First proposed by Mayers and Yao, self-testing provides a certification method to infer the underlying physics of quantum experiments in a black-box scenario. Numerous demonstrations have been reported to self-test various types of entangled states. However, all the multiparticle self-testing experiments reported so far suffer from both detection and locality loopholes. Here, we report the first experimental realization of multiparticle entanglement self-testing closing the locality loophole in a photonic system, and the detection loophole in a superconducting system, respectively. We certify three-party and four-party GHZ states with at least 0.84(1) and 0.86(3) fidelities in a device-independent way. These results can be viewed as a meaningful advance in multiparticle loophole-free self-testing, and also significant progress on the foundations of quantum entanglement certification.

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable $x_B$. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of $x_B$, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of ${}_{\mathrm{\Lambda }}{}^3\mathrm{H}$ in $p$-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$ is presented in this Letter. Its production yield measured in the rapidity interval $-1<y<0$ for the 40% highest-multiplicity $p$-Pb collisions is $\mathrm{d}N/\mathrm{d}y=[6.3\pm 1.8(\mathrm{stat})\pm 1.2(\mathrm{syst})]\times {10}^{-7}$. The measurement is compared with the expectations of statistical hadronization and coalescence models, which describe the nucleosynthesis in hadronic collisions. These two models predict very different yields of the hypertriton in charged particle multiplicity environments relevant to small collision systems such as $p$-Pb, and therefore the measurement of $\mathrm{d}N/\mathrm{d}y$ is crucial to distinguish between them. The precision of this measurement leads to the exclusion with a significance larger than $6.9\sigma$ of some configurations of the statistical hadronization model, thus constraining the theory behind the production of loosely bound states at hadron colliders.

In absence of external torque, plasma rotation in tokamaks results from a balance between collisional magnetic braking and turbulent drive. The outcome of this competition and cooperation is essential to determine the plasma flow. A reduced model, supported by gyrokinetic simulations, is first used to explain and quantify the competition only. The ripple amplitude above which magnetic drag overcomes turbulent viscosity is obtained. The synergetic impact of ripple on the turbulent toroidal Reynolds stress is explored. Simulations show that the main effect comes from an enhancement of the radial electric field shear by the ripple, which in turn impacts the residual stress.

The induction of synthetic magnetic fields on lattice structures allows an effective control of their localization and transport properties. In this Letter, we generate effective $\pi$ magnetic fluxes on a multiorbital diamond lattice, where first-order ($S$) and second-order ($P$) modes effectively interact. We implement a $z$-scan method on femtosecond-laser-written photonic lattices and experimentally observe Aharonov-Bohm caging for $S$ and $P$ modes, as a consequence of a band transformation and the emergence of a spectrum composed of three degenerated flat bands. As an application, we demonstrate a perfect control of the dynamics, where we translate an input excitation across the lattice in a completely linear and controlled way. Our model, based on a flat band spectrum, allows us to choose the direction of transport depending on the excitation site or input phase.

Many dense particulate suspensions show a stress induced transformation from a liquidlike state to a solidlike shear jammed (SJ) state. However, the underlying particle-scale dynamics leading to such striking, reversible transition of the bulk remains unknown. Here, we study transient stress relaxation behaviour of SJ states formed by a well-characterized dense suspension under a step strain perturbation. We observe a strongly nonexponential relaxation that develops a sharp discontinuous stress drop at short time for high enough peak-stress values. High resolution boundary imaging and normal stress measurements confirm that such stress discontinuity originates from the localized plastic events, whereas system spanning dilation controls the slower relaxation process. We also find an intriguing correlation between the nature of transient relaxation and the steady-state shear jamming phase diagram obtained from the Wyart-Cates model.

We probe local phase fluctuations of trapped two-dimensional Bose gases using matter-wave interferometry. This enables us to measure the phase correlation function, which changes from an algebraic to an exponential decay when the system crosses the Berezinskii-Kosterlitz-Thouless (BKT) transition. We determine the temperature dependence of the BKT exponent $\eta$ and find the critical value ${\eta }_c=0.17(3)$ for our trapped system. Furthermore, we measure the local vortex density as a function of the local phase-space density, which shows a scale-invariant behavior across the transition. Our experimental investigation is supported by Monte Carlo simulations and provides a comprehensive understanding of the BKT transition in a trapped system.

