Astrophysicists now have enough black-hole mergers to map their frequency over the cosmos’s history.

Laser-cooled and trapped atomic ions form an ideal standard for the simulation of interacting quantum spin models. Effective spins are represented by appropriate internal energy levels within each ion, and the spins can be measured with near-perfect efciency using state-dependent uorescence techniques. By applying optical elds that exert optical dipole forces on the ions, their Coulomb interaction

We have investigated the thermal-transport properties of the kagome antiferromagnet Cd-kapellasite (Cd-K). We find that a field suppression effect on the longitudinal thermal conductivity κxx sets in below $$25,K. This field suppression effect at 15,T becomes as large as 80% at low temperatures, suggesting a large spin contribution κxxsp in κxx. We also find clear thermal Hall signals in the spin liquid

The quantum anomalous Hall (QAH) effect in magnetic topological insulator (TI) represents a new state of matter originated from the interplay between topology and magnetism. The defining characteristics of the QAH ground state are the quantized Hall resistivity (}{$$}}${}${) and vanishing longitudinal resistivity (}{$$}}${}${) in the absence of external magnetic field. A fundamental question concerning

Layered van-der-Waals 2D magnetic materials are of great interest in fundamental condensed-matter physics research, as well as for potential applications in spintronics and device physics. We present neutron powder diffraction data using new ultra-high-pressure techniques to measure the magnetic structure of Mott-insulating 2D honeycomb antiferromagnet FePS3 at pressures up to 183 kbar and temperatures

In recent years, social media has become an important platform for political discourse, being a site of both political conversations between voters and political advertisements from campaigns. While their individual influences on public discourse have been well-documented, the interplay between individual-level cognitive biases, social influence processes, dueling campaign efforts, and social media

We explore field and temperature scaling of magnetoresistance in under-doped (x=0, x=0.19) and optimally-doped (x=0.31) samples of the high-temperature superconductor~. In all cases the magnetoresistance is H-linear at high fields. We demonstrate that the data can be explained by an orbital model in the presence of strongly anisotropic quasiparticle spectra and scattering time due to antiferromagnetism

We present modeling of the COVID-19 epidemic in Illinois, USA, capturing the implementation of a Stay-at-Home order and scenarios for its eventual release. We use a non-Markovian age-of-infection model that is capable of handling long and variable time delays without changing its model topology. Bayesian estimation of model parameters is carried out using Markov Chain Monte Carlo (MCMC) methods. This

The partition of irreversible heating between ions and electrons in compressively driven (but subsonic) collisionless turbulence is investigated by means of nonlinear hybrid gyrokinetic} simulations. We derive a prescription for the ion-to-electron heating ratio $Q_\rmi/Q_\rme$ as a function of the compressive-to-Alfv'enic driving power ratio $P_\compr/P_\AW$, of the ratio of ion thermal pressure to

We present a theoretical study of the temporal and spatial coherence properties of a topological laser device built by including saturable gain on the edge sites of a Harper–Hofstadter lattice for photons. {For small enough lattices the Bogoliubov analysis applies and the coherence time is almost determined by the total number of photons in the device {in agreement with the standard Schawlow-Townes

We present a joint theoretical and experimental analysis of thermo-refractive noise in high quality factor (Q), small mode volume (V) optical microcavities. Analogous to well-studied stability limits imposed by Brownian motion in macroscopic Fabry-Perot resonators, we show that microcavity thermo-refractive noise gives rise to a mode volume-dependent maximum effective quality factor. State-of-the-art

DOI:https://doi.org/10.1103/PhysRevX.10.049901

We present a class of Hamiltonians H for which a sector of the Hilbert space invariant under a Lie group G, which is not a symmetry of H, possesses the essential properties of many-body scar states. These include the absence of thermalization and the “revivals” of special initial states in time evolution. A particular class of examples concerns interacting spin-1/2 fermions on a lattice consisting

