Recent works reveal a simplicity in equal-time correlators absent from wave functions. We show that it follows from the fact that correlators are full spacetime integrals rather than half-spacetime integrals as for the wave function. This makes striking properties manifest: some wave function singularities are absent, factorization simplifies, and around every pole the Laurent expansion has a vanishing first subleading term. Near the total-energy pole, the expansion to second order is generated by a differential operator on scattering amplitudes.

We present the first lattice-QCD validation of multiple sum rules associated with quark-gluon decomposition of hadron mass by computing all relevant tensor components of the quark and gluon energy-momentum tensor matrix elements from first principles. We achieve this through nonperturbative renormalization of the QCD energy-momentum tensor, including its trace, in a gradient-flow scheme, followed by continuum extrapolations, two-loop matching to the $\overline{\mathrm{MS}}$ scheme, and zero-flow-time extrapolations. These ingredients enable a direct and simultaneous verification, in a common renormalization scheme and scale, of multiple energy-density-based and trace-based mass decomposition sum rules proposed in the literature. We demonstrate the framework for the ${\eta }_c$ and $J/\psi$ charmonia using three fine lattice spacings with a physical strange-quark and near-physical up- and down-quark masses. We present the first lattice-QCD results for the gravitational form factor $\overline{C}$. We find sizable gluonic contributions to charmonia masses at the hadronic scale, $\sim 15\%$ in the Lorcé and Metz-Pasquini-Rodini decompositions. The trace-anomaly contribution in the Ji sum rule is $\sim 6\%$, while the gluonic component of the trace anomaly in the Hatta-Rajan-Tanaka sum rule is $\sim 35\%$. The method is general and can be straightforwardly adopted for lattice-QCD calculations of mass and spin decompositions as well as gravitational form factors of other hadrons and nuclei.

Dense nucleonic matter is of vital importance for understanding compact stars and inferring the transition into deconfined quark phase. We present ab initio exact calculations of infinite nucleonic matter with the state-of-the-art full configuration-interaction quantum Monte Carlo method, enabling us to rigorously benchmark many-body methods and assess the degree to which the nucleonic matter is correlated. Our method has been numerically validated against exact diagonalization within a small model space. Calculations of nucleonic matter using chiral nuclear forces reveal that symmetric nuclear matter is strikingly strongly correlated, raising questions on previous ab initio calculations of nuclear matter with many-body expansion truncations and offering insights into simultaneous descriptions of finite nuclei and infinite nucleonic matter from first principles.

The Stark effect in autoionizing high-$n$ Rydberg states decouples the Rydberg electron from the ion core through $\ell$ mixing with core-nonpenetrating high-$\ell$ states. The Rydberg states become long-lived, which is ideal for precision spectroscopy, and their structures reflect the fine and hyperfine structures of the ion-core levels. We report on precision measurements, in weak electric fields, of the fine and hyperfine structures of two distinct categories of high autoionizing molecular Rydberg-Stark states differing by the nature of the ion-core angular momentum: Rydberg states of para-${\mathrm{H}}_2$ (total nuclear spin $I=0\mathrm{,}2$) with a rotationally excited ($N^{+}=2$) ${\mathrm{H}}_2^{+}$ ion core and Rydberg states of ortho-${\mathrm{D}}_2$ ($I=0,2$) with a rotationless ($N^{+}=0$) ion core. The spectra reveal striking differences which are interpreted as arising from the dominance of anisotropic charge-quadrupole interactions between the rotating quadrupolar ion core and the Rydberg electron in para-${\mathrm{H}}_2$ and the absence of such interactions in rotationless ortho-${\mathrm{D}}_2$ Rydberg states. In ortho-${\mathrm{D}}_2$, the dominant interaction, the magnetic Fermi-contact hyperfine interaction in the ion core, does not significantly affect the motion of the Rydberg electron. By analyzing these spectra based on a treatment combining multichannel quantum-defect theory and matrix diagonalization, we derive new experimental values of the hyperfine coupling constant $b_F=139.84(5)\mathrm{MHz}$ of ${\mathrm{D}}_2^{+}(v^{+}=1,N^{+}=0)$, the spin-rotation coupling constant $c_e=39.62(11)\mathrm{MHz}$ of ${\mathrm{H}}_2^{+}(v^{+}=1,N^{+}=2)$ and the fundamental vibrational interval of ortho-${{\mathrm{D}}_2}^{+}$ [47 279 980.8(1.9) MHz]. The approach followed here in the study of molecular Rydberg-Stark states is general and broadly applicable to measurements of the fine and hyperfine structures of molecular cations.

