NÖTHER’S SYMMETRIES IN (n+1)-DIMENSIONAL NONMINIMALLY COUPLED COSMOLOGIES

1993 ◽  
Vol 02 (04) ◽  
pp. 463-476 ◽  
Author(s):  
SALVATORE CAPOZZIELLO ◽  
RUGGIERO DE RITIS ◽  
PAOLO SCUDELLARO
Keyword(s):  
Scalar Field ◽  
General Solution ◽  
Effective Action ◽  
The Other ◽  
Spatial Curvature ◽  
General Transformation ◽  
Systematic Analysis ◽  
Induced Gravity ◽  
Constant Of Motion ◽  
Spatial Dimensions

We perform a systematic analysis of nonminimally coupled cosmologies in (n+1)-dimensional homogeneous and isotropic spacetimes, searching for Nöther’s symmetries and generalizing the results of our previous works. We obtain (i) the absence of symmetries when the spatial curvature constant k is nonzero and n=2, 3, but their existence for all the other n; (ii) the existence of such symmetries for every number of spatial dimensions (except n=1) when k=0. In this latter case, we are able to find a general transformation through which we recover the string-dilaton effective action in (n+1) dimensions and the major peculiarity of string cosmology: the scale factor duality. Furthermore, the symmetry fixes a relation among the coupling F(ϕ), the potential V(ϕ) of the scalar field ϕ, the number of spatial dimensions and the spatial curvature constant. When this is the case, it is possible to find a constant of motion and then get the general solution of the dynamics. Finally, in the framework of the so-called Induced Gravity Theories, we are able to obtain the Newton constant at the present time (t→∞) depending on the number of spatial dimensions and directly related to the constant of motion existing in such a model.

A Timeless, Boundless, Equilibrium Universe

1982 ◽  
Vol 4 (4) ◽  
pp. 482-483 ◽  
Author(s):  
Grote Reber
Keyword(s):  
Steady State ◽  
Relative Motion ◽  
Big Bang ◽  
The Other ◽  
Expanding Universe ◽  
Spatial Curvature ◽  
Doppler Shifts ◽  
Spatial Dimensions ◽  
State Models ◽  
The Universe

For more than half a century the theory that the universe is expanding has dominated cosmology. All current cosmological theories, from the various Big Bang models to the various Steady State models, explicitly assume an expanding universe. The evidence in favour of an expanding universe is purely circumstantial, and is based on a “sheer assumption”, (Hubble 1936a) that red-shifts in the light received by an observer on Earth from distant objects are caused by relative motion and hence may be interpreted as Doppler shifts. Hubble (1936b) continues: “…the ever expanding model … seems rather dubious”, and “On the other hand, if the recession factor is dropped, if red-shifts are not primarily velocity-shifts, the picture is simple and plausible. There is no evidence of expansion and no restriction of time-scale, no trace of spatial curvature and no limitations of spatial dimensions.” (Hubble 1936c). These statements are as true today as they were in 1936.

Admiration and Awe

2017 ◽  
Author(s):  
Antonio Urquízar-Herrera
Keyword(s):  
Early Modern ◽  
The Other ◽  
Cultural Hybridity ◽  
Early Modern Spain ◽  
Systematic Analysis ◽  
Historical Discourse ◽  
Ecclesiastical History ◽  
Bell Tower ◽  
Negotiation Of Identity ◽  
Historical Controversy

This book offers the first systematic analysis of the cultural and religious appropriation of Andalusian architecture by Spanish historians during the sixteenth and seventeenth centuries. Early Modern Spain was left with a significant Islamic heritage: Córdoba Mosque had been turned into a cathedral, in Seville the Aljama Mosque’s minaret was transformed into a Christian bell tower, and Granada Alhambra had become a Renaissance palace. To date this process of Christian appropriation has frequently been discussed as a phenomenon of hybridisation. However, during that period the construction of a Spanish national identity became a key focus of historical discourse. The aforementioned cultural hybridity encountered partial opposition from those seeking to establish cultural and religious homogeneity. The Iberian Peninsula’s Islamic past became a major concern and historical writing served as the site for a complex negotiation of identity. Historians and antiquarians used a range of strategies to re-appropriate the meaning of medieval Islamic heritage as befitted the new identity of Spain as a Catholic monarchy and empire. On one hand, the monuments’ Islamic origin was subjected to historical revisions and re-identified as Roman or Phoenician. On the other hand, religious forgeries were invented that staked claims for buildings and cities having been founded by Christians prior to the arrival of the Muslims in Spain. Islamic stones were used as core evidence in debates shaping the early development of archaeology, and they also became the centre of a historical controversy about the origin of Spain as a nation and its ecclesiastical history.

