Horizon Formation in High-Energy Particles Collision

We investigate a classical formation of a trapped surface in 4-dimensional flat space-time in a process of a non-head-on collision of two high-energy particles which are treated as Aichelburg-Sexl shock waves. From the condition of the horizon volume local maximality an equation for the trapped surface is deduced. Using a known solution on the shocks we find a time-dependent solution describing the trapped surface between the shocks. We analyze the horizon appearance and evolution. Obtained results may describe qualitatively the horizon formation in higher dimensional space-time.Comment: Latex2e, 8 pages, 6 figures, references adde

Intensity distribution in rotational line spectra

Completely resolved Doppler-free rotational line spectra of six vibronic two-photon bands in benzene C6 H6 and C6 D6 are presented. The excited final states possess different excess energies in S1 (1567 to 2727 cm−1 ) and are embedded in dense manifolds of background states with differing densities of states (1<rho<60 1/cm−1 ). The bands are analyzed by a statistical procedure. The intensity distribution of several hundreds of lines of each band is investigated. It is found that all weakly perturbed bands display a similar, peaked intensity distribution while in strongly perturbed bands the number of lines decreases monotonically with increasing intensity. The origin of this difference is discussed in terms of coupling to the many background states. The Journal of Chemical Physics is copyrighted by The American Institute of Physics

Dicke Coherent Narrowing in Two-Photon and Raman Spectroscopy of Thin Vapour Cells

The principle of coherent Dicke narrowing in a thin vapour cell, in which sub-Doppler spectral lineshapes are observed under a normal irradiation for a l/2 thickness, is generalized to two-photon spectroscopy. Only the sum of the two wave vectors must be normal to the cell, making the two-photon scheme highly versatile. A comparison is provided between the Dicke narrowing with copropagating fields, and the residual Doppler-broadening occurring with counterpropagating geometries. The experimental feasibility is discussed on the basis of a first observation of a two-photon resonance in a 300 nm-thick Cs cell. Extension to the Raman situation is finally considered

Some solutions of linearized 5-d gravity with brane

We consider linearized 5-d gravity in the Randall-Sundrum brane world. The class of static solutions for linearized Einstein equations is found. Also we obtaine wave solutions describing radiation from an imaginary point source located at the Planck distance from the brane. We analyze the fields asymptotic behavior and peculiarities of matter sources.Comment: Latex, 8 page

Non-linear spectroscopy of rubidium: An undergraduate experiment

In this paper, we describe two complementary non-linear spectroscopy methods which both allow to achieve Doppler-free spectra of atomic gases. First, saturated absorption spectroscopy is used to investigate the structure of the $5{\rm S}_{1/2}\to 5{\rm P}_{3/2}$ transition in rubidium. Using a slightly modified experimental setup, Doppler-free two-photon absorption spectroscopy is then performed on the $5{\rm S}_{1/2}\to 5{\rm D}_{5/2}$ transition in rubidium, leading to accurate measurements of the hyperfine structure of the $5{\rm D}_{5/2}$ energy level. In addition, electric dipole selection rules of the two-photon transition are investigated, first by modifying the polarization of the excitation laser, and then by measuring two-photon absorption spectra when a magnetic field is applied close to the rubidium vapor. All experiments are performed with the same grating-feedback laser diode, providing an opportunity to compare different high resolution spectroscopy methods using a single experimental setup. Such experiments may acquaint students with quantum mechanics selection rules, atomic spectra and Zeeman effect.Comment: 16 pages, 8 figure

Brane Decay of a (4+n)-Dimensional Rotating Black Hole. II: spin-1 particles

The present works complements and expands a previous one, focused on the emission of scalar fields by a (4+n)-dimensional rotating black hole on the brane, by studying the emission of gauge fields on the brane from a similar black hole. A comprehensive analysis of the particle, energy and angular momentum emission rates is undertaken, for arbitrary angular momentum of the black hole and dimensionality of spacetime. Our analysis reveals the existence of a number of distinct features associated with the emission of spin-1 fields from a rotating black hole on the brane, such as the behaviour and magnitude of the different emission rates, the angular distribution of particles and energy, the relative enhancement compared to the scalar fields, and the magnitude of the superradiance effect. Apart from their theoretical interest, these features can comprise clear signatures of the emission of Hawking radiation from a brane-world black hole during its spin-down phase upon successful detection of this effect during an experiment.Comment: 35 pages, 19 figures, Latex fil

