. With applied RMP, the locked mode and RE impact phase is pushed to a new location. When the tearing mode is $(m/n)=(2/1)$, the phase is well controlled and tracks the applied RMP phase, but in the case of an $(m/n)=(3/2)$ tearing mode, the new phase location is not well controlled. These results could have an application in international thermonuclear experimental reactor and other fusion power plant-sized tokamaks as a method for spreading disruption first wall damage from REs.

Mielnik’s cannonball argument uses the Zeno effect to argue that projective measurements for time of arrival are impossible. If one repeatedly measures the position of a particle (or a cannonball!) that has yet to arrive at a detector, the Zeno effect will repeatedly collapse its wave function away from it: the particle never arrives. Here we introduce quantum stroboscopic measurements where we accumulate statistics of projective position measurements, performed on different copies of the system at different times, to obtain a time-of-arrival distribution. We show that, under appropriate limits, this gives the same statistics as time measurements of conventional “always on” particle detectors that bypass Mielnik’s argument using nonprojective, weak continuous measurements. In addition to time of arrival, quantum stroboscopy can describe distributions of general time measurements. It can also be adapted to obtain the conditional probability distribution of arrival times, given that the particle was not previously detected at the detector.

We quantify in a unified approach the nonlocal resources of bipartite quantum channels and identify their component resisting the effects of dephasing noise. Despite its classical nature, we demonstrate that the latter plays a relevant role in performing quantum protocols, such as state transformations and quantum coding for noisy communication. When comparing different resource types, we show that simulating certain stochastic processes with quantum channels has a communication advantage with respect to their classical simulation, even when dephasing noise occurs. This approach also allows us to lower bound the amount of shared entanglement and communication needed to simulate bipartite quantum channels and to inner approximate the set of $n$-round local operations, assisted with classical communication.

High-fidelity quantum entanglement enables key quantum networking capabilities such as secure communication and distributed quantum computing, but long-distance entanglement distribution is limited by noise and loss. Entanglement distillation protocols address this problem by extracting high-fidelity Bell pairs from multiple noisy ones. The primary objective is minimizing the resource overhead: the number of noisy input pairs needed to distill each high-fidelity output pair. While protocols achieving optimal overhead are known in theory, they often require complex decoding operations that make practical implementation challenging. We circumvent this challenge by introducing protocols that use quantum scrambling—the spreading of quantum information under chaotic dynamics—through random Clifford operations. Based on this scrambling mechanism, our protocol maintains asymptotically constant overhead, independent of the desired output error rate $\overline{ϵ}$, and can be implemented with shallow quantum circuits of depth $O(\mathrm{poly}\log \log {\overline{ϵ}}^{-1})$ and memory $O(\mathrm{poly}\log {\overline{ϵ}}^{-1})$. Our protocol remains effective even with noisy quantum gates. By incorporating error correction, our protocol achieves state-of-the-art performance: starting with pairs of 10% initial infidelity, we require only seven noisy inputs per output pair to distill a single Bell pair with infidelity $\overline{ϵ}={10}^{-12}$, substantially outperforming existing schemes. We demonstrate the utility of our protocols for quantum repeater networks.

Entanglement is widely regarded as an essential resource for a number of tasks and can in some cases be quantified by figures of merit related to those tasks. In quantum metrology, this is showcased by the connections between the quantum Fisher information (QFI), providing a bound to the precision, and multipartite entanglement quantifiers such as the entanglement depth. However, a connection between the QFI and entanglement monotones, i.e., functions that do not increase under Local Operations and Classical Communications, has so far remained elusive. In this Letter, we fill this gap by introducing a family of uncertainty relations that bound bipartite entanglement monotones from below via elements of a quantum Fisher information matrix. To further emphasize the significance of our results, we connect these relations to the achievable precision in multiparameter estimation. Considering a system split into two parts with arbitrary dimension, we also show that, while two-dimensional entanglement is sufficient to estimate a single parameter with maximal precision, genuine high-dimensional entanglement is required for multiparameter estimation. We conclude by illustrating how our method extends naturally to a multipartite splitting.

We delineate the maximal parameter space of sterile neutrino dark matter in the presence of lepton-flavor asymmetries. We focus on large flavor asymmetries with vanishing total lepton asymmetry, which are washed out by neutrino oscillations at MeV temperatures and hence are consistent with big bang nucleosynthesis and cosmic microwave background constraints. We derive a semiclassical Boltzmann equation for sterile neutrinos applicable in this regime and validate it against quantum kinetic equations. For sterile neutrino masses up to 60 keV, the viable range of mixing angles extends by up to 2 orders of magnitude, with broad prospects for tests in forthcoming x-ray, cosmic microwave background, and structure formation observations. We also release a public framework to compute the production of sterile neutrinos, and in particular their momentum distribution, enabling dedicated structure formation analyses.

