skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Domain wall cosmology and multiple accelerations

Abstract

We classify the cosmological behaviors of the domain wall under junctions between two spacetimes in terms of various parameters: cosmological constants of bulk spacetime, a tension of a domain wall, and mass parameters of the black-hole-type metric. Especially, we consider the false-true vacuum-type junctions and the domain wall connecting between an inner AdS space and an outer AdS Reissner-Nordstroem black hole. We find that there exists a solution to the junction equations with multiple accelerations.

Authors:
 [1];  [2]; ; ;  [3]
  1. CQUeST, Sogang University, Seoul, Korea 121-742 (Korea, Republic of)
  2. (Korea, Republic of)
  3. CQUeST, Sogang University, Seoul, 121-742 (Korea, Republic of)
Publication Date:
OSTI Identifier:
20935249
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevD.75.103506; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCELERATION; ANTI DE SITTER SPACE; BLACK HOLES; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; COSMOLOGY; EQUATIONS; MASS; MATHEMATICAL SOLUTIONS; SPACE-TIME

Citation Formats

Lee, Bum-Hoon, Department of Physics, Sogang University, Seoul, 121-742, Lee, Wonwoo, Nam, Siyoung, and Park, Chanyong. Domain wall cosmology and multiple accelerations. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.103506.
Lee, Bum-Hoon, Department of Physics, Sogang University, Seoul, 121-742, Lee, Wonwoo, Nam, Siyoung, & Park, Chanyong. Domain wall cosmology and multiple accelerations. United States. doi:10.1103/PHYSREVD.75.103506.
Lee, Bum-Hoon, Department of Physics, Sogang University, Seoul, 121-742, Lee, Wonwoo, Nam, Siyoung, and Park, Chanyong. Tue . "Domain wall cosmology and multiple accelerations". United States. doi:10.1103/PHYSREVD.75.103506.
@article{osti_20935249,
title = {Domain wall cosmology and multiple accelerations},
author = {Lee, Bum-Hoon and Department of Physics, Sogang University, Seoul, 121-742 and Lee, Wonwoo and Nam, Siyoung and Park, Chanyong},
abstractNote = {We classify the cosmological behaviors of the domain wall under junctions between two spacetimes in terms of various parameters: cosmological constants of bulk spacetime, a tension of a domain wall, and mass parameters of the black-hole-type metric. Especially, we consider the false-true vacuum-type junctions and the domain wall connecting between an inner AdS space and an outer AdS Reissner-Nordstroem black hole. We find that there exists a solution to the junction equations with multiple accelerations.},
doi = {10.1103/PHYSREVD.75.103506},
journal = {Physical Review. D, Particles Fields},
number = 10,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Magnetic domain structures in the UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} compounds were studied using the powder pattern method. The domain structure observed is typical for uniaxial materials. The domain-wall energy density {gamma} was determined from the average surface domain width D{sub s} observed on surfaces perpendicular to the easy axis as equal to 16 erg/cm{sup 2} for UFe{sub 8}Ni{sub 2}Si{sub 2} and 10 erg/cm{sup 2} for UFe{sub 6}Ni{sub 4}Si{sub 2}. Moreover, the critical diameter for single domain particle D{sub c} was calculated for the studied compounds.
  • In magnetically coupled, planar ferromagnet-superconductor (F/ S) hybrid structures, magnetic domain walls can be used to spatially confine the superconductivity. In contrast to a superconductor in a uniform applied magnetic field, the nucleation of the superconducting order parameter in F/ S structures is governed by the inhomogeneous magnetic field distribution. The interplay between the superconductivity localized at the domain walls and far from the walls leads to effects such as re-entrant superconductivity and reverse domain superconductivity with the critical temperature depending upon the location. Here we use scanning tunneling spectroscopy to directly image the nucleation of superconductivity at the domainmore » wall in F/ S structures realized with Co-Pd multilayers and Pb thin films. Our results demonstrate that such F/ S structures are attractive model systems that offer the possibility to control the strength and the location of the superconducting nucleus by applying an external magnetic field, potentially useful to guide vortices for computing application.« less
  • We report the observation of standing wave modes in an array of stripe domains confined by a pair of parallel cracks in a Gd, Ga:YIG film. These modes appear in the response spectrum of the confined lattice as shallow minima or maxima at frequencies lower than that of the usual domain wall resonance peak. A simple model, analogous to the forced response of a membrane clamped at the edges, fits the spatial patterns of wall motion observed at the frequencies of the maxima and minima. Experimental frequency-wave vector values, interpreted with guidance from this analogy, provide the first experimental dispersionmore » curve for a stripe domain lattice. We compare this result with recent theoretical calculations. The experimental value of the uniform mode frequency is 41.5 +- 0.2 MHz, with a long wavelength group velocity of 330 +- 50 m/sec. A surprising conclusion from the observed extrema of the spatial patterns is that the damping of the waves is an order of magnitude less than expected from the damping of the uniform mode. The estimated decay length for a propagating wave is 400 ..mu...« less
  • Lorentz electron transmission microscopy investigations of the magnetization structure as a function of temperature (6 Kapprox.
  • An approach to image the domains and domain walls of small ferromagnetic entities using atomic force microscopy (AFM), with a nonmagnetic AFM probe, has been developed. Exciting the sample in an external ac magnetic field, the distribution of magnetostrictive response at the surface is detected. By this technique, the domains and domain walls of submicron Co dots have been imaged with a 1 nm lateral resolution. In elliptical Co dots with a 350-nm-long axis on a triangular lattice array with 400 nm periodicity, we find evidence for two domains with opposite magnetization orientation across a wall. The domain-wall width inmore » these dots is found to be about 35 nm. Furthermore, we observe a ferromagnetic alignment of the domains in the neighboring dots, which suggests a magnetostatic interaction among the dots. (c) 2000 American Institute of Physics.« less