The Boltzmann–Langevin approach: A simple quantum-mechanical derivation

We present a simple quantum-mechanical derivation of correlation function of Langevin sources in the semiclassical Boltzmann–Langevin equation. The specific case of electron–phonon scattering is considered. It is shown that the assumption of weak scattering leads to the Poisson nature of the scattering fluxes.     

A control volume derivation of the energy equation for LII modeling

This paper considers the unsteady energy equation for a particle undergoing processes relevant to laser-induced incandescence. The energy equation is derived using both an integral control volume formalism and a differential approach. Confusion in the previous literature over the form of the energy equation is traced to the evaluation of the energy flux terms to and from the particle surface. Terms such as the heat of sublimation or heat of combustion are shown to arise naturally in both the control volume and differential derivations. Problems associated with the confusion regarding the flux terms resulting in incorrect energy equations are also identified.     

A comment on “critique of home and sengupta's derivation of a Bell inequality”

We clarify some aspects of our derivation of a Bell-type inequality, in response to a paper by Elby.The following comments refer to Andrew Elby's discussion note immediately following our present paper.(a) We wish to stress that physical distinction between NC and LC is particularly important in the case of local realist theories violating NC for any single system but satisfying LC for any correlated many-component system. Arguments given by Elby do not rule out a reasonable theory violating NC but obeying LC. Therefore, a physically meaningful possibility exists that while Bell's inequality derived from NC is violated for a single system, the inequality derived from LC is satisfied for correlated and spatially separated (non-interacting) systems. It is precisely this possibility which was explored by HS in deriving Bell's inequality from NC.(b) Since Elby's formulation of locality condition necessarily involves a relativistic constraint at the level of individual measurements, it is pointless to discuss its compatibility with predictions derived from non-relativistic quantum mechanics, which is well known to allow superluminal communication by mechanisms such as wavepacket travel or spread. Recently this aspect has been discussed in depth by P. Ghose and D. Home,Phys. Rev. A 43, 6382 (1991). It needs to be stressed that our formulation of LC is in line with the separability condition articulated by Einstein in different contexts; see, for example,J. Franklin Inst. 221, 349 (1936), reprinted inIdeas and Opinions (Crown, New York, 1954), pp. 290–323.On leave from: Department of Physics, Bose Institute, Calcutta 700009, India.     

Spectrum of b-baryons: color hyperfine interaction vs. experiment

I discuss several recent highly accurate theoretical predictions for masses of baryons containing the b quark,especially Ωb （ssb） very recently reported by CDF.I also point out an approximate effective supersymmetry between heavy quark baryons and mesons and provide predictions for the magnetic moments of Λc and Λb .Proper treatment of the color-magnetic hyperfine interaction in QCD is crucial for obtaining these results.     

A novel derivation of the boundary term for the action in Lanczos–Lovelock gravity

We present a novel derivation of the boundary term for the action in Lanczos–Lovelock gravity, starting from the boundary contribution in the variation of the Lanczos–Lovelock action. The derivation presented here is straightforward, i.e., one starts from the Lanczos–Lovelock action principle and the action itself dictates the boundary structure and hence the boundary term one needs to add to the action to make it well-posed. It also gives the full structure of the contribution at the boundary of the complete action, enabling us to read off the degrees of freedom to be fixed at the boundary, their corresponding conjugate momenta and the total derivative contribution on the boundary. We also provide a separate derivation of the Gauss–Bonnet case.     

A Family of Schrödinger Operators Whose Spectrum is an Interval

By approximation, I show that the spectrum of the Schrödinger operator with potential V(n) = f (n ^ρ (mod 1)) for f continuous and \({\rho > 0, \rho \notin \mathbb{N}}\) is an interval.     

Fluorescence Spectrum Characteristics of Gold Nanorods

Aqueous solutions containing a high yield of suspended gold nanorods with mean aspect ratio 2.5 have been synthesized via an electrochemical method. The fluorescence emission peaks fixed at 37Onm and 670nm are due to the local field enhancement via coupling to the transverse and longitudinal surface plasmon resonance.The quasi-static calculation results indicate that with the increasing aspect ratio of the nanorods, the longer wavelength emission peak decreases and red shifts, whereas the shorter wavelength emission peak blue shifts slightly.     

