Inspired by the unexpectedly large difference between the $CP$ violation of $D$ decays into $K^{+}{K}^{-}$ and ${\pi }^{+}{\pi }^{-}$, we explore the impact on the extraction of $\gamma$ via the $B\to DK$ process with the $D$ meson reconstructed in the $K^{+}{K}^{-}$, ${\pi }^{+}{\pi }^{-}$ final state. We show that the extracted results for $\gamma$ can be shifted by $O(A_{CP}/r_B^K)$, where $A_{CP}$ is the direct $CP$ asymmetry in $D$ decays and $r_B^K$ is the ratio of the decay amplitudes of $B^{-}\to {\overline{D}}^0{K}^{-}$ and $B^{-}\to D^0{K}^{-}$. Using the recent data on $CP$ asymmetry, we demonstrate that the correction to physical observables in $B\to DK$ can reach 6%, which corresponds to the shift of $\gamma$ by roughly 5°. The remanent corrections depend on the strong phase of the $D$ decays but are less than 0.5°. With the increasing precision in the $\gamma$ determination on the LHCb experiment and the Super $B$ factories, the inclusion of the $CP$ violation of $D$ decays will therefore soon become important.

The damping of the nuclear shell effect with excitation energy has been measured through an analysis of the neutron spectra following the triton transfer in the ${}^7\mathrm{Li}$ induced reaction on ${}^{205}\mathrm{Tl}$. The measured neutron spectra demonstrate the expected large shell correction energy for the nuclei in the vicinity of doubly magic ${}^{208}\mathrm{Pb}$ and a small value around ${}^{184}\mathrm{W}$. A quantitative extraction of the allowed values of the damping parameter $\gamma$, along with those for the asymptotic nuclear level density parameter $\tilde{a}$, has been made for the first time.

Our theoretical study shows that the spectral minimum and the giant enhancement structures observed in the high harmonic spectra also exist in the photoelectron spectra from driven Xe atoms. They are attributed to the inherent property of the radial part of the wave function of the Xe $5p$ subshell in momentum space. The spectral minimum is caused by the nodal point in the modulus of the radial wave function in momentum space, and the giant enhancement reflects the increase in magnitude of the modulus of the wave function. To observe these structures, midinfrared lasers of about $0.2\mathrm{PW}/{\mathrm{cm}}^2$ intensity are preferred. Employing circularly polarized laser light is suggested for exhibiting these structures in photoelectron spectra.

When both electric and magnetic mechanisms contribute to a particular nonlinear optical process, there exists the possibility for nonlinear interference, often characterized by constructive or destructive interference in the radiation pattern of harmonics and mix waves. However, observation of a significant effect from nonlinear interference requires careful balancing of the various contributions. For this purpose, we propose an artificial metamaterial, using the formalism of nonlinear magnetoelectric coupling to simultaneously engineer the nonlinear polarization and magnetization. We confirm our predictions of nonlinear interference with both simulations and experiment, demonstrating unidirectional wave mixing in two microwave metamaterials. Our results point toward an ever wider range of nonlinear properties, in which nonlinear interference is just one of many potential applications.

We consider the Kuramoto model of an ensemble of interacting oscillators allowing for an arbitrary distribution of frequencies and coupling strengths. We define a family of traveling wave states as stationary in a rotating frame, and derive general equations for their parameters. We suggest empirical stability conditions which, for the case of incoherence, become exact. In addition to making new theoretical predictions, we show that many earlier results follow naturally from our general framework. The results are applicable in scientific contexts ranging from physics to biology.

Do relativistic quantum scars in classically chaotic systems possess unique features that are not shared by nonrelativistic quantum scars? We report a class of relativistic quantum scars in massless Dirac fermion systems whose phases return to the original values or acquire a $2\pi$ change only after circulating twice about some classical unstable periodic orbits. We name such scars chiral scars, the successful identification of which has been facilitated tremendously by our development of an analytic, conformal-mapping-based method to calculate an unprecedentedly large number of eigenstates with high accuracy. Our semiclassical theory indicates that the physical origin of chiral scars can be attributed to a combined effect of chirality intrinsic to massless Dirac fermions and the geometry of the underlying classical orbit.