We utilize the universality of pion-pion ($\pi \pi$) final-state interactions at small invariant masses to understand the enhanced localized $CP$ violation in $B^{\pm }\to K^{\pm }{\pi }^{+}{\pi }^{-}$, using a dispersive approach. From a fit to the integrated $CP$-asymmetry data, we successfully predict the Dalitz-plot kinematic distribution of the asymmetry in the low-energy $\pi \pi$ region, including the large localized $CP$ violation recently observed by LHCb. An essential role is played by the contributions of isospin 2. This formalism, whose parameters have a physical meaning, can be adapted straightforwardly to other systems with $CP$ violation enhanced by final-state interactions.

Lattice simulations and theoretical analyses consistently identify center vortices and monopoles as key nonperturbative configurations in Yang-Mills theory. In the continuum, the effective representation of mixed oriented and nonoriented center vortices showed that these degrees of freedom generate a confining flux tube with $N$-ality. Independently, studies of correlation functions reveal an infrared behavior characterized by massivelike scales. In this Letter, field correlators are computed for the first time in a theoretical framework based on center vortices. Using an Abelian-projected vacuum wave functional peaked on the mixed ensemble, we show the emergence of a massivelike gauge-invariant field strength correlator. For this behavior, the nonoriented component in the center-vortex condensate turns out to be essential, as is also the case for producing the correct properties of confining flux tubes.

Resonant energy transfer (RET) between the equal parity 1s65s ${}^3{\mathrm{S}}_1$ and 1s66s ${}^3{\mathrm{S}}_1$ Rydberg levels in helium has been observed in low-temperature ($\sim 80\mathrm{mK}$) collisions with ammonia molecules that undergo inversion transitions in their X ${}^1{\mathrm{A}}_1$ ground electronic state. This hybrid Rydberg-atom–polar-molecule resonant energy transfer represents a monopole-dipole energy exchange reaction that necessarily requires spatial overlap of the Rydberg-electron and molecular wave functions. Calculations that account explicitly for the charge-dipole interaction between the Rydberg electron and the molecule provide a quantitative explanation of the observations. Total parity is conserved in the reaction through the mixing of collisional angular momentum in the atom-molecule complex. This work opens opportunities to expand the toolbox for quantum science with charge-dipole-mediated energy exchange in hybrid atom–polar-molecule platforms.

Understanding plasma self-magnetization is one of the fundamental challenges in both laboratory and astrophysical plasmas. Self-magnetization can modify plasma transport properties, altering the dynamical evolution of plasmas. Multiple high-energy-density (HED) experiments have observed the formation of ion-scale magnetic filaments of megagauss strength, though their origin remains debated. Here, we conduct 2D collisional particle-in-cell (PIC) simulations with a laser ray-tracing module for a fully self-consistent simulation of the plasma ablation, expansion, and magnetization. The simulations use a planar geometry, effectively suppressing the Biermann magnetic fields, to focus on anisotropy-driven instabilities. The laser intensity is varied between ${10}^{13}$ and ${10}^{14}\mathrm{W}/{\mathrm{cm}}^2$, which is relevant to HED and inertial fusion experiments where collisions must be considered. We find that, above a critical intensity, the plasma rapidly self-magnetizes via an expansion-driven Weibel process, producing a plasma beta of 100 ($\beta =8\pi k_B{n}_e{T}_e/B^2$) and Hall parameter ${\omega }_{\mathrm{ce}}{\tau }_e>1$ within the first few hundred picoseconds. The magnetic field is sufficiently strong to modify plasma heat transport, and simulations with an artificially suppressed magnetic field show noticeably different temperature profiles.

Entanglement plays a central role in quantum technologies, yet its characterization and control in materials remain challenging. Recent developments in spectrum-based entanglement witnesses have enabled new strategies for quantifying many-body entanglement in macroscopic materials. Here, we develop a protocol for detecting spin-orbital entanglement using experiment-accessible resonant inelastic x-ray scattering. Central to our approach is the construction of a Hermitian generator from measurable spectra, which allows us to compute the quantum Fisher information (QFI) available in spin-orbital systems. The resulting QFI provides upper bounds for $k$-producible states and thus serves as a robust witness of spin-orbital entanglement. To account for realistic experimental limitations, we further extend our framework to include relaxed QFI bounds applicable to measurements lacking full polarization resolution.

