The polarization of the $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$ hyperons along the beam direction has been measured in proton-lead ($p\text{-Pb}$) collisions at a center-of-mass energy per nucleon pair of 8.16 TeV. The data were obtained with the CMS detector at the LHC and correspond to an integrated luminosity of $186.0\pm 6.5{\mathrm{nb}}^{-1}$. A significant azimuthal dependence of the hyperon polarization, characterized by the second-order Fourier sine coefficient $P_{z,\mathrm{s}2}$, is observed. The $P_{z,\mathrm{s}2}$ values decrease as a function of charged particle multiplicity, but increase with transverse momentum. A hydrodynamic model that describes the observed $P_{z,\mathrm{s}2}$ values in nucleus-nucleus collisions by introducing vorticity effects does not reproduce either the sign or the magnitude of the $p\text{-Pb}$ results. These observations pose a challenge to the current theoretical implementation of spin polarization in heavy ion collisions and offer new insights into the origin of spin polarization in hadronic collisions at LHC energies.

The question of whether there are enough superfluid neutrons in the inner crust of neutron stars to explain pulsar glitches remains a topic of debate. Previous band structure calculations suggest that the entrainment effect significantly reduces the superfluid density. In this Letter, a new derivation of the BCS expression for the superfluid density is given. We compute it in the superfluid band theory framework through linear response theory, for a small relative velocity between superfluid and normal components, under the assumption that the pairing gap in the rest frame of the superfluid is constant and not affected by the perturbation. Our result suggests that a formula extensively used in neutron star physics is incomplete. Numerical evaluations for two realistic configurations reveal that the previously neglected contribution drastically alters the picture of the superfluid reservoir in the inner crust of neutron stars, suggesting that about 90% of the neutrons are effectively superfluid.

The superradiant phenomenon, usually described by the Dicke model, is a hallmark of strong light-matter interaction. We explore how matter-matter interactions influence this phenomenon by performing ground-state simulations of Dicke-like models with both isotropic and anisotropic interactions. We find that Ising-type interactions produce two qualitatively distinct phase boundaries, one of which gives rise to an antiferromagnetic-normal phase connected to the superradiant regime via a first-order phase transition. Under anisotropic couplings, we uncover a strongly correlated phase where in-plane spin order coexists with superradiance, exhibiting sublinear scaling of the photon occupation per site and power-law decay of spin correlations. Furthermore, superradiance is strengthened by tuning either isotropic or anisotropic interactions, highlighting the role of intrinsic many-body correlations in shaping light-matter quantum phases.

Chaos enables randomness-based applications, particularly in photonic systems. Integrated optical frequency combs (microcombs) have previously been observed in either chaotic modulation instability or stable, low-noise dissipative Kerr soliton (DKS) regimes. In this Letter, we demonstrate a new microcomb state where a single DKS exhibits chaotic behavior. By phase modulating the Kerr-induced synchronization (KIS) between a DKS and an externally injected reference laser, we observe chaotic group velocity hopping of the soliton, causing random transitions of the repetition rate. Using a chip-integrated octave-spanning microcomb, we experimentally validate the second-order Adler equation describing KIS, allowing us to predict and demonstrate this chaotic DKS hopping. This Letter connects nonlinear dynamics with optical soliton physics, providing a deterministic framework for triggering microcomb chaos in the solitonic state.

Most superconductors exhibit spin-singlet pairing within a single band. In multiband systems with strong spin-orbit coupling, more exotic scenarios can emerge, including Cooper pairs between bands with distinct symmetries. Here, we present evidence of the formation of Cooper pairs between spin-nondegenerate helical surface bands in the superconductor $\beta \text{−}{\text{Bi}}_2\mathrm{Pd}$. Scanning tunneling microscopy reveals anisotropic Yu-Shiba-Rusinov (YSR) resonances induced by vanadium impurities, with long-range amplitude modulations attributed to spin-conserving Bogoliubov quasiparticle interference (BQPI). Analysis of BQPI at the subgap YSR energy shows that only a selective subset of normal-state scattering processes contributes to Cooper pair formation, indicating interband mixing. We trace this selectivity to the hybridization of a helical surface band with others via the impurity.

