We present a derivation and experimental implementation of a dimension-dependent contextuality inequality to certify both the quantumness and dimensionality of a given system. Existing methods for certification of the dimension of a quantum system can be cheated by using larger classical systems, creating a potential loophole in these benchmarks, or can in practice only be evaluated assuming pure quantum states. Our approach uses contextuality inequalities that cannot be violated by classical systems thus closing the previous loopholes. We validate this framework experimentally with photons, observing violations of a CHSH-based contextuality inequality and surpassing the qutrit bound of the ${\mathrm{CGLMP}}_4$-based contextuality inequality. These show that contextuality can be used for noise-robust tests of the number of qubits.

We study the 1D Ising model with long-range interactions decaying as $1/r^{1+s}$. The critical model corresponds to a family of 1D conformal field theories whose data depend nontrivially on $s$ in the range $1/2\le s\le 1$. The model is known to be described by a generalized free field with quartic interaction, which is weakly coupled near $s=1/2$ but strongly coupled near the short-range crossover at $s=1$. We propose a dual description that becomes weakly coupled at $s=1$. At $s=1$, our model becomes an exactly solvable conformal boundary condition for the 2D free scalar. We perform a number of consistency checks of our proposal and calculate the perturbative conformal field theory data around $s=1$ analytically using both (1) our proposed field theory and (2) the analytic conformal bootstrap. Our results show complete agreement between the two methods.

We present the first amplitude analysis and branching fraction measurement of the decay $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0$, using $e^{+}{e}^{-}$ collision data collected with the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV corresponding to an integrated luminosity of $7.33{\mathrm{fb}}^{-1}$, and report the first observation of the pure $W$-annihilation decay $D_s^{+}\to \omega {\rho }^{+}$ with a branching fraction of $(0.99\pm 0.08_{\mathrm{stat}}{{}_{-0.07}^{+0.05}}_{\mathrm{syst}})\%$. In comparison to the low significance of the $\mathcal{D}$ wave in the decay $D_s^{+}\to \varphi {\rho }^{+}$, the dominance of the $\mathcal{D}$ wave over the $\mathcal{S}$ and $\mathcal{P}$ waves, with a fraction of $(51.85\pm 7.28_{\mathrm{stat}}{{}_{-7.90}^{+4.83}}_{\mathrm{syst}})\%$ observed in the decay $D_s^{+}\to \omega {\rho }^{+}$, provides crucial information for the “polarization puzzle,” as well as for the understanding of charm meson decays. The branching fraction of $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0$ is measured to be $(4.41\pm 0.15_{\mathrm{stat}}\pm 0.13_{\mathrm{syst}})\%$. Moreover, the branching fraction of $D_s^{+}\to \varphi {\rho }^{+}$ is measured to be $(3.98\pm 0.33_{\mathrm{stat}}{{}_{-0.19}^{+0.21}}_{\mathrm{syst}})\%$, and the $R_{\varphi }=\mathcal{B}(\varphi \to {\pi }^{+}{\pi }^{-}{\pi }^0)/\mathcal{B}(\varphi \to K^{+}{K}^{-})$ is determined to be ($0.222\pm 0.019_{\mathrm{stat}}{{}_{-0.016}^{+0.016}}_{\mathrm{syst}}$), which is consistent with the previous measurement based on charm meson decays, but deviates from the results from $e^{+}{e}^{-}$ annihilation and $K-N$ scattering experiments by more than $3\sigma$.

Valley photonics, with its rapid advancements and immense potential, lays one pivotal cornerstone toward next-generation topological photonic devices. It enables valley-polarized topological states, whose valleys are intrinsically locked up with transmission directivity. However, these states are prone to defects in photonic structures, and backscattering may easily induce valley flipping. Hence, achieving a one-way valley-robust photonic crystal, immune to perturbations, remains elusive. Here, we demonstrate a one-way, valley-polarized state in an edge-tailored photonic crystal that is robust against defects. Such crystal possesses a Chern band gap and is achieved without using an interface between two crystals with opposite Berry curvatures. We show $K$-valley-robust transport in a defective crystal and demonstrate perfect conversion between the $K$ and $K^{\prime }$ valleys in a hybridized crystal while backscattering is greatly suppressed. Our results offer a promising approach for unidirectional control of the valley degrees of freedom in light.

