Statistical mechanics of a dynamical system based on Conway's game of Life

We study a discrete dynamical system whose evolution is governed by rules similar to those of Conway's game of Life but also include a stochastic element (parametrized by a temperature). Statistical properties that are examined are density as a function of temperature and entropy (suitably defined). A phase transition and a certain thermodynamic constant of the motion are observed.Lady Davis Visiting Scientist at the Technion 1974–75.     

Spectral Complex for Controlling the Parameters of the Plasmachemical‐Reactor Working Medium

An automated spectral complex for controlling the parameters of the plasmachemicalreactor working medium by the emission and absorption spectra in the 200–1100 and 2000–5000nm ranges has been developed. To record radiation, a CCD array and a pyroelectric detector are used. Control of the spectral device functions, data recording, and the obtaining of results reflecting the workingmedium parameters and the concentration in it of components being measured are carried out by means of a personal computer. The complex makes it possible to study the temporal behavior of the workingmedium parameters being measured with a resolution of up to 10^–2 sec.     

Analysis of the Abraham-Minkowski Controversy by Means of Two Simple Examples

Using a very simple example, H. M. Lai [1] argued in favor of Abraham's proposal for defining electromagnetic field momentum density. Later, using another simple device, Johnson et al. [2] argued in favor of Minkowski's proposal. This indicates that the Abraham-Minkowski controversy remains open. Both models consider nonmagnetic media ( = 1). In this work we analyze both models pointing out some weak points and extend the analysis to magnetic media ( 1). We show that in this case Minkowski's proposal is better than Abraham's. Our analysis throws some light on this very old controversy.     

The soliton correlation matrix and the reduction problem for integrable systems

Integrable 1+1 dimensional systems associated to linear first-order matrix equations meromorphic in a complex parameter, as formulated by Zakharov, Mikhailov, and Shabat [1–3] (ZMS) are analyzed by a new method based upon the soliton correlation matrix (M-matrix). The multi-Bäcklund transformation, which is equivalent to the introduction of an arbitrary number of poles in the ZMS dressing matrix, is expressed by a pair of matrix Riccati equations for theM-matrix. Through a geometrical interpretation based upon group actions on Grassman manifolds, the solution of this system is explicitly determined in terms of the solutions to the ZMS linear system. Reductions of the system corresponding to invariance under finite groups of automorphisms are also solved by reducing theM-matrix suitably so as to preserve the class of invariant solutions.Supported in part by the Natural Sciences and Engineering Research Council of Canada and the Fonds FCAC pour l'aide et le soutien à la recherche     

The application of a raman-shifted tunable KrF excimer laser for laser-induced fluorescence combustion diagnostics

Four wavelength extensions have been investigated by stimulated Raman scattering in hydrogen or deuterium gas of the 248 nm fundamental output of a narrow-band tunable KrF excimer laser. They have been used to acquire laser-induced fluorescence spectra of NO and OH in flames at atmospheric pressure. NO is detected in relatively high rotational states within the -band electronic system at 225 nm. OH was excited at 291.5 nm in the (1–0), at 313 nm in the (1–1) and at 268.5 nm in the predissociative (3–1) band of the ²–² electronic band system, respectively. Prospects of 2D imaging for concentration and temperature measurements in flames using these wavelength extensions are discussed.     

Thermodynamics of a 1—d fermion system by cluster expansions

The thermodynamics of a 1—d fermion system can be perfectly mapped onto the thermodynamics of a two-component classical real gas on the surface of a cylinder. The latter system is studied by a modified Mayer cluster expansion method (Debye-Hückel theory and corrections to it). Simple reinterpretation of thermodynamic variables then leads to an exponentially activated behavior of the fermions' specific heat (spin density contribution). The exponent in Luther's recent gap formula is obtained as well as Zittartz's structure of the ground state energy. The method is applied to the case of strongly attractive spin-non-flip coupling (–1< <–3/5) when the spin-flip coupling is small. For large there is a gap everywhere.Abbreviated version of the author'sHabilitationsschrift     

The theory of a rotating plasma in crossed electric and magnetic fields

The paper presents an analysis of the behaviour of a weakly ionized gas confined by cylindrical electrodes and dielectric fronts. An ionized gas is put into a rotational movement by transverse electric and longitudinal magnetic fields. Quantities describing a plasma in the stationary state have been obtained by solving a system of macroscopic equations. Some of them are compared with experimental data.I would like to express my thanks to ing. L. ípek CSc for providing me with the experimental data obtained with the device BXE1. My thanks are also due to ing. V. Kopecký CSc for valuable comments.     