The response of ultrathin superconducting materials under parallel magnetic fields is often leveraged to obtain insight into the nature of the condensate, including features attributable to unconventional forms of pairing. Despite there being multiple competing mechanisms responsible for suppressing superconductivity, it is common for these analyses to overlook certain depairing channels. Here, we report an analysis of thickness-dependent superconductivity in thin films of ${\mathrm{LaBi}}_2$ using the multimechanism Kharitonov-Feigel’man framework. By resolving field-enhanced superconductivity in the thin limit, we obtain an estimate the role of spin exchange scattering, in addition to paramagnetic and orbital effects. Our analyses offer insight into how fundamental quantities such as the critical temperature as well as Pauli limit are defined, recasting the landscape for how scattering times in two-dimensional superconductors can be interpreted.

Charge-$4e$ superconductivity is an exotic state of matter that may emerge as a vestigial order from a charge-$2e$ superconductor with multicomponent superconducting order parameters. Showing its emergence in a lattice phase model from numerically exact large-scale computations has remained rare. Here, we propose a kagome lattice model with a nematic superconducting ground state and show that it supports a rich set of vestigial phases at elevated temperatures, including a charge-$4e$ phase and a quasi-long-range nematic phase, through large-scale Monte Carlo simulations. Combining theoretical analysis with Monte Carlo simulations, we uncover the nature of these phases and show that the phase transitions are governed by the proliferation of distinct topological defects: the $(\frac{1}{2},0)$ half superconducting vortices, the $(\frac{1}{2},\frac{1}{2})$ vortices, the (0, 1) integer nematic vortices, and domain-wall excitations. In particular, we demonstrate that domain-wall proliferation is crucial for the quasinematic phase and should be carefully accounted for when analyzing phase transitions associated with vestigial charge-$4e$ order.

The composite Fermi liquid in the half-filled Landau level is a cornerstone of the quantum Hall phase diagram. Recent experiments and numerics indicate that an anomalous composite Fermi liquid (ACFL) can also arise at half filling of a Chern band without any external magnetic field, opening new possibilities for paired states of composite fermions beyond the fully gapped Pfaffian phase. We argue that, in inversion-asymmetric Chern bands with lattice rotational symmetry reduced to $C_3$, as realized in experimental platforms where signatures of the ACFL have been observed, composite fermions can form a superconductor with neutral gapless Bogoliubov Fermi surfaces. We term the resulting electronic state the composite Bogoliubov Fermi liquid. This phase has a number of properties that make it distinct from both the ACFL and the fully gapped Pfaffian. For instance, it is incompressible, has quantized Hall conductance, shows no quantum oscillations as a function of magnetic field or doping, and has topological ground state degeneracy on a torus despite the presence of gapless quasiparticles. At the same time, the neutral Bogoliubov Fermi surface yields metallic $T$-linear specific heat, nonquantized thermal conductance, Landau damping of density fluctuations, and a nonanalytic $|\mathit{q}{|}^3$ contribution to the equal-time structure factor $S(\mathit{q})$. We also discuss vortices and fractionalized daughter states induced by doping or external magnetic fields. Our results pave the way for a broader understanding of gapless topological phases arising from paired composite fermions in Chern bands beyond the conventional Landau level paradigm.

