Spatial and energy resolution of electronic states by shot noise
Shot-noise measurements are widely used for the characterization of nonequilibrium configurations in
electronic conductors. The recently introduced quantum tomography approach was implemented for the studies
of electronic wave functions of few-electron excitations created by periodic voltage pulses in phase-coherent
ballistic conductors based on the high-quality GaAs two-dimensional electron gas. Still relying on the manifestation
of Fermi correlations in noise, we focus on the simpler and more general approach beneficial for local
measurements of energy distribution (ED) in electronic systems with arbitrary excitations with well-defined
energies and random phases. Using biased diffusive metallic wire as a test bed, we demonstrate the power of this
approach and extract the well-known double-step ED from the shot noise of a weakly coupled tunnel junction.
Our experiment paves the way for local measurements of generic nonequilibrium configurations applicable to
virtually any conductor.
Quantum phase slips (QPS) may produce non-equilibrium voltage fluctuations in current-biased superconducting nanowires. Making use of the Keldysh technique and employing the phase-charge duality arguments we investigate such fluctuations within the four-point measurement scheme and demonstrate that shot noise of the voltage detected in such nanowires may essentially depend on the particular measurement setup. In long wires, the shot noise power decreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T→0.
Quantum phase slips (QPSs) generate voltage fluctuations in superconducting nanowires. Employing the Keldysh technique and making use of the phase-charge duality arguments, we develop a theory of QPS-induced voltage noise in such nanowires. We demonstrate that quantum tunneling of the magnetic flux quanta across the wire yields quantum shot noise which obeys Poisson statistics and is characterized by a power-law dependence of its spectrum SΩ on the external bias. In long wires, SΩdecreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T→0. The quantum coherent nature of QPS noise yields nonmonotonous dependence of SΩ on T at small Ω.
This book constitutes the thoroughly refereed conference proceedings of the 6th International Conference on Finite Difference Methods, FDM 2014, held in Lozenetz, Bulgaria, in June 2014. The 36 revised full papers were carefully reviewed and selected from 62 submissions. These papers together with 12 invited papers cover topics such as finite difference finite element methods and various its applications in physics, chemistry, biology and finance.
Contributions of the Thirteenth International Kazan summer scientific school-conference (Kazan, August 21-27, 2017).
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.