While being extensively studied as an important physical process to alter exciton population in nanostructures at the fs time scale, carrier multiplication has not been considered seriously as a major mechanism for phase transition. Real-time time-dependent density functional theory study of ${\mathrm{Ge}}_2{\mathrm{Sb}}_2{\mathrm{Te}}_5$ reveals that carrier multiplication can induce an ultrafast phase transition in the solid state despite that the lattice remains cold. The results also unify the experimental findings in other semiconductors for which the explanation remains to be the 30-year old phenomenological plasma annealing model.

A classical spin which is antiferromagnetically coupled to a system of strongly correlated conduction electrons is shown to exhibit unconventional real-time dynamics which cannot be described by Gilbert damping. Depending on the strength of the local Coulomb interaction $U$, the two main electronic dissipation channels, namely transport of excitations via correlated hopping and via excitations of correlation-induced magnetic moments, become active on largely different time scales. We demonstrate that correlations can lead to a strongly suppressed relaxation which so far has been observed in purely electronic systems only and which is governed here by proximity to the divergent magnetic time scale in the infinite-$U$ limit.

The stochastic kinetics of transcription is typically inferred from the distribution of RNA numbers in individual cells. However, cellular RNA reflects additional processes downstream of transcription, hampering this analysis. In contrast, nascent (actively transcribed) RNA closely reflects the kinetics of transcription. We present a theoretical model for the stochastic kinetics of nascent RNA, which we solve to obtain the probability distribution of nascent RNA per gene. The model allows us to evaluate the kinetic parameters of transcription from single-cell measurements of nascent RNA. The model also predicts surprising discontinuities in the distribution of nascent RNA, a feature which we verify experimentally.

We consider a six-partite, continuous-variable quantum state that we have effectively generated by the parametric down-conversion of a femtosecond frequency comb. We show that, though this state is two-separable, i.e., it does not exhibit “genuine entanglement,” it is undoubtedly multipartite entangled. The consideration of not only the entanglement of individual mode decompositions, but also of combinations of those, solves the puzzle and exemplifies the importance of studying different categories of multipartite entanglement.

At present, all physical models of diffuse Galactic $\gamma$-ray emission assume that the distribution of cosmic-ray sources traces the observed populations of either OB stars, pulsars, or supernova remnants. However, since ${\mathrm{H}}_2$-rich regions host significant star formation and numerous supernova remnants, the morphology of observed ${\mathrm{H}}_2$ gas (as traced by CO line surveys) should also provide a physically motivated, high-resolution tracer for cosmic-ray injection. We assess the impact of utilizing ${\mathrm{H}}_2$ as a tracer for cosmic-ray injection on models of diffuse Galactic $\gamma$-ray emission. We employ state-of-the-art 3D particle diffusion and gas density models, along with a physical model for the star-formation rate based on global Schmidt laws. Allowing a fraction, $f_{H_2}$, of cosmic-ray sources to trace the observed ${\mathrm{H}}_2$ density, we find that a theoretically well-motivated value $f_{H_2}\sim 0.20–0.25$ (i) provides a significantly better global fit to the diffuse Galactic $\gamma$-ray sky and (ii) highly suppresses the intensity of the residual $\gamma$-ray emission from the Galactic center region. Specifically, in models utilizing our best global fit values of $f_{H_2}\sim 0.20–0.25$, the spectrum of the galactic center $\gamma$-ray excess is drastically affected, and the morphology of the excess becomes inconsistent with predictions for dark matter annihilation.

Measurements are reported of the cross-correlation of spectra of differential position signals from the Fermilab Holometer, a pair of colocated 39 m long, high power Michelson interferometers with flat broadband frequency response in the MHz range. The instrument obtains sensitivity to high frequency correlated signals far exceeding any previous measurement in a broad frequency band extending beyond the 3.8 MHz inverse light-crossing time of the apparatus. The dominant but uncorrelated shot noise is averaged down over $2\times 10^8$ independent spectral measurements with 381 Hz frequency resolution to obtain $2.1\times {10}^{-20}\mathrm{m}/\sqrt{\mathrm{Hz}}$ sensitivity to stationary signals. For signal bandwidths $\mathrm{\Delta }f>11\mathrm{kHz}$, the sensitivity to strain $h$ or shear power spectral density of classical or exotic origin surpasses a milestone ${\mathrm{PSD}}_{\delta h}<t_p$ where $t_p=5.39\times {10}^{-44}/\mathrm{Hz}$ is the Planck time.

A search for the decays of the Higgs and $Z$ bosons to a $\varphi$ meson and a photon is performed with a $pp$ collision data sample corresponding to an integrated luminosity of $2.7{\mathrm{fb}}^{-1}$ collected at $\sqrt{s}=13\mathrm{TeV}$ with the ATLAS detector at the LHC. No significant excess of events is observed above the background, and 95% confidence level upper limits on the branching fractions of the Higgs and $Z$ boson decays to $\varphi \gamma$ of $1.4\times 10^{-3}$ and $8.3\times 10^{-6}$, respectively, are obtained.

We show that, in $U(1{)}_R$-symmetric supersymmetric models, the bino and its Dirac partner (the singlino) can play the role of right-handed neutrinos and generate the neutrino masses and mixing, without the need for traditional bilinear or trilinear $R$-parity violating operators. The two particles form a pseudo-Dirac pair, the “$\mathrm{bi}\nu \mathrm{o}$.” An inverse seesaw texture is generated for the neutrino-$\mathrm{bi}\nu \mathrm{o}$ sector, and the lightest neutrino is predicted to be massless. Unlike in most models with heavy right-handed neutrinos, the $\mathrm{bi}\nu \mathrm{o}$ can be sizably produced at the LHC through its interactions with colored particles, while respecting low energy constraints from neutrinoless double-beta decay and charged lepton flavor violation.

