Circular Rydberg atoms (CRAs), i.e., Rydberg atoms with maximal orbital momentum, are highly promising for quantum computation, simulation, and sensing. They combine long natural lifetimes with strong interatomic interactions and coupling to electromagnetic fields. Trapping individual CRAs is essential to harness these unique features. We report the first demonstration of CRAs laser trapping in a programmable array of optical bottle beams. We observe the decay of a trapped rubidium circular level over 5 ms using a novel optical detection method. This first optical detection of alkali CRAs is both spatially and level selective. We finally observe the mechanical oscillations of the CRAs in the traps. This work opens the route to the use of circular levels in quantum devices. It is also promising for quantum simulation and information processing using the full extent of Rydberg manifolds.

It is known that rogue waves (RWs) are generated by the modulational instability (MI) of the baseband type. Starting with the Bers-Kaup-Reiman system for three-wave resonant interactions, we identify a specific RW-building mechanism based on MI which includes zero wavenumber in the gain band. An essential finding is that this mechanism works solely under a linear relation between the MI gain and a vanishingly small wavenumber of the modulational perturbation. The same mechanism leads to the creation of RWs by MI in other multicomponent systems—in particular, in the massive Thirring model.

We address Coulomb drag and near-field heat transfer in a double-layer system of incoherent metals. Each layer is modeled by an array of tunnel-coupled SYK dots with random interlayer interactions. Depending on the strength of intradot interactions and interdot tunneling, this model captures the crossover from the Fermi liquid to a strange metal phase. The absence of quasiparticles in the strange metal leads to temperature-independent drag resistivity, which is in strong contrast with the quadratic temperature dependence in the Fermi liquid regime. We show that all the parameters can be independently measured in near-field heat transfer experiments, performed in Fermi liquid and strange metal regimes.

We propose a simple family of valence-bond crystals as potential ground states of the $S=1/2$ and $S=1$ Heisenberg antiferromagnet on the pyrochlore lattice. Exponentially numerous in the linear size of the system, these can be visualized as hard-hexagon coverings, with each hexagon representing a resonating valence-bond ring. This ensemble spontaneously breaks rotation, inversion, and translation symmetries. A simple, yet accurate, variational wave function allows a precise determination of the energy, confirmed by the density matrix renormalization group and numerical linked cluster expansion, and extended by an analysis of excited states. The identification of the origin of the stability indicates applicability to a broad class of frustrated lattices, which we demonstrate for the checkerboard and ruby lattices. Our work suggests a perspective on such quantum magnets, in which unfrustrated motifs are effectively uncoupled by the frustration of their interactions.

We show that it is possible for fermion condensation of the Nambu-Jona-Lasinio type to induce a nonsingular bounce that smoothly connects a phase of slow contraction to a phase of expansion. A chiral condensate—a nonzero vacuum expectation value of the spinor bilinear $⟨\overline{\mathrm{\Psi }}\mathrm{\Psi }⟩$—can form spontaneously after a slow contraction phase smooths and flattens the universe and the Ricci curvature exceeds a critical value. In this approach, a high density of spin-aligned free fermions is not required, which avoids the problem of generating a large anisotropy and initiating chaotic mixmaster behavior during the bounce phase.

Exotic spin-dependent interactions involving new light particles address key questions in modern physics. Interactions between polarized neutrons ($n$) and unpolarized nucleons ($N$) occur in three forms: $g_{\mathrm{S}}^N{g}_{\mathrm{P}}^n\mathit{\sigma }·\mathit{r}$, $g_{\mathrm{V}}^N{g}_{\mathrm{A}}^n\mathit{\sigma }·\mathit{v}$, and $g_{\mathrm{A}}^N{g}_{\mathrm{A}}^n\mathit{\sigma }·\mathit{v}\times \mathit{r}$, where $\mathit{\sigma }$ is the spin and $g$’s are the corresponding coupling constants for scalar, pseudoscalar, vector, and axial-vector vertexes. If such interactions exist, the Sun and Moon could induce sidereal variations of effective fields in laboratories. By analyzing existing data from laboratory measurements on Lorentz and $CPT$ violation, we derive new experimental upper limits on these exotic spin-dependent interactions at astronomical ranges. Our limits on $g_{\mathrm{S}}^N{g}_{\mathrm{P}}^n$ surpass the previous combined astrophysical-laboratory limits, setting the most stringent experimental constraints to date. We also report new constraints on vector-axial-vector and axial-axial-vector interactions at astronomical scales, with vector-axial-vector limits improved by $\sim 12$ orders of magnitude. We extend our analysis to Hari Dass interactions and obtain new constraints.

