The framework of superconductivity unveiled the striking concept that electrons form Cooper pairs through the subtle interplay of lattice vibrations, surmounting their Coulombic repulsion in the process. The concept of Cooper pairs has been established beyond the Fermi system, and this pairing mechanism is expected to extend to quasiparticle systems. Here, we report the soliton Cooper pairs in a Mamyshev oscillator. The soliton-phonon coupling yields a long-range attraction between solitons, balancing the Coulomb-like force, i.e., the gain depletion and recovery effect. With this, two solitons can form high-stable bound pair, even in the presence of intervening solitons. We characterize these long-range paired solitons comprehensively both in the time and phase domains. These discoveries herald a new method to manipulate nonlocal response for applications in optical systems and can help to understand particle-phonon coupling in fundamental physics.

Future applications of the spectrally narrow x-ray resonances in Mössbauer nuclei require x-ray sources with exceptionally high peak and average spectral flux. Here, we introduce a superradiant parametric Mössbauer radiation (SPMR) source, which utilizes the scattering of spatially microstructured electron bunches produced in x-ray free-electron laser (XFEL) accelerators on crystals. The spatial structuring leads to a coherent add-up of the radiation from different electrons, thereby enhancing the Mössbauer radiation by many orders of magnitude. We find that the performance is optimized at qualitatively different operation conditions than considered so far. For a focused electron beam with parameters based on the European XFEL facility, our approach predicts the generation of more than 900 SPMR photons per pulse within one linewidth of the ${}_{26}{}^{57}\mathrm{Fe}$ Mössbauer resonance. This opens up new opportunities for precision metrology, and for hard x-ray pump-probe spectroscopy techniques via the parallel use of the bunched XFEL electron and photon beams.

The origin of the difference in the high-confinement ($H$-mode) power threshold between favorable and unfavorable drift configurations in tokamaks—experimentally linked to a deeper radial electric field ($E_r$) well in the former—remains unresolved. Using first-principles gyrokinetic simulations of edge and scrape-off-layer turbulence in the ASDEX Upgrade tokamak, we show that turbulence-driven poloidal flows generate this deeper $E_r$ well in the favorable configuration through enhanced nonlinear turbulence-mean flow energy transfer. This transfer is significantly weaker in the unfavorable case, yielding a shallower $E_r$ well, while turbulence intensity is simultaneously higher. Within the turbulence-flow shear suppression paradigm, the combination of stronger shear and reduced turbulence facilitates $H$-mode access in the favorable configuration. These results provide the first validated, self-consistent full-$f$ gyrokinetic explanation of how drift configuration controls the nonlinear dynamics of profiles, $E_r$, flows, and turbulence, thereby setting the $H$-mode power threshold.

Chiral magnetic states give rise to rich phenomena, from the anomalous Hall effect and the nonlinear electrical current to multiferroics and magnetochiral dichroism. Most of the studies on electrical transport so far have focused on the cases where the magnetic moments are well approximated by classical local moments. Here, we reveal that the coexistence of quantum fluctuations and chiral spin correlations gives rise to a $\log (T)$ temperature dependence in the electrical magnetochiral effect, a nonreciprocal response. Using the Green’s function method and a scattering theory approach, we show that the $\log (T)$ temperature dependence occurs through a scattering process similar to that of the Kondo effect. The electrical magnetochiral effect is sensitive to the sign of vector spin chirality and the magnetic field. The results demonstrate that local spin correlations and quantum fluctuations cooperatively induce nontrivial properties in transport phenomena.

