A fundamental manifestation of the nontrivial correlations of an incompressible fractional quantum Hall (FQH) state is that an electron added to it disintegrates into more elementary particles, namely fractionally-charged composite fermions (CFs). We show here that the Girvin-MacDonald-Platzman (GMP) density-wave excitation of the $\nu =n/(2pn\pm 1)$ FQH states also splits into more elementary single CF excitons. In particular, the GMP graviton, which refers to the recently observed spin-2 neutral excitation in the vanishing wave vector limit [Liang et al., Nature 628, 78 (2024)], remains undivided for $\nu =n/(2n\pm 1)$ but splits into two gravitons at $\nu =n/(4n\pm 1)$ with $n>1$. A detailed experimental confirmation of the many observable consequences of the splitting of the GMP mode should provide a unique window into the correlations underlying the FQH effect.

Recent studies have attracted widespread attention on magnet-superconductor hybrid systems with emergent topological superconductivity. Here, we present the Floquet engineering of realistic two-dimensional topological nodal-point superconductors that are composed of antiferromagnetic monolayers in proximity to an $s$-wave superconductor. We show that Floquet chiral topological superconductivity arises due to light-induced breaking of the effective time-reversal symmetry. More strikingly, we find that the Floquet chiral topological superconducting phases can be flexibly controlled by irradiating elliptically polarized light, with the photon-dressed quasienergy spectrum carrying different Chern numbers. Such optically switchable topological transitions arise from the simultaneous creations (or annihilations) of valley pairs, which are attributed to the intertwining with magnetic symmetry, superconductivity, and topology. Our findings provide a feasible approach for achieving the Floquet chiral topological superconductivity with flexible tunability, which would draw extensive attention in experiments.

Quantum error correction is believed to be essential for scalable quantum computation, but its implementation is challenging due to its considerable space-time overhead. Motivated by recent experiments demonstrating efficient manipulation of logical qubits using transversal gates [Bluvstein et al., Nature (London) 626, 58 (2024)], we show that the performance of logical algorithms can be substantially improved by decoding the qubits jointly to account for error propagation during transversal entangling gates. We find that such correlated decoding improves the performance of both Clifford and non-Clifford transversal entangling gates, and explore two decoders offering different computational runtimes and accuracies. In particular, by leveraging the deterministic propagation of stabilizer measurement errors, we find that correlated decoding enables the number of noisy syndrome extraction rounds between gates to be reduced from $O(d)$ to $O(1)$ in transversal Clifford circuits, where $d$ is the code distance. We verify numerically that this approach substantially reduces the space-time cost of deep logical Clifford circuits. These results demonstrate that correlated decoding provides a major advantage in early fault-tolerant computation, as realized in recent experiments, and further indicate it has considerable potential to reduce the space-time cost in large-scale logical algorithms.

Given some group $G$ of logical gates, for instance the Clifford group, what are the quantum encodings for which these logical gates can be implemented by simple physical operations, described by some physical representation of $G$? We study this question by constructing a general form of such encoding maps. For instance, we recover that the $⟦5,1,3⟧$ and Steane codes admit transversal implementations of the binary tetrahedral and binary octahedral groups, respectively. For bosonic encodings, we show how to obtain the GKP and cat qudit encodings by considering the appropriate groups, and essentially the simplest physical implementations. We further illustrate this approach by introducing a two-mode bosonic code defined from a constellation of 48 coherent states, for which all single-qubit Clifford gates correspond to passive Gaussian unitaries.

We performed the first simulations of accretion onto the compact objects in the Reissner-Nordström (RN) space-time. The results obtained in general relativity are representative of those for spherically symmetric naked singularities and black holes in a number of modified gravity theories. A possible application of these calculations is to the active galactic nuclei with their powerful jets and outflows. It is now possible to compare the results of such simulations with the accreting supermassive objects in our own Milky Way and a nearby galaxy: observations of the core regions of galactic nuclei (Sgr A* and M87) performed with unprecedented resolution by the Event Horizon Telescope (EHT) collaboration allow fairly direct tests of the space-time metric of the central compact object. In this context we present general-relativistic hydrodynamical simulation results of accretion from an orbiting accretion torus (with a cusp) onto a RN black hole and a RN naked singularity. The results could not be more different for the two cases. For a black hole, just as in the familiar Kerr case, matter overflowing the cusp plunges into the black hole horizon. For the naked singularity, the accreting matter forms an inner structure of toroidal topology and leaves the system via powerful outflows. It is an open question whether this inner structure can give rise to an image quantitatively similar to the ones reported by EHT for M87 and Sgr A*.

