We demonstrate the defect-free assembly of versatile target patterns of up 111 neutral atoms, building on a 361-site subset of a micro-optical architecture that readily provides thousands of sites for single-atom quantum systems. By performing multiple assembly cycles in rapid succession, we drastically increase achievable structure sizes and success probabilities. We implement repeated target pattern reconstruction after atom loss and deterministic transport of partial atom clusters necessary for distributing entanglement in large-scale systems. This technique will propel assembled-atom architectures beyond the threshold of quantum advantage and into a regime with abundant applications in quantum sensing and metrology, Rydberg-state mediated quantum simulation, and error-corrected quantum computation.

In this Letter we show that a set of old conjectures about symmetries in quantum gravity hold within the anti–de Sitter/conformal field theory correspondence. These conjectures are that no global symmetries are possible, that internal gauge symmetries must come with dynamical objects that transform in all irreducible representations, and that internal gauge groups must be compact. These conjectures are not obviously true from a bulk perspective, they are nontrivial consequences of the nonperturbative consistency of the correspondence. More details of and background for these arguments are presented in an accompanying paper.

Acquiring ultrafast and high spectral resolution optical images is key to measure transient physical or chemical processes, such as photon propagation, plasma dynamics, and femtosecond chemical reactions. At a trillion Hz frame rate, most ultrafast imaging modalities can acquire only a limited number of frames. Here, we present a compressed ultrafast spectral-temporal (CUST) photographic technique, enabling both an ultrahigh frame rate of 3.85 trillion Hz and a large frame number. We demonstrate that CUST photography records 60 frames, enabling precisely recording light propagation, reflection, and self-focusing in nonlinear media over 30 ps. CUST photography has the potential to further increase the frame number beyond hundreds of frames. Using spectral-temporal coupling, CUST photography can record multiple frames with a subnanometer spectral resolution with a single laser exposure, enabling ultrafast spectral imaging. CUST photography with high frame rate, high spectral resolution, and high frame number in a single modality offer a new tool for observing many transient phenomena with high temporal complexity and high spectral precision.

The change in mean-square nuclear charge radii $\delta ⟨r^2⟩$ along the even-$A$ tin isotopic chain ${}^{108-134}\mathrm{Sn}$ has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions $5p^2{{}^{1}S}_0\to 5p6s{{}^{1}P}_1$ and $5p^2{{}^{3}P}_0\to 5p6s{{}^{3}P}_1$. With the determination of the charge radius of ${}^{134}\mathrm{Sn}$ and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the $N=82$ shell closure is established. A clear kink at the doubly magic ${}^{132}\mathrm{Sn}$ is revealed, similar to what has been observed at $N=82$ in other isotopic chains with larger proton numbers, and at the $N=126$ shell closure in doubly magic ${}^{208}\mathrm{Pb}$. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, ${}^{132}\mathrm{Sn}$ and ${}^{208}\mathrm{Pb}$, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects.

A new short-lived neutron-deficient isotope ${}^{220}\mathrm{Np}$ was synthesized in the fusion-evaporation reaction ${}^{185}\mathrm{Re}({}^{40}\mathrm{Ar},5n){}^{220}\mathrm{Np}$ at the gas-filled recoil separator SHANS. Based on the measurement of the correlated $\alpha$-decay chains, the decay properties of ${}^{220}\mathrm{Np}$ with $E_{\alpha }=10040(18)\mathrm{keV}$ and $T_{1/2}=25_{-7}^{+14}\mu \mathrm{s}$ were determined, which are in good agreement with theoretical predictions. From the new experimental results coupled with the recently reported $\alpha$-decay data of ${}^{219,223}\mathrm{Np}$, the $\alpha$-decay systematics for Np isotopes around $N=126$ was established, which allows us for the first time to test the robustness of the $N=126$ shell closure in $Z=93$ Np isotopes. The results also indicate that, in the region of nuclei with $Z\ge 83$, the proton drip line has been reached for all odd-$Z$ isotopes up to Np.

We present a highly accurate, fully analytical model for the late inspiral, merger, and ringdown of black-hole binaries with arbitrary mass ratios and spin vectors and the associated gravitational radiation, including the contributions of harmonics beyond the fundamental mode. This model assumes only that nonlinear effects remain small throughout the entire coalescence and is developed based on a physical understanding of the dynamics of late stage binary evolution, in particular, on the tendency of the dynamical binary spacetime to behave like a linear perturbation of the stationary merger-remnant spacetime, even at times before the merger has occurred. We demonstrate that our model agrees with the most accurate numerical relativity results to within their own uncertainties throughout the merger-ringdown phase, and it does so for example cases spanning the full range of binary parameter space that is currently testable with numerical relativity. Furthermore, our model maintains accuracy back to the innermost stable circular orbit of the merger-remnant spacetime over much of the relevant parameter space, greatly decreasing the need to introduce phenomenological degrees of freedom to describe the late inspiral.

We find that the polarimetric observations of protoplanetary disks are useful to search for ultralight axion dark matter. Axion dark matter predicts the rotation of the linear polarization plane of propagating light, and protoplanetary disks are ideal targets to observe it. We show that a recent observation puts the tightest constraint on the axion-photon coupling constant for an axion mass $m\lesssim {10}^{-21}\mathrm{eV}$.