Lewis' Indexical Argument for World-Relative Actuality

Dialogue ◽  
1989 ◽  
Vol 28 (2) ◽  
pp. 289-304 ◽  
Author(s):  
Richard M. Gale
Keyword(s):  
David Lewis ◽  
Cost Benefit ◽  
The Other ◽  
Abstract Entity ◽  
Modal Realism ◽  
Possible World ◽  
States Of Affairs ◽  
Systematic Analysis ◽  
Reductio Ad Absurdum ◽  
Critical Scrutiny

David Lewis has shocked the philosophical community with his original version of extreme modal realism according to which “every way that a world could possibly be is a way that some world is”. Logical Space is a plenitude of isolated physical worlds, each being the actualization of some way in which a world could be, that bear neither spatiotemporal nor causal relations to each other. Lewis has given independent, converging arguments for this. One is the argument from the indexicality of actuality, the other an elaborate cost-benefit argument of the inference-to-the-best explanation sort to the effect that a systematic analysis of a number of concepts, including modality, causality, propositions and properties, fares better under his theory than under any rival one that takes a possible world to be either a linguistic entity or an ersatz abstract entity such as a maximal compossible set of properties, propositions or states of affairs. Lewis' legion of critics have confined themselves mostly to attempts at a reductio ad absurdum of his theory or to objections to his various analyses. The indexical argument, on the other hand, has not been subject to careful critical scrutiny. It is the purpose of this paper to show that this argument cannot withstand such scrutiny. Its demise, however, leaves untouched his argument from the explanatory superiority for his extreme modal realism.

scholarly journals Effective action for a quantum scalar field in warped spaces

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
J. M. Hoff da Silva ◽  
E. L. Mendonça ◽  
E. Scatena
Keyword(s):  
Scalar Field ◽  
Effective Action

scholarly journals Weak scale from Planck scale: Mass scale generation in a classically conformal two-scalar system

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Junichi Haruna ◽  
Hikaru Kawai
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Planck Scale ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
The Other ◽  
Expectation Value ◽  
Weak Scale ◽  
The Standard Model ◽  
The One

Abstract In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself cannot explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for some small corrections, the standard model has increased the possibility of being an effective theory up to the Planck scale. From these facts, it is naturally inferred that the weak scale is determined by some dynamics from the Planck scale. In order to answer this question, we rely on the multiple point criticality principle as a clue and consider the classically conformal $\mathbb{Z}_2\times \mathbb{Z}_2$ invariant two-scalar model as a minimal model in which the weak scale is generated dynamically from the Planck scale. This model contains only two real scalar fields and does not contain any fermions or gauge fields. In this model, due to a Coleman–Weinberg-like mechanism, the one-scalar field spontaneously breaks the $ \mathbb{Z}_2$ symmetry with a vacuum expectation value connected with the cutoff momentum. We investigate this using the one-loop effective potential, renormalization group and large-$N$ limit. We also investigate whether it is possible to reproduce the mass term and vacuum expectation value of the Higgs field by coupling this model with the standard model in the Higgs portal framework. In this case, the one-scalar field that does not break $\mathbb{Z}_2$ can be a candidate for dark matter and have a mass of about several TeV in appropriate parameters. On the other hand, the other scalar field breaks $\mathbb{Z}_2$ and has a mass of several tens of GeV. These results will be verifiable in near-future experiments.