There exist ten distinct closed flat 3D manifolds, known as “platycosms,” that hold significance in mathematics and have been postulated as potential geometric models for our Universe. In this Letter, we demonstrate their manifestation as universes of Bloch particles, namely as momentum-space units referred to as Brillouin platycosms, which are natural extensions of the Brillouin torus within a broader framework of projective crystallographic symmetries. Moreover, we provide exact $K$-theoretical classifications of topological insulators over these platycosms by the Atiyah-Hirzebruch spectral sequence, and formulate a complete set of topological invariants for their identification. Topological phase transitions are generically characterized by Weyl semimetals, adhering to the generalized Nielsen-Ninomiya theorem: the total chirality number over a Brillouin platycosm is even (zero) if the platycosm is nonorientable (orientable). Our Letter generalizes the notion of Brillouin torus to ten Brillouin platycosms and therefore fundamentally diversifies the stages on which Bloch wave functions can perform their topological dance.

We derive fundamental bounds for general quantum metrological models involving both temporal or spatial correlations (mathematically described by quantum combs), which may be effectively computed in the limit of a large number of probes or sensing channels involved. Although the bounds are not guaranteed to be tight in general, their tightness may be systematically increased by increasing the numerical complexity of the procedure. Interestingly, this approach yields bounds tighter than the state of the art also for uncorrelated channels. We apply the bounds to study the limits for the most general adaptive phase estimation models in the presence of temporally correlated dephasing. We consider dephasing both parallel (no Heisenberg scaling) and perpendicular (Heisenberg scaling possible) to the signal. In the former case our new bounds show that negative correlations are beneficial; for the latter we show evidence that the bounds are tight. We also apply the bounds to collisional thermometry, i.e., estimation of a parameter of the environment, showing evidence that entangled probes may provide only a limited advantage.

Recent investigations into the geometric structure of scattering amplitudes have revealed the surprising existence of “hidden zeros”: secret kinematic loci where tree-level amplitudes in $\mathrm{Tr}({\varphi }^3)$ theory, the nonlinear sigma model (NLSM), and Yang-Mills theory vanish. In this Letter, we propose the extension of hidden zeros to one-loop order in $\mathrm{Tr}({\varphi }^3)$ theory and the NLSM using the “surface integrand” technology introduced by Arkani-Hamed et al. We demonstrate that, under the assumption of locality, one-loop integrands in $\mathrm{Tr}({\varphi }^3)$ are unitary if and only if they satisfy these loop hidden zeros. We also present strong evidence that the hidden zeros themselves contain the constraints from locality, leading us to conjecture that the one-loop $\mathrm{Tr}({\varphi }^3)$ integrand can be fixed by hidden zeros from a generically nonlocal, nonunitary Ansatz. Near the one-loop zeros, we uncover a simple factorization behavior and conjecture that NLSM integrands are fixed by this property, also assuming neither locality nor unitarity. This Letter represents the first extension of such uniqueness results to loop integrands, demonstrating that locality and unitarity emerge from other principles even beyond leading order in perturbation theory.

We demonstrate that measurements of coherent elastic neutrino-nucleus scattering at spallation sources are valuable probes of muon-decay physics. Using COHERENT data we derive the first direct constraint on the Michel parameters governing the ${\overline{\nu }}_{\mu }$ energy distribution. We also discuss future sensitivities, the implications for the Lorentz structure of the interactions mediating muon decay, and the application to other neutrino-production mechanisms like pion decay.

We present a novel technique to incorporate precision calculations from quantum chromodynamics into fully differential particle-level Monte Carlo simulations. By minimizing an information-theoretic quantity subject to constraints, our reweighted Monte Carlo incorporates systematic uncertainties absent in individual Monte Carlo predictions, achieving consistency with the theory input in precision and its estimated systematic uncertainties. Our method can be applied to arbitrary observables known from precision calculations, including multiple observables simultaneously. It generates strictly positive weights, thus offering a clear path to statistically powerful and theoretically precise computations for current and future collider experiments. As a proof of concept, we apply our technique to event-shape observables at electron-positron colliders, leveraging existing precision calculations of thrust. Our analysis highlights the importance of logarithmic moments of event shapes, which have not been previously studied in the collider physics literature.

The magnetic dipolar splitting of a $p$-wave Feshbach resonance is governed by the spin-orbital configuration of the valence electrons in the triplet molecular state. We perform high-resolution trap-loss spectroscopy on ultracold ${}^6\mathrm{Li}$ atoms to resolve this splitting with sub-milligauss precision. By comparing electron-spin-polarized ($|m_S|=1$) and electron-spin-mixture ($m_S=0$) configurations of the triplet state, we observe a clear spin-dependent reversal in the splitting structure, confirmed via momentum-resolved absorption imaging. This behavior directly reflects the interplay between electron spin projection $m_S$ and orbital angular momentum $m_{\ell }$ in the molecular states. Our results provide a stringent benchmark for dipole-dipole interaction models and lay the groundwork for controlling the pairing in $p$-wave superfluid systems.

