We describe a superconducting-circuit lattice design for the implementation and simulation of dynamical lattice gauge theories. We illustrate our proposal by analyzing a one-dimensional U(1) quantum-link model, where superconducting qubits play the role of matter fields on the lattice sites and the gauge fields are represented by two coupled microwave resonators on each link between neighboring sites. A detailed analysis of a minimal experimental protocol for probing the physics related to string breaking effects shows that, despite the presence of decoherence in these systems, distinctive phenomena from condensed-matter and high-energy physics can be visualized with state-of-the-art technology in small superconducting-circuit arrays.

Pumped heat electricity storage (PHES) has been recently suggested as a potential solution to the large-scale energy storage problem. PHES requires neither underground caverns as compressed air energy storage (CAES) nor kilometer-sized water reservoirs like pumped hydrostorage and can therefore be constructed anywhere in the world. However, since no large PHES system exists yet, and theoretical predictions are scarce, the efficiency of such systems is unknown. Here we formulate a simple thermodynamic model that predicts the efficiency of PHES as a function of the temperature of the thermal energy storage at maximum output power. The resulting equation is free of adjustable parameters and nearly as simple as the well-known Carnot formula. Our theory predicts that for storage temperatures above $400°\mathrm{C}$ PHES has a higher efficiency than existing CAES and that PHES can even compete with the efficiencies predicted for advanced-adiabatic CAES.

We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for $gg\to \gamma \gamma$. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through “interferometry.” We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the $Z{Z}^{*}$ channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.

We show that a slightly modified Breit-Wigner formula can successfully describe the total cross section even for the broad resonances, from the light $\rho (770)$ to the heavy $Z$ boson. In addition to the mass, width, and branching fraction, we include another resonance parameter that turns out to be directly related to the pole residue phase. The new formula has two mathematically equivalent forms: one with the pole and the other with the Breit-Wigner parameters.

Quark mass dependence of the equation of state (EOS) for nucleonic matter is investigated, on the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon interaction extracted from lattice QCD simulations. We observe saturation of nuclear matter at the lightest available quark mass corresponding to the pseudoscalar meson mass $\simeq 469\mathrm{MeV}$. Mass-radius relation of the neutron stars is also studied with the EOS for neutron-star matter from the same nuclear force in lattice QCD. We observe that the EOS becomes stiffer and thus the maximum mass of neutron star increases as the quark mass decreases toward the physical point.

We report on the observation of discrete structures in the electron energy distribution for strong field double ionization of argon at 394 nm. The experimental conditions were chosen in order to ensure a nonsequential ejection of both electrons with an intermediate rescattering step. We have found discrete above-threshold ionization like peaks in the sum energy of both electrons, as predicted by all quantum mechanical calculations. More surprisingly, however, is the observation of two above-threshold ionization combs in the energy distribution of the individual electrons.

We predict theoretically and numerically the existence of incoherent dispersive shock waves. They manifest themselves as an unstable singular behavior of the spectrum of incoherent waves that evolve in a noninstantaneous nonlinear environment. This phenomenon of “spectral wave breaking” develops in the weakly nonlinear regime of the random wave. We elaborate a general theoretical formulation of these incoherent objects on the basis of a weakly nonlinear statistical approach: a family of singular integro-differential kinetic equations is derived, which provides a detailed deterministic description of the incoherent dispersive shock wave phenomenon.

We introduce a novel family of analytic solutions of the three-wave resonant interaction equations for the purpose of modeling unique events, i.e., “amplitude peaks” which are isolated in space and time. The description of these solutions is likely to be a crucial step in the understanding and forecasting of rogue waves in a variety of multicomponent wave dynamics, from oceanography to optics and from plasma physics to acoustics.

In open chaotic systems the number of long-lived resonance states obeys a fractal Weyl law, which depends on the fractal dimension of the chaotic saddle. We study the generic case of a mixed phase space with regular and chaotic dynamics. We find a hierarchy of fractal Weyl laws, one for each region of the hierarchical decomposition of the chaotic phase-space component. This is based on our observation of hierarchical resonance states localizing on these regions. Numerically this is verified for the standard map and a hierarchical model system.

We present the experimental demonstration of a new scheme for the generation of ultrashort pulse trains based on free-electron-laser (FEL) emission from a multipeaked electron energy distribution. Two electron beamlets with energy difference larger than the FEL parameter $\rho$ have been generated by illuminating the cathode with two ps-spaced laser pulses, followed by a rotation of the longitudinal phase space by velocity bunching in the linac. The resulting self-amplified spontaneous emission FEL radiation, measured through frequency-resolved optical gating diagnostics, reveals a double-peaked spectrum and a temporally modulated pulse structure.

Thomson backscattering of intense laser pulses from relativistic electrons not only allows for the generation of bright x-ray pulses but also for the investigation of the complex particle dynamics at the interaction point. For this purpose a complete spectral characterization of a Thomson source powered by a compact linear electron accelerator is performed with unprecedented angular and energy resolution. A rigorous statistical analysis comparing experimental data to 3D simulations enables, e.g., the extraction of the angular distribution of electrons with 1.5% accuracy and, in total, provides predictive capability for the future high brightness hard x-ray source PHOENIX (photon electron collider for narrow bandwidth intense x rays) and potential gamma-ray sources.

Excitation of low frequency drift waves in a radial region of a weak density gradient is demonstrated experimentally by strong temporal modulation of the plasma density. Though a parallel electron current can destabilize drift waves throughout the region, we observe mode selection at the resonant location matching the frequency of modulation. Parametric mode-mode interaction among two excited drift modes to destabilize a higher frequency one is reported under the specific condition of the growth rate. Theoretically estimated growth rates fit well with the experiment.

