We demonstrate the enhanced robustness of the supercurrent through graphene-based Josephson junctions in which strong spin-orbit interactions (SOIs) are induced. We compare the persistence of a supercurrent at high out-of-plane magnetic fields between Josephson junctions with graphene on hexagonal boron-nitride and graphene on ${\mathrm{WS}}_2$, where strong SOIs are induced via the proximity effect. We find that in the shortest junctions both systems display signatures of induced superconductivity, characterized by a suppressed differential resistance at a low current, in magnetic fields up to 1 T. In longer junctions, however, only graphene on ${\mathrm{WS}}_2$ exhibits induced superconductivity features in such high magnetic fields, and they even persist up to 7 T. We argue that these robust superconducting signatures arise from quasiballistic edge states stabilized by the strong SOIs induced in graphene by ${\mathrm{WS}}_2$.

We experimentally demonstrate dressing of the excited exciton states by a continuously tunable Fermi sea of free charge carriers in a monolayer semiconductor. It represents an unusual scenario of two-particle excitations of charged excitons previously inaccessible in conventional material systems. We identify excited state trions, accurately determine their binding energies in the zero-density limit for both electron- and hole-doped regimes, and observe emerging many-body phenomena at elevated doping. Combining experiment and theory we gain access to the intra-exciton coupling facilitated by the interaction with free charge carriers. We provide evidence for a process of autoionization for quasiparticles, a unique scattering pathway available for excited states in atomic systems. Finally, we demonstrate a complete transfer of the optical transition strength from the excited excitons to dressed Fermi-polaron states as well as the associated light emission from their nonequilibrium populations.

We present a gauge theory formulation of a two-dimensional quantum smectic and its relatives, motivated by their realizations in correlated quantum matter. The description gives a unified treatment of phonons and topological defects, respectively, encoded in a pair of coupled gauge fields and corresponding charges. The charges exhibit subdimensional constrained quantum dynamics and anomalously slow highly anisotropic diffusion of disclinations inside a smectic. This approach gives a transparent description of a multistage quantum melting transition of a two-dimensional commensurate crystal (through an incommensurate crystal—a supersolid) into a quantum smectic, which subsequently melts into a quantum nematic and isotropic superfluids, all in terms of a sequence of Higgs transitions.

The equation of state of the osmotic pressure for linear-polymer solutions in good solvents is universally described by a scaling function. We experimentally measure the osmotic pressure of the gelation process via osmotic deswelling. We find that the same scaling function for linear-polymer solutions also describes the osmotic pressure throughout the gelation process involving both the sol and gel states. Furthermore, we reveal that the osmotic pressure of polymer gels is universally governed by the semidilute scaling law of linear-polymer solutions.

We consider a noninteracting many-fermion system populating levels of a unitary random matrix ensemble (equivalent to the $q=2$ complex Sachdev-Ye-Kitaev model)—a generic model of single-particle quantum chaos. We study the corresponding many-particle level statistics by calculating the spectral form factor analytically using algebraic methods of random matrix theory, and match it with an exact numerical simulation. Despite the integrability of the theory, the many-body spectral rigidity is found to have a surprisingly rich landscape. In particular, we find a residual repulsion of distant many-body levels stemming from single-particle chaos, together with islands of level attraction. These results are encoded in an exponential ramp in the spectral form factor, which we show to be a universal feature of nonergodic many-fermion systems embedded in a chaotic medium.

A long period of linear growth in the spectral form factor provides a universal diagnostic of quantum chaos at intermediate times. By contrast, the behavior of the spectral form factor in disordered integrable many-body models is not well understood. Here we study the two-body Sachdev-Ye-Kitaev model and show that the spectral form factor features an exponential ramp, in sharp contrast to the linear ramp in chaotic models. We find a novel mechanism for this exponential ramp in terms of a high-dimensional manifold of saddle points in the path integral formulation of the spectral form factor. This manifold arises because the theory enjoys a large symmetry group. With finite nonintegrable interaction strength, these delicate symmetries reduce to a relative time translation, causing the exponential ramp to give way to a linear ramp.