We develop an effective field theory (EFT) to describe the few- and many-body propagation of one-dimensional Rydberg polaritons. We show that the photonic transmission through the Rydberg medium can be found by mapping the propagation problem to a nonequilibrium quench, where the role of time and space are reversed. We include effective range corrections in the EFT and show that they dominate the dynamics near scattering resonances in the presence of deep bound states. Finally, we show how the long-range nature of the Rydberg-Rydberg interactions induces strong effective $N$-body interactions between Rydberg polaritons. These results pave the way towards studying nonperturbative effects in quantum field theories using Rydberg polaritons.

Identifying subwavelength objects and displacements is of crucial importance in optical nanometrology. We show in this Letter that nanoantennas with subwavelength structures can be excited precisely by incident beams with singularity. This accurate feeding beyond the diffraction limit can lead to dynamic control of the unidirectional scattering in the far field. The combination of the field discontinuity of the incoming singular beam with the rapid phase variation near the antenna leads to remarkable sensitivity of the far-field scattering to the displacement at a scale much smaller than the wavelength. This Letter introduces a far-field deep subwavelength position detection method based on the interaction of singular optics with nanoantennas.

An interesting deflection effect deviating the optical reflection law is revealed in the relativistic regime of intense vortex laser plasma interaction. When an intense vortex laser obliquely impinges onto an overdense plasma target, the reflected beam deflects out of the plane of incidence with an experimentally observable deflection angle. The mechanism is demonstrated by full three-dimensional particle-in-cell simulation as well as analytical modeling using the Maxwell stress tensor. The deflection results from the rotational symmetry breaking of the foil driven by the unsymmetrical shear stress of the vortex beam. The $l$-dependent shear stress, where $l$ is the topological charge, as an intrinsic characteristic to the vortex beam, plays an important role as the ponderomotive force in relativistic vortex laser matter interaction.

We report a unique collapse mechanism by exploiting the negative stiffness observed in the folding of an origami solid, which consists of pressurized cells made by stacking origami sheets. Such a collapse mechanism is recoverable, since it only involves rigid folding of the origami sheets and it is programmable by pressure control and the custom design of the crease pattern. The collapse mechanism features many attractive characteristics for applications such as energy absorption. The reported results also suggest a new branch of origami study focused on its nonlinear mechanics associated with folding.

Evidence of a nonlinear transition from mitigation to suppression of the edge localized mode (ELM) by using resonant magnetic perturbations (RMPs) in the EAST tokamak is presented. This is the first demonstration of ELM suppression with RMPs in slowly rotating plasmas with dominant radio-frequency wave heating. Changes of edge magnetic topology after the transition are indicated by a gradual phase shift in the plasma response field from a linear magneto hydro dynamics modeling result to a vacuum one and a sudden increase of three-dimensional particle flux to the divertor. The transition threshold depends on the spectrum of RMPs and plasma rotation as well as perturbation amplitude. This means that edge topological changes resulting from nonlinear plasma response plays a key role in the suppression of ELM with RMPs.

Recently synthesized nanotwinned diamond (NTD) exhibits unprecedented Vickers hardness exceeding 200 GPa [Q. Huang et al., Nature (London) 510, 250 (2014)]. This extraordinary finding challenges the prevailing understanding of material deformation and stress response under extreme loading conditions. Here we unveil by first-principles calculations a novel indenter-deformation generated stress confinement mechanism that suppresses the graphitization or bond collapse failure modes commonly known in strong covalent solids, leading to greatly enhanced peak stress and strain range in the indented diamond lattice. Moreover, the twin boundaries in NTD promote a strong stress concentration that drives preferential bond realignments, producing a giant indentation strain stiffening. These results explain the exceptional indentation strength of NTD and offer insights into the extreme mechanics of the intricate interplay of the indenter and indented crystal in probing ultrahard materials.

We study the thermal conductivity of the one-dimensional Fermi-Hubbard model at a finite temperature using a density matrix renormalization group approach. The integrability of this model gives rise to ballistic thermal transport. We calculate the temperature dependence of the thermal Drude weight at half filling for various interaction strengths. The finite-frequency contributions originating from the fact that the energy current is not a conserved quantity are investigated as well. We report evidence that breaking the integrability through a nearest-neighbor interaction leads to vanishing Drude weights and diffusive energy transport. Moreover, we demonstrate that energy spreads ballistically in local quenches with initially inhomogeneous energy density profiles in the integrable case. We discuss the relevance of our results for thermalization in ultracold quantum-gas experiments and for transport measurements with quasi-one-dimensional materials.

Polarons in metal oxides are important in processes such as catalysis, high temperature superconductivity, and dielectric breakdown in nanoscale electronics. Here, we study the behavior of electron small polarons associated with oxygen vacancies at rutile ${\mathrm{TiO}}_2(110)$, using a combination of low temperature scanning tunneling microscopy (STM), density functional theory, and classical molecular dynamics calculations. We find that the electrons are symmetrically distributed around isolated vacancies at 78 K, but as the temperature is reduced, their distributions become increasingly asymmetric, confirming their polaronic nature. By manipulating isolated vacancies with the STM tip, we show that particular configurations of polarons are preferred for given locations of the vacancies, which we ascribe to small residual electric fields in the surface. We also form a series of vacancy complexes and manipulate the Ti ions surrounding them, both of which change the associated electronic distributions. Thus, we demonstrate that the configurations of polarons can be engineered, paving the way for the construction of conductive pathways relevant to resistive switching devices.