Spatial mapping of optical modes in plasmonic nanoantenna by scanning tunneling microscopy

Using of inelastic electron tunnelling is very promising approach to study of subwavelength photons and plasmons sources. Such sources are very important for improving of on-chip data processing. One of the ways for development of efficient and compact optical electrically-driven sources is using of nanoantenna placed into the tunnel junction. In this work, singe optical nanoantenna was investigated under ultra-high vacuum and ambient conditions. Photon maps of nanoantenna excited under scanning tunnel microscope tip was observed and the obtained results was compared with the theoretical predictions of electromagnetic near-field distribution.

Dijet impact factor in DIS at next-to-leading order in the Color Glass Condensate

We compute the next-to-leading order impact factor for inclusive dijet production in deeply inelastic electron-nucleus scattering at small xBj. Our computation, performed in the framework of the Color Glass Condensate effective field theory, includes all real and virtual contributions in the gluon shock wave background of all-twist lightlike Wilson line correlators. We demonstrate explicitly that the rapidity evolution of these correlators, to leading logarithmic accuracy, is described by the JIMWLK Hamiltonian. When combined with the next-to-leading order JIMWLK Hamiltonian, our results for the impact factor improve the accuracy of the inclusive dijet cross-section to $$ \mathcal{O} $$ O ($$ {\alpha}_s^2 $$ α s 2 ln(xf/xBj)), where xf is a rapidity factorization scale. These results are an essential ingredient in assessing the discovery potential of inclusive dijets to uncover the physics of gluon saturation at the Electron-Ion Collider.

The Strong Interactions

For many years strong interactions had a well-deserved reputation for complexity. Their apparent strength rendered perturbation theory inapplicable. However, in the late 1960s a series of experiments studying the deep inelastic electron–nucleon scattering showed that at a more fundamental level, the strong interactions among the constituent quarks can be described perturbatively by an asymptotically free gauge theory. We present the theory of quantum chromodynamics, the unbroken gauge theory of the colour SU(3) group. We show how we can compute its predictions in the kinematic regions in which perturbation theory is applicable, but also in the strong coupling regime through numerical simulations on a space-time lattice.

Elastic and Inelastic form factors with inclusion 2-body short-range correlations effect

The charge distributions and elastic electron form factors for ¹⁸O, ^42,44Ca,⁵⁸Ni, and ¹¹⁸Sn nuclei are considered using the cluster extension of the 1- and 2-body terms. Inelastic electron form factors to 2+ states with Core-Polarization effects studied where the nuclear collective modes beside to the shell model transition density are considered. The influence of SRC's be calculated by the parameter β which is introduced into the ground state charge distribution concluded the Jastrow function. It is found that the inclusion of 2-body correlations are necessary to describe the observed data of elastic and inelastic form factor at high range of momentum transfer q > 3 fm^-1.

Electron scattering cross-sections for particle transport modeling in a weakly ionized air plasma

Data on processes of electron scattering on ions and neutral atoms are required in fundamental studies and in applied research in such fields as astro- and laser physics, low density plasma simulations, kinetic modeling etc. Experimental and computational data on elastic and inelastic electron scattering in a wide range of electron energies is available mostly for the electron interaction with neutral atoms, but are very limited for the scattering on ions, notably for elastic processes. In present work the calculational approaches for the cross-section computation of electron elastic and inelastic scattering on neutral atoms and ions are considered. The atomic and ion properties obtained in quantum-statistical Hartree-Fock-Slater model are used in the direct computation of electron elastic scattering and ionization cross-sections by a partial waves method, semiclassical and distorted-wave approximations. Calculated cross-sections for elastic scattering on nitrogen and oxygen atoms and ions, and electron ionisation cross-sections are compared with the available experimental data and widely used approximations and propose consistent results. Considering applicability of Hartree-Fock-Slater model in wide scope of temperatures and densities, such approach to the cross-section calculation can be used in a broad range of energies and ion charges.

Quantum stochastic resonance of individual Fe atoms

Stochastic resonance, where noise synchronizes a system’s response to an external drive, is a wide-reaching phenomenon found in noisy systems spanning from the dynamics of neurons to the periodicity of ice ages. Quantum tunneling can extend stochastic resonance to the quantum realm. We demonstrate quantum stochastic resonance for magnetic transitions in atoms by inelastic electron tunneling with a scanning tunneling microscope. Stochastic resonance is shown deep in the quantum regime, where spin-state fluctuations are driven by tunneling of the magnetization, and in a semiclassical crossover region, where thermally excited electrons drive transitions between ground and excited states. Inducing synchronization by periodically modulating transition rates provides a general mechanism to determine real-time spin dynamics ranging from milliseconds to picoseconds.