scholarly journals Images of Europeans in the Chinese Woodblock Book Huangqing zhigongtu

2020 ◽  
Vol 65 (4) ◽  
pp. 1259-1271
Author(s):  
Nikolay A. Samoylov ◽  
◽  
Dmitriy I. Mayatskiy ◽  
Keyword(s):  
18Th Century ◽  
Geographical Location ◽  
The Other ◽  
Qing Empire ◽  
Cultural Stereotypes ◽  
Systematic Analysis ◽  
General Picture ◽  
The Qing Dynasty ◽  
Rich Material ◽  
Shed Light

This article explores the Chinese historical and ethnographic work of the second half of the 18th century “Illustrated tributaries of the Qing Empire” (“Huangqing zhigongtu”). This book provides rich material for a systematic analysis of the views of the Chinese about European countries during the reign of the Qing Dynasty (1644–1911). Twenty eight images and descriptions of a number of European nations — Russians, Poles, Hungarians, Swedes, the English, the Dutch, etc. — which were found in the book, have been identified, classified, and analyzed. A range of issues and problems related to the content of the descriptions has been established and compared with the illustrations from the book. The article pays particular attention to identifying and explaining the anthropological and socio-cultural stereotypes that shaped the image of Europeans in China. The authors of this paper have found out that due to Catholic missionaries the Chinese compilers of “Huangqing zhigongtu” must have had enough information about Europe in the first part of the Qing period. Nevertheless, they made a large number of mistakes when describing the geographical location of several nations and relations between some of them. They also misunderstood some habits, traditions or anthropological features of their inhabitants. On the other hand, the compilers were more accurate and precise with regard to political and trade activities of the Europeans in China or near its frontier. Studying the “Huangqing zhigongtu” can shed light not only on important factors that formed the general picture of the Chinese worldview, but also contribute to a better understanding of motives that determined the foreign policy of the Qing Empire.

Transfer Matrix Eigensolutions for Damped Torsional Systems

1985 ◽  
Vol 107 (1) ◽  
pp. 128-132 ◽  
Author(s):  
S. Doughty ◽  
G. Vafaee
Keyword(s):  
General Solution ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Solution Method ◽  
The Other ◽  
Torsional Vibrations

A transfer matrix method is presented for the determination of complex eigensolutions associated with the damped torsional vibrations of single shaft machine trains. The system is described and the natures of the eigenvalues are discussed. The general solution method is developed, and the method is applied to two example problems. One of the examples is quite simple, while the other is entirely realistic.

scholarly journals DECOHERENCE FUNCTIONAL AND INHOMOGENEITIES IN THE EARLY UNIVERSE

1993 ◽  
Vol 02 (02) ◽  
pp. 171-181 ◽  
Author(s):  
R. LAFLAMME ◽  
A. MATACZ
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Coarse Graining ◽  
The Other ◽  
Classical Transition ◽  
Decoherence Functional

We investigate the quantum to classical transition of small inhomogeneous fluctuations in the early Universe using the decoherence functional of Gell-Mann and Hartle. We study two types of coarse graining; one due to coarse graining the value of the scalar field and the other due to summing over an environment. We compare the results with a previous study using an environment and the off-diagonal rule proposed by Zurek. We show that the two methods give different results.

scholarly journals Wormholes in Wyman's solution

2014 ◽  
Vol 23 (11) ◽  
pp. 1450086 ◽  
Author(s):  
J. B. Formiga ◽  
T. S. Almeida
Keyword(s):  
Scalar Field ◽  
General Solution ◽  
Detailed Analysis ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Human Beings ◽  
Einstein Field Equations ◽  
Field Equations

The most general solution of the Einstein field equations coupled with a massless scalar field is known as Wyman's solution. This solution is also present in the Brans–Dicke theory and, due to its importance, it has been studied in detail by many authors. However, this solutions has not been studied from the perspective of a possible wormhole. In this paper, we perform a detailed analysis of this issue. It turns out that there is a wormhole. Although we prove that the so-called throat cannot be traversed by human beings, it can be traversed by particles and bodies that can last long enough.

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