scholarly journals Domain walls and superpotentials from M-theory on Calabi–Yau three-folds

2000 ◽  
Vol 580 (1-2) ◽  
pp. 225-242 ◽  
Author(s):  
Klaus Behrndt ◽  
Sergei Gukov
Keyword(s):  
Domain Walls ◽  
M Theory

scholarly journals Domain Walls from M-Branes

1997 ◽  
Vol 12 (15) ◽  
pp. 1087-1094 ◽  
Author(s):  
H. Lü ◽  
C. N. Pope
Keyword(s):  
Domain Wall ◽  
Dimensional Reduction ◽  
Domain Walls ◽  
Additional Term ◽  
Cosmological Term ◽  
Domain Wall Solution ◽  
Toroidal Compactifications ◽  
Four Manifolds ◽  
M Theory ◽  
Kaluza Klein

We discuss the vertical dimensional reduction of M-sbranes to domain walls in D=7 and D=4, by dimensional reduction on Ricci-flat four-manifolds and seven-manifolds. In order to interpret the vertically-reduced five-brane as a domain wall solution of a dimensionally-reduced theory in D=7, it is necessary to generalize the usual Kaluza–Klein ansatz, so that the three-form potential in D=11 has an additional term that can generate the necessary cosmological term in D=7. We show how this can be done for general four-manifolds, extending previous results for toroidal compactifications. By contrast, no generalization of the Kaluza–Klein ansatz is necessary for the compactification of M-theory to a D=4 theory that admits the domain-wall solution coming from the membrane in D=11.

scholarly journals A correspondence between Ricci-flat Kerr and Kaluza-Klein AdS black hole

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Liang Ma ◽  
H. Lü
Keyword(s):  
Domain Walls ◽  
Einstein Gravity ◽  
Gravitational Instantons ◽  
Four Dimensions ◽  
Ricci Flat ◽  
Angular Momenta ◽  
Ads Black Holes ◽  
M Theory ◽  
Odd Dimensions ◽  
Kaluza Klein

Abstract We establish an explicit correspondence of Einstein gravity on the squashed spheres that are the U(1) bundles over ℂℙm to the Kaluza-Klein AdS gravity on the tori. This allows us to map the Ricci-flat Kerr metrics in odd dimensions with all equal angular momenta to charged Kaluza-Klein AdS black holes that can be lifted to become singly rotating M-branes and D3-branes. Furthermore, we find maps between Ricci-flat gravitational instantons to the AdS domain walls. In particular the supersymmetric bolt instantons correspond to domain walls that can be interpreted as distributed M-branes and D3-branes, whilst the non-supersymmetric Taub-NUT solutions yield new domain walls that can be lifted to become solutions in M-theory or type IIB supergravity. The correspondence also inspires us to obtain a new superpotential in the Kaluza-Klein AdS gravity in four dimensions.

scholarly journals Instanton cosmology and domain walls from M-theory and string theory

1999 ◽  
Vol 543 (1-2) ◽  
pp. 321-364 ◽  
Author(s):  
M.S. Bremer ◽  
M.J. Duff ◽  
H. Lü ◽  
C.N. Pope ◽  
K.S. Stelle
Keyword(s):  
String Theory ◽  
Domain Walls ◽  
M Theory

scholarly journals The Domain Walls of Gauged Maximal Supergravities and their M-theory Origin

2004 ◽  
Vol 2004 (07) ◽  
pp. 006-006 ◽  
Author(s):  
Eric Bergshoeff ◽  
Mikkel Nielsen ◽  
Diederik Roest
Keyword(s):  
Domain Walls ◽  
M Theory

scholarly journals Dynamical Cobordism and Swampland Distance Conjectures

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Ginevra Buratti ◽  
José Calderón-Infante ◽  
Matilda Delgado ◽  
Angel M. Uranga
Keyword(s):  
Moduli Space ◽  
Domain Walls ◽  
Scalar Fields ◽  
Recent Proposal ◽  
Run Off ◽  
Finite Distance ◽  
Scalar Potentials ◽  
M Theory ◽  
Space Distance ◽  
Finite Extent

Abstract We consider spacetime-dependent solutions to string theory models with tadpoles for dynamical fields, arising from non-trivial scalar potentials. The solutions have necessarily finite extent in spacetime, and are capped off by boundaries at a finite distance, in a dynamical realization of the Cobordism Conjecture. We show that as the configuration approaches these cobordism walls of nothing, the scalar fields run off to infinite distance in moduli space, allowing to explore the implications of the Swampland Distance Conjecture. We uncover new interesting scaling relations linking the moduli space distance and the SDC tower scale to spacetime geometric quantities, such as the distance to the wall and the scalar curvature. We show that walls at which scalars remain at finite distance in moduli space correspond to domain walls separating different (but cobordant) theories/vacua; this still applies even if the scalars reach finite distance singularities in moduli space, such as conifold points.We illustrate our ideas with explicit examples in massive IIA theory, M-theory on CY threefolds, and 10d non-supersymmetric strings. In 4d $$ \mathcal{N} $$ N = 1 theories, our framework reproduces a recent proposal to explore the SDC using 4d string-like solutions.

scholarly journals Single-sided domain walls in M-theory

2000 ◽  
Vol 32 (3) ◽  
pp. 311-340 ◽  
Author(s):  
G.W. Gibbons ◽  
P. Rychenkova
Keyword(s):  
Domain Walls ◽  
M Theory

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

Lorentz microscopy study of magnetic domain walls in Fe-Cr-Co alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 462-463
Author(s):  
Yalcin Belli
Keyword(s):  
Domain Walls ◽  
Magnetic Domain ◽  
Microscopy Study ◽  
Ferromagnetic Phase ◽  
Stable Phase ◽  
Magnetic Domains ◽  
Lorentz Microscopy ◽  
Magnetic Hardening ◽  
Electron Microscopes ◽  
Co Alloys

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

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