Influence of doping on the electron spectrum of silicon

An energy difference of 1.0 eV has been found between the silicon 2p electron peaks in the electron spectra from heavily doped silicon of n- and p-     

Asymmetric polarity reversals, bimodal field distribution, and coherence resonance in a spherically symmetric mean-field dynamo model

Using a mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha which is algebraically quenched and disturbed by additional noise, the basic features of geomagnetic polarity reversals are shown to be generic consequences of the dynamo action in the vicinity of exceptional points of the spectrum. This simple paradigmatic model yields long periods of constant polarity which are interrupted by self-accelerating field decays leading to asymmetric polarity reversals. It shows the recently discovered bimodal field distribution, and it gives a natural explanation of the correlation between polarity persistence time and field strength. The dependence of the persistence time on the noise shows typical features of coherence resonance.     

Ballistic and localized transport for the atom optics kicked rotor in the limit of a vanishing kicking period

We present mean energy measurements for the atom optics kicked rotor as the kicking period tends to zero. A narrow resonance is observed marked by quadratic energy growth, in parallel with a complete freezing of the energy absorption away from the resonance peak. Both phenomena are explained by classical means, taking proper account of the atoms' initial momentum distribution.     

Generation of classical groups

Each finite simple group other thanU ₃(3) can be generated by three of its involutions. In fact, each such group is generated by two elements, of which one is strongly real and the other is an involution.The authors thank the MSRI in Berkeley, where this work was begun in Fall 1990, for its hospitality. The first and third author gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft.     

Some aspects of matrix interference caused by elements of low ionization potential in inductively coupled plasma atomic emission spectromctry

This paper deals with results of experiments performed with a 9 MHz free-running rf generator for producing an inductively coupled plasma (ICP) in argon. Samples were introduced as wet aerosols after nebulization with a concentric pneumatic nebulizer. The nett emission .signals of spectral lines emitted by Sr in the atomic as well as first ionized state were measured for volumes of plasma with projected square areas of 0.25 mm². These measurements were made while varying the observation height above the rf coil and the gas flow in the central nebulizer tube as well as adding Cs to a concentration level of 1000 μg ml^?1 to the samples.Ionic excitation temperatures were calculated and found not to be influenced by the presence of the Cs matrix. An interference induced by Cs causes an increase in both Sr atomic and ionic line intensities only in the so called preheating zone at the higher nebulizer gas flows and just above the rf coil.The Cs induced interference at these conditions results in an increase of the Sr ionic and atomic line intensity ratio, signifying a non-LTE process changing the relative population distribution of the Sr and Sr⁺ energy states.     

The influence of phase-modulation on femtosecond time-resolved coherent Raman spectroscopy

The influence of phase-modulation on femtosecond time-resolved coherent Raman scattering is investigated theoretically and experimentally. The coherent Raman signal taken as a function of the spectral position shows unexpected temporal oscillations close to time zero. A theoretical analysis of the coherent Raman scattering process indicates that the femtosecond light pulses are amplitude and phase modulated. The pulses are asymmetric in time with more slowly decaying trailing wings. The phase of the pulse amplitude contains quadratic and higher-order contributions.     

Exact solution of the master equation for the asymmetric exclusion process

Using the Bethe ansatz, we obtain the exact solution of the master equation for the totally asymmetric exclusion process on an infinite one-dimensional lattice. We derive explicit expressions for the conditional probabilitiesP(x₁,...,x_N;t/y ₁,...,y_N; 0) of findingN particles on lattices sitesx ₁,...,x_N at timet with initial occupationy ₁,...,y_N at timet=0.     

Covering groups of almost simple groups as Galois groups over ℚab(t)

In this paper we construct Galois extensions with the rigidity method and apply a criterion [15] for solving central embedding problems over ?^ab(t) to realize regularly the covering groups of most of the classical groups and the sporadic groups as Galois groups over ?^ab(t).     

Überp-auflösbare Gruppen mit genau zwei Defektgruppen

Ohne Zusammenfassung