Study of the subsurface photorefractive effect in lithium niobate

A new phenomenon of a strong irreversible variation of the refractive index (n–0.2) in a skin layer (thickness 300 Å) has been discovered. The effect arises under the strong absorption of high-power uv radiation (249 nm, 5 ns, 20 MW/cm²). The characteristics of the subsurface photorefractive effect (SPRE) were identified by using the data on measurements of the reflection coefficient of a crystal and of the diffraction efficiency of a recorded phase grating.     

On the indistinguishability of classical particles

If no property of a system of many particles discriminates among the particles, they are said to be indistinguishable. This indistinguishability is equivalent to the requirement that the many-particle distribution function and all of the dynamic functions for the system be symmetric. The indistinguishability defined in terms of the discrete symmetry of many-particle functions cannot change in the continuous classical statistical limit in which the number density n and the reciprocal temperature become small. Thus, microscopic particles like electrons must remain indistinguishable in the classical statistical limit although their behavior can be calculated as if they move following the classical laws of motion. In the classical mechanical limit in which quantum cells of volume (2)³ are reduced to points in the phase space, the partition functionTr{exp(–) for N identical bosons (fermions) approaches (2)^–3N(N!) ... d³r₁ d³p₁ ... d³r_N d³p_N exp(–H). The two factors, (2)^–3N and (N!)^–1, which are often added in anad hoc manner in many books on statistical mechanics, are thus derived from the first principles. The criterion of the classical statistical approximation is that the thermal de Broglie wavelength be much shorter than the interparticle distance irrespective of any translation-invariant interparticle interaction. A new derivation of the Maxwell velocity distribution from Boltzmann's principle is given with the assumption of indistinguishable classical particles.     

Nanoscale observations of the operational failure for phase-change-type nonvolatile memory devices using Ge2Sb2Te5 chalcogenide thin films

In this study, a phase-change memory device was fabricated and the origin of device failure mode was examined using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Ge₂Sb₂Te₅ (GST) was used as the active phase-change material in the memory device and the active pore size was designed to be 0.5 m. After the programming signals of more than 2×10⁶ cycles were repeatedly applied to the device, the high-resistance memory state (reset) could not be rewritten and the cell resistance was fixed at the low-resistance state (set). Based on TEM and EDS studies, Sb excess and Ge deficiency in the device operating region had a strong effect on device reliability, especially under endurance-demanding conditions. An abnormal segregation and oxidation of Ge also was observed in the region between the device operating and inactive peripheral regions. To guarantee an data endurability of more than 1×10¹⁰ cycles of PRAM, it is very important to develop phase-change materials with more stable compositions and to reduce the current required for programming.     

Faux-boolean algebras,classical probability,and determinism

It is possible to define, for any quantum system, an algebra of definite-valued events—those events that are definitely occurrent or non-occurrent. It is shown that two different sets of constraints on the algebra of definite-valued events are each equivalent to the definition of that set as a certain pseudo-Boolean algebra.     