Using the time-dependent Lanczos method, we study the nonequilibrium dynamics of the half-filled one-dimensional ionic Hubbard model, deep within the Mott insulating regime, under the influence of a transient laser pulse. In equilibrium, increasing the staggered potential in the Mott regime reduces the Mott gap and broadens the Hubbard bands, creating favorable conditions for impact ionization. After laser excitation, impact ionization is observed, with its occurrence depending on both the staggered potential and the laser pump frequency. By analyzing the time evolution of the kinetic, ionic, and Coulomb interaction energies, we identify a novel mechanism for impact ionization, in which excess ionic potential energy is converted into additional double occupancy—distinct from the conventional mechanism where excess kinetic energy drives this process. We further reveal that impact ionization arises from interference between excited states driven by photon excitations of the same order. These results present a new pathway for realizing impact ionization in strongly correlated electron systems.

Recent studies suggest that the candidate Kitaev magnet ${\mathrm{Na}}_2{\mathrm{Co}}_2{\mathrm{TeO}}_6$ possesses novel triple-$\mathbf{q}$ magnetic order instead of conventional single-$\mathbf{q}$ zigzag order. Here we present dedicated experiments in a search for distinct properties expected of the triple-$\mathbf{q}$ order, namely, insensitivity of the magnetic Bragg intensities to weak $C_3$ symmetry-breaking fields and fictitious magnetic fields generated by the spin vorticity. In structurally pristine single crystals, we show that $C_3$ symmetry-breaking in-plane uniaxial strains do not affect the order’s magnetic neutron diffraction signals. We further show that $c$-axis propagating light exhibits large Faraday rotations in the ordered state due to the spin vorticity, the sign of which can be trained via the system’s ferrimagnetic moment. These results favor the triple-$\mathbf{q}$ order in ${\mathrm{Na}}_2{\mathrm{Co}}_2{\mathrm{TeO}}_6$ and reveal its unique emerging behavior.

The interplay between magnetic order and electronic band structure in antiferromagnets has garnered increasing interest due to its potential for spintronic applications. While magnetic transitions have been shown to induce substantial band structure modifications in optical measurements, their influence on electronic transport remains poorly understood. In this work, we investigate the transport properties of CrSBr, a van der Waals antiferromagnetic semiconductor, over a wide range of carrier densities modulated by gate voltage. We observe a drastic contrast in magnetoresistance behavior between the low- and high-carrier density regimes. Through a combination of experiment and modeling, we identify magnetically driven carrier concentration modulation and mobility modulation as the dominant mechanisms governing magnetoresistance in the respective regimes. These findings advance the understanding of magnetoelectric transport in antiferromagnets and suggest promising routes for energy-efficient spintronic technologies in memory, logic, and sensing applications.

The molecular motion in heterogeneous media displays anomalous diffusion by the mean-squared displacement $⟨X^2(t)⟩=2D{t}^{\alpha }$. Motivated by experiments reporting populations of the anomalous diffusion parameters $\alpha$ and $D$, we aim to disentangle their respective contributions to the observed variability when this last is due to a true population of these parameters and when it arises due to finite-duration recordings. We introduce estimators of the anomalous diffusion parameters on the basis of the time-averaged mean-squared displacement and study their statistical properties. By using a copula approach, we derive a formula for the joint density function of their estimations conditioned on their actual values. The methodology introduced is indeed universal, it is valid for any Gaussian process and can be applied to any quadratic time-averaged statistics. We also explain the experimentally reported relation $D\propto \exp (\alpha c_1+c_2)$ for which we provide the exact expression. We compare our findings to numerical simulations of the fractional Brownian motion and quantify their accuracy by using the Hellinger distance. Finally, we provide guidelines and routines for fitting experimental data.

Aqueous cations permeate subnanoscale pores by crossing free energy barriers dominated by competing enthalpic contributions from transiently decreased ion-solvent and increased ion-pore electrostatic interactions. This commonly accepted view is rooted in the studies of monovalent cation transport. Divalent cations, however, have significantly higher desolvation costs, requiring considerably larger pores to enable retention of the first hydration shell and subsequently transport. We show that this scenario gives rise to a strong enthalpy-entropy competition. Specifically, the first hydration shell is shown to undergo rotational ordering inside the pore, resulting in a tight transition state. Our results shed light on the basic mechanisms of transport barrier formation for aqueous divalent cations permeating nanoporous 2D membranes.