Observations of a merging neutron star binary in both gravitational waves, by the Laser Interferometer Gravitational-Wave Observatory (LIGO), and across the spectrum of electromagnetic radiation, by myriad telescopes, have been used to show that gravitational waves travel in vacuum at a speed that is indistinguishable from that of light to within one part in a quadrillion. However, it has long been expected mathematically that, when electromagnetic or gravitational waves travel through vacuum in a curved spacetime, the waves develop tails that travel more slowly. The associated signal has been thought to be undetectably weak. Here we demonstrate that gravitational waves are efficiently scattered by the curvature sourced by ordinary compact objects—stars, white dwarfs, neutron stars, and planets—and certain candidates for dark matter, populating the interior of the null cone. The resulting gravitational glint should imminently be detectable, and be recognizable (for all but planets) as briefly delayed echoes of the primary signal emanating from extremely near the direction of the primary source. This opens the prospect for using Gravitational Detection and Ranging to map the Universe and conduct a comprehensive census of massive compact objects, and ultimately to explore their interiors.

We propose a new theory of second-order viscous relativistic hydrodynamics which does not impose any frame conditions on the choice of the hydrodynamic variables. It differs from Mueller-Israel-Stewart theory by including additional transient degrees of freedom, and its first-order truncation reduces to Bemfica-Disconzi-Noronha-Kovtun theory. Conditions for causality and stability are explicitly given in the conformal regime. As an illustrative example, we consider Bjorken flow solutions to our equations and identify variables which make a hydrodynamic attractor manifest.

The effect of freezing on contact line motion is a scientific challenge in the understanding of the solidification of capillary flows. In this Letter, we experimentally investigate the spreading and freezing of a water droplet on a cold substrate. We demonstrate that solidification stops the spreading because the ice crystals catch up with the advancing contact line. Indeed, we observe the formation and growth of ice crystals along the substrate during the drop spreading, and show that their velocity equals the contact line velocity when the drop stops. Modeling the growth of the crystals, we predict the shape of the crystal front and show that the substrate thermal properties play a major role on the frozen drop radius.

We investigate entanglement detection when the local measurements only nearly correspond to those intended. This corresponds to a scenario in which measurement devices are not perfectly controlled, but nevertheless operate with bounded inaccuracy. We formalize this through an operational notion of inaccuracy that can be estimated directly in the lab. To demonstrate the relevance of this approach, we show that small magnitudes of inaccuracy can significantly compromise several well-known entanglement witnesses. For two arbitrary-dimensional systems, we show how to compute tight corrections to a family of standard entanglement witnesses due to any given level of measurement inaccuracy. We also develop semidefinite programming methods to bound correlations in these scenarios.

We show how the index of the fermion operator from the Euclidean action can be used to uncover the existence of gapless modes living on defects (such as edges and vortices) in topological insulators and superconductors. The 1-loop Feynman diagram that computes the index reveals an analog of the quantum Hall current flowing on and off the defect—even in systems without conserved currents or chiral anomalies—and makes explicit the interplay between topology in momentum and coordinate space. We provide several explicit examples.

The Drell-Yan process at hadron colliders is a fundamental benchmark for the study of strong interactions and the extraction of electroweak parameters. The outstanding precision of the LHC demands very accurate theoretical predictions with a full account of fiducial experimental cuts. In this Letter we present a state-of-the-art calculation of the fiducial cross section and of differential distributions for this process at third order in the strict fixed-order expansion in the strong coupling, as well as including the all-order resummation of logarithmic corrections. Together with these results, we present a detailed study of the subtraction technique used to carry out the calculation for different sets of experimental cuts, as well as of the sensitivity of the fiducial cross section to infrared physics. We find that residual theory uncertainties are reduced to the percent level and that the robustness of the predictions can be improved by a suitable adjustment of fiducial cuts.