We discuss exploration for isotropic gravitational wave backgrounds around 1 mHz by correlation analysis, targeting both parity odd and even polarization modes. Even though the space interferometer LISA alone cannot probe the two modes due to cancellations, the outlook is being changed drastically by the strong development of other space detectors such as Taiji. In fact, a heliocentric interferometer network can hold a preferable geometrical symmetry illuminated by a virtual sphere off-center from the Sun. By utilizing an internal symmetry of data streams, we can optimally decompose the odd and even parity modes at the correlation analysis. By simultaneously using LISA and Taiji for ten years, our sensitivity to the two modes could reach $\sim {10}^{-12}$ in terms of the normalized energy density.

In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from $10\mathrm{GeV}/n$ to $2.2\mathrm{TeV}/n$ with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index change of $\sim 0.15$ around $200\mathrm{GeV}/n$ established with a significance $>3\sigma$. They have the same energy dependence with a constant $\mathrm{C}/\mathrm{O}$ flux ratio $0.911\pm 0.006$ above $25\mathrm{GeV}/n$. The spectral hardening is consistent with that measured by AMS-02, but the absolute normalization of the flux is about 27% lower, though in agreement with observations from previous experiments including the PAMELA spectrometer and the calorimetric balloon-borne experiment CREAM.

Invoking increasingly higher dimension operators to encode novel UV physics in effective gauge and gravity theories traditionally means working with increasingly more finicky and difficult expressions. We find that the duality between color and kinematics provides a powerful tool towards drastic simplification. Local higher-derivative gauge and gravity operators at four points can be absorbed into simpler higher-derivative corrections to scalar theories, requiring only a small number of building blocks to generate gauge and gravity four-point amplitudes to all orders in mass dimension.

This Letter presents a search for the production of new heavy resonances decaying into a Higgs boson and a photon using proton-proton collision data at $\sqrt{s}=13\mathrm{TeV}$ collected by the ATLAS detector at the LHC. The data correspond to an integrated luminosity of $139{\mathrm{fb}}^{-1}$. The analysis is performed by reconstructing hadronically decaying Higgs boson $(H\to b\overline{b})$ candidates as single large-radius jets. A novel algorithm using information about the jet constituents in the center-of-mass frame of the jet is implemented to identify the two $b$ quarks in the single jet. No significant excess of events is observed above the expected background. Upper limits are set on the production cross-section times branching fraction for narrow spin-1 resonances decaying into a Higgs boson and a photon in the resonance mass range from 0.7 to 4 TeV, cross-section times branching fractions are excluded between 11.6 fb and 0.11 fb at a 95% confidence level.

We propose a new type of superradiant laser based on a hot atomic beam traversing an optical cavity. We show that the theoretical minimum linewidth and maximum power are competitive with the best ultracoherent clock lasers. Also, our system operates naturally in continuous wave mode, which has been elusive for superradiant lasers so far. Unlike existing ultracoherent lasers, our design is simple and rugged. This makes it a candidate for the first widely accessible ultracoherent laser, as well as the first to realize sought-after applications of ultracoherent lasers in challenging environments.

We study the spreading of a Newtonian fluid by a deformable blade, a common industrial problem, characteristic of elastohydrodynamic situations. Here, we consider the case of a finite reservoir of liquid, emptying as the liquid is spread. We evidence the role of a central variable: the wetting length $l_w$, which sets a boundary between the wet and dry parts of the blade. We show that the deposited film thickness $e$ depends quadratically with $l_w$. We study this problem experimentally and numerically by integration of the elastohydrodynamic equations, and finally propose a scaling law model to explain how $l_w$ influences the spreading dynamics.

We present an x-ray regenerative amplifier free-electron laser design capable of producing fully coherent hard x-ray pulses across a broad tuning range at a high steady state repetition rate. The scheme leverages a strong undulator taper and an apertured diamond output-coupling cavity crystal to produce both high peak and average spectral brightness radiation that is 2 to 3 orders of magnitude greater than conventional single-pass self-amplified spontaneous emission free-electron laser amplifiers. Refractive guiding in the postsaturation regime is found to play a key role in passively controlling the stored cavity power. The scheme is explored both analytically and numerically in the context of the Linac Coherent Light Source II High Energy upgrade.