We report the precise measurements of the cross section of $e^{+}{e}^{-}\to \text{hadrons}$ at center-of-mass energies from 3.645 to 3.871 GeV. We thereby perform the most precise study of the cross sections and find a complex system composed of three resonances of $\mathcal{R}(3760)$, $\mathcal{R}(3780)$, and $\mathcal{R}(3810)$. For the first time, we measure the $\mathcal{R}(3810)$ electronic width to be $(19.4\pm 7.4\pm 12.1)\mathrm{eV}$. For the $\mathcal{R}(3760)$ resonance, we measure the mass to be $(3751.9\pm 3.8\pm 2.8)\mathrm{MeV}/c^2$, the total width to be $(32.8\pm 5.8\pm 8.7)\mathrm{MeV}$, and the electronic width to be $(184\pm 75\pm 86)\mathrm{eV}$. For the $\mathcal{R}(3780)$ resonance, we measure its mass to be $(3778.7\pm 0.5\pm 0.3)\mathrm{MeV}/c^2$, total width to be $(20.3\pm 0.8\pm 1.7)\mathrm{MeV}$, and electronic width to be $(265\pm 67\pm 83)\mathrm{eV}$. Forty-seven years ago, the $\psi (3770)$ resonance was discovered, and was subsequently interpreted as the $1{}^3{D}_1$-wave dominant state of charmonium. However, our analysis of the total-hadron cross sections indicates that the $\psi (3770)$ is not a single state, but a complex system composed of the $\mathcal{R}(3760)$, $\mathcal{R}(3780)$, and $\mathcal{R}(3810)$ resonances. Among these, we interpret the $\mathcal{R}(3780)$ is a resonance dominated by the $1{}^3{D}_1$ charmonium state.

We introduce a novel technique for enhancing the robustness of light-pulse atom interferometers against the pulse infidelities that typically limit their sensitivities. The technique uses quantum optimal control to favorably harness the multipath interference of the stray trajectories produced by imperfect atom-optics operations. We apply this method to a resonant atom interferometer and achieve thousandfold phase amplification, representing a 50-fold improvement over the performance observed without optimized control. Moreover, we find that spurious interference can arise from the interplay of spontaneous emission and many-pulse sequences and demonstrate optimization strategies to mitigate this effect. Given the ubiquity of spontaneous emission in quantum systems, these results may be valuable for improving the performance of a diverse array of quantum sensors. We anticipate our findings will significantly benefit the performance of matter-wave interferometers for a variety of applications, including dark matter, dark energy, and gravitational wave detection.

An apparent contact angle is formed when a droplet is deposited on a solid substrate. Young’s law has been employed to describe the equilibrium contact angle. Often in experiments, the equilibrium contact angle deviates from Young’s law and depends on the volume of the droplet, known as the line tension effect. However, the physical origin of the line tension is quite controversial. Especially, the sign and the quantity of the line tension spanning 6 orders of magnitude are unsolved problems. Here, we quantify the line energy in terms of physical parameters and demonstrate that both positive and negative line tensions exist. The results are quantitatively compared with existing experiments as well as with previous theories.

We propose a mechanism to obtain chiral phononlike excitations from the bond-dependent magnetoelastic couplings in the absence of out-of-plane magnetization and magnetic fields. By mapping the hybrid excitation to its phononic analog, we reveal the impact of the lattice symmetry on the origin of the chirality. In the example of a triangular lattice ferromagnet, we recognize that the system is equivalent to the class D of topological phonons, and show the tunable chirality and topology by an in-plane magnetic field. As a possible experimental probe, we evaluate the phonon magnetization and planar thermal Hall conductivity. Our study gives a new perspective on tunable topological and chiral excitations beyond the Raman spin-lattice coupling, suggesting possible applications of spintronics and phononics in various anisotropic magnets and/or Kitaev materials.

