On the ultimate capabilities of the quantum key distribution with the control over the statistics of a non-single-photon source

The upper bound of the length of a quantum communication channel has been determined for the key distribution in the decoy state method.     

Relativistic effects in the calibration of electrostatic electron analyzers. I. Toroidal analyzers

Relativistic correction terms up to the second order are derived for the kinetic energy of an electron travelling along the circular central trajectory of a toroidal analyzer. Furthermore, a practical energy calibration equation of the spherical sector plate analyzer is written for the variable-plate-voltage recording mode. Accurate measurements with a spherical analyzer performed using kinetic energies from 600 to 2100 eV are in good agreement with this theory showing our approximation (neglect of fringing fields, and source and detector geometry) is realistic enough for actual calibration purposes.     

A comparative study of the self-propelled jumping capabilities of coalesced droplets on RTV surfaces and superhydrophobic surfaces

Understanding the mechanism of coalescence-induced self-propelled jumping behavior provides distinct insights in designing and optimizing functional coatings with self-cleaning and anti-icing properties.However,to date self-propelled jumping phenomenon has only been observed and studied on superhydrophobic surfaces,other than those hydrophobic surfaces with weaker but fairish water-repellency,for instance,vulcanized silicon rubber(RTV) coatings.In this work,from the perspective of thermodynamic-based energy balance aspect,the reason that self-propelled jumping phenomenon does not happen on RTV coatings is studied.The apparent contact angles of droplets on RTV coatings can be less than the theoretical critical values therefore cannot promise energy surplus for the coalesced droplets onside.Besides,on RTV and superhydrophobic surfaces,the droplet-size dependent variation characteristics of the energy leftover from the coalescence process are opposite.For the droplets coalescing on RTV coatings,the magnitudes of energy dissipations are more sensitive to the increase in droplet size,compared to that of released surface energy.While for superhydrophobic coatings,the energy generated during the coalescence process can be more sensitive than the dissipations to the change in droplet size.     

The stability of Mott polarization analyzers

The stability of Mott conventional spherically symmetric and retarding-potential conical polarimeters are compared for the case when the position of the electron beam at their inputs is changed. The primary electron energies are 500 and 1600 eV. When the electron beam is shifted by 0.6 mm, the count rate of the former polarimeter remains unchanged, while for the latter, it changes by ≈7 and ≈18% for the energies 1600 and 500 eV, respectively. This instability may cause errors in measuring the degree of polarization of the electron beam.     

Express method of designing magnetic mass analyzers

An original method for designing magnetic mass analyzers that is represented in the form of a computer program is proposed. The thorough optimization of the method makes it possible to rapidly and accurately simulate the focusing properties of a mass analyzer along its focal line, as well as to select designs appropriate for a given problem.     

Energy levels and their correlations in quasicrystals

Quasicrystals can be considered, from the point of view of their electronic properties, as being intermediate between metals and insulators. For example, experiments show that quasicrystalline alloys such as AlCuFe or AlPdMn have conductivities far smaller than those of the metals that these alloys are composed from. Wavefunctions in a quasicrystal are typically intermediate in character between the extended states of a crystal and the exponentially localized states in the insulating phase, and this is also reflected in the energy spectrum and the density of states. In the theoretical studies we consider in this review, the quasicrystals are described by a pure hopping tight binding model on simple tilings. We focus on spectral properties, which we compare with those of other complex systems, in particular, the Anderson model of a disordered metal. We discuss ‘strong‘ and ‘weak’ quasicrystals, which are described by different universal laws. We find similarities and universal behaviour, but also significant differences between quasiperiodic models and models with disorder. Like weakly disordered metals, the quasicrystal can be described by the universal level statistics that can be derived from random matrix theory. These level statistics are only one aspect of the energy spectrum, whose very large fluctuations can also be described by a level spacing distribution that is log-normal. An analysis of spectral rigidity shows that electrons diffuse with a bigger exponent (super-diffusion) than in a disordered metal. Adding disorder attenuates the singular properties of the perfect quasicrystal, and leads to improved transport. Spectral properties are also used in computing conductances of such systems, and to attempt to resolve the experimental enigmas such as whether quasicrystals are intrinsically conductors, and if so, how conductances depend on the structure.     

