scholarly journals A TWO-DIMENSIONAL REPRESENTATION OF FOUR-DIMENSIONAL GRAVITATIONAL WAVES

1998 ◽  
Vol 07 (02) ◽  
pp. 215-223 ◽  
Author(s):  
HANS-JÜRGEN SCHMIDT
Keyword(s):  
Gravitational Waves ◽  
Scalar Fields ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Hidden Symmetries ◽  
Plane Symmetric ◽  
Four Dimensions ◽  
Birkhoff Theorem ◽  
Symmetric Spacetimes ◽  
Dimensional Spacetime

The Einstein equation in D dimensions, if restricted to the class of spacetimes possessing n = D - 2 commuting hypersurface-orthogonal Killing vectors, can be equivalently written as metric-dilaton gravity in two dimensions with n scalar fields. For n = 2, this result reduces to the known reduction of certain four-dimensional metrics which include gravitational waves. Here, we give such a representation which leads to a new proof of the Birkhoff theorem for plane-symmetric spacetimes, and which leads to an explanation, in which sense two (spin zero-) scalar fields in two dimensions may incorporate the (spin two-) gravitational waves in four dimensions. (This result should not be mixed up with well–known analogous statements where, however, the four-dimensional spacetime is supposed to be spherically symmetric, and then, of course, the equivalent two-dimensional picture cannot mimic any gravitational waves.) Finally, remarks on hidden symmetries in two dimensions are made.

scholarly journals Niemeier Lattices in the Free Fermionic Heterotic–String Formulation

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Panos Athanasopoulos ◽  
Alon E. Faraggi
Keyword(s):  
Two Dimensions ◽  
Heterotic String ◽  
Two Dimensional ◽  
Four Dimensions ◽  
Duality Symmetry ◽  
String Compactifications ◽  
Heterotic String Theories ◽  
The One ◽  
String Models ◽  
String Theories

The spinor–vector duality was discovered in free fermionic constructions of the heterotic string in four dimensions. It played a key role in the construction of heterotic–string models with an anomaly-free extra Z′ symmetry that may remain unbroken down to low energy scales. A generic signature of the low scale string derived Z′ model is via diphoton excess that may be within reach of the LHC. A fascinating possibility is that the spinor–vector duality symmetry is rooted in the structure of the heterotic–string compactifications to two dimensions. The two-dimensional heterotic–string theories are in turn related to the so-called moonshine symmetries that underlie the two-dimensional compactifications. In this paper, we embark on exploration of this connection by the free fermionic formulation to classify the symmetries of the two-dimensional heterotic–string theories. We use two complementary approaches in our classification. The first utilises a construction which is akin to the one used in the spinor–vector duality. Underlying this method is the triality property of SO(8) representations. In the second approach, we use the free fermionic tools to classify the twenty-four-dimensional Niemeier lattices.

Impact of Job Stress and Social Support on Job Satisfaction among Academic Staff

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Kumari Kumkum ◽  
R. N. Singh ◽  
Yogershi Rajpoot
Keyword(s):  
Social Support ◽  
Job Satisfaction ◽  
Job Stress ◽  
Positive Impact ◽  
Academic Staff ◽  
Two Dimensions ◽  
The Other ◽  
Human Beings ◽  
Negative Consequences ◽  
Four Dimensions

There may be so many negative consequences of stress for human beings and dissatisfaction among employees happens to be one of the major problems. It indicates negative feelings that individuals have regarding their jobs or its facets. On the other hand, social support is assumed to be mitigating the relationship between negative aspects of the work environment and job satisfaction. Job stress is said to be associated with job dissatisfaction as well as experience of strain. In view of the above, this study examined the role of job stress and social support in job satisfaction. The sample consisted of 30 school teachers from different school of Varanasi (U.P.). The job stress, job satisfaction and social support scales were administered on the participants. The responses of the participants were converted into scores for statistical analyses. The scores of participants on the scales were correlated. The findings revealed that job stress led to increased job satisfaction. It is against the proposed hypothesis and it appears as if the social support received by the participants is a factor behind it. Two of the four dimensions of social support were found to exert positive impact on job satisfaction but the other two dimensions were not found to be correlated with it. The findings are thoroughly discussed and interpreted.