Dark matter (DM) from the galactic halo can accumulate in neutron stars and transmute them into sub-$2.5M_{\odot }$ black holes if the dark matter particles are heavy, stable, and have interactions with nucleons. We show that nondetection of gravitational waves from mergers of such low-mass black holes can constrain the interactions of nonannihilating dark matter particles with nucleons. We find benchmark constraints with LIGO O3 data, viz., ${\sigma }_{\chi n}\ge \mathcal{O}({10}^{-47}){\mathrm{cm}}^2$ for bosonic DM with $m_{\chi }\sim \mathrm{PeV}$ (or $m_{\chi }\sim \mathrm{GeV}$, if they can Bose-condense) and $\ge \mathcal{O}({10}^{-46}){\mathrm{cm}}^2$ for fermionic DM with $m_{\chi }\sim {10}^3\mathrm{PeV}$. These bounds depend on the priors on DM parameters and on the currently uncertain binary neutron star merger rate density. However, with increased exposure by the end of this decade, LIGO will probe cross sections that are many orders of magnitude below the neutrino floor and completely test the dark matter solution to missing pulsars in the Galactic center, demonstrating a windfall science case for gravitational wave detectors as probes of particle dark matter.

Searches for the rare hadronic decays $B^0\to p\overline{p}p\overline{p}$ and $B_s^0\to p\overline{p}p\overline{p}$ are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. Significances of $9.3\sigma$ and $4.0\sigma$, including statistical and systematic uncertainties, are obtained for the $B^0\to p\overline{p}p\overline{p}$ and $B_s^0\to p\overline{p}p\overline{p}$ signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays $B^0\to J/\psi (\to p\overline{p})K^{*0}(\to K^{+}{\pi }^{-})$ and $B_s^0\to J/\psi (\to p\overline{p})\varphi (\to K^{+}{K}^{-})$. The branching fractions are measured to be $\mathcal{B}(B^0\to p\overline{p}p\overline{p})=(2.2\pm 0.4\pm 0.1\pm 0.1)\times {10}^{-8}$ and $\mathcal{B}(B_s^0\to p\overline{p}p\overline{p})=(2.3\pm 1.0\pm 0.2\pm 0.1)\times {10}^{-8}$. In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.

The last proton bound calcium isotope ${}^{35}\mathrm{Ca}$ has been studied for the first time, using the ${}^{37}\mathrm{Ca}(p,t){}^{35}\mathrm{Ca}$ two neutron transfer reaction. The radioactive ${}^{37}\mathrm{Ca}$ nuclei, produced by the LISE spectrometer at GANIL, interacted with the protons of the liquid hydrogen target CRYPTA, to produce tritons $t$ that were detected in the MUST2 detector array, in coincidence with the heavy residues Ca or Ar. The atomic mass of ${}^{35}\mathrm{Ca}$ and the energy of its first $3/2^{+}$ state are reported. A large $N=16$ gap of 4.61(11) MeV is deduced from the mass measurement, which together with other measured properties, makes ${}^{36}\mathrm{Ca}$ a doubly magic nucleus. The $N=16$ shell gaps in ${}^{36}\mathrm{Ca}$ and ${}^{24}\mathrm{O}$ are of similar amplitude, at both edges of the valley of stability. This feature is discussed in terms of nuclear forces involved, within state-of-the-art shell model calculations. Even though the global agreement with data is quite convincing, the calculations underestimate the size of the $N=16$ gap in ${}^{36}\mathrm{Ca}$ by 840 keV.

The Josephson rectification effect, where the resistance is finite in one direction while zero in the other, has been recently realized experimentally. The resulting Josephson diode has many potential applications on superconducting devices, including quantum computers. Here, we theoretically show that a superconductor-normal metal-superconductor Josephson junction diode on the two-dimensional surface of a topological insulator has large tunability. The magnitude and sign of the diode quality factor strongly depend on the external magnetic field, gate voltage, and the length of the junction. Such rich properties stem from the interplay between different current-phase relations for the multiple transverse transport channels, and can be used for designing realistic superconducting diode devices.