Relativistic effects in the calibration of electrostatic electron analyzers. II. Parallel plate and cylindrical mirror analyzers

Relativistic correction terms up to the second order are derived for the kinetic energy of an electron travelling along the central trajectory, which crosses the non-relativistic foci of electrostatic parallel plate and cylindrical mirror analyzers. The effects of fringing fields and source geometry are neglected. In both cases the magnitude of relativistic corrections depends on the geometry of the analyzer, but generally it is smaller than for the toroidal family of analyzers.     

Goniopolarimetry: Space-borne radio astronomy with imaging capabilities

The principles of space-based low-frequency radio astronomy (below 50 MHz) are briefly introduced. As the wavelength range considered does not allow the use of focusing systems, goniopolarimetric (or direction-finding) techniques have been developed. These inversion techniques provide the direction of the wave vector, the polarization state and the flux of the observed electromagnetic wave. In case of spatially extended sources, we can also infer an order of magnitude of the apparent source size. These techniques are presented, and their limitations are discussed. An example from a recent study illustrates the techniques and capabilities.     

Energy principles: A non-equilibrium thermodynamic approach

A formal derivation and generalization of the Sudan-Rosenbluth and other well-known energy principles of plasma physics is obtained from the principle of balance of power of non-equilibrium thermodynamics, by working in the entropy representation. The role of the complex excess power is stressed and clarified in this approach to plasma stability.     

Formative ceramics from the Andes and their production: A Mössbauer study

The potential of Mössbauer spectroscopy in the reconstruction of production techniques of early ceramics is demonstrated by the results of a study of a Formative kiln site at the Archaeological Park at Batán Grande, Perú, and of ceramics from the nearby settlement of Huaca Chólope.     

A multi-parameter optical fiber sensor with interrogation and discrimination capabilities

A multi-parameter and multi-function, but low-cost, optical fiber grating sensor with self-interrogation and self-discrimination capabilities is presented theoretically and experimentally. The sensor bases on three fiber Bragg gratings (FBG) and one fiber long period grating (LPG). Strain, vibration, pressure, ordinary temperature (−10 to 100 °C) and high temperature (100–800 °C) can be measured by the sensor. When high temperature (100–800 °C) is measured, the LPG is used as a high temperture sensor head and FBG₁ is used as an interrogation element. Alternatively, when one of the other four measurands is measured, FBG₁ (or FBG₂) is used as a sensor head and LPG is used as an interrogation element. When two of the other four measurands are measured simultaneously, FBG₁ and FBG₂ are used as sensor heads and LPG is used as a shared interrogation element. FBG₃ is used as a reference element to eliminate the errors resulted from light source fluctuation and the cross-sensitivity between measurand and environmental temperature. The measurands can be interrogated according to the signals of the photodiodes (PDs), which are related to the relative wavelength shift of the LPG and the FBGs. Experimental results agree well with theoretical analyses. The interrogation scheme is immune to light source fluctuation and the cross-sensitivity between measurands and enviromental temperature, and also the dynamic range is large.     

Entanglement capabilities of nonlocal Hamiltonians

We quantify the capability of creating entanglement for a general physical interaction acting on two qubits. We give a procedure for optimizing the generation of entanglement. We also show that a Hamiltonian can create more entanglement if one uses auxiliary systems.     

Range-resolved pulsed and CWFM lidars: potential capabilities comparison

An analytical comparison of key capabilities for both continuous wave frequency modulated (CWFM) lidar and incoherent pulsed lidar is presented. Principles of CWFM-lidar architectures are described and the CWFM-lidar equation is derived. The dimensionless parameterization methodology is applied to both broad- and narrow-band lidars to perform their detailed estimates and a comparison of the operation range and sensitivity. PACS 42.68.Wt; 42.79.Qx; 92.60.Sz; 07.88.+y     

Glasses for erbium-doped fiber amplifiers: A comparison based on the ultimate spectral efficiency of information transmission

A new figure of merit—the ultimate spectral efficiency of information transmission in the regime of unsaturated gain in the case of a quasi-two-level scheme of pumping—is proposed to compare host glasses for erbium-doped fiber amplifiers (EDFAs) that are considered as a constituent of an optical communication system. It is shown that the amplifiers based on silicate glasses possess the best characteristics, whereas the amplifiers based on phosphate and tellurite glasses have somewhat worse and substantially worse characteristics, respectively.