We experimentally investigate the two-dimensional photoelectron momentum spectra of aligned diatomic molecules in an intense laser field. Our results reveal a novel prominent valley structure in the molecular alignment dependence of the high-energy photoelectron spectra along the laser polarization. Resorting to the molecular strong-field approximation and a simple semiclassical analysis, we show that this valley structure stems from the destructive two-center interference of the laser-driven rescattered electrons in diatomic molecules. Based on this two-center interference with aligned diatomic molecules, we demonstrate for the first time a tomographic method to extract the molecular internuclear separation, providing a more straightforward approach of molecular imaging, in comparison with, e.g., laser-induced electron diffraction and fixed-angle broadband laser-driven electron scattering.

Sign-changing interactions constitute a crucial ingredient in the creation of frustrated many-body systems such as spin glasses. We present here the demonstration of a photon-mediated sign-changing interaction between Bose-Einstein-condensed atoms in a confocal cavity. The interaction between two atoms is of an unusual, nonlocal form proportional to the cosine of the inner product of the atoms’ position vectors. This interaction arises from the differing Gouy phase shifts of the cavity’s degenerate modes. The interaction drives a nonequilibrium Dicke-type phase transition in the system leading to atomic checkerboard density-wave order. Because of the Gouy phase anomalies, the checkerboard pattern can assume either a sinelike or cosinelike character. This state is detected via the holographic imaging of the cavity’s superradiant emission. Together with a companion paper [Y. Guo, V. D. Vaidya, R. M. Kroeze, R. A. Lunney, B. L. Lev, and J. Keeling, Emergent and broken symmetries of atomic self-organization arising from Gouy phases in multimode cavity QED, Phys. Rev. A 99, 053818 (2019)], we explore this interaction’s influence on superradiant phase transitions in multimode cavities. Employing this interaction in cavity QED spin systems may enable the creation of artificial spin glasses and quantum neural networks.

It is known that the quantum mechanical ground state of a nanoscale junction has a significant impact on its electrical transport properties. This becomes particularly important in transistors consisting of a single molecule. Because of strong electron-electron interactions and the possibility of accessing ground states with high spins, these systems are eligible hosts of a current-blockade phenomenon called a ground-state spin blockade. This effect arises from the inability of a charge carrier to account for the spin difference required to enter the junction, as that process would violate the spin selection rules. Here, we present a direct experimental demonstration of a ground-state spin blockade in a high-spin single-molecule transistor. The measured transport characteristics of this device exhibit a complete suppression of resonant transport due to a ground-state spin difference of $3/2$ between subsequent charge states. Strikingly, the blockade can be reversibly lifted by driving the system through a magnetic ground-state transition in one charge state, using the tunability offered by both magnetic and electric fields.

A measurement of the ratio of branching fractions of the decays $B^{+}\to K^{+}{\mu }^{+}{\mu }^{-}$ and $B^{+}\to K^{+}{e}^{+}{e}^{-}$ is presented. The proton-proton collision data used correspond to an integrated luminosity of $5.0{\mathrm{fb}}^{-1}$ recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range $1.1<q^2<6.0{\mathrm{GeV}}^2/c^4$ the ratio of branching fractions is measured to be $R_K=0.84{6_{-0.054}^{+0.060}}_{-0.014}^{+0.016}$, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of $R_K$ to date and is compatible with the standard model at the level of 2.5 standard deviations.

The chemical structure and orientation of molecules on surfaces can be visualized using low temperature atomic force microscopy with CO-functionalized tips. Conventionally, this is done in constant-height mode by measuring the frequency shift of the oscillating force sensor. However, this method is unsuitable for analyzing 3D objects. We are using the tunneling current to track the topography while simultaneously obtaining submolecular resolution from the frequency shift signal. Thereby, the conformation of 3D molecules and the adsorption sites on the atomic lattice can be reliably determined.

In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from $-2.81\pm 0.03$ (50–500 GeV) neglecting solar modulation effects (or $-2.87\pm 0.06$ including solar modulation effects in the lower energy region) to $-2.56\pm 0.04$ (1–10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than $3\sigma$.

Heavy particles are traditionally believed to gather at the nodes of a resonating plate, forming standard Chladni patterns. Here, for the first time, we experimentally show that heavy particles, i.e., sub-mm particles, can move towards the antinodes of a resonating plate. By submerging the resonating plate inside a fluidic medium, the acoustic radiation force and the lateral effective weight become dominant at the sub-mm scale. Those forces, averaged over a vibration cycle, move the particles towards the antinodes and generate sophisticated patterns. We create a statistical model that relates the complex motion of particles to their locations and plate vibration frequencies in a wide spectrum of both resonant and nonresonant frequencies. Additionally, we employ our model to control the motion of single particles and a swarm of particles on the submerged plate. Our device can move particles with sufficient power at an exceptionally wide frequency range, potentially opening a path to new particle manipulation techniques at sub-mm scale in fluidic media.