Even-denominator fractional quantum Hall states at half-filling are of particular interest because they can host non-Abelian quasiparticles. Here, we report the emergence of such states in the zeroth Landau level ($N=0$) of ABA trilayer graphene (TLG), challenging the conventional expectation that they are confined to the first excited Landau level. We observe robust incompressible states at $\nu =7/2$, $9/2$, and $5/2$ with their associated Levin-Halperin daughter states: $\nu =59/17$ and $46/13$ near $7/2$; $\nu =58/13$ and $77/17$ near $9/2$; and $\nu =43/17$ near $5/2$. These states appear exclusively within a finite displacement-field window coincident with crossings between symmetry-broken $N=0$ Landau levels carrying distinct isospin indices. The quantitative correspondence between the calculated crossing loci and the experimentally determined stability regions identifies Landau-level mixing as the microscopic origin. We attribute the stabilization of these even-denominator states to inversion-symmetry breaking in TLG, which enhances valley-resolved Landau-level hybridization and renormalizes short-range Coulomb interactions. Our results expand the landscape of even-denominator fractional quantum Hall states to multilayer graphene and establish TLG as a tunable platform for realizing non-Abelian anyons.

In many developmental systems, cells differentiate into a tissue by reading out morphogen concentration fields, a process fundamentally limited by noise. How much can the precision of this process be improved by nonlocal information, e.g., via cell-cell communication? Using a Bayes-optimal framework, we show that positional inference depends crucially on morphogen spatial correlations and on the “structural prior” that encodes the geometry of the cellular lattice performing the readout, thereby determining what a cell can reliably assume about the position of its neighbors when interpreting nonlocal morphogen signals. We derive upper bounds on positional information gain due to nonlocal readout and identify signal processing algorithms that approximate optimal positional inference, as well as simple chemical reaction schemes which implement such algorithms. Our theory suggests that correlational information can be exploited to significantly enhance developmental precision.

The principle that heat spontaneously flows from higher temperatures to lower temperatures is a cornerstone of classical thermodynamics. While this principle holds true for macroscopic systems at equilibrium, here we show that, when a quantum system undergoes two thermalization processes in an indefinite causal order, it can absorb heat even if its initial temperature was higher than the temperature of the reservoirs involved in the two thermalizations. Exploiting this anomalous heat flow, we design a quantum Otto cycle with indefinite causal order, which generates work and simultaneously achieves refrigeration. These unconventional features can be achieved by a process with indefinite causal order known as the quantum switch, but are not uniquely associated to indefinite causal order. In general, we prove that the action of two thermalizations in a quantum switch can be exactly reproduced by letting the two thermalizations act in parallel in an equivalent, causally ordered quantum circuit. Compared to its causally ordered counterpart, however, the quantum switch setup is more friendly to free-space photonic implementations. To illustrate this fact, we experimentally realize two photonic setups that reproduce the anomalous heat flow and the quantum Otto cycle with indefinite causal order, respectively.

Custodial naturalness is a recently introduced idea that combines conformal and scalar sector custodial symmetry to address the electroweak (EW) scale hierarchy problem of the standard model (SM). We introduce a new model that realizes custodial naturalness without extension of the SM gauge group. The number of new dynamical degrees of freedom is minimized, and the custodial symmetry is reduced to SO(5). This requires a new scalar singlet field that automatically is a good dark matter (DM) candidate, produced via freeze-in with moderate couplings. The most minimal scenario allows the quantum critical generation of the EW scale in a phenomenologically viable way requiring a UV completion at around ${10}^{11}\mathrm{GeV}$. Including ingredients for neutrino mass generation can push this scale to $M_{\mathrm{Pl}}$.

We have performed hyperfine spectroscopy of two transitions in ground-state deuterium and searched for violations of $CPT$ and Lorentz symmetry that would manifest as sidereal variations of the observed transition frequencies. Several nonrelativistic proton coefficients of the Standard-Model extension framework have been addressed. The spin-independent coefficients with momentum power $k=2$, 4 are constrained for the first time. Bounds on spin-dependent coefficients are improved by exploiting a sensitivity enhancement originating from the relative momenta of the nucleons in the deuteron. The best previous constraints by hydrogen maser measurements are surpassed by 4 and 14 orders of magnitude for coefficients with $k=2$ and 4, respectively.