We introduce a model of trapped bosons with contact interactions as well as Coulomb repulsion or gravitational attraction in one spatial dimension. We find the exact ground state energy and many-body wave function. The density profile and the pair correlation function are sampled using Monte Carlo method and show a rich variety of regimes with crossovers between them. Strong attraction leads to a trapped

Laser decoherence limits the stability of optical clocks by broadening the observable resonance linewidths and adding noise during the dead time between clock probes. Correlation spectroscopy avoids these limitations by measuring correlated atomic transitions between two ensembles, which provides a frequency difference measurement independent of laser noise. Here, we apply this technique to perform

We report on the evaporation of hexane from porous alumina and silicon membranes. These membranes contain billions of independent nanopores tailored to an ink-bottle shape, where a cavity several tens of nanometers in diameter is separated from the bulk vapor by a constriction. For alumina membranes with narrow enough constrictions, we demonstrate that cavity evaporation proceeds by cavitation. Measurements

We demonstrate a widely applicable technique to absolutely calibrate the energy scale of x-ray spectra with experimentally well-known and accurately calculable transitions of highly charged ions, allowing us to measure the K-shell Rydberg spectrum of molecular O2 with 8,meV-uncertainty. We reveal a systematic $450meVshiftfrompreviousliteraturevalues,andsettleanextraordinarydiscrepancybetweenastrop

Current models of phoretic transport rely on molecular forces creating a "diffuse’’ particle–fluid interface. We investigate theoretically an alternative mechanism, in which a diffuse interface emerges solely due to a non-vanishing correlation length of the surrounding solution. This mechanism can drive self-motility of a chemically active particle. Numerical estimates indicate that the velocity can

We report on transport signatures of hidden quantum Hall stripe (hQHS) phases in high (N>2) half-filled Landau levels of AlxGa1−xAs/Al0.24Ga0.76As quantum wells with varying Al mole fraction $x

We present the first analytical results for the ${\cal O}(\alpha\alpha_s)$ corrections to the total cross section for the inclusive production of an on-shell Z boson at hadron colliders. We include the complete set of contributions, with photonic and massive weak gauge boson effects, which have been computed in analytical form and expressed in terms of polylogarithmic and elliptic integrals. We present

The Coulomb drag effect has been observed as a tiny current induced by both electron-hole asymmetry and interactions in normal coupled quantum dot devices. In the present work we show that the effect can be boosted by replacing one of the normal electrodes by a superconducting one. Moreover, we show that at low temperatures and for sufficiently strong coupling to the superconducting lead, the Coulomb

A photonic cluster state with a tree-type entanglement structure constitutes an efficient resource for quantum error correction of photon loss. But the generation of a tree cluster state with an arbitrary size is notoriously difficult. Here, we propose a protocol to deterministically generate photonic tree states of arbitrary size by using only a single quantum emitter. Photonic entanglement is established

We investigate the role of the effective range on the bulk viscosity of s- and p-wave Fermi gases. At resonance, the presence of the effective range breaks the scale invariance of the system, and hence results in a non-zero bulk viscosity. However, we show that the effective range plays a very different role in the two cases. In the s-wave case, the role of the effective range is perturbative, and

We provide a systematic and self-consistent method to calculate the generalized Brillouin Zone (GBZ) analytically in one dimensional non-Hermitian systems, which helps us to understand the non-Hermitian bulk-boundary correspondence. In general, a n-band non-Hermitian Hamiltonian is constituted by n distinct sub-GBZs, each of which is a piecewise analytic closed loop. Based on the concept of resultant

The ability to reroute and control flow is vital to the function of venation networks across a wide range of organisms. By modifying individual edges in these networks, either by adjusting edge conductances or creating and destroying edges, organisms robustly control the propagation of inputs to perform specific tasks. However, a fundamental disconnect exists between the structure and function: networks

