Rényi entropies, $S_n$, admit a natural generalization in the presence of global symmetries. These “charged Rényi entropies” are functions of the chemical potential $\mu$ conjugate to the charge contained in the entangling region and reduce to the usual notions as $\mu \to 0$. For $n=1$, this provides a notion of charged entanglement entropy. In this Letter, we prove that for a general $d(\ge 3)$-dimensional conformal field theory, the leading correction to the uncharged entanglement entropy across a spherical entangling surface is quadratic in the chemical potential, positive definite, and universally controlled (up to fixed $d$-dependent constants) by the coefficients $C_J$ and $a_2$. These fully characterize, for a given theory, the current correlators $⟨JJ⟩$ and $⟨TJJ⟩$, as well as the energy flux measured at infinity produced by the insertion of the current operator. Our result is motivated by analytic holographic calculations for a special class of higher-curvature gravities coupled to a ($d-2$) form in general dimensions as well as for free fields in $d=4$. A proof for general theories and dimensions follows from previously known universal identities involving the magnetic response of twist operators introduced in A. Belin et al. [J. High Energy Phys. 12 (2013) 059.] and basic thermodynamic relations.

An analytic formula is given for the three-point energy correlator at leading order in maximally supersymmetric Yang-Mills theory ($\mathcal{N}=4\mathrm{sYM}$). This is the first analytic calculation of a three-parameter event shape observable, which provides valuable data for various studies ranging from conformal field theories to jet substructure. The associated class of functions define a new type of single-valued polylogarithms characterized by 16 alphabet letters, which manifest a $D_6\times Z_2$ dihedral symmetry of the event shape. With the unexplored simplicity in the perturbative structure of the three-point energy correlator, all kinematic regions including collinear, squeezed and coplanar limits are now available.

A search for resonances decaying into a $W$ boson and a radion, where the radion decays into two $W$ bosons, is presented. The data analyzed correspond to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ recorded in proton-proton collisions with the CMS detector at $\sqrt{s}=13\mathrm{TeV}$. One isolated charged lepton is required, together with missing transverse momentum and one or two massive large-radius jets, containing the decay products of either two or one $W$ bosons, respectively. No excess over the background estimation is observed. The results are combined with those from a complementary channel with an all-hadronic final state, described in an accompanying paper. Limits are set on parameters of an extended warped extra-dimensional model. These searches are the first of their kind at the LHC.

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, probes nuclear effects that govern neutrino-nucleus interactions. This Letter reports the first measurement of the triple-differential cross section for ${\nu }_{\mu }$ quasielastic-like reactions using the hydrocarbon medium of the MINERvA detector exposed to a wideband beam spanning $2\le {\mathrm{E}}_{\nu }\le 20\mathrm{GeV}$. The measurement maps the correlations among transverse and longitudinal muon momenta and summed proton kinetic energies, and compares them to predictions from a state-of-art simulation. Discrepancies are observed that likely reflect shortfalls with modeling of pion and nucleon intranuclear scattering and/or spectator nucleon ejection from struck nuclei. The separate determination of leptonic and hadronic variables can inform experimental approaches to neutrino-energy estimation.

Using a sample of about ${10}^{10}J/\psi$ events collected at a center-of-mass energy $\sqrt{s}=3.097\mathrm{GeV}$ with the BESIII detector, the electromagnetic Dalitz decays $J/\psi \to e^{+}{e}^{-}{\pi }^{+}{\pi }^{-}{\eta }^{\prime }$, with ${\eta }^{\prime }\to \gamma {\pi }^{+}{\pi }^{-}$ and ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}\eta$, have been studied. The decay $J/\psi \to e^{+}{e}^{-}X(1835)$ is observed with a significance of $15\sigma$, and also an $e^{+}{e}^{-}$ invariant-mass dependent transition form factor of $J/\psi \to e^{+}{e}^{-}X(1835)$ is presented for the first time. The intermediate states $X(2120)$ and $X(2370)$ are also observed in the ${\pi }^{+}{\pi }^{-}{\eta }^{\prime }$ invariant-mass spectrum with significances of $5.3\sigma$ and $7.3\sigma$. The corresponding product branching fractions for $J/\psi \to e^{+}{e}^{-}X$, $X\to {\pi }^{+}{\pi }^{-}{\eta }^{\prime }$ [$X=X(1835)$, $X(2120)$, and $X(2370)]$ are reported.