Organic light-emitting diodes with improved hole-electron balance by using molecular layers of phthalocyanine to modify the anode surface

By using the Langmuir–Blodgett (LB) technique, well-defined molecular layers of 2,9,16-tri(tert-butyl)-23-(10-hydroxydecyloxy)phthalocyanine were fabricated. These LB films have been employed to modify an anode surface of organic light-emitting devices. The insertion of LB films between an indium tin oxide (ITO) and hole-transport layers leads to an increase in device efficiency as a result of an improvement of the balanced carrier injection. An external quantum efficiency of 0.88% and a brightness of 10840 cd/m² for a device with a structure of ITO/two LB layers/N,N-diphenyl-N,N-bis(3-methylphenyl)-1,1-biphenyl-4,4-diamine (TPD)/tris(8-hydroquinolinato)aluminium (Alq₃)/Al were obtained, while the external quantum efficiency and brightness for the device without LB layers of ITO/TPD/Alq₃/Al were 0.51% and 5744 cd/m², respectively. PACS 68.47.Pe; 78.60.Fi; 85.60.Jb     

Bounded Fluctuations and Translation Symmetry Breaking: A Solvable Model

The variance of the particle number (equivalently the total charge) in a domain of length of a one-component plasma (OCP) on a cylinder of circumference W at the reciprocal temperature =2, is shown to remain bounded as . This exactly solvable system with average density has a density profile which is periodic with period (W)^–1 along the axis of the infinitely long cylinder. This illustrates the connection between bounded variance and periodicity in (quasi) one-dimensional systems.⁽¹⁾ When W the system approaches the two-dimensional OCP and the variance in a domain grows like its perimeter ||. In this limit, the system is translation invariant with rapid decay of correlations.     

Design and Fabrication of Silcon Microlens with Low SAG for 528(H) × 528(V) Infrared Charge-Coupled Device Application

Microlens array is an important optical element to improve the photosensitivity of charge-coupled device (CCD). In this paper, a monolithic integration technology between microlens and 528 × 528 element PtSi Schottky-barrier infrared charge-coupled device (IRCCD) with a pixel size of 30m × 30m has been developed. The microlens array with low sag and long focal length is designed based on geometrical optics theory. It is directly formed on the back side of the substrate in IRCCD chip using successive photolithography and A⁺ ion beam etching (IBE) technology. The microlens array is characterized by both surface stylus and point spread function (PSF). The experiment results of integration device between IRCCD and microlens array indicate that the optical signal response is improved obviously and a responsivity increase by a factor of 1.8 in the operation band.     

Another Return of “Return to Equilibrium”

The property of return to equilibrium is established for a class of quantum-mechanical models describing interactions of a (toy) atom with black-body radiation, or of a spin with a heat bath of scalar bosons, under the assumption that the interaction strength is sufficiently weak. For models describing the first class of systems, our upper bound on the interaction strength is independent of the temperature T, (with 0<TT₀<), while, for the spin-boson model, it tends to zero logarithmically, as T0. Our result holds for interaction form factors with physically realistic infrared behaviour. Three key ingredients of our analysis are: a suitable concrete form of the Araki-Woods representation of the radiation field, Mourres positive commutator method combined with a recent virial theorem, and a norm bound on the difference between the equilibrium states of the interacting and the non-interacting system (which, for the system of an atom coupled to black-body radiation, is valid for all temperatures T0, assuming only that the interaction strength is sufficiently weak).Acknowledgements We thank V. Bach and I.M. Sigal for countless discussions on related problems and spectral methods without which this work would never have been done. M.M. is grateful to V. Jaksi for illuminating discussions. We have enjoyed the hospitality of IHES during the initial and final stages of this work.     

Study of the Excitation Conditions and Characteristics of Ionospheric Plasma Turbulence at the Development Stage of the Ponderomotive Parametric Instability