We show that excitability is generic in systems displaying dissipative solitons when spatial inhomogeneities and drift are present. Thus, dissipative solitons in systems which do not have oscillatory states, such as the prototypical Swift-Hohenberg equation, display oscillations and type I and II excitability when adding inhomogeneities and drift to the system. This rich dynamical behavior arises from the interplay between the pinning to the inhomogeneity and the pulling of the drift. The scenario presented here provides a general theoretical understanding of oscillatory regimes of dissipative solitons reported in semiconductor microresonators. Our results open also the possibility to observe this phenomenon in a wide variety of physical systems.

Combining high-speed photography with electric current measurement, we investigate the electrocoalescence of Pickering emulsion droplets. Under a high enough electric field, the originally stable droplets coalesce via two distinct approaches: normal coalescence and abnormal coalescence. In the normal coalescence, a liquid bridge grows continuously and merges two droplets together, similar to the classical picture. In the abnormal coalescence, however, the bridge fails to grow indefinitely; instead, it breaks up spontaneously due to the geometric constraint from particle shells. Such connecting-then-breaking cycles repeat multiple times, until a stable connection is established. In depth analysis indicates that the defect size in particle shells determines the exact merging behaviors: when the defect size is larger than a critical size around the particle diameter, normal coalescence will show up, while abnormal coalescence will appear for coatings with smaller defects.

A novel approach to generating coherent x rays with ${10}^9–{10}^{10}$ photons and femtoseconds duration per laser pulse is proposed. This high intensity x-ray source is realized first by the pulse front tilt of a lateral fed laser to extend the electron-laser synchronic interaction time by several orders, which accomplishes the high-gain free-electron-laser-type exponential growth process and coherent emission with highly microbunched electron beam. Second, two methods are presented to enhance the effective optical undulator strength parameter. One is to invoke lenses to focus two counterpropagating lasers that are at normal incidence to the electron beam as a transverse standing wave; the other is to invent a periodic microstructure that can significantly enhance the center electromagnetic field realized by a resonant standing wave and the quadrupole waveguides. The energy coupling efficiency between the electron beam and laser is therefore greatly improved to generate the high brightness x rays, which is demonstrated by analytical and simulation results.

A class of generalized Kapchinskij-Vladimirskij solutions of the Vlasov-Maxwell equations and the associated envelope equations for high-intensity beams in an uncoupled lattice is derived. It includes the classical Kapchinskij-Vladimirskij solution as a special case. For a given lattice, the distribution functions and the envelope equations are specified by ten free parameters. The class of solutions derived captures a wider range of dynamical envelope behavior for high-intensity beams, and thus provides a new theoretical tool to investigate the dynamics of high-intensity beams.

The strong ion-ion correlation peak characteristic of warm dense matter (WDM) is observed for the first time using simultaneous angularly, temporally, and spectrally resolved x-ray scattering measurements in laser-driven shock-compressed aluminum. Laser-produced molybdenum x-ray line emission at an energy of 17.9 keV is employed to probe aluminum compressed to a density of $\rho >8\mathrm{g}/{\mathrm{cm}}^3$. We observe a well pronounced peak in the static structure factor at a wave number of $k=4.0{\AA }^{-1}$. The measurements of the magnitude and position of this correlation peak are precise enough to test different theoretical models for the ion structure and show that only models taking the complex interaction in WDM into account agree with the data. This also demonstrates a new highly accurate diagnostic to directly measure the state of compression of warm dense matter.

We report on artificial descending plasma layers created in the ionosphere $F$ region by high-power high-frequency (HF) radio waves from High-frequency Active Auroral Research Program at frequencies $f_0$ near the fourth electron gyroharmonic $4f_{\mathrm{ce}}$. The data come from concurrent measurements of the secondary escaping radiation from the HF-pumped ionosphere, also known as stimulated electromagnetic emission, reflected probing signals at $f_0$, and plasma line radar echoes. The artificial layers appeared only for injections along the magnetic field and $f_0>4f_{\mathrm{ce}}$ at the nominal HF interaction altitude in the background ionosphere. Their average downward speed $\sim 0.5\mathrm{km}/\mathrm{s}$ holds until the terminal altitude where the local fourth gyroharmonic matches $f_0$. The total descent increases with the nominal offset $f_0-4f_{\mathrm{ce}}$.