The $B_c^{+}$ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the $B_c^{+}$ meson in lead-lead (Pb-Pb) and proton-proton ($pp$) collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{NN}}=5.02\mathrm{TeV}$, via the $B_c^{+}\to (J/\psi \to {\mu }^{+}{\mu }^{-}){\mu }^{+}{\nu }_{\mu }$ decay. The $B_c^{+}$ nuclear modification factor, derived from the Pb-Pb–to–$pp$ ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the Pb-Pb collision centrality. The $B_c^{+}$ meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma.

The electric monopole ($E0$) transition strength ${\rho }^2$ for the transition connecting the third $0^{+}$ level, a “superdeformed” band head, to the “spherical” $0^{+}$ ground state in doubly magic ${}^{40}\mathrm{Ca}$ is determined via $e^{+}{e}^{-}$ pair-conversion spectroscopy. The measured value ${\rho }^2(E0;0_3^{+}\to 0_1^{+})=2.3(5)\times {10}^{-3}$ is the smallest ${\rho }^2(E0;0^{+}\to 0^{+})$ found in $A<50$ nuclei. In contrast, the $E0$ transition strength to the ground state observed from the second $0^{+}$ state, a band head of “normal” deformation, is an order of magnitude larger ${\rho }^2(E0;0_2^{+}\to 0_1^{+})=25.9(16)\times {10}^{-3}$, which shows significant mixing between these two states. Large-scale shell-model (LSSM) calculations are performed to understand the microscopic structure of the excited states and the configuration mixing between them; experimental ${\rho }^2$ values in ${}^{40}\mathrm{Ca}$ and neighboring isotopes are well reproduced by the LSSM calculations. The unusually small ${\rho }^2(E0;0_3^{+}\to 0_1^{+})$ value is due to destructive interference in the mixing of shape-coexisting structures, which are based on several different multiparticle-multihole excitations. This observation goes beyond the usual treatment of $E0$ strengths, where two-state shape mixing cannot result in destructive interference.

The anomaly in lithium abundance is a well-known unresolved problem in nuclear astrophysics. A recent revisit to the problem tried the avenue of resonance enhancement to account for the primordial ${}^7\mathrm{Li}$ abundance in standard big-bang nucleosynthesis. Prior measurements of the ${}^7\mathrm{Be}(d,p){}^8{\mathrm{Be}}^{*}$ reaction could not account for the individual contributions of the different excited states involved, particularly at higher energies close to the $Q$ value of the reaction. We carried out an experiment at HIE-ISOLDE, CERN to study this reaction at $E_{\mathrm{c}.\mathrm{m}.}=7.8\mathrm{MeV}$, populating excitations up to 22 MeV in ${}^8\mathrm{Be}$ for the first time. The angular distributions of the several excited states have been measured and the contributions of the higher excited states in the total cross section at the relevant big-bang energies were obtained by extrapolation to the Gamow window using the talys code. The results show that by including the contribution of the 16.63 MeV state, the maximum value of the total $S$ factor inside the Gamow window comes out to be 167 MeV b as compared to earlier estimate of 100 MeV b. However, this still does not account for the lithium discrepancy.

The novel physics of twisted bilayer graphene has motivated extensive studies of magic-angle flat bands hosted by moiré structures in electronic, photonic, and acoustic systems. On the other hand, bound states in the continuum (BICs) have also attracted great attention in recent years because of their potential applications in the field of designing superior optical devices. Here, we combine these two independent concepts to construct a new optical state in a twisted bilayer photonic crystal slab, which is called as moiré quasi-BIC, and numerically demonstrate that such an exotic optical state possesses dual characteristics of moiré flat bands and quasi-BICs. To illustrate the mechanism for the formation of moiré flat bands, we develop an effective model at the center of the Brillouin zone and show that moiré flat bands could be fulfilled by balancing the interlayer coupling strength and the twist angle around the band edge above the light line. Moreover, by decreasing the twist angle of moiré photonic crystal slabs with flat bands, it is shown that the moiré flat-band mode at the Brillouin center gradually approaches a perfect BIC, where the total radiation loss from all diffraction channels is significantly suppressed. To clarify the advantage of moiré quasi-BICs, enhanced second-harmonic generation (SHG) is numerically proven with a wide-angle optical source. The efficiency of SHG assisted by designed moiré quasi-BICs can be greatly improved compared with that based on dispersive quasi-BICs with similar quality factors.