We report on the low-temperature magnetoelastic properties of the skyrmion-lattice compound ${\mathrm{GdRu}}_2{\mathrm{Si}}_2$ under magnetic fields applied along the [001] axis. Our sound-velocity measurements reveal a series of pronounced anomalies related to the skyrmion-lattice phase. The emergence of hysteresis and steplike features indicates intrinsic metastability of the skyrmion lattice in ${\mathrm{GdRu}}_2{\mathrm{Si}}_2$, deviating from other skyrmion-lattice compounds. Analysis of multiple elastic modes allows us to disentangle the compressional and shear responses, with the latter showing a stronger sensitivity to the metastability of the skyrmion lattice.

Many real-world infrastructures, from sensor and road networks to power grids, are spatially embedded and anisotropic, with constraints on the maximum number of links each node can establish. Such systems can be represented as anisotropic limited-degree networks, in which each node forms at most $q$ outgoing links preferentially oriented along a fixed direction. By increasing the node density $\sigma$ at fixed $q$, we uncover a reentrant percolation transition: a giant strongly connected component emerges, but unexpectedly disintegrates again at high densities. This counterintuitive behavior implies that adding nodes, normally expected to enhance robustness, can instead reduce mutual accessibility and weaken global connectivity. The critical behavior displays two coexisting “faces”: random-percolation scaling along the preferred direction and directed-percolation scaling transversely, therefore we name this phenomenon “Janus percolation,” in analogy with the dual-faced Roman god. These findings demonstrate that anisotropy and degree limitation can jointly induce a novel reentrant connectivity with mixed universality that bridges the universality classes of random and directed percolation, providing fresh insight into how structural constraints shape connectivity and resilience in spatial networks.

The question of thermalization in quantum many-body systems has long been studied through the properties of matrix elements of operators corresponding to local observables. More recently, the focus has shifted to the dynamics of operators, which lead to seminal works proposing universal bounds on the rate of operator growth. In this Letter, we unify these two approaches: we show that exponential operator growth in Hilbert space, as measured by Krylov complexity, is governed by an exponential off-diagonal decay of the operator matrix elements in the system eigenbasis. When this decay is algebraic or slower, the growth rate saturates the universal bound, thereby establishing a microscopic origin of operator growth which is independent of chaos, dimensionality or the presence of many-body interactions.

Recent pulsar timing array (PTA) analyses show evidence for a gravitational wave background (GWB) with angular correlations consistent with the Hellings-Downs curve. Anisotropies are a key discriminator of the origin of this GWB, as they are expected to be at 1%–20% for astrophysical sources, but suppressed for cosmological GWBs. However, contrary to gravitational wave detectors at higher frequencies, PTAs only take a few independent measurements of a GWB and consequently are highly sensitive to cosmic variance, which induces apparent anisotropies in individual realizations of an isotropic GWB. We demonstrate explicitly that statistical inference nevertheless remains robust, i.e., measurements are consistent with the underlying assumption of isotropy. This confirms that searches for anisotropies will be able to robustly discriminate astrophysical from cosmological GWBs. To this end, we demonstrate that the maximum multipole constrained by a PTA dataset scales linearly with the number of pulsars ${\ell }_{\max }\sim N_p$.

Supernova (SN) 1987A provides classic bounds on gamma-ray flashes from the radiative decay of sub-GeV particles, but the latter may decay so rapidly as to be shielded by the stellar envelope. Using axionlike particles with photon coupling as a benchmark, we show that Type Ic core-collapse supernovae largely evade this attenuation due to their compact progenitors. We identify two regimes. At small couplings, while individual flashes may be missed by Fermi-LAT, the high Type Ic rate enables a stacking analysis of nondetections. At larger couplings, decay photons trigger fireball formation; the absence of a signal from the rare broad-lined Type Ic SN 1998bw excludes this scenario. The resulting bounds significantly exceed those from SN 1987A for short decay lengths.

Recent lattice evidence may suggest the chiral phase transition in QCD is second order for $N_f\ge 2$ massless flavors. We constrain conformal field theory (CFT) descriptions of a critical line in temperature $T$ and imaginary baryon chemical potential ${\theta }_B=i{\mu }_B/T$. An ’t Hooft anomaly at general ${\theta }_B$ constrains the transition even at ${\theta }_B=0$, leaving only three minimal scenarios. The best-motivated scenario for $N_f\ge 3$, and perhaps also $N_f=2$, is beyond Ginzburg-Landau, featuring a conformal manifold of ${\theta }_B$-dependent universality classes with an exactly marginal operator related to baryon density.