We report an experimental investigation of the reactions $\overline{n}p\to 2{\pi }^{+}{\pi }^{-}$, $\overline{n}p\to 2{\pi }^{+}{\pi }^{-}{\pi }^0$, and $\overline{n}p\to 2{\pi }^{+}{\pi }^{-}2{\pi }^0$ using $(10.087\pm 0.044)\times {10}^{9}J/\psi$ events collected with the BESIII detector at the BEPCII storage ring. The antineutron ($\overline{n}$) is produced in the decay $J/\psi \to p{\pi }^{-}\overline{n}$ with studied momentum from 200 to $1174\mathrm{MeV}/c$, while the target proton originates from the hydrogen nuclei in the cooling oil of the beam pipe. This novel method pioneers the study of $\overline{n}$-nucleon interactions at an $e^{+}{e}^{-}$ collider, providing the first experimental data for $\overline{n}$ momenta exceeding $800\mathrm{MeV}/c$.

We report high-precision frequency ratio measurements between optical atomic clocks based on ${}^{27}{\mathrm{Al}}^{+}$, ${}^{171}\mathrm{Yb}$, and ${}^{87}\mathrm{Sr}$. With total fractional uncertainties at or below $3.2\times {10}^{-18}$, these measurements meet an important milestone criterion for redefinition of the second in the International System of Units. Discrepancies in ${}^{87}\mathrm{Sr}$ ratios at approximately $1\times {10}^{-16}$ and the ${\mathrm{Al}}^{+}/\mathrm{Yb}$ ratio at $1.6\times {10}^{-17}$ in fractional units compared to our previous measurements underscore the importance of repeated, high-precision comparisons by different laboratories. A key upgrade from our previous work is the use of a common ultrastable reference delivered to all clocks via a 3.6-km phase-stabilized fiber link between two institutions, enabling better accuracy and stability in frequency transfer. Derived from a cryogenic single-crystal silicon cavity, this reference improves comparison stability by a factor of 2–3 over previous systems, with an optical lattice clock ratio achieving a fractional instability of $1.3\times {10}^{-16}$ at 1 s. Identifying individual clock stabilities with a three-corner-hat measurement, we demonstrate the most stable optical lattice and trapped-ion clocks used in a multispecies comparison. By enabling faster comparisons, this stability will improve sensitivity to nonwhite noise processes and other underlying limits of state-of-the-art optical frequency standards.

Gyrokinetic simulations of a turbulence-reduced Wendelstein 7-X discharge—characterized by a steep density gradient, moderate temperature gradients, and low plasma beta—show that microtearing mode (MTM) turbulence dominates transport. The simulated heat and particle fluxes agree with experimental measurements, leaving MTMs as the only mode consistent with the data. These conditions, the quasi-isodynamic and nearly max-$J$ magnetic configuration of the Wendelstein 7-X stabilize ion temperature gradient modes and density-gradient-driven trapped-electron modes, while moderate collisionality and low magnetic shear further enable MTM growth. Further nonlinear scans of the density gradient reveal a significant reduction in turbulent transport at the experimentally observed threshold, which we identify as an ion temperature gradient to MTM-dominated turbulence transition. These findings provide a robust explanation for the turbulence suppression and deepen our understanding of low turbulent transport regimes in optimized stellarators.

Indentation is one of the simplest ways to feel the stiffness of matter. Interpreting indentation, however, requires care, especially for thin films—such as biological cells or soft coatings supported by rigid substrates—because the substrate effect can make a film appear orders of magnitude stiffer than it actually is. To minimize this artifact, the empirical “10% rule of thumb,” which limits indentation depth to one-tenth of the film thickness, has often been adopted, though it becomes unreliable and impractical for ultrathin films. Here, we explore the traditionally forbidden regime: deep indentation, where the indentation depth is comparable to the film thickness. We develop an asymptotic theory that incorporates nonlinear geometry and elasticity, elucidating a simple indentation force-depth relation in this deep regime. We further show that the pull-off force in such indentation tests is remarkably independent of both the material law and geometric nonlinearity. The results provide a unified framework for interpreting thin-film mechanics under deep indentation, a regime that is generally much more accessible in experiments on very thin films.