Conventional lattice formulations of $\theta$ vacua in the $1+1$-dimensional O(3) nonlinear sigma model suffer from a sign problem. Here, we construct the first sign-problem-free regularization for arbitrary $\theta$. Using efficient lattice Monte Carlo algorithms, we demonstrate how a Hamiltonian model of spin-$\frac{1}{2}$ degrees of freedom on a two-dimensional spatial lattice reproduces both the infrared sector for arbitrary $\theta$, as well as the ultraviolet physics of asymptotic freedom. Furthermore, as a model of qubits on a two-dimensional square lattice with only nearest-neighbor interactions, it is naturally suited for studying the physics of $\theta$ vacua and asymptotic freedom on near-term quantum devices. Our construction generalizes to $\theta$ vacua in all $\mathrm{C}\mathrm{P}(N-1)$ models, solving a long-standing sign problem.

We perform collective spin measurements to study the buildup of two-body correlations between $\approx {10}^4$ spin $s=3$ chromium atoms pinned in a 3D optical lattice. The spins interact via long range and anisotropic dipolar interactions. From the fluctuations of total magnetization, measured at the standard quantum limit, we estimate the dynamical growth of the connected pairwise correlations associated with magnetization. The quantum nature of the correlations is assessed by comparisons with analytical short- and long-time expansions and numerical simulations. Our Letter shows that measuring fluctuations of spin populations for $s>1/2$ spins provides new ways to characterize correlations in quantum many-body systems.

Photonic quantum information processing relies on operating the quantum state of photons, which usually involves bulky optical components unfavorable for system miniaturization and integration. Here, we report on the transformation and distribution of polarization-entangled photon pairs with multichannel dielectric metasurfaces. The entangled photon pairs interact with metasurface building blocks, where the geometrical-scaling-induced phase gradients are imposed, and are transformed into two-photon entangled states with the desired polarization. Two metasurfaces, each simultaneously distributing polarization-entangled photons to spatially separated multiple channels $M$ ($N$), may accomplish $M\times N$ channels of entanglement distribution and transformation. Experimentally we demonstrate $2\times 2$ and $4\times 4$ distributed entanglement states, including Bell states and superposition of Bell states, with high fidelity and strong polarization correlation. We expect this approach paves the way for future integration of quantum information networks.

We present an experimental realization of a biased optical periodic potential in the low friction limit. The noise-induced bistability between locked (torsional) and running (spinning) states in the rotational motion of a nanodumbbell is driven by an elliptically polarized light beam tilting the angular potential. By varying the gas pressure around the point of maximum intermittency, the rotational effective diffusion coefficient increases by more than 3 orders of magnitude over free-space diffusion. These experimental results are in agreement with a simple two-state model that is derived from the Langevin equation through using timescale separation. Our work provides a new experimental platform to study the weak thermal noise limit for diffusion in this system.

We study free electron dynamics during inelastic interaction with the ponderomotive potential of a traveling optical wave using classical and quantum-mechanical models. We show that in the strong interaction regime, the electrons trapped in the periodic potential oscillate leading to periodic revolutions of sharp peaks of the density distributions in the real and momentum spaces. In this regime, the synchronicity between the velocity of the optical wave and the electron propagation velocity is not required. Asynchronous interaction enables acceleration or deceleration of a significant fraction of the electrons to a final spectrum with a relative spectral width of 0.5%–2.5%. This technique allows one to accelerate electrons from rest to keV energies while reaching a narrow spectrum of kinetic energies and femtosecond pulsed operation.

In this Letter, we analyze the dipole-dipole correlations obtained from the molecular dynamics simulations for strongly and weakly polar model liquids. As a result, we find that the cross-correlations’ contribution to the system’s total dipole moment correlation function, which is directly measured in the dielectric spectroscopy experiment, is negligible for weakly polar liquids. In contrast, the cross-correlations’ term dominates over the self-correlations’ term for the examined strongly polar liquid. Consequently, our studies strongly support the interpretation of the dielectric spectra nature of glass-forming liquids recently proposed by Pabst et al.