Spin-orbit interaction (SOI) plays a key role in creating Majorana zero modes in semiconductor nanowires proximity coupled to a superconductor. We track the evolution of the induced superconducting gap in InSb nanowires coupled to a NbTiN superconductor in a large range of magnetic field strengths and orientations. Based on realistic simulations of our devices, we reveal SOI with a strength of 0.15–0.35 eV Å. Our approach identifies the direction of the spin-orbit field, which is strongly affected by the superconductor geometry and electrostatic gates.

From everyday experience, we all know that a solid edge can deflect a liquid flowing over it significantly, up to the point where the liquid completely sticks to the solid. Although important in pouring, printing, and extrusion processes, there is no predictive model of this so-called “teapot effect.” By grazing vertical cylinders with inclined capillary liquid jets, here we use the teapot effect to attach the jet to the solid and form a new structure: the liquid helix. Using mass and momentum conservation along the liquid stream, we first quantitatively predict the shape of the helix and then provide a parameter-free inertial-capillary adhesion model for the jet deflection and critical velocity for helix formation.

Neutron scattering measurements on the pyrochlore magnet ${\mathrm{Ce}}_2{\mathrm{Zr}}_2{\mathrm{O}}_7$ reveal an unusual crystal field splitting of its lowest $J=5/2$ multiplet, such that its ground-state doublet is composed of $m_J=\pm 3/2$, giving these doublets a dipole-octupole (DO) character with local Ising anisotropy. Its magnetic susceptibility shows weak antiferromagnetic correlations with ${\theta }_{\mathrm{CW}}=-0.4(2)\mathrm{K}$, leading to a naive expectation of an all-in, all-out ordered state at low temperatures. Instead, our low-energy inelastic neutron scattering measurements show a dynamic quantum spin ice state, with suppressed scattering near $|\mathbf{Q}|=0$, and no long-range order at low temperatures. This is consistent with recent theory predicting symmetry-enriched U(1) quantum spin liquids for such DO doublets decorating the pyrochlore lattice. Finally, we show that disorder, especially oxidation of powder samples, is important in ${\mathrm{Ce}}_2{\mathrm{Zr}}_2{\mathrm{O}}_7$ and could play an important role in the low-temperature behavior of this material.

Motivated by the important role of the normalized second-order coherence function, often called $g^{(2)}$, in the field of quantum optics, we propose a method to determine magnon coherence in solid-state devices. Namely, we show that the cross-correlations of pure spin currents injected by a ferromagnet into two metal leads, normalized by their dc value, replicate the behavior of $g^{(2)}$ when magnons are driven far from equilibrium. We consider two scenarios: driving by ferromagnetic resonance, which leads to the coherent occupation of a single mode, and driving by heating of the magnons, which leads to an excess of incoherent magnons. We find an enhanced normalized cross-correlation in the latter case, thereby demonstrating bunching of nonequilibrium thermal magnons due to their bosonic statistics. Our results contribute to the burgeoning field of quantum magnonics, which seeks to explore and exploit the quantum nature of magnons.

Distinct to type-I Weyl semimetals (WSMs) that host quasiparticles described by the Weyl equation, the energy dispersion of quasiparticles in type-II WSMs violates Lorentz invariance and the Weyl cones in the momentum space are tilted. Since it was proposed that type-II Weyl fermions could emerge from $(\mathrm{W},\mathrm{Mo}){\mathrm{Te}}_2$ and $(\mathrm{W},\mathrm{Mo}){\mathrm{P}}_2$ families of materials, a large number of experiments have been dedicated to unveiling the possible manifestation of type-II WSMs, e.g., surface-state Fermi arcs. However, the interpretations of the experimental results are very controversial. Here, using angle-resolved photoemission spectroscopy supported by the first-principles calculations, we probe the tilted Weyl cone bands in the bulk electronic structure of ${\mathrm{WP}}_2$ directly, which are at the origin of Fermi arcs at the surfaces and transport properties related to the chiral anomaly in type-II WSMs. Our results ascertain that, due to the spin-orbit coupling, the Weyl nodes originate from the splitting of fourfold degenerate band-crossing points with Chern numbers $C=\pm 2$ induced by the crystal symmetries of ${\mathrm{WP}}_2$, which is unique among all the discovered WSMs. Our finding also provides a guiding line to observe the chiral anomaly that could manifest in novel transport properties.

We have made the first observation of the nuclear Barnett effect. In the electronic Barnett effect, which was first observed in 1915 by Samuel Barnett, a ferromagnetic rod was spun about its long axis and a magnetization developed in the rod along the axis of rotation. This effect is caused by the coupling between the angular momentum of the electronic spins in the sample and the rotational motion of the rod. In our experiment, we measured the nuclear Barnett effect by rotating a sample of water at rotational speeds up to 13.5 kHz in a weak magnetic field and observed a change in the polarization of the protons in the sample that is proportional to the frequency of rotation. We measured this polarization by observing the change in the size of a nuclear magnetic resonance (NMR) signal. No NMR frequency shift was observed due to rotation, meaning that this magnetization was not produced by a real magnetic field.