The applicability of hydrodynamics in small collision systems remains controversial due to the small size and short lifetime of the system. In this Letter, we employ viscous anisotropic hydrodynamics (VAH), which incorporates large pressure anisotropies, to study the collectivity in $\mathrm{p}+\mathrm{p}$ collisions at $\sqrt{s}=13\mathrm{TeV}$. VAH provides a good description for $v_2\{2\}$ and $v_3\{2\}$ over a wide range of multiplicities and correctly reproduces the experimentally observed negative $c_2\{4\}$. Traditional second-order viscous hydrodynamics (VH), on the other hand, can describe the measurements, in particular the negative $c_2\{4\}$, only with model parameters for which the bulk of the evolution is characterized by large values of the shear Knudsen number. It also cannot capture the large pressure anisotropy between the longitudinal and transverse directions during the early evolution. These demonstrate the failure of traditional viscous hydrodynamics in small collision systems and establish viscous anisotropic hydrodynamics as a more reliable framework to describe the bulk evolution and the observed anisotropic flow in p–p collisions at the LHC.

High-precision multireflection time-of-flight mass spectrometry has been applied at BigRIPS-SLOWRI of the Radioactive Isotope Beam Factory (RIBF). The atomic mass of ${}^{50}\mathrm{Ar}$ was measured for the first time, and the mass value of ${}^{49}\mathrm{Ar}$ was determined to be 674 keV lower than the one from a previous $B\rho -$ TOF measurement, with a precision improved by a factor of 250. The new mass data enable us to determine the empirical proton-neutron interaction strength in the unconventional doubly magic nucleus ${}^{52}\mathrm{Ca}$. This strength exhibits a conspicuous variation across shell closures, analogously to what observed in classical doubly magic nuclei. Meanwhile, our measurements support the existence of a weak shell effect at $N=32$ in Ar isotopes. To supplement these experimental findings, theoretical calculations were performed for the isotopes of interest, which, compared with data, illustrate the capacity of ab initio expansion methods to capture key quadrupole correlations in doubly open-shell nuclei via an explicit account of nuclear deformation.

We directly observe and spatially map an optical analog of the Magnus effect, where intrinsic spin-orbit-like coupling of light generates a spin-dependent transverse displacement of the atom-light interaction profile for a ${}^{40}{\mathrm{Ca}}^{+}$ ion. Probed on a quadrupole transition using a tightly focused beam, we observe displacements of the maximum in the profile of the effective interaction by several 100 nm originating from intrinsic longitudinal electric field components beyond the paraxial approximation. The tight focus of the beam induces additional transverse polarization gradients, which we characterize through a phase-sensitive measurement and spatial maps for different beam configurations. The results establish the physical basis of polarization-gradient interactions relevant to optical tweezer-based quantum control.

State-dependent conformational changes play a central role in molecular dynamics, yet they are often difficult to observe or simulate due to their complexity and ultrafast nature. One alternative approach is to emulate such phenomena using quantum simulations with cold, trapped ions. In their electronic ground state, these ions form long-lived Wigner crystals. When excited to high-lying electronic Rydberg states, the ions experience a modified trapping potential, resulting in a strong coupling between their electronic and vibrational degrees of freedom. In an ion crystal, this vibronic coupling creates electronic state-dependent potential energy surfaces that can support distinct crystal structures—closely resembling the conformational changes of molecules driven by electronic excitations. Here, we present the first experimental observation of this effect, by laser coupling a single ion at the center of a three-ion crystal to a Rydberg state. By tuning the system close to a structural phase transition, the excitation induces a state-dependent conformational change, transforming the Wigner crystal from a linear to a zigzag configuration. This structural change leads to a strong hybridization between vibrational and electronic states, producing a clear spectroscopic signature in the Rydberg excitation. Our findings mark the first experimental step toward using Rydberg ions to create and study artificial molecular systems.