RENORMALIZATION OF HAMILTONIAN

2001 ◽  
Vol 16 (11) ◽  
pp. 1983-1988
Author(s):  
GARNIK G. ALEXANIAN ◽  
E. F. MORENO

In this talk we describe a novel method for the renormalization of the Hamiltonian operator in Quantum Field Theory in the spirit of the Wilson renormalization group1. By a series of unitary transformations that successively decouple the high-frequency degrees of freedom and partially diagonalizes the high-energy part, we obtain the effective Hamiltonian for the low energy degrees of freedom. Using this technique we study λϕ4 theory at two loops and QED and Yang-Mills theory at one loop.

Author(s):  
S. Likharev ◽  
A. Kramarenko ◽  
V. Vybornov

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.


2005 ◽  
Vol 878 ◽  
Author(s):  
J. Mass ◽  
M. Avella ◽  
J. Jiménez ◽  
M. Callahan ◽  
E. Grant ◽  
...  

AbstractLarge hydrothermal ZnO crystals were grown using 3N NaOH, 1N KOH and 0.5N Li2CO3mineralizer. The crystals were studied by cathodoluminescence (CL), showing a good crystalline quality. Different growth regions were identified by CL imaging. These regions were characterized by their corresponding luminescence spectra, showing that the incorporation of impurities and non radiative recombination centers depend on the growth sector. The surface is shown to introduce band tailing modifying the high energy part of the spectrum. The main spectral signatures of each sector are discussed.


1948 ◽  
Vol 74 (1) ◽  
pp. 102-103 ◽  
Author(s):  
S. Franchetti ◽  
M. Giovanozzi

2020 ◽  
Vol 128 (9) ◽  
pp. 1264
Author(s):  
К.Н. Болдырев ◽  
Д.Д. Гуценко ◽  
С.А. Климин ◽  
Н.Н. Новикова ◽  
Б.Н. Маврин ◽  
...  

Low-temperature infrared luminescence and high-resolution absorption spectra of undoped high-quality SiC single crystals of hexagonal modifications 4H and 6H were investigated. Narrow lines with widths less than 0.2 cm^(-1) were detected, several of which were observed for the first time. It was found that some of the lines in the 4H and 6H modifications have a similar structure, however, the lines in SiC-4H are shifted to the high-energy part of the spectrum by ~ 180 cm^(-1). For the most intense quartet in the region of 1.3 μm, the energy scheme of the levels for both 4H and 6H modifications were constructed.


1962 ◽  
Vol 40 (12) ◽  
pp. 1765-1771 ◽  
Author(s):  
Guy Paquette

A nonrelativistic calculation of the continuous gamma spectrum accompanying the capture of 1S orbital electrons in A37 is presented. The calculation takes into account the retardation effects in treating the electromagnetic interaction. A comparison with the relativistic calculation of Martin and Glauber (1958) shows that relativistic effects and screening corrections do not affect the high-energy part of the gamma spectrum. On the other hand, the retardation effects are important over the whole spectrum, except at the very lowest photon energies. The method employed in the calculation allows one to ascertain the relative importance of various intermediate states in their contribution to the spectrum intensity.


The object of this work was to obtain information about the shape of the low energy end of the continuous β-ray spectrum of radium E, an element convenient because of its negligible γ-ray emission. The failure of theory to explain the continuous spectrum makes it of interest to obtain all possible experimental information, and although much is now known about the high energy part of the curve, the low energy region has remained obscure owing to certain experimental difficulties. The chief of these has been the contamination of the low energy end of the curve by rays reflected with unknown energy loss from the material on which the radioactive body was deposited. This effect can be eliminated by mounting it on sufficiently thin metal leaf so that no particles can be reflected with appreciable loss of energy. Such a source would be too weak to use in a magnetic spectrograph, and the method therefore adopted in this work was out to mount it in a Wilson expansion chamber and take stereoscopic photographs from which the ranges of any slow tracks formed could be measured, a method already used by the writer for radium D.


Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 82 ◽  
Author(s):  
Amit Kashi

More luminous than classical novae, but less luminous than supernovae, lies the exotic stellar eruptions known as Intermediate luminosity optical transients (ILOTs). They are divided into a number of sub-groups depending on the erupting progenitor and the properties of the eruption. A large part of the ILOTs is positioned on the slanted Optical Transient Stripe (OTS) in the Energy-Time Diagram (ETD) that shows their total energy vs. duration of their eruption. We describe the different kinds of ILOTs that populate the OTS and other parts of the ETD. The high energy part of the OTS hosts the supernova impostors—giant eruptions (GE) of very massive stars. We show the results of the 3D hydrodynamical simulations of GEs that expose the mechanism behind these GEs and present new models for recent ILOTs. We discuss the connection between different kinds of ILOTs and suggest that they have a common energy source—gravitational energy released by mass transfer. We emphasize similarities between Planetary Nebulae (PNe) and ILOTs, and suggest that some PNe were formed in an ILOT event. Therefore, simulations used for GEs can be adapted for PNe, and used to learn about the influence of the ILOT events on the central star of the planetary nebula.


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