We investigate the zero magnetization and ground state phase diagram of a spin-$1/2$ chain with competing ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor exchange couplings in the strongly interacting regime. Using density matrix renormalization group (DMRG) simulations, we discover two successive commensurate-incommensurate transitions of the nonconformal Pokrovsky-Talapov universality class, occurring even at zero magnetic field. We argue that the first transition marks the proliferation of solitonic discommensurations (kink-antikink pairs) in a critical phase with central charge $c=2$, emerging from a period-4 gapped phase. At the second transition, an incommensurate quadrupolar (or nematic) Luttinger liquid forms out of a gapped phase separation, via the condensation of two-magnon bound pairs. In the strongly interacting limit, the location of the two Pokrovsky-Talapov transitions can be analytically predicted with degenerate perturbation theory. Our results demonstrate that frustration alone is sufficient to drive continuous commensurate-incommensurate transitions of Mott type and stabilize complex objects with incommensurate quasi–long-range order without doping.

Motivated by the recent discovery of anomalously large magnetic response of chiral phonons in dipolar magnets, we introduce the concept of pseudochiral phonons which are shown to emerge in multipolar magnets. We consider Raman active quantum phonons, such as doublet $E_g$ phonons $(d_{x^2-y^2},d_{3z^2-r^2})$ in cubic crystals, which feature a symmetry-allowed linear coupling to local quadrupolar moments. We show that distinct multipolar orders can imprint distinct patterns of degeneracy breaking for phonons, with quadrupolar orders favoring nonchiral eigenmodes and time-reversal breaking octupolar orders favoring unconventional pseudochiral phonons. We compute the temperature dependent phonon matrix Green’s function using a path integral approach where “fast” phonon modes sense “slow” pseudospin fluctuations over a thermal background sampled using Monte Carlo simulations. We propose helicity-resolved Raman spectroscopy of these pseudochiral phonons as a probe of hidden octupolar order in quantum materials such as ${\mathrm{Ba}}_2{\mathrm{CaOsO}}_6$ and ${\mathrm{PrV}}_2{\mathrm{Al}}_{20}$.

We report the discovery of a geometric pathway for tuning ferroelectric properties through a thermally driven reconfiguration between coexisting polar states in Li-substituted ${\mathrm{NaNbO}}_3$. Using a first-principles density functional theory calculation and ${}^7\mathrm{Li}$ solid-state nuclear magnetic resonance spectroscopy measurement, we reveal that Li substitution creates two distinct polar configurations whose transformation under annealing enhances the Curie temperature and induces piezoelectric hardening. Our findings establish a geometrically driven polar state reconfiguration mechanism, providing a general design principle for ferroics whereby macroscopic functional properties can be engineered via lattice geometry.

Under unitary evolution, chaotic quantum systems initialized in simple states rapidly develop high complexity, precluding any efficient classical description. The hardness of classical simulation within the stabilizer formalism, commonly referred to as magic resources, can be quantified by the stabilizer Rényi entropy, while quantum chaos can be characterized by spectral properties of the Hamiltonian, most notably through the spectral form factor. In this Letter, we propose a relation between the dynamics of the stabilizer Rényi entropy for thermofield double states and the spectral form factor, based on general arguments for chaotic systems with all-to-all interactions. This relation implies that the saturation of the stabilizer Rényi entropy is governed by a first-order dynamical transition. We then demonstrate this relation explicitly in the Sachdev-Ye-Kitaev model, using an auxiliary-spin representation of the stabilizer Rényi entropy that exhibits an emergent $Z_2$ symmetry. We further find that, in the high-temperature regime of the SYK model, the transition occurs at a finite time, with the long-time phase marked by spontaneous $Z_2$ symmetry breaking. By contrast, at low temperatures, the transition is pushed to times exponentially long in the system size. Our results reveal an intriguing interplay between quantum chaos and magic resources.

We introduce a simplified version of Connes-Narnhofer-Thirring’s quantum dynamical entropy for quantum systems. It quantifies the amount of information gained about the initial condition from continuously monitoring an observable. A nonzero entropy growth rate can be obtained by monitoring the thermal fluctuation of an extensive observable in a generic many-body system, away from classical or large $N$ limits. We explicitly compute the entropy rate in the thermodynamic and long-time limit in terms of the two-point correlation functions. We conjecture a universal Planckian bound for the entropy rate. Related results on the purification rate are also obtained.