High-pressure single-crystal x-ray diffraction is used to experimentally map the electron-density distribution changes in (Fe,Mg)O as ferrous iron undergoes a pressure-induced transition from high- to low-spin states. As the bulk density and elasticity of magnesiowüstite—one of the dominant mineral phases of Earth’s mantle—are affected by this electronic transition, our results have applications to geophysics as well as to validating first-principles calculations. The observed changes in diffraction intensities indicate a spin-transition-induced change in orbital occupancies of the Fe ion in general accord with crystal-field theory, illustrating the use of electron density measurements for characterizing high-pressure $d$-block chemistry and motivating further studies characterizing chemical bonding under pressure.

The anisotropic fracture toughness $G(\theta )$ is an intrinsic feature of graphene and is fundamental for fabrication, functioning, and robustness of graphene-based devices. However, existing results show significant discrepancies on the anisotropic factor, i.e., the ratio between zigzag (ZZ) and armchair (AC) directions, $G_{\mathrm{ZZ}}/G_{\mathrm{AC}}$, both qualitatively and quantitatively. Here, we investigate the anisotropic fracture of graphene by atomic steps on cleaved graphite surfaces. Depending on the relation between the peeling direction and local lattice orientation, two categories of steps with different structures and behaviors are observed. In one category are straight steps well aligned with local ZZ directions, while in the other are steps consisting of nanoscale ZZ and AC segments. Combined with an analysis on fracture mechanics, the microscale morphology of steps and statistics of their directions provides a measurement on the anisotropic factor of $G_{\mathrm{ZZ}}/G_{\mathrm{AC}}=0.971$, suggesting that the ZZ direction has a slightly lower fracture toughness. The results provide an experimental benchmark for the widely scattered existing results, and offer constraints on future models of graphene fracture.

We showcase the importance of global band topology in a study of the Weyl semimetal CoSi as a representative of chiral space group (SG) 198. We identify a network of band crossings comprising topological nodal planes, multifold degeneracies, and Weyl points consistent with the fermion doubling theorem. To confirm these findings, we combined the general analysis of the band topology of SG 198 with Shubnikov–de Haas oscillations and material-specific calculations of the electronic structure and Berry curvature. The observation of two nearly dispersionless Shubnikov–de Haas frequency branches provides unambiguous evidence of four Fermi surface sheets at the $R$ point that reflect the symmetry-enforced orthogonality of the underlying wave functions at the intersections with the nodal planes. Hence, irrespective of the spin-orbit coupling strength, SG 198 features always six- and fourfold degenerate crossings at $R$ and $\mathrm{\Gamma }$ that are intimately connected to the topological charges distributed across the network.

Magnetic molecules on surfaces have been widely investigated to reveal delicate interfacial couplings and for potential technological applications. In these endeavors, one prevailing challenge is how to preserve or recover the molecular spins, especially on highly metallic substrates that can readily quench the magnetic moments of the admolecules. Here, we use scanning tunneling microscopy and spectroscopy to exploit the semimetallic nature of antimony and observe, surprisingly yet pleasantly, that the spin of Co-phthalocyanine is well preserved on Sb(111), as unambiguously evidenced by the emergent strong Kondo resonance across the molecule. Our first-principles calculations further confirm that the optimal density of states near the Fermi level of the semimetal is a decisive factor, weakening the overall interfacial coupling, while still ensuring sufficiently effective electron-spin scattering in the many-body system. Beyond isolated admolecules, we discover that each of the magnetic moments in a molecular dimer or a densely packed island is distinctly preserved as well, rendering such molecular magnets immense potentials for ultrahigh density memory devices.

Superconductivity in infinite-layer nickelates holds exciting analogies with that of cuprates, with similar structures and $3d$-electron count. Using resonant inelastic x-ray scattering, we studied electronic and magnetic excitations and charge density correlations in ${\mathrm{Nd}}_{1-x}{\mathrm{Sr}}_x{\mathrm{NiO}}_2$ thin films with and without an ${\mathrm{SrTiO}}_3$ capping layer. We observe dispersing magnons only in the capped samples, progressively dampened at higher doping. We detect an elastic resonant scattering peak in the uncapped $x=0$ compound at wave vector $(\sim ⅓,0)$, remindful of the charge order signal in hole doped cuprates. The peak weakens at $x=0.05$ and disappears in the superconducting $x=0.20$ film. The role of the capping on the electronic reconstruction far from the interface remains to be understood.