The temporal evolution of the magnetic field associated with electron thermal Weibel instability in optical-field ionized plasmas is measured using ultrashort (1.8 ps), relativistic (45 MeV) electron bunches from a linear accelerator. The self-generated magnetic fields are found to self-organize into a quasistatic structure consistent with a helicoid topology within a few picoseconds and such a structure lasts for tens of picoseconds in underdense plasmas. The measured growth rate agrees well with that predicted by the kinetic theory of plasmas taking into account collisions. Magnetic trapping is identified as the dominant saturation mechanism.

The effectiveness of a dome-shaped wall covered by a thin gold foil (hollow wall) [M. Vandenboomgaerde et al., Phys. Plasmas 25, 012713 (2018)] in holding back the high-$Z$ plasma expansion in a gas-filled hohlraum is demonstrated for the first time in experiments reproducing the irradiation conditions of indirect drive at the ignition scale. The setup exploits a 1D geometry enabling record of the complete history of the gold expansion for 8 ns by imaging its emission in multiple x-ray energy ranges featuring either the absorption zones or the thermal emission regions. The measured expansion dynamics is well reproduced by numerical simulations. This novel wall design could now be tailored for the megajoule scale to enable the propagation of the inner beams up to the equator in low gas-filled hohlraum thus allowing the fine-tuning of the irradiation symmetry on the timescale required for ignition.

We show that the radial electric field ($E_r$) plays a dual role in edge magnetohydrodynamics (MHD) activity. While $E_r$ shear (first spatial derivative of $E_r$) dephases radial velocity and displacement, and so is stabilizing, a new finding here is that $E_r$ curvature (second spatial derivative of $E_r$) tends to synchronize the radial velocity and displacement, and so destabilizes MHD. As a highlighted result, we analytically demonstrate that $E_r$ curvature can destabilize an otherwise stable kink mode, and so form a joint vortex-kink mode. The synergetic effects of $E_r$ shear and $E_r$ curvature in edge MHD extend the familiar $E\times B$ shearing paradigm. This theory thus explains the experimental findings that a deeper $E\times B$ well may aggravate edge MHD, and so trigger the formation of the edge harmonic oscillation. A simple criterion linking $E_r$ structure and the edge MHD activity is derived.

We determine the phase diagram of excitons in a symmetric transition-metal dichalcogenide 3-layer heterostructure. First principles calculations reveal interlayer exciton states of a symmetric quadrupole, from which higher energy asymmetric dipole states are composed. We find quantum phase transitions between a repulsive quadrupolar and an attractive staggered dipolar lattice phases, driven by a competition between interactions and single exciton energies. The different internal quantum state of excitons in each phase is a striking example of a system where single-particle and interacting many-body states are coupled.

We report a new hydrogen clathrate hydrate synthesized at 1.2 GPa and 298 K documented by single-crystal x-ray diffraction, Raman spectroscopy, and first-principles calculations. The oxygen sublattice of the new clathrate hydrate matches that of ice II, while hydrogen molecules are in the ring cavities, which results in the trigonal $\mathit{R}3\mathit{c}$ or $\mathit{R}\overline{3}\mathit{c}$ space group (proton ordered or disordered, respectively) and the composition of ${({\mathrm{H}}_2\mathrm{O})}_6{\mathrm{H}}_2$. Raman spectroscopy and theoretical calculations reveal a hydrogen disordered nature of the new phase $C_1^{\prime }$, distinct from the well-known ordered $C_1$ clathrate, to which this new structure transforms upon compression and/or cooling. This new clathrate phase can be viewed as a realization of a disordered ice II, unobserved before, in contrast to all other ordered ice structures.

While the study of space-charge potentials has a long history, present models are largely based on the notion of steady state equilibrium, ill-suited to describe wide band gap semiconductors with moderate to low concentrations of defects. Here we build on color centers in diamond both to locally inject carriers into the crystal and probe their evolution as they propagate in the presence of external and internal potentials. We witness the formation of metastable charge patterns whose shape—and concomitant field—can be engineered through the timing of carrier injection and applied voltages. With the help of previously crafted charge patterns, we unveil a rich interplay between local and extended sources of space-charge field, which we then exploit to show space-charge-induced carrier guiding.