Silicate melts not only govern key processes in the Earth’s early evolution, but also significantly influence its interior dynamics today. ${\mathrm{MgSiO}}_3$, a primary component of silicate melts, undergoes significant structural changes and exhibits complex macroscopic properties from the Earth’s surface to the core-mantle boundary. Despite extensive studies, the atomic structure, densification mechanisms, and their connection to dynamics remain unclear. In this Letter, using molecular dynamics simulations with a deep neural network potential, we investigate the atomic structure of ${\mathrm{MgSiO}}_3$ liquid. Our results reveal significant structural heterogeneity in ${\mathrm{MgSiO}}_3$ liquid, with distinct Mg- and Si-enriched regions present throughout the entire mantle pressure range. This heterogeneity offers a new perspective on understanding the densification mechanism, and explains the atomic origin of the viscosity anomaly, as the lifetime of structural heterogeneity aligns well with the Maxwell relaxation time. Our findings provide new insights into the behavior of silicate melts under extreme conditions.

The x-ray vortex optical beam, distinguished by its topological charge and orbital angular momentum, offers new insights in probing complex electronic structures, enhancing material characterization, and advancing high-resolution imaging techniques. Here we propose a novel and reliable method to generate intense x-ray vortices with tunable wavelengths in high-gain free-electron lasers (FELs). By simply adjusting the wavefront tilt of the radiation pulse during the FEL gain process, high-quality vortex beam can be amplified until saturation. Compared with existing methods for FEL vortex generation, the proposed technique offers broader wavelength tunability and can be easily implemented in high-gain FEL facilities, regardless of the operating modes.

The exotic quantum states emerging in the quasicrystal (QC) have attracted extensive interest because of various properties absent in the crystal. In this Letter, we systematically study the Holstein model at half filling on a prototypical structure of QC, namely rhombic Penrose lattice, aiming at investigating the superconductivity (SC) and other intertwined ordering arising from the interplay between quasiperiodicity and electron-phonon interaction. Through unbiased sign-problem-free determinant quantum Monte Carlo simulations, we reveal the salient features of the ground state phase diagram. Distinct from the results on bipartite periodic lattices at half filling, SC is dominant in a large parameter regime of the electron-phonon coupling (EPC) strength on the Penrose lattice. The strongest SC emerges in the intermediate EPC strength regime, where it coexists with the charge density wave. The charge density wave dominates the SC only in the sufficiently strong EPC regime. Our results also reveal pronounced pairing fluctuation above the transition temperature $T_c$ of the SC. The strong pairing and its fluctuation originate from the cooperative effects of the QC structure without translational symmetry and the macroscopically degenerate confined states at the Fermi energy, which uniquely exist on the Penrose lattice. Our unbiased numerical results suggest that the Penrose lattice is a potential platform to realize strong SC pairing, providing a promising avenue to discover relatively high-$T_c$ SC predominantly induced by the EPC.

We report tunneling spectroscopy of Andreev subgap states in hybrid nanowires with a thin superconducting full shell surrounding a semiconducting core. The combination of the quantized fluxoid of the shell and the Andreev reflection at the superconductor-semiconductor interface gives rise to analogs of Caroli–de Gennes–Matricon states found in Abrikosov vortices in type-II superconductors. Unlike in metallic superconductors, Caroli–de Gennes–Matricon analogs in full-shell hybrid nanowires manifest as one-dimensional Van Hove singularities with energy spacings comparable to the superconducting gap and independent of the Fermi energy, making them readily observable. Evolution of these analogs with axial magnetic field, skewed within the Little-Parks lobe structure, is consistent with theory and yields information about the radial distribution and angular momenta of the corresponding subbands.

Topologically protected edge states have been extensively studied in systems characterized by the topological invariants in band gaps (also called line gaps). In this study, we unveil a whole new form of edge states supported by non-Hermitian systems that transcends the established paradigms of band-gap topology. In contrast to the traditional stable edge states in topological insulators with specific band gaps, the one-dimensional systems we investigate are inherently gapless with the Brillouin zones being mapped to the loops encircling hypersurface singularities in a higher-dimensional space with parity-time symmetry. These hypersurface singularities are nonisolated degeneracies embedded entirely on exceptional surfaces, rendering the energy gaps in our systems inevitably closed at the intersections of the Brillouin zone loop and the exceptional surfaces. Unexpectedly, such gapless systems still afford topologically protected edge states at system boundaries, challenging the conventional understanding based on band gaps. To elucidate the existence of these edge states in the absence of a band-gap-based invariant, we propose a theoretical framework based on eigenframe rotation and deformation that incorporates non-Bloch band theory. Finally, we experimentally demonstrate this new form of topological edge states with nonreciprocal circuits for the first time. Our work extends topological edge states from gapped phases to gapless phases, offering new insights into topological phenomena.