We present the results of studying the development features of nonlinear effects at the initial stage of interaction of powerful HF radio waves with the plasma in the ionospheric F region. Experimental measurements were performed at the Sura heating facility for a wide pump frequency range (4.5–9.0 MHz) and a variety of pulse durations (0.3–100 ms) and effective radiated powers (1–30 MW) at various times of a day. The performed measurements allow us to study the excitation thresholds and time–amplitude characteristics of the ponderomotive self-action of a pump wave as well as the relaxation characteristics of the stimulated electromagnetic emission of the ionosphere as functions of the pump parameters and ionospheric conditions. The measured development features of the ponderomotive parametric instability in the ionospheric plasma are compared with the calculation results. The instability threshold fields (E_th 220 mV/m) and the damping rates (_e 450 s^-1) of plasma waves, measured under evening-time conditions, are close to the estimates obtained on the assumption of collisional damping of Langmuir turbulence. A significant increase in the threshold field and the damping rate (by factors of up to 3 and 6, respectively) was observed under daytime conditions. In this case, the minimum values of these quantities (E_th 350 mV/m and _e 600 s^-1) were observed for pump-wave reflection heights of about z 230 km. The measurement and simulation results are indicative of the dominant effect of photoelectrons on the development features of ionospheric plasma turbulence under daytime conditions. We discuss the possibilities of using the developed method for comprehensive monitoring of the parameters of Langmuir turbulence and the background ionospheric plasma.     

Calculation of Systematic Errors in Determining Light‐Scattering Matrix Elements

We consider systematic errors in determining lightscattering matrix elements by a device in which the polarization properties of probing radiation change depending on different angular positionings of the principal directions of the first phase plate, and we perform polarization analysis of scattered radiation using the Fourier expansion of the signal from a photodetector that records the intensity of radiation passed through the rotating second phase plate and a stationary analyzer. Formulas estimating the errors arising in separate deviation of the axes of the anisotropic optical elements in the illuminating and lightreceiving channels of the measuring device were derived. Using the method of mathematical simulation, we consider the combined influence of various inaccuracies in positioning anisotropic elements.     

An Electrodischarge Source of Ultraviolet Radiation on Chlorine Molecules

We investigated the characteristics of a transverse glowing discharge and of a volume discharge in a system of sphereplane electrodes in chlorine of low pressure (P = 40–160 Pa). The formation of a single plasma domain has been revealed. It is a selective source of UV radiation at electronicvibrational transitions of the chlorine molecule. Due to the development of the discharge plasma instability in chlorine, the radiation of the plasma is represented in the form of pulses with a repetition rate f = 1–50 kHz on increase in the mean discharge current from 2 to 50 mA. For this range of discharge currents, the dependence of the brightness of the radiation bands for molecular chlorine with = 200 and 257 nm has a character which increases with the current. The plasma of the chlorinebased domain can be used in a source of shortwave radiation source having no quartz discharge tube (or any other tube transparent in the UV–VUV range of wavelengths) which contracts the plasma and needs cooling and when in the source of the lamp pumping there are no commutators (thyratrons, tacitrons, or spark gaps).     

A total internal reflection device using KTN

A total internal reflection diffraction device has been constructed using a quadratic electro-optic material (KTN). This device exhibits a best zero order extinction voltage of 40 V, and a capacitance of 630 pf at room temperature (20° C above Curie temperature). Useful modulation is achieved with coarse gratings (0.4 mm pitch at 0.63m) and mildly striated material can often be used.     

The electronic structure of Rhodium: Angle-resolved studies of photoelectron and secondary electron emission

We report electron spectroscopic studies of the Rh(111) surface, with the aim to obtain bulk band-structure information. We have measured normal photoemision using tunable synchrotron radiation in the range of photon energies between 11 eV and 55 eV, and angle-dependent photoemission along the LUX and LKL azimuths using the He resonance lines (=21.2 eV, 40.8 eV). To complement these data, we studied angleresolved secondary electron emission after excitation with electrons and photons. We derive parts of the one-electron energy dispersionE(k) along L, and determine the energies of several bulk critical points (in eV):E(> ₇₊/₈₊)=–2.75±0.10,E(> ₈₊=–0.85±0.10,E(> _7–=16.1±0.5,E(> _6–/> _8–)=20.5±0.5,E(X ₇₊)=–5.0±0.1,E(L ₆₊)=–5.6±0.5,E(L ₆₊/L ₄₊₊₅₊)=–2.65±0.10,E(L ₆₊)=9.0±0.5 eV. Our results are compared to several available band structure calculations.