Determination of water content in clay and organic soil using microwave oven

The article deals with the techniques of soil water content determination using microwave radiation. Its practical application would allow solving the problems of resource efficiency in geotechnical survey due to reduction of energy and resource intensity of laboratory analysis as well as its acceleration by means of decreasing labour intensity and, as a result, cost reduction. The article presents a detail analysis of approaches to soil water content determination and soil drying, considers its features and application. The study in soil of different composition, typical for Western Siberia including organic and organic-mineral ones, is a peculiarity of the given article, which makes it rather topical. The article compares and analyzes the results of the investigation into soil water content, which are obtained via conventional techniques and the original one developed by the authors, consisting in microwave drying. The authors also give recommendation on microwave technique application to dry soil

The balance of «soul» and «body» categories in human consciousness as a catalyzer of social transformations (in the context of antique philosophical theories)

У статті розглянуто погляди філософів часів античності на такі категорії як «душа», «тіло» та «калокагатія» (як синтезуюче поняття гармонії протилежних філософських таборів). Шляхом аналізу авторами виявлено пряму залежність суспільних трансформацій від суб’єктивного сприйняття вищезазначених категорій та вирішення основного питання філософії. Встановлено, що дуалістична природа людини диктує чіткі правила, згідно яких суспільна свідомість, а разом із нею її розвиток, ґрунтуються на особистому рішенні стосовно балансу душевного та тілесного. Фундаментально протилежні феномени та точки зору поєднуються у синтезуючому понятті, яке зберігає конструктив кожного з вихідних понять та дає поштовх до подальшого розвитку думки; у даному випадку таким синтезуючим поняттям є гармонія. Калокагатія античного суспільства з точки зору сучасності залишається однією із основних причин невщухаючого інтересу до того часу, адже не тільки споконвічна недосяжність ідеалів, проте й постійні суспільні трансформації (серед яких – зміни в царині людських душі та тіла) спонукають людину до пошуку ідеальних форм та істинної гармонії.The article discusses the views of ancient philosophers on such categories as «soul», «body» and «kalokagathia» as a synthesizing concept of harmony of opposing philosophical camps. By the analysis authors discovered a direct correlation of social transformations from the subjective perception of the mentioned categories and the solution of the basic question of philosophy. It is established that the dualistic human nature dictates the precise rules by which the public consciousness and its development with it is based on the personal decision regarding the balance of mental and physical. The opposite phenomena and points of view are combined fundamentally in a synthesizing concept which saves that positive, that is in each of initial concepts and gives a shove to subsequent development of idea; in this case such synthesizing concept is harmony. Kalokagathia of ancient society from point of contemporaneity it remains one of principal reasons of interest to this period, in fact not only eternal inaccessibility of ideals but also permanent public transformations (among which – change in the spheres of the human soul and body) induce a man to the search of ideal forms and veritable harmony

Brane decay of a (4+n)-dimensional rotating black hole: spin-0 particles

In this work, we study the `scalar channel' of the emission of Hawking radiation from a (4+n)-dimensional, rotating black hole on the brane. We numerically solve both the radial and angular part of the equation of motion for the scalar field, and determine the exact values of the absorption probability and of the spheroidal harmonics, respectively. With these, we calculate the particle, energy and angular momentum emission rates, as well as the angular variation in the flux and power spectra -- a distinctive feature of emission during the spin-down phase of the life of the produced black hole. Our analysis is free from any approximations, with our results being valid for arbitrarily large values of the energy of the emitted particle, angular momentum of the black hole and dimensionality of spacetime. We finally compute the total emissivities for the number of particles, energy and angular momentum and compare their relative behaviour for different values of the parameters of the theory.Comment: 24 pages, 13 figure