Topological defects are found in particles confined to planar disks interacting via the $1/r$ Coulomb potential. The total interior topological charge is found to monotonically converge to a negative value as the energy decreases during the relaxation process regardless of initial configurations; it is more negative in a larger cluster. The comparison with a uniform hyperbolic tessellation reveals an underlying hyperbolic structure in a low-energy configuration where the particle density increases from the center of the disk to its boundary. An elliptic structure is identified in an opposite particle distribution where the particle density decreases from the center to the edge of the disk. The novel mechanism of density inhomogeneity driven topological defects as well as the underlying geometric structure may shed light in understanding a wide variety of relevant systems.

We study the temperature dependence of the critical current modulation $I_{\mathrm{c}}(H)$ for two types of planar Josephson junctions: a low-$T_{\mathrm{c}}$ $\mathrm{Nb}/\mathrm{CuNi}/\mathrm{Nb}$ and a high-$T_{\mathrm{c}}$ ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$ bicrystal grain-boundary junction. At low $T$ both junctions exhibit a conventional behavior, described by the local sine-Gordon equation. However, at elevated $T$ the behavior becomes qualitatively different: the $I_{\mathrm{c}}(H)$ modulation field $\Delta H$ becomes almost $T$ independent and neither $\Delta H$ nor the critical field for the penetration of Josephson vortices vanish at $T_{\mathrm{c}}$. Such an unusual behavior is in good agreement with theoretical predictions for junctions with nonlocal electrodynamics. We extract absolute values of the London penetration depth $\lambda$ from our data and show that a crossover from local to nonlocal electrodynamics occurs with increasing $T$ when $\lambda (T)$ becomes larger than the electrode thickness.

To compare the increasing number of optical frequency standards, highly stable optical signals have to be transferred over continental distances. We demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of $2\times {10}^{-15}$ for a gate time $\tau$ of 1 s reaching $4\times {10}^{-19}$ in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about $3\times {10}^{-19}$. The spectral noise distribution of our fiber link at low Fourier frequencies leads to a ${\tau }^{-2}$ slope in the modified Allan deviation, which is also derived theoretically.

For the first time the emission of neutron bursts in the process of high-voltage discharge in air was observed. Experiments were carried out at an average electric field strength of $\sim 1\mathrm{MV}·{\mathrm{m}}^{-1}$ and discharge current of $\sim 10\mathrm{kA}$. Two independent methods (CR-39 track detectors and plastic scintillation detectors) registered neutrons within the range from thermal energies up to energies above 10 MeV and with an average flux density of $\gtrsim {10}^6{\mathrm{cm}}^{-2}$ per shot inside the discharge zone. Neutron generation occurs at the initial phase of the discharge and correlates with x-ray generation. The data obtained allow us to assume that during the discharge fast neutrons are mainly produced.

The condensed matter properties of the nominal terminating element of the halogen group with atomic number 85, astatine, are as yet unknown. In the intervening more than 70 years since its discovery significant advances have been made in substrate cooling and the other techniques necessary for the production of the element to the point where we might now enquire about the key properties astatine might have if it attained a condensed phase. This subject is addressed here using density functional theory and structural selection methods, with an accounting for relativistic physics that is essential. Condensed astatine is predicted to be quite different in fascinating ways from iodine, being already at 1 atm a metal, and monatomic at that, and possibly a superconductor (as is dense iodine).

We evaluate the self-diffusion and transport diffusion of interacting particles in a discrete geometry consisting of a linear chain of cavities, with interactions within a cavity described by a free-energy function. Exact analytical expressions are obtained in the absence of correlations, showing that the self-diffusion can exceed the transport diffusion if the free-energy function is concave. The effect of correlations is elucidated by comparison with numerical results. Quantitative agreement is obtained with recent experimental data for diffusion in a nanoporous zeolitic imidazolate framework material, ZIF-8.

We present a generally covariant and parity-invariant two-frame field (“zwei-dreibein”) action for gravity in three space-time dimensions that propagates two massive spin-2 modes, unitarily, and we use Hamiltonian methods to confirm the absence of unphysical degrees of freedom. We show how zwei-dreibein gravity unifies previous “3D massive gravity” models and extends them, in the context of the AdS/CFT correspondence, to allow for a positive central charge consistent with bulk unitarity.

We have carried out photodisintegration cross-section measurements on ${}^{86}\mathrm{Kr}$ using monoenergetic photon beams ranging from the neutron separation energy, $S_n=9.86\mathrm{MeV}$, to 13 MeV. We combine our experimental ${}^{86}\mathrm{Kr}(\gamma ,n){}^{85}\mathrm{Kr}$ cross section with results from our recent ${}^{86}\mathrm{Kr}(\gamma ,{\gamma }^{\prime })$ measurement below the neutron separation energy to obtain the complete nuclear dipole response of ${}^{86}\mathrm{Kr}$. The new experimental information is used to predict the neutron capture cross section of ${}^{85}\mathrm{Kr}$, an important branching point nucleus on the abundance flow path during $s$-process nucleosynthesis. Our new and more precise ${}^{85}\mathrm{Kr}(n,\gamma ){}^{86}\mathrm{Kr}$ cross section allows us to produce more precise predictions of the ${}^{86}\mathrm{Kr}$ abundance from $s$-process models. In particular, we find that the models of the $s$ process in asymptotic giant branch stars of mass $<1.5{\mathrm{M}}_{\odot }$, where the ${}^{13}\mathrm{C}$ neutron source burns convectively rather than radiatively, represent a possible solution for the highest ${}^{86}\mathrm{Kr}:{}^{82}\mathrm{Kr}$ ratios observed in meteoritic stardust SiC grains.