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 DOMAIN WALLS IN AdS-EINSTEIN-SCALAR GRAVITY

2011 ◽  
Vol 26 (12) ◽  
pp. 2075-2085
Author(s):  
SANGHEON YUN
Keyword(s):  
Field Theory ◽  
Domain Wall ◽  
Dimensional Reduction ◽  
Domain Walls ◽  
Symmetric Domain ◽  
Einstein Gravity ◽  
Supergravity Theory ◽  
Small Fluctuation ◽  
Domain Wall Solution ◽  
Scalar Gravity

In this paper, we show that the supergravity theory which is dual to ABJM field theory can be consistently reduced to scalar-coupled AdS-Einstein gravity and then consider the reflection symmetric domain wall and its small fluctuation. It is also shown that this domain wall solution is none other than dimensional reduction of M2-brane configuration.

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 ULTRALIGHT SCALARS AND SPIRAL GALAXIES

2001 ◽  
Vol 16 (08) ◽  
pp. 513-530 ◽  
Author(s):  
GIA DVALI ◽  
GREGORY GABADADZE ◽  
M. SHIFMAN
Keyword(s):  
Scalar Field ◽  
Domain Wall ◽  
Wall Thickness ◽  
Domain Walls ◽  
Spiral Galaxies ◽  
Zero Mode ◽  
Scalar Particle ◽  
Additional Term ◽  
Massless Scalar ◽  
Logarithmic Term

We study some possible astrophysical implications of a very weakly coupled ultralight dilaton-type scalar field. Such a field may develop an (approximately stable) network of domain walls. The domain wall thickness is assumed to be comparable with the thickness of the luminous part of the spiral galaxies. The walls provide trapping for galactic matter. This is used to motivate the very existence of the spiral galaxies. A zero-mode existing on the domain wall is a massless scalar particle confined to (1+2) dimensions. At distances much larger than the galaxy/wall thickness, the zero-mode exchange generates a logarithmic potential, acting as an additional term with respect to Newton's gravity. The logarithmic term naturally leads to constant rotational velocities at the periphery. We estimate the scalar field coupling to the matter energy–momentum tensor needed to fit the observable flat rotational curves of the spiral galaxies. The value of this coupling turns out to be reasonable — we find no contradiction with the existing data.

On generalized geometric domain-wall models

2011 ◽  
Vol 141 (4) ◽  
pp. 881-895 ◽  
Author(s):  
Ruifeng Zhang ◽  
Xiaojing Wang
Keyword(s):  
Domain Wall ◽  
Cross Section ◽  
Domain Walls ◽  
Integrability Condition ◽  
Transition Process ◽  
Existence Theory ◽  
Domain Wall Solution ◽  
Wall Models ◽  
The Cross ◽  
Geometrically Constrained

We study domain walls that are topological solitons in one dimension. We present an existence theory for the solutions of the basic governing equations of some extended geometrically constrained domain-wall models. When the cross-section and potential density are both even, we establish the existence of an odd domain-wall solution realizing the phase-transition process between two adjacent domain phases. When the cross-section satisfies a certain integrability condition, we prove that a domain-wall solution always exists that links two arbitrarily designated domain phases.

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.

The need of electron microscopy in the study of domains and domain walls in ferroelectrics

1994 ◽  
Vol 52 ◽  
pp. 550-551
Author(s):  
Wenwu Cao
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
High Mobility ◽  
Continuum Theory ◽  
Polarization Vector ◽  
Ferroelectric Materials ◽  
Dielectric Constants ◽  
Nonlocal Coupling ◽  
Cubic Symmetry ◽  
Gradient Energy

Domain structures play a key role in determining the physical properties of ferroelectric materials. The formation of these ferroelectric domains and domain walls are determined by the intrinsic nonlinearity and the nonlocal coupling of the polarization. Analogous to soliton excitations, domain walls can have high mobility when the domain wall energy is high. The domain wall can be describes by a continuum theory owning to the long range nature of the dipole-dipole interactions in ferroelectrics. The simplest form for the Landau energy is the so called ϕ model which can be used to describe a second order phase transition from a cubic prototype,where Pi (i =1, 2, 3) are the components of polarization vector, α's are the linear and nonlinear dielectric constants. In order to take into account the nonlocal coupling, a gradient energy should be included, for cubic symmetry the gradient energy is given by,

scholarly journals Giant conductivity of mobile non-oxide domain walls

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. Ghara ◽  
K. Geirhos ◽  
L. Kuerten ◽  
P. Lunkenheimer ◽  
V. Tsurkan ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Domain Wall ◽  
Domain Walls ◽  
Building Blocks ◽  
External Fields ◽  
Tail Domain ◽  
Oxide Electronics ◽  
Domain Wall Mobility ◽  
Conductance Changes ◽  
Wall Mobility

