201 research outputs found
From Topology to Generalised Dimensional Reduction
In the usual procedure for toroidal Kaluza-Klein reduction, all the
higher-dimensional fields are taken to be independent of the coordinates on the
internal space. It has recently been observed that a generalisation of this
procedure is possible, which gives rise to lower-dimensional ``massive''
supergravities. The generalised reduction involves allowing gauge potentials in
the higher dimension to have an additional linear dependence on the toroidal
coordinates. In this paper, we show that a much wider class of generalised
reductions is possible, in which higher-dimensional potentials have additional
terms involving differential forms on the internal manifold whose exterior
derivatives yield representatives of certain of its cohomology classes. We
consider various examples, including the generalised reduction of M-theory and
type II strings on K3, Calabi-Yau and 7-dimensional Joyce manifolds. The
resulting massive supergravities support domain-wall solutions that arise by
the vertical dimensional reduction of higher-dimensional solitonic p-branes and
intersecting p-branes.Comment: Latex, 24 pages, no figures, typo corrected, reference added and
discussion of duality extende
Euclidean-signature Supergravities, Dualities and Instantons
We study the Euclidean-signature supergravities that arise by compactifying
D=11 supergravity or type IIB supergravity on a torus that includes the time
direction. We show that the usual T-duality relation between type IIA and type
IIB supergravities compactified on a spatial circle no longer holds if the
reduction is performed on the time direction. Thus there are two inequivalent
Euclidean-signature nine-dimensional maximal supergravities. They become
equivalent upon further spatial compactification to D=8. We also show that
duality symmetries of Euclidean-signature supergravities allow the harmonic
functions of any single-charge or multi-charge instanton to be rescaled and
shifted by constant factors. Combined with the usual diagonal dimensional
reduction and oxidation procedures, this allows us to use the duality
symmetries to map any single-charge or multi-charge p-brane soliton, or any
intersection, into its near-horizon regime. Similar transformations can also be
made on non-extremal p-branes. We also study the structures of duality
multiplets of instanton and (D-3)-brane solutions.Comment: Latex, 50 pages, typos corrected and references adde
English Slogans on Clothing: Linguistic Distinctiveness and Pragmatic Functions
A semantic analysis of inscriptions on T-shirts (slogans) as elements of everyday discourse is provided in the article. Attention is paid to slogans that convey meanings significant in youth communication. The scientific novelty of the presented work lies in the fact that for the first time the features of slogans placed on clothes are revealed, their content, pragmatic functions and lexical-semantic features, as well as the correlation of slogans with the linguistic personality of the owner of a T-shirt with an inscription are considered. The author revealed that the basic pragmatic functions of slogans are self-presentation, appeal and shocking. Each of these functions has a number of sub-functions. Self-presentation is the leading pragmatic function. It has been proved that slogans are important components of the modern socio-cultural environment, integral elements of the communication process, verbal markers of the peculiarities of a linguistic personality. The key features of the linguistic personality of a young man who implements communication through a slogan on clothes are openness to social contacts, demonstration of personal qualities, attitude towards others and towards society as a whole, social activity, dedication, unconventional worldview, innovative thinking
U-duality as General Coordinate Transformations, and Spacetime Geometry
We show that the full global symmetry groups of all the D-dimensional maximal
supergravities can be described in terms of the closure of the internal general
coordinate transformations of the toroidal compactifications of D=11
supergravity and of type IIB supergravity, with type IIA/IIB T-duality
providing an intertwining between the two pictures. At the quantum level, the
part of the U-duality group that corresponds to the surviving discretised
internal general coordinate transformations in a given picture leaves the
internal torus invariant, while the part that is not described by internal
general coordinate transformations can have the effect of altering the size or
shape of the internal torus. For example, M-theory compactified on a large
torus T^n can be related by duality to a compactification on a small torus, if
and only if n\ge 3. We also discuss related issues in the toroidal
compactification of the self-dual string to D=4. An appendix includes the
complete results for the toroidal reduction of the bosonic sector of type IIB
supergravity to arbitrary dimensions D\ge3.Comment: Latex, 28 page
Structural Features of Metaphors in English Aphorisms within Philosophical Discourse
Structural analysis of aphorisms in philosophical discourse is conducted using a semantic-cognitive approach. The study focuses on aphorisms from Francis Bacon’s treatise “Novum Organum”. The objects, purposes, and bases of metaphorization are identified and classified, revealing phenomena that are objectified through metaphors and denote key areas of conceptualization in Bacon’s linguistic worldview. It is determined that the objects, sources, and bases of metaphorization are highly differentiated, highlighting personifications of the human image in Bacon’s linguistic worldview: the thinking, spiritual, social, and emotional aspects of humans. The majority of objects are anthropomorphic phenomena, including categories of moral order, age characteristics, intellectual abilities, and attributes of social interaction. The sources of metaphors touch upon the social role of humans, their physio-logical sensations from interacting with the environment, and demonstrate the empirical nature of the author’s linguistic personality. Among the sources of metaphors, the most representative group consists of naturalistic images. Francis Bacon refers to natural phenomena and objects as tools for creating complex philosophical concepts
Harmonic superpositions of non-extremal p-branes
The plot of allowed p and D values for p-brane solitons in D-dimensional
supergravity is the same whether the solitons are extremal or non-extremal. One
of the useful tools for relating different points on the plot is vertical
dimensional reduction, which is possible if periodic arrays of p-brane solitons
can be constructed. This is straightforward for extremal p-branes, since the
no-force condition allows arbitrary multi-centre solutions to be constructed in
terms of a general harmonic function on the transverse space. This has also
been shown to be possible in the special case of non-extremal black holes in
D=4 arrayed along an axis. In this paper, we extend previous results to include
multi-scalar black holes, and dyonic black holes. We also consider their
oxidation to higher dimensions, and we discuss general procedures for
constructing the solutions, and studying their symmetries.Comment: Latex, 23 page
Direct amplitude-phase near-field observation of higher-order anapole states
Anapole states associated with the resonant suppression of electric-dipole
scattering exhibit minimized extinction and maximized storage of
electromagnetic energy inside a particle. Using numerical simulations, optical
extinction spectroscopy and amplitude-phase near-field mapping of silicon
dielectric disks, we demonstrate high-order anapole states in the near-infrared
wavelength range (900-1700 nm). We develop the procedure for unambiguously
identifying anapole states by monitoring the normal component of the electric
near-field and experimentally detect the first two anapole states as verified
by far-field extinction spectroscopy and confirmed with the numerical
simulations. We demonstrate that higher order anapole states possess stronger
energy concentration and narrower resonances, a remarkable feature that is
advantageous for their applications in metasurfaces and nanophotonics
components, such as non-linear higher-harmonic generators and nanoscale lasers
- …