Even though no local order parameter in the sense of the Landau theory exists for topological quantum phase transitions in Chern insulators, the highly non-local Berry curvature exhibits critical behavior near a quantum critical point. We investigate the critical properties of its real space analog, the local Chern marker, in weakly disordered Chern insulators. Due to disorder, inhomogeneities appear

We introduce relativistic charge distributions for targets with arbitrary average momentum, providing a natural interpolation between the usual Breit frame and infinite-momentum frame distributions. Among the remarkable results, we find that Breit frame distributions can be interpreted from a phase-space perspective as internal charge quasi-densities in the rest frame of a localized target, without

Quantum mechanics challenges our intuition on the cause-effect relations in nature. Some fundamental concepts, including Reichenbach’s common cause principle or the notion of local realism, have to be reconsidered. Traditionally, this is witnessed by the violation of a Bell inequality. But are Bell inequalities the only signature of the incompatibility between quantum correlations and causality theory

The early detection of tipping points, which describe a rapid departure from a stable state, is an important theoretical and practical challenge. Tipping points are most commonly associated with the disappearance of steady-state or periodic solutions at fold bifurcations. We discuss here multi-frequency tipping (M-tipping), which is tipping due to the disappearance of an attracting torus. M-tipping

Scattering from conformal interfaces in two dimensions is universal in that the flux of reflected and transmitted energy does not depend on the details of the initial state. In this letter, we present the first gravitational calculation of energy reflection and transmission coefficients for interfaces with thin-brane holographic duals. Our result for the reflection coefficient depends monotonically

Using quantum walks (QW) to rank the centrality of nodes in networks, represented by graphs, is advantageous comparing to certain widely used classical algorithms. However, it is challenging to implement a directed graph via QW, since it corresponds to a non-Hermitian Hamiltonian and thus cannot be accomplished by conventional QW. Here we report the realizations of centrality rankings of a three-,

Understanding surface mechanics of soft solids, such as soft polymeric gels, is crucial in many engineering processes, such as dynamic wetting and adhesive failure. In these situations, a combination of capillary and elastic forces drives the motion, which is balanced by dissipative mechanisms to determine the rate. While shear rheology ( viscoelasticity) has long been assumed to dominate the dissipation

Based on the first-principles prediction, we report the magnetoelectric coupling effect in the two-dimensional multiferroic bilayer VS2. The ground-state 3R type stacking breaks space inversion symmetry, therefore introducing a spontaneous polarization perpendicular to the layer plane. We further reveal that the out-of-plane ferroelectric polarization of bilayer VS2 can be reversed upon interlayer

Measuring the cosmic ray flux over timescales comparable to the age of the solar system, ∼4.5Gyr, could provide a new window on the history of the Earth, the solar system, and even our galaxy. We present a technique to indirectly measure the rate of cosmic rays as a function of time using the imprints of atmospheric neutrinos in {}, natural minerals which record damage tracks from nuclear recoils.

The cell cycle duration is a variable cellular phenotype that underlies long-term population growth and age structures. By analyzing the stationary solutions of a branching process with heritable cell division times, we demonstrate existence of a phase transition, which can be continuous or first-order, by which a non-zero fraction of the population becomes localized at a minimal division time. Just

Starting from the Quantum-Phase-Estimate (QPE) algorithm, a method is proposed to construct entangled states that describe correlated many-body systems on quantum computers. Using operators for which the discrete set of eigenvalues is known, the QPE approach is followed by measurements that serve as projectors on the entangled states. These states can then be used as inputs for further quantum or hybrid

Low-dimensional electron systems such as Silicon nanowires (NWs) exhibit weak screening which is detrimental to the performance and scalability of nanodevices, e.g. tunnel field-effect transistors (TFETs). By atomistic quantum transport simulations, we show how bound charges can be engineered at interfaces of Si and low-κ oxides to strengthen screening. To avoid compromising gate control, low-κ and