AbstractAtomically sharp domain walls in ferroelectrics are considered as an ideal platform to realize easy-to-reconfigure nanoelectronic building blocks, created, manipulated and erased by external fields. However, conductive domain walls have been exclusively observed in oxides, where domain wall mobility and conductivity is largely influenced by stoichiometry and defects. Here, we report on giant conductivity of domain walls in the non-oxide ferroelectric GaV4S8. We observe conductive domain walls forming in zig-zagging structures, that are composed of head-to-head and tail-to-tail domain wall segments alternating on the nanoscale. Remarkably, both types of segments possess high conductivity, unimaginable in oxide ferroelectrics. These effectively 2D domain walls, dominating the 3D conductance, can be mobilized by magnetic fields, triggering abrupt conductance changes as large as eight orders of magnitude. These unique properties demonstrate that non-oxide ferroelectrics can be the source of novel phenomena beyond the realm of oxide electronics.

scholarly journals Subsystem domination influence on magnetization reversal in designed magnetic patterns in ferrimagnetic Tb/Co multilayers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Łukasz Frąckowiak ◽  
Feliks Stobiecki ◽  
Gabriel David Chaves-O’Flynn ◽  
Maciej Urbaniak ◽  
Marek Schmidt ◽  
...  
Keyword(s):  
Domain Wall ◽  
Magnetization Reversal ◽  
Domain Walls ◽  
Compensation Point ◽  
Relative Sign ◽  
Reversal Process ◽  
Effective Magnetization ◽  
Domain Wall Propagation ◽  
Characteristic Features ◽  
Magnetization Reversal Process

AbstractRecent results showed that the ferrimagnetic compensation point and other characteristic features of Tb/Co ferrimagnetic multilayers can be tailored by He+ ion bombardment. With appropriate choices of the He+ ion dose, we prepared two types of lattices composed of squares with either Tb or Co domination. The magnetization reversal of the first lattice is similar to that seen in ferromagnetic heterostructures consisting of areas with different switching fields. However, in the second lattice, the creation of domains without accompanying domain walls is possible. These domain patterns are particularly stable because they simultaneously lower the demagnetizing energy and the energy associated with the presence of domain walls (exchange and anisotropy). For both lattices, studies of magnetization reversal show that this process takes place by the propagation of the domain walls. If they are not present at the onset, the reversal starts from the nucleation of reversed domains and it is followed by domain wall propagation. The magnetization reversal process does not depend significantly on the relative sign of the effective magnetization in areas separated by domain walls.

scholarly journals Domain walls in 4d $$ \mathcal{N} $$ = 1 SYM

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Diego Delmastro ◽  
Jaume Gomis
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
Simons Theory ◽  
Partition Functions ◽  
Quantum Field Theories ◽  
Yang Mills ◽  
Stable Domain ◽  
Coxeter Number ◽  
Topological Quantum ◽  
Simply Connected

Abstract 4d$$ \mathcal{N} $$ N = 1 super Yang-Mills (SYM) with simply connected gauge group G has h gapped vacua arising from the spontaneously broken discrete R-symmetry, where h is the dual Coxeter number of G. Therefore, the theory admits stable domain walls interpolating between any two vacua, but it is a nonperturbative problem to determine the low energy theory on the domain wall. We put forward an explicit answer to this question for all the domain walls for G = SU(N), Sp(N), Spin(N) and G2, and for the minimal domain wall connecting neighboring vacua for arbitrary G. We propose that the domain wall theories support specific nontrivial topological quantum field theories (TQFTs), which include the Chern-Simons theory proposed long ago by Acharya-Vafa for SU(N). We provide nontrivial evidence for our proposals by exactly matching renormalization group invariant partition functions twisted by global symmetries of SYM computed in the ultraviolet with those computed in our proposed infrared TQFTs. A crucial element in this matching is constructing the Hilbert space of spin TQFTs, that is, theories that depend on the spin structure of spacetime and admit fermionic states — a subject we delve into in some detail.

scholarly journals Fibre-base duality of 5d KK theories

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Andreas P. Braun ◽  
Jin Chen ◽  
Babak Haghighat ◽  
Marcus Sperling ◽  
Shuhang Yang
Keyword(s):  
Field Theory ◽  
Field Theories ◽  
Quantum Field ◽  
Explicit Dependence ◽  
Superconformal Field Theories ◽  
Study Circle ◽  
Rank 2 ◽  
M Theory ◽  
Kaluza Klein ◽  
Theory Interpretation

Abstract We study circle compactifications of 6d superconformal field theories giving rise to 5d rank 1 and rank 2 Kaluza-Klein theories. We realise the resulting theories as M-theory compactifications on local Calabi-Yau 3-folds and match the prepotentials from geometry and field theory. One novelty in our approach is that we include explicit dependence on bare gauge couplings and mass parameters in the description which in turn leads to an accurate parametrisation of the prepotential including all parameters of the field theory. We find that the resulting geometries admit “fibre-base” duality which relates their six-dimensional origin with the purely five-dimensional quantum field theory interpretation. The fibre-base duality is realised simply by swapping base and fibre curves of compact surfaces in the local Calabi-Yau which can be viewed as the total space of the anti-canonical bundle over such surfaces. Our results show that such swappings precisely occur for surfaces with a zero self-intersection of the base curve and result in an exchange of the 6d and 5d pictures.

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