Quantum points

It is therefore clear that there is more than sufficient motivation for investigating the notion of nonlinearity in classical and quantum theories. The main point of this article is to provide an angle of vision which sets nonlinearity in its experimentally relevant context. Familiar to control theorists (P.S. Maybeck Jacobs, 1993) - but much less so to most physicists - this perspective bridges the classical and quantum points of view and smoothly connects them with each other. 

The previous assumption, >o = 0, can be also justified from the quantum point of view, as the most relevant transitions in metals take place within a band, usually the conduction band. The energy levels within a band of a sohd are separated by energies of about 10 eV, and so in the optical range (photon energies of some eV) the validity of assuming coj = 0 for transitions between these levels is evident. Consequently, the classical assumption >o = > = 0 is also justified from the quantum viewpoint. 

H. van Houten, C. W. J. Beenakker, and B. J. van Wees, Quantum Point Contacts G. Timp, When Does a Wire Become an Electron Waveguide ... 

Now we show that the validity of the cascade Langevin approach extends beyond the limits of validity of Boltzmann equation. Consider a frequency-dependent noise in a chaotic cavity, i.e. in a metallic island of irregular shape connected to the electrodes L, R via two quantum point contacts of conductances Gl,r e1 /h and arbitrary transparencies / /. . As the dwell time of... 

This model is quite universal, describing a variety of correlated electron systems coupled to the leads the Anderson impurity model, the multilevel quantum dot with diagonal noninteracting Hamiltonian quantum dots, when the off-diagonal matrix elements of eap describe hopping between individual dots, and, finally, the ID and 2D quantum point contacts. 

An optical MZ interferometer is described schematically in Fig. 1 a. In the electronic counterpart, depicted in Fig. 1 b, a quantum point contact (QPC) functions as a beam splitter and an Ohmic contact serves as a detector. The QPC is formed in the 2DEG by depositing split metallic gates, separated by a small gap, on the surface of the semiconduuctor and biasing them negatively... 

A numerical analysis, based on a Green s function approach, has been carried out to explain the interference patterns of an electron beam injected and detected via quantum point contacts. The calculations show the profound influence of back-scattering from potential fluctuations located close to the injector or detector on the transmission probability of the propagated electron beam. The interference patterns are sensitive to even small changes of the scatter location. 

TTie subject of nanotechnology thus now covers the search for and synthesis of new materials of advanced technology which possess the sizes of nanometres the determination of their characteristics, and their practical application. Nanostructures are the bridge between individual atoms and molecules, where the laws of quantum mechanics apply, and bulk phases, whose properties usually result from the collective behaviour of billions of atoms. Individual nanostructures may be clusters, nanomolecules, nanocrystals, so-called quantum points, nanowires and nanotubes. They possess orderly structures and some large molecules can form single nanostructures [2], The quantum sizes and shapes of nanomolecules affect their mechanical, chemical, electrical, nuclear-electronic, electric-optical and dynamic properties. They may exhibit new, unique physicoehemical phenomena, quantitatively different from those of the bulk phase. This leads to the possible control of the action and application of nanostructures... 

Ligand exchange and temperature effects on formation of nanocomposites based on semiconductor quantum points of CdSe/ZnS and porphyrins Measuring of assembles and single objects 12MG98. 

Quantum Object Sets and Quantum Point Clouds.353... 

Laser-induced breakdown is a phenomenon which occurs when the light is focused into a small volume and the electric field strength exceeds the breakdown threshold. From a quantum point of view, one may define the breakdown process as the formation of a plasma region due to multiphoton ionization processes. 

Planck s formula a hypothesis of quanta—intensity of light from wave and quantum points of view... 

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