Urbanicity, City Delegations, and Two-Dimensional Liberalism

2018 ◽  
Author(s):  
Thomas K. Ogorzalek
Keyword(s):  
National Level ◽  
Two Dimensions ◽  
Political Order ◽  
Two Dimensional ◽  
Local Institutions ◽  
Horizontal Integration ◽  
National Politics ◽  
United Front ◽  
Strategies For Success

This theoretical chapter develops the argument that the conditions of cities—large, densely populated, heterogeneous communities—generate distinctive governance demands supporting (1) market interventions and (2) group pluralism. Together, these positions constitute the two dimensions of progressive liberalism. Because of the nature of federalism, such policies are often best pursued at higher levels of government, which means that cities must present a united front in support of city-friendly politics. Such unity is far from assured on the national level, however, because of deep divisions between and within cities that undermine cohesive representation. Strategies for success are enhanced by local institutions of horizontal integration developed to address the governance demands of urbanicity, the effects of which are felt both locally and nationally in the development of cohesive city delegations and a unified urban political order capable of contending with other interests and geographical constituencies in national politics.

scholarly journals Interface Roughening in Two Dimensions

2021 ◽  
Vol 182 (3) ◽  
Author(s):  
Gernot Münster ◽  
Manuel Cañizares Guerrero
Keyword(s):  
Field Theory ◽  
Monte Carlo ◽  
Capillary Wave ◽  
System Size ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Wave Approximation ◽  
Statistical Field ◽  
Statistical Field Theory ◽  
Interface Roughening

AbstractRoughening of interfaces implies the divergence of the interface width w with the system size L. For two-dimensional systems the divergence of $$w^2$$ w 2 is linear in L. In the framework of a detailed capillary wave approximation and of statistical field theory we derive an expression for the asymptotic behaviour of $$w^2$$ w 2 , which differs from results in the literature. It is confirmed by Monte Carlo simulations.

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

scholarly journals Calderón problem for Maxwell's equations in two dimensions

2016 ◽  
Vol 24 (3) ◽  
Author(s):  
Oleg Y. Imanuvilov ◽  
Masahiro Yamamoto
Keyword(s):  
Maxwell’S Equations ◽  
Maxwell Equations ◽  
Maxwell's Equations ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Global Uniqueness ◽  
Calderón Problem ◽  
Dirichlet To Neumann Map

AbstractWe prove the global uniqueness in determination of the conductivity, the permeability and the permittivity of the two-dimensional Maxwell equations by the partial Dirichlet-to-Neumann map limited to an arbitrary subboundary.

Estimates of critical percolation probabilities for a set of two-dimensional lattices

1972 ◽  
Vol 71 (1) ◽  
pp. 97-106 ◽  
Author(s):  
D. G. Neal
Keyword(s):  
Monte Carlo ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Critical Percolation ◽  
Site Percolation

AbstractThis paper describes new detailed Monte Carlo investigations into bond and site percolation problems on the set of eleven regular and semi-regular (Archimedean) lattices in two dimensions.

scholarly journals On String Integrability: A Journey through the Two-Dimensional Hidden Symmetries in the AdS/CFT Dualities

2010 ◽  
Vol 2010 ◽  
pp. 1-133 ◽  
Author(s):  
Valentina Giangreco Marotta Puletti
Keyword(s):  
String Theory ◽  
Two Dimensional ◽  
Pure Spinor ◽  
Hidden Symmetries ◽  
Quantum Integrability ◽  
Conserved Charges ◽  
Phd Thesis

One of the main topics in the modern String Theory are the AdS/CFT dualities. Proving such conjectures is extremely difficult since the gauge and string theory perturbative regimes do not overlap. In this perspective, the discovery of infinitely many conserved charges, that is, the integrability, in the planar AdS/CFT has allowed us to reach immense progresses in understanding and confirming the duality. We review the fundamental concepts and properties of integrability in two-dimensionalσ-models and in the AdS/CFT context. The first part is focused on theAdS5/CFT4duality, especially the classical and quantum integrability of the type IIB superstring onAdS5×S5which is discussed in both pure spinor and Green-Schwarz formulations. The second part is dedicated to theAdS4/CFT3duality with particular attention to the type IIA superstring onAdS4×ℂP3and its integrability. This review is based on the author's PhD thesis discussed at Uppsala University the 21st September 2009.

Quantum fluctuations of the metric, three-geometries and conformal embeddings in four-manifolds

2021 ◽  
Author(s):  
Simon Davis
Keyword(s):  
Path Integrals ◽  
Invariance Group ◽  
Two Dimensional ◽  
Four Dimensions ◽  
Physical Conditions ◽  
Exponential Expansion ◽  
Cotangent Bundles ◽  
Four Manifolds ◽  
Conformal Embeddings ◽  
Natural Relation

In this paper, connections between the path integrals for four-dimensional quantum gravity and string theory are emphasized. It is shown that there is a natural relation between these two path integrals based on the theorems on embeddings of two-dimensional surfaces in four dimensions and four-dimensional manifolds in ten dimensions. The isometry groups of the three-geometries that are spatial hypersurfaces confomally embedded in the four-manifolds are required to be subgroups of [Formula: see text], which is the invariance group of the Pfaffian differential system satisfied by one form in the cotangent bundles on the four-manifolds. Based on this and other physical conditions, the three-geometries are restricted to be [Formula: see text], [Formula: see text] and [Formula: see text] with a boundary, which may be included in the quantum gravitational path integral over four-manifolds which are closed at initial times followed by an exponential expansion compatible with supersymmetry.

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