Explicit derivation of a new hyper-Kähler metric

Using the harmonic superspace techniques in D = 2 N = 4, we present an explicit derivation of a new hyper-Kähler metric associated to the Toda-like self-interaction H⁴⁺ (ω, u) = (ζ⁺⁺/γ)² exp (2γω). Some important features are also discussed.     

Spectrum Simulation of Li-Like Aluminium Plasma

X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion （Al^9＋ and Al^11＋ ） charge states of the target ion （Al^10＋） are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.     

Direct Numerical Simulation of Acoustic Turbulence: Zakharov–Sagdeev Spectrum

JETP Letters - We present the results of direct numerical simulation of three-dimensional acoustic turbulence in medium with weak positive dispersion. It is shown that at the beginning of the...     

A soluble γ-unstable hamiltonian

A simple five-dimensional hamiltonian for the nuclear shape is solved analytically for any value of a parameter whose variation describes vibration about a spherical equilibrium at one extreme and a rigid non-spherical but γ-unstable nucleus at the other. Spectra and E2 transition rates are compared with results from the interacting boson model.     

Is the derivation of the Langevin formula correct?

The derivation of the Langevin formula is analyzed. It is shown that a basic assumption in it is incorrect. A more correct derivation of a similar formula is proposed.     

Analysis of Frequency Spectrum of Laser-Induced Vibration of Microbeam Resonators

The vibration phenomenon during pulsed laser heating of micro-beams is investigated. The beam is made of silicon and is heated by a laser pulse with a non-Gaussian temporal profile and with an ultrashort pulse duration of 2ps, which incites vibration due to the thermoelastic damping effect. This coupled thermoelastic problem is solved using an analytical-numerical technique based on the Laplace transformation. The damping ratio and resonant frequency shift ratio of beams due to the air damping effect and the thermoelastic damping effect are also examined and discussed.     

A quantitative assessment of the three-dimensional microstructure of a γ-γ ′ alloy

We present the first quantitative analysis of the three-dimensional microstructure of a n- n' alloy that does not make any a priori assumptions about the n'-particle morphologies. The n'-particle size distribution is derived using the particle volumes to provide a measure of the particle sizes that is independent of particle morphology and is found to be somewhat broader and to have a lower maximum peak height than the theoretical prediction in the absence of elastic stress. Non-equiaxed n' particles are found to be approximately equally likely to have rod-like, plate-like or mixed-character morphologies. In contrast with theoretical predictions, smaller particles tend to be more non-equiaxed than larger particles. The latter two findings are a result of the attractive interparticle configurational forces induced by stress at the corners of neighbouring particles. By analysing the distribution of particle side lengths, it is concluded that the average thickness of the sheets of n'-particles is between 0.4 and 0.6 µm.     

A statistical analysis of the wave numbers of triplet rovibronic transitions of the D2 molecule: II. An experimental study of “dubious” lines

The spectral lines whose identification and wave numbers were acknowledged to be dubious in a statistical analysis of all the experimental data on the triplet rovibronic transitions of the D₂ molecule published by now were studied. The capillary-arc discharge spectrum in a D₂-H₂ (9: 1) mixture was measured at p ≈ 6 torr and current density j ≈ 10 A/cm². The wave numbers of 123 lines (of a total of 138 dubious lines) situated in the spectral region accessible to us (430–730 nm) were determined. The error in wave numbers was ≈ 0.06 cm^?1 because of the low intensity of the lines under study and overlap of their contours resulting from fortuitous superpositions of closely lying lines of other band systems (the so-called blending effect). The new wave number values were substantially different from the literature data. These differences were largely caused by random counting and blending errors and, in four instances, erroneous identification of lines in previous works.     

Energy Spectrum and Optical Absorption Spectrum of Fullerene С26 within the Hubbard Model

Physics of the Solid State - Anticommutator Green functions and energy spectra of fullerene C26 and endohedral fullerene U@C26 with D3h symmetry groups are obtained in the analytical form within...