Cold atoms in optical lattices allow for accurate studies of many body dynamics. Rapid time-dependent modifications of optical lattice potentials may result in significant excitations in atomic systems. The dynamics in such a case is frequently quite incompletely described by standard applications of tight-binding models (such as, e.g., Bose-Hubbard model or its extensions) that typically neglect the effect of the dynamics on the transformation between the real space and the tight-binding basis. We illustrate the importance of a proper quantum mechanical description using a multiband extended Bose-Hubbard model with time-dependent Wannier functions. We apply it to situations directly related to experiments.

Structural defects inevitably appear during the nucleation event that determines the structure and properties of single-walled carbon nanotubes. By combining ion bombardment experiments with atomistic simulations we reveal that ion bombardment in a suitable energy range allows these defects to be healed resulting in an enhanced nucleation of the carbon nanotube cap. The enhanced growth of the nanotube cap is explained by a nonthermal ion-induced graphene network restructuring mechanism.

Tetragonal semimetallic phases are predicted for ${\mathrm{Hf}}_2{\mathrm{O}}_3$ and ${\mathrm{Zr}}_2{\mathrm{O}}_3$ using density functional theory. The structures belong to space group $P\overline{4}m2$ and are more stable than their corundum counterparts. Many body corrections at first order confirm their semimetallic character. The carrier concentrations are very similar for both materials, and are estimated as $1.8\times {10}^{21}{\mathrm{cm}}^{-3}$ for both electrons and holes, allowing for electric conduction. This could serve as a basic explanation for the low resistance state of hafnia-based resistive random access memory.

It is shown that quantum effects lead to a significant decrease of the glass transition temperature $T_g$ with respect to the melting temperature $T_m$, so that the ratio $T_g/T_m$ can be much smaller than the typical value of $2/3$ in materials where $T_g$ is near or below $\sim 60\mathrm{K}$. Furthermore, it is demonstrated that the viscosity or structural relaxation time in such low temperature glass formers should exhibit highly unusual temperature dependence, namely a decrease of the apparent activation energy upon approaching $T_g$ (instead of traditional increase).

Using first-principles molecular dynamics, we study the influence of nuclear quantum effects (NQEs) and nonlocal exchange-correlation density functionals (DFs) near molecular dissociation in liquid hydrogen. NQEs strongly influence intramolecular properties, such as bond stability, and are thus an essential part of the dissociation process. Moreover, by including DFs that account for either the self-interaction error or dispersion interactions, we find a much better description of molecular dissociation and metallization than previous studies based on classical protons and/or local or semilocal DFs. We obtain excellent agreement with experimentally measured optical properties along Hugoniot curves for precompressed states, and while we still find a first-order liquid-liquid transition at low temperatures, transition pressures are increased by more than 100 GPa.

Synchrotron-based in situ tensile testing was used to study the dominant deformation mechanisms of nanocrystalline Pd thin films on a compliant substrate. An x-ray diffraction peak profile analysis reveals an ($hkl$) independent deformation induced peak asymmetry. It is argued that the asymmetry is caused by a broad distribution of elastic strains among individual grains and the complexity of accommodation processes. The reversal of peak asymmetry manifests the transition from heterogeneous microplasticity to dislocation-based macroplasticity. Independently, stress-driven grain boundary migration is active.

We present a large $N$ solution of a microscopic model describing the Mott-Anderson transition on a finite-coordination Bethe lattice. Our results demonstrate that strong spatial fluctuations, due to Anderson localization effects, dramatically modify the quantum critical behavior near disordered Mott transitions. The leading critical behavior of quasiparticle wave functions is shown to assume a universal form in the full range from weak to strong disorder, in contrast to disorder-driven non-Fermi liquid (“electronic Griffiths phase”) behavior, which is found only in the strongly correlated regime.

Single band theories of quantum criticality successfully describe a single-particle lifetime with non-Fermi liquid temperature dependence, but they fail to obtain a charge transport rate with the same dependence unless the interaction is assumed to be momentum independent. Here we demonstrate that a quantum critical material, with a long-range mode that transmutes electrons between light and heavy bands, exhibits a quasilinear temperature dependence for both the single-particle and the charge transport lifetimes, despite the strong momentum dependence of the interaction.