The role of classical symmetries in the low-energy limit of superstring theories

This study explores the interior geometry of static relativistic charged spheres in the background of a recently proposed modified [Formula: see text] gravity, where [Formula: see text] and [Formula: see text] are the Gauss–Bonnet (GB) invariant and trace of energy–momentum tensor, respectively. The GB gravity is the low-energy limit of superstring theories. The structures of specific relativistic charged spheres Vela [Formula: see text], [Formula: see text], and [Formula: see text] are studied in this theory of gravity. We analyzed several physical behaviors of these relativistic charged spheres with the help of observational data and investigated the various aspects like density profile, stresses, the distribution of charges, stability, etc.

Download Full-text

Spin-exchange scattering cross sections for hydrogen atoms at low temperatures

Canadian Journal of Physics ◽

10.1139/p80-119 ◽

1980 ◽

Vol 58 (6) ◽

pp. 881-885 ◽

Cited By ~ 29

Author(s):

A. J. Berlinsky ◽

B. Shizgal

Keyword(s):

Cross Sections ◽

Low Temperatures ◽

Atomic Hydrogen ◽

Spin Exchange ◽

Low Energy ◽

Energy Limit ◽

Hydrogen Atoms ◽

Exchange Scattering ◽

Scattering Cross Sections

Calculations are presented of the low energy (0 < E ≤ 10−2 eV) spin exchange and frequency shift cross sections for (H,H) scattering, and of their thermal averages for 0 < T < 10 K. In particular, the behaviour of the cross sections in this low energy limit and the role of resonances due to orbiting collisions is studied in detail. A comparison is made with recent nmr measurements on gaseous atomic hydrogen at liquid helium temperatures. The results of this work suggest further useful experiments at low temperatures.

Download Full-text

On the low-energy limit of superstring theories

Nuclear Physics B ◽

10.1016/0550-3213(86)90396-2 ◽

1986 ◽

Vol 267 (2) ◽

pp. 365-414 ◽

Cited By ~ 240

Author(s):

J.P. Derendinger ◽

L.E. Ibañez ◽

H.P. Nilles

Keyword(s):

Low Energy ◽

Energy Limit ◽

Superstring Theories

Download Full-text

NEUTRINO MASSES IN SUPERSTRING THEORIES WITH INTERMEDIATE SCALES

International Journal of Modern Physics A ◽

10.1142/s0217751x88000904 ◽

1988 ◽

Vol 03 (09) ◽

pp. 2165-2173 ◽

Cited By ~ 5

Author(s):

UTPAL SARKAR ◽

ROBERT B. MANN

Keyword(s):

Low Energy ◽

Neutrino Masses ◽

Energy Limit ◽

Intermediate Mass ◽

Superstring Theories

Three generation superstring models require intermediate mass scales to be consistent with perturbative unification. We study the problem of neutrino masses in theories with intermediate mass scales which can evolve in the low energy limit of superstring theories.

Download Full-text

Influence of TOPO and TOPO-CdSe/ZnS Quantum Dots on Luminescence Photodynamics of InP/InAsP/InPHeterostructure Nanowires

Nanomaterials ◽

10.3390/nano11030640 ◽

2021 ◽

Vol 11 (3) ◽

pp. 640

Author(s):

Artem I. Khrebtov ◽

Vladimir V. Danilov ◽

Anastasia S. Kulagina ◽

Rodion R. Reznik ◽

Ivan D. Skurlov ◽

...

Keyword(s):

Quantum Dots ◽

Excited States ◽

Molecular Beam ◽

Surface Passivation ◽

Low Energy ◽

Trioctylphosphine Oxide ◽

Reverse Transfer ◽

Semiconductor Heterostructure ◽

Ligand Type

The passivation influence by ligands coverage with trioctylphosphine oxide (TOPO) and TOPO including colloidal CdSe/ZnS quantum dots (QDs) on optical properties of the semiconductor heterostructure, namely an array of InP nanowires (NWs) with InAsP nanoinsertion grown by Au-assisted molecular beam epitaxy on Si (111) substrates, was investigated. A significant dependence of the photoluminescence (PL) dynamics of the InAsP insertions on the ligand type was shown, which was associated with the changes in the excitation translation channels in the heterostructure. This change was caused by a different interaction of the ligand shells with the surface of InP NWs, which led to the formation of different interfacial low-energy states at the NW-ligand boundary, such as surface-localized antibonding orbitals and hybridized states that were energetically close to the radiating state and participate in the transfer of excitation. It was shown that the quenching of excited states associated with the capture of excitation to interfacial low-energy traps was compensated by the increasing role of the “reverse transfer” mechanism. As a result, the effectiveness of TOPO-CdSe/ZnS QDs as a novel surface passivation coating was demonstrated.

Download Full-text