scholarly journals Two-dimensional self-consistent quantum-corrected geometries with a constant dilaton field

1998 ◽  
Vol 424 (3-4) ◽  
pp. 271-274 ◽  
Author(s):  
O.B Zaslavskii
Keyword(s):  
Two Dimensional ◽  
Dilaton Field ◽  
Self Consistent ◽  
Constant Dilaton

CESIUM-INDUCED QUANTIZED 2D ELECTRON CHANNEL ON THE InAs(110) SURFACE

1995 ◽  
Vol 02 (06) ◽  
pp. 723-729 ◽  
Author(s):  
V. YU. ARISTOV ◽  
G. LE LAY ◽  
M. GREHK ◽  
V.M. ZHILIN ◽  
A. TALEB-IBRAHIMI ◽  
...  
Keyword(s):  
Electron Emission ◽  
Electronic States ◽  
Photoemission Spectroscopy ◽  
Spectral Features ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Discrete Energy ◽  
Electron Channel ◽  
Self Consistent ◽  
Electron Photoemission

We present the first clear evidence of electron emission arising directly from a quantized two-dimensional electron channel from the InAs (110) surface covered by a few Cs atoms (≈ 0.01 Cs ML). Spectral features observed by photoemission spectroscopy using synchrotron radiation reveal discrete-energy electronic states resulting from quantization in the direction normal to the surface. The electron photoemission originates from the vicinities of [Formula: see text] points in the first and second surface Brillouin zones corresponding to the bottom of the conduction band. These findings are in agreement with self-consistent theoretical energy-level calculations using a jellium-like model.

scholarly journals DIFFICULTIES OF AN INFRARED EXTENSION OF DIFFERENTIAL RENORMALIZATION

1994 ◽  
Vol 09 (07) ◽  
pp. 1067-1096 ◽  
Author(s):  
L. V. AVDEEV ◽  
D. I. KAZAKOV ◽  
I. N. KONDRASHUK
Keyword(s):  
Perturbation Theory ◽  
Fourier Transformation ◽  
Two Dimensions ◽  
Test Scheme ◽  
Two Dimensional ◽  
Differential Identities ◽  
Feynman Integrals ◽  
Differential Renormalization ◽  
Self Consistent ◽  
Infrared Singularities

We investigate the possibility of generalizing the differential renormalization of D. Z. Freedman, K. Johnson and J. I. Latorre in an invariant fashion to theories with infrared divergencies via an infrared [Formula: see text] operation. Two-dimensional σ models and the four-dimensional ɸ4-theory diagrams with exceptional momenta are used as examples, while dimensional renormalization serves as a test scheme for comparison. We write the basic differential identities of the method simultaneously in co-ordinate and momentum space, introducing two scales which remove ultraviolet and infrared singularities. A consistent set of Fourier-transformation formulae is derived. However, the values for tadpole-type Feynman integrals in higher orders of perturbation theory prove to be ambiguous, depending on the order of evaluation of the subgraphs. In two dimensions, even earlier than this ambiguity manifests itself, renormalization-group calculations based on the infrared extension of differential renormalization lead to incorrect results. We conclude that the procedure of extended differential renormalization does not perform the infrared [Formula: see text] operation in a self-consistent way.

UNIVERSAL PRANDTL NUMBER IN TWO-DIMENSIONAL KRAICHNAN-BATCHELOR TURBULENCE

2008 ◽  
Vol 22 (20) ◽  
pp. 3421-3431
Author(s):  
MALAY K. NANDY
Keyword(s):  
Prandtl Number ◽  
Mode Coupling ◽  
Perturbation Expansion ◽  
Dynamic Scaling ◽  
Two Dimensional ◽  
Turbulent Prandtl Number ◽  
Energy Regime ◽  
Self Consistent ◽  
Prandtl Numbers

We evaluate the universal turbulent Prandtl numbers in the energy and enstrophy régimes of the Kraichnan-Batchelor spectra of two-dimensional turbulence using a self-consistent mode-coupling formulation coming from a renormalized perturbation expansion coupled with dynamic scaling ideas. The turbulent Prandtl number is found to be exactly unity in the (logarithmic) enstrophy régime, where the theory is infrared marginal. In the energy régime, the theory being finite, we extract singularities coming from both ultraviolet and infrared ends by means of Laurent expansions about these poles. This yields the turbulent Prandtl number σ ≈ 0.9 in the energy régime.

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