Finding efficient and ultrafast ways to control antiferromagnets is believed to be instrumental in unlocking their potential for magnetic devices operating at THz frequencies. Still, it is challenged by the absence of net magnetization in the ground state. Here, we show that the magnetization emerging from a state of coherent spin precession in antiferromagnetic iron borate ${\mathrm{FeBO}}_3$ can be used to enable the nonlinear coupling of light to another, otherwise weakly susceptible, mode of spin precession. This nonlinear mechanism can facilitate conceptually new ways of controlling antiferromagnetism.

We experimentally elucidate the origin of the anomalous Hall conductivity in a three-dimensional Dirac semimetal, ${\mathrm{Cd}}_3{\mathrm{As}}_2$, driven by circularly polarized light. Using time-resolved terahertz Faraday rotation spectroscopy, we determine the transient Hall conductivity spectrum with special attention to its sign. Our results clearly show the dominance of direct photocurrent generation assisted by the terahertz electric field. The contribution from the Floquet-Weyl nodes is found to be minor when the driving light is in resonance with interband transitions. We develop a generally applicable classification of microscopic mechanisms of light-induced anomalous Hall conductivity.

The fact that quantum mechanics predicts stronger correlations than classical physics is an essential cornerstone of quantum information processing. Indeed, these quantum correlations are a valuable resource for various tasks, such as quantum key distribution or quantum teleportation, but characterizing these correlations in an experimental setting is a formidable task, especially in scenarios where no shared reference frames are available. By definition, quantum correlations are reference-frame independent, i.e., invariant under local transformations; this physically motivated invariance implies, however, a dedicated mathematical structure and, therefore, constitutes a roadblock for an efficient analysis of these correlations in experiments. Here we provide a method to directly measure any locally invariant property of quantum states using locally randomized measurements, and we present a detailed toolbox to analyze these correlations for two quantum bits. We implement these methods experimentally using pairs of entangled photons, characterizing their usefulness for quantum teleportation and their potential to display quantum nonlocality in its simplest form. Our results can be applied to various quantum computing platforms, allowing simple analysis of correlations between arbitrary distant qubits in the architecture.

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

Electrical double layer (EDL) formation determines the reversible heat generation of supercapacitors. While classical theories suggest an exothermic nature, experiments revealed that it can be endothermic, depending on the polarization and electrolyte. Here, we perform constant-potential molecular dynamics simulations and develop a lattice gas model to explore the reversible heat of EDL formation in aqueous and ionic liquid (IL) electrolytes. Our Letter reveals that EDL formation in aqueous electrolytes exhibits endothermicity under negative polarization; it shows new complexity of endothermicity followed by exothermicity in ILs, regardless of electrode polarity. These thermal behaviors are determined by the structural evolution during EDL formation, dominated by adsorbed solvent molecules rather than ions in aqueous electrolytes but governed by “demixing” and “vacancy occupation” phenomena in ILs. This Letter provides new insights into the reversible heat of supercapacitors and presents a theoretical approach to investigating thermal behaviors involving the dynamics of EDLs.

Which nonlocal correlations can be obtained, when a party has access to more than one subsystem? While traditionally nonlocality deals with spacelike separated parties, this question becomes important with quantum technologies that connect devices by means of small shared systems. Here, we study Bell inequalities where measurements of different parties can have overlap. This allows us to accommodate problems in quantum information such as the existence of quantum error correction codes in the framework of nonlocality. The scenarios considered show an interesting behavior with respect to Hilbert space dimension, overlap, and symmetry.

Yang-Lee edge singularities (YLES) are the edges of the partition function zeros of an interacting spin model in the space of complex control parameters. They play an important role in understanding non-Hermitian phase transitions in many-body physics, as well as characterizing the corresponding nonunitary criticality. Even though such partition function zeroes have been measured in dynamical experiments where time acts as the imaginary control field, experimentally demonstrating such YLES criticality with a physical imaginary field has remained elusive due to the difficulty of physically realizing non-Hermitian many-body models. We provide a protocol for observing the YLES by detecting kinked dynamical magnetization responses due to broken $\mathcal{P}\mathcal{T}$ symmetry, thus enabling the physical probing of nonunitary phase transitions in nonequilibrium settings. In particular, scaling analyses based on our nonunitary time evolution circuit with matrix product states accurately recover the exponents uniquely associated with the corresponding nonunitary CFT. We provide an explicit proposal for observing YLES criticality in Floquet quenched Rydberg atomic arrays with laser-induced loss, which paves the way towards a universal platform for simulating non-Hermitian many-body dynamical phenomena.