We present the first results of a search for invisible axion dark matter using a multiple-cell cavity haloscope. This cavity concept was proposed to provide a highly efficient approach to high mass regions compared to the conventional multiple-cavity design, with larger detection volume, simpler detector setup, and unique phase-matching mechanism. Searches with a double-cell cavity superseded previous

We devise an approach to characterizing the intricate interplay between classical and quantum interference of two-photon states in a network, which comprises multiple time-bin modes. By controlling the phases of delocalized single photons, we manipulate the global mode structure, resulting in distinct two-photon interference phenomena for time-bin resolved (local) and time-bucket (global) coincidence

Typically, energy levels change without bifurcating in response to a change of a control parameter. Bifurcations can lead to loops or swallowtails in the energy spectrum. The simplest quantum Hamiltonian that supports swallowtails is a non-linear 2×2 Hamiltonian with non-zero off-diagonal elements and diagonal elements that depend on the population difference of the two states. This work implements

We study scalar fields in a black hole background and show that, when the scalar is suitably coupled to curvature, rapid rotation can induce a tachyonic instability. This instability, which is the hallmark of spontaneous scalarization in the linearized regime, is expected to be quenched by nonlinearities and endow the black hole with scalar hair. Hence, our results demonstrate the existence of a broad

Dispersive shock waves in thermal optical media are nonlinear phenomena whose intrinsic irreversibility is described by time asymmetric quantum mechanics. Recent studies demonstrated that the nonlocal wave breaking evolves in an exponentially decaying dynamics ruled by the reversed harmonic oscillator, namely, the simplest irreversible quantum system in the rigged Hilbert spaces. The generalization

We theoretically propose and experimentally demonstrate the use of motional sidebands in a trapped ensemble of 87Rb atoms to engineer tunable long-range XXZ spin models. We benchmark our simulator by probing a ferromagnetic to paramagnetic dynamical phase transition in the Lipkin-Meshkov-Glick (LMG) model, a collective XXZ model plus additional transverse and longitudinal fields, via Rabi spectroscopy

Muscles are biological actuators extensively studied in the frame of Hill’s classic empirical model as isolated biomechanical entities, which hardly applies to a living organism subjected to physiological and environmental constraints. Here we elucidate the overarching principle of a muscle action for locomotion, considering it from the thermodynamic viewpoint as an assembly of actuators (muscle units)

Hybrid magnonics has recently attracted intensive attentions as a promising platform for coherent information processing. In spite of its rapid development, on-demand control over the interaction of magnons with other information carriers, in particular microwave photons in electromagnonic systems, has been long missing, significantly limiting the potential broad applications of hybrid magnonics. Here

We consider the problem of encoding pairwise correlations between coupled dynamical systems in a low-dimensional latent space based on few distinct observations. We used variational autoencoders (VAE) to embed temporal correlations between coupled nonlinear oscillators that model brain states in the wake-sleep cycle into a two-dimensional manifold. Training a VAE with samples generated using two different

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

When a strongly correlated system supports well-defined quasiparticles, it allows for an elegant one-bady effective description within the non-Hermitian topological theory. While the microscopic many-body Hamiltonian of a closed system remains Hermitian, the one-body quasiparticle Hamiltonian is non-Hermitian due to the finite quasiparticle lifetime. We use such non-Hermitian description in the heavy-fermion

We study collisional loss of a quasi-one-dimensional (1D) spin-polarized Fermi gas near a p-wave Feshbach resonance in ultracold 6Li atoms. We measure the location of the p-wave resonance in quasi-1D and observe a confinement-induced shift and broadening. We find that the three-body loss coefficient L3 as a function of the quasi-1D confinement has little dependence on confinement strength. We also

It is well known that superconductivity in quasi-one-dimensional (Q1D) materials is hindered by large fluctuations of the order parameter. They reduce the critical temperature and can even destroy the superconductivity altogether. Here it is demonstrated that the situation changes dramatically when a Q1D pair condensate is coupled to a higher-dimensional stable one, as in recently discovered multiband