Bell nonlocality is a fundamental phenomenon of quantum physics as well as an essential resource for various tasks in quantum information processing. It is known that for the observation of nonlocality the measurements on a quantum system have to be incompatible, but the question of which incompatible measurements are useful, remained open. Here we prove that any set of incompatible measurements on qubits leads to a violation of a suitable Bell inequality in a multiparticle scenario, where all parties perform the same set of measurements. Since there exists incompatible measurements on qubits which do not lead to Bell nonlocality for two particles, our results demonstrate a fundamental difference between two-particle and multiparticle nonlocality, pointing at the superactivation of measurement incompatibility as a resource. In addition, our results imply that measurement incompatibility for qubits can always be certified in a device-independent manner.

We introduce a single-qubit quantum measurement engine fuelled by backaction energy input. To reduce energetic costs associated with information processing, the measurement outcomes are only used with a prescribed laziness probability in the feedback step. As a result, we show that the work extracted over consecutive cycles is a second-order Markov process, analogous to a run-and-tumble process with transient anomalous diffusion. We derive exact analytical expressions for the work finite-time moments and first-passage-time statistics. Furthermore, we find the optimal laziness probability maximizing the mean power extracted per cycle.

The exploitation of certification tools by end users represents a fundamental aspect of the development of quantum technologies as the hardware scales up beyond the regime of classical simulability. Certifying quantum networks becomes even more crucial when the privacy of their users is exposed to malicious quantum nodes or servers as in the case of multiclient distributed blind quantum computing, where several clients delegate a joint private computation to remote quantum servers, such as federated quantum machine learning. In such protocols, security must be provided not only by keeping data hidden but also by verifying that the server is correctly performing the requested computation while minimizing the hardware assumptions on the employed devices. Notably, standard verification techniques fail in scenarios where the clients receive quantum states from untrusted sources such as in a recently demonstrated linear quantum network performing multiclient blind quantum computation. However, recent theoretical results provide techniques to verify blind quantum computations even in the case of untrusted state preparation. Equipped with such theoretical tools, in this Letter we provide the first experimental implementation of a multiclient verifiable blind quantum computing protocol in a distributed architecture. Our results represent novel perspectives for the verification of multitenant distributed quantum computation in large-scale networks.

We calculate the four-graviton scattering amplitude in Type II superstring theory at one loop up to seventh order in the low-energy expansion through the recently developed iterated integral formalism of Modular Graph Functions (MGFs). The machinery of the novel method allows us to propose a general form of the amplitude, which suggests that the expansion is expressible in terms of single-valued multiple zeta values and logarithmic derivatives of the Riemann zeta function at positive and negative odd integers. Furthermore, we comment on the transcendental behavior of the amplitude.

This Letter reports the precise measurement of the reactor antineutrino spectrum and flux based on the full dataset of $4.7\times {10}^6$ inverse-beta-decay candidates collected at Daya Bay near detectors. Expressed in terms of the inverse-beta-decay yield per fission, the antineutrino spectra from all reactor fissile isotopes and the specific ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ isotopes are measured with 1.3%, 3%, and 8% uncertainties, respectively, near the 3 MeV spectrum peak in reconstructed energy, reaching the best precision in the world. The total antineutrino flux and isotopic ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ fluxes are precisely measured to be $5.84\pm 0.07$, $6.16\pm 0.12$, and $4.16\pm 0.21$ in units of ${10}^{-43}{\mathrm{cm}}^2/\text{fission}$. These measurements are compared with the Huber-Mueller model, the reevaluated conversion model based on the Kurchatov Institute measurement, and the latest summation model (SM2023). The Daya Bay flux shows good consistency with the Kurchatov Institute and SM2023 models but disagrees with the Huber-Mueller model. The Daya Bay spectrum, however, disagrees with all model predictions.

Fast rotation can improve the stability and confinement of fusion plasmas. However, to maintain a rapidly rotating fusion plasma in steady state, significant energy must be invested in spinning up each incoming fuel ion. We show here that, under the right circumstances, collisional cross-field radial fueling can directly transfer drift energy between outgoing and incoming ions without the need for external power recirculation, thereby reducing the energy costs of maintaining the rotation.