The quantum geometric tensor unifies the Berry curvature (its imaginary part) and the quantum metric (its real part), yet Raman studies of chiral phonons have so far accessed only the former. We perform circularly polarized Raman spectroscopy on the quantum magnet ${\mathrm{K}}_2\mathrm{Co}({\mathrm{SeO}}_3{)}_2$, where the field-odd chiral splitting $\mathrm{\Delta }\omega$ and the field-even center shift $\delta {\omega }_c$ collapse onto a single curve across temperature and magnetic field, revealing a common microscopic origin for both observables. Since $\mathrm{\Delta }\omega$ reflects the Berry curvature, the concomitant even component $\delta {\omega }_c$, arising from the same microscopic origin, captures the field-induced change of the quantum metric—the diagonal Born-Oppenheimer correction. Across two resolvable $E_g$ modes, the unified data are well captured by a simple empirical relation, $\delta {\omega }_c=\gamma (\mathrm{\Delta }\omega {)}^2$. These results establish Raman spectroscopy as a direct probe of the quantum metric and an operational decomposition of quantum geometry within a single measurement.

Altermagnets are collinear antiferromagnets with non-relativistic spin splitting of the electronic states. We identify the Ruddlesden-Popper chromates $\mathrm{S}{\mathrm{r}}_{n+1}\mathrm{C}{\mathrm{r}}_n{\mathrm{O}}_{3n+1}$, including the perovskite ${\mathrm{SrCrO}}_3$, as candidate materials in which altermagnetism can emerge from spontaneous orbital ordering rather than crystal symmetry. First-principles calculations reveal a layer-dependent spin splitting whose net effect depends on the relative alignment of spin and orbital order: when spin and orbital orders align in adjacent layers, the system exhibits overall spin splitting and thus altermagnetism. When either the spin or orbital order is reversed between adjacent layers, the sign of the spin splitting reverses as well. As a result, the splitting remains finite within each layer but cancels overall. We refer to this compensated state, consisting of two altermagnetic sublattices with opposite spin splitting, as antialtermagnetism. In the Ruddlesden-Popper chromates, odd-$n$ members can host both altermagnetic and antialtermagnetic states, whereas even-$n$ compounds and the perovskite limit are strictly antialtermagnetic.

The generation of spin currents is a key challenge in the field of spintronics. We propose using surface acoustic waves (SAWs) to generate spin currents in altermagnetic thin films, thereby realizing an acoustic spin splitter. Altermagnets, characterized by spin-polarized electrons and magnons, provide a versatile platform where SAWs can drive spin currents carried by both charge carriers and magnons. This acoustic spin splitter can be implemented in both metallic and insulating altermagnetic thin films, offering broad material applicability and a novel way to detect the spin-splitter effect in insulating altermagnetic thin film. We examine a realistic experimental setup where a heavy metal layer, such as platinum, is used to convert the spin current into a measurable charge current via the inverse spin Hall effect. For representative material parameters, we calculate the expected spin current and the corresponding inverse spin Hall voltage. Furthermore, we demonstrate that tuning the SAW frequency allows for precise control over the spin current, highlighting the versatility and potential of the acoustic spin splitter for future spintronics applications.

Cubic boron arsenide (BAs) is a promising semiconductor for next-generation electronics due to its outstanding ambipolar mobility and thermal conductivity, the latter of which is attributed to the suppression of three-phonon scattering. However, precisely accounting for different high-order anharmonic scattering processes is challenging from both theory and experiment, so that questions remain open regarding the ultimate limit of phonon lifetime and thermal conductivity in BAs. Here we show that this gap nearly eliminates three-phonon scattering for zone-center optical phonons in a wide temperature range, leading to a record-high, isotope purity-limited phonon coherence with a quality factor above $3.7\times {10}^3$ for $>98\%$ enriched ${}^{11}\mathrm{BAs}$ below 100 K. We discriminate three decoherence mechanisms by their temperature-dependent contribution to the damping rate using high-resolution Raman and Fourier transform infrared spectroscopy. For the as-synthesized crystals, we find that defect scattering has negligible contributions to the linewidth of optical phonons in comparison to isotope scattering. These results provide critical insights into the intrinsic and extrinsic scattering mechanisms of optical phonons in BAs, motivating further studies to quantify anharmonic effects and realize superior phonon transport.

We measured the energy efficiency of information erasure using silicon DRAM cells capable of counting charges on capacitors at the single-electron level. Our measurements revealed that the efficiency decreased as the erasure error probability decreased, and notably, the Landauer limit was not achieved, even under effectively infinite-time bit erasure. By comparing the measured efficiency with the Landauer limit, we identified a thermodynamic constraint that prevents DRAM from reaching this limit: the inability to prepare the initial state in thermal equilibrium, which in turn, prohibits quasistatic operations. This finding has broad implications for DRAM cells and for many electronic circuits sharing similar structures. Furthermore, it validates our experimental approach to discovering thermodynamic constraints that impose tighter, practically relevant limits, opening a new direction in information thermodynamics research.