Quantum magnetic materials can provide explicit realizations of paradigm models in quantum many-body physics. In this context, ${\mathrm{SrCu}}_2({\mathrm{BO}}_3{)}_2$ is a faithful realization of the Shastry-Sutherland model for ideally frustrated spin dimers, even displaying several of its quantum magnetic phases as a function of pressure. We perform inelastic neutron scattering measurements on ${\mathrm{SrCu}}_2({\mathrm{BO}}_3{)}_2$ at 5.5 GPa and 4.5 K, observing spin waves that characterize the high-pressure antiferromagnetic phase. The experimental spectra are well described by linear spin-wave calculations on a Shastry-Sutherland model with an interlayer interaction, which is determined accurately as $J_c=0.053(3)\mathrm{meV}$. The presence of $J_c$ indicates the need to account for the three-dimensional nature of ${\mathrm{SrCu}}_2({\mathrm{BO}}_3{)}_2$ in theoretical models, also at lower pressures. We find that the ratio between in-plane interactions, $J^{\prime }/J=1.8(2)$, undergoes a dramatic change compared to lower pressures that we deduce is driven by a sharp drop in the dimer coupling, $J$. Our results underline the wide horizons opened by high-pressure inelastic neutron scattering experiments on quantum magnetic materials.

We introduce a string-based parametrization for nucleon quark and gluon generalized parton distributions (GPDs) that is valid for all skewness. Our approach leverages conformal moments, representing them as the sum of spin-$j$ nucleon $A$-form factor and skewness-dependent spin-$j$ nucleon $D$-form factor, derived from $t$-channel string exchange in AdS spaces consistent with Lorentz invariance and unitarity. This model-independent framework, satisfying the polynomiality condition due to Lorentz invariance, uses Mellin moments from empirical data to estimate these form factors. With just five Regge slope parameters, our method accurately produces various nucleon quark GPD types and symmetric nucleon gluon GPDs through pertinent Mellin-Barnes integrals. Our isovector nucleon quark GPD is in agreement with existing lattice data, promising to improve the empirical extraction and global analysis of nucleon GPDs in exclusive processes, by avoiding the deconvolution problem at any skewness, for the first time.

The global chaos caused by the July 19, 2024 technology meltdown highlights the need for a theory of what large-scale cohesive behaviors—dangerous or desirable—could suddenly emerge from future systems of interacting humans, machinery, and software, including artificial intelligence; when they will emerge; and how they will evolve and be controlled. Here, we offer answers by introducing an aggregation model that accounts for the interacting entities’ inter- and intraspecies diversities. It yields a novel multidimensional generalization of existing aggregation physics. We derive exact analytic solutions for the time to cohesion and growth of cohesion for two species, and some generalizations for an arbitrary number of species. These solutions reproduce—and offer a microscopic explanation for—an anomalous nonlinear growth feature observed in various current real-world systems. Our theory suggests good and bad “surprises” will appear sooner and more strongly as humans, machinery, artificial intelligence, and so on interact more, but it also offers a rigorous approach for understanding and controlling this.

In contrast to normal diffusion processes, thermal conduction in one-dimensional systems is anomalous. The thermal conductivity is found to vary with the length as $\kappa \sim L^{\alpha }(\alpha >0)$, but there is a long-standing debate on the value $\alpha$. Here, we present a canonical example of this behavior in polymer-grafted spherical nanoparticle (GNP) melts at fixed grafting density and nanoparticle radius. For long chains (chain length $N\ge 945$), the experimental $\kappa (N)$ of GNP melts decreases with $N$, i.e., polymer concentration. For $N<945$, however, $\kappa (N)$ unexpectedly increases with $N$ with a maximum near $N\sim 945$. For these systems, the extensional free energy per polymer chain is predicted to be maximized near $N_{\max }\approx 940$ for $\sigma \approx 0.47\mathrm{chains}/{\mathrm{nm}}^2$, which indicates the dominance of extended conformations at short $N$ and Gaussian-like conformation for longer $N$. In the former regime, the thermal conductivity of extended polymer chains increases with $N$ and follows ${\kappa }_{\mathrm{p}}\sim N_{\mathrm{dry}}^{0.46\pm 0.02}$, which provides experimental evidence of a novel class of superdiffusive thermal transport with $\alpha =1/2$.

Operational contextuality forms a rapidly developing subfield of quantum information theory. However, the characterization of the quantum mechanical entities that fuel the phenomenon has remained unknown with many partial results existing. Here, we present a resolution to this problem by connecting operational contextuality one-to-one with the no-broadcasting theorem. The connection works both on the level of full quantum theory and subtheories thereof. We demonstrate the connection in various relevant cases, showing especially that for quantum states the possibility of demonstrating contextuality is exactly characterized by non-commutativity, and for measurements this is done by a norm-1 property closely related to repeatability. Moreover, we show how techniques from broadcasting can be used to simplify known foundational results in contextuality.