343 research outputs found
Spin 3 cubic vertices in a frame-like formalism
Till now most of the results on interaction vertices for massless higher spin
fields were obtained in a metric-like formalism using completely symmetric
(spin-)tensors. In this, the Lagrangians turn out to be very complicated and
the main reason is that the higher the spin one want to consider the more
derivatives one has to introduce. In this paper we show that such
investigations can be greatly simplified if one works in a frame-like
formalism. As an illustration we consider massless spin 3 particle and
reconstruct a number of vertices describing its interactions with lower spin 2,
1 and 0 ones. In all cases considered we give explicit expressions for the
Lagrangians and gauge transformations and check that the algebra of gauge
transformations is indeed closed.Comment: 17 pades, no figure
Canonical differential geometry of string backgrounds
String backgrounds and D-branes do not possess the structure of Lorentzian
manifolds, but that of manifolds with area metric. Area metric geometry is a
true generalization of metric geometry, which in particular may accommodate a
B-field. While an area metric does not determine a connection, we identify the
appropriate differential geometric structure which is of relevance for the
minimal surface equation in such a generalized geometry. In particular the
notion of a derivative action of areas on areas emerges naturally. Area metric
geometry provides new tools in differential geometry, which promise to play a
role in the description of gravitational dynamics on D-branes.Comment: 20 pages, no figures, improved journal versio
Youth mobilities, crisis, and agency in Greece: second generation lives in liminal spaces and austere times
This paper explores various dimensions of “mobility” and “agency” among second-generation immigrants in Greece who have experienced the economic crisis throughout their studies at Higher Education Institutions. Following their studies in Greece, second-generation youth migrants graduated at a time when the crisis had already been leading hundreds of thousands of mostly highly skilled Greeks to emigration, resulting in a severe “brain drain” for Greece. First-generation immigrants’ investment in their children’s education has been vital as an integration strategy and as a means of achieving social mobility. It has also been an asset during crisis times when the prospect of re-migration seems more than a possible option setting new challenges for youth mobility on a local, global, and transnational level. Nevertheless, the vast majority of our participants manifest their will to remain in Greece and struggle for their future in the host country. Through in-depth interviews with 130 participants, all second-generation Albanian, Bulgarian, and Romanian immigrants in Greece, 30 born in the host country and the rest in the country of origin, the paper addresses youth agency in relation to geographical mobility, education, and personal development
Higher spin interactions with scalar matter on constant curvature spacetimes: conserved current and cubic coupling generating functions
Cubic couplings between a complex scalar field and a tower of symmetric
tensor gauge fields of all ranks are investigated on any constant curvature
spacetime of dimension d>2. Following Noether's method, the gauge fields
interact with the scalar field via minimal coupling to the conserved currents.
A symmetric conserved current, bilinear in the scalar field and containing up
to r derivatives, is obtained for any rank r from its flat spacetime
counterpart in dimension d+1, via a radial dimensional reduction valid
precisely for the mass-square domain of unitarity in (anti) de Sitter spacetime
of dimension d. The infinite collection of conserved currents and cubic
vertices are summarized in a compact form by making use of generating functions
and of the Weyl/Wigner quantization on constant curvature spaces.Comment: 35+1 pages, v2: two references added, typos corrected, enlarged
discussions in Subsection 5.2 and in Conclusion, to appear in JHE
Higher-Spin Fermionic Gauge Fields and Their Electromagnetic Coupling
We study the electromagnetic coupling of massless higher-spin fermions in
flat space. Under the assumptions of locality and Poincare invariance, we
employ the BRST-BV cohomological methods to construct consistent
parity-preserving off-shell cubic 1-s-s vertices. Consistency and
non-triviality of the deformations not only rule out minimal coupling, but also
restrict the possible number of derivatives. Our findings are in complete
agreement with, but derived in a manner independent from, the
light-cone-formulation results of Metsaev and the string-theory-inspired
results of Sagnotti-Taronna. We prove that any gauge-algebra-preserving vertex
cannot deform the gauge transformations. We also show that in a local theory,
without additional dynamical higher-spin gauge fields, the non-abelian vertices
are eliminated by the lack of consistent second-order deformations.Comment: 44 pages; references added, minor changes made, to appear in JHE
Searching for stochastic gravitational-wave background with the co-located LIGO interferometers
This paper presents techniques developed by the LIGO Scientific Collaboration
to search for the stochastic gravitational-wave background using the co-located
pair of LIGO interferometers at Hanford, WA. We use correlations between
interferometers and environment monitoring instruments, as well as time-shifts
between two interferometers (described here for the first time) to identify
correlated noise from non-gravitational sources. We veto particularly noisy
frequency bands and assess the level of residual non-gravitational coupling
that exists in the surviving data.Comment: Proceedings paper from the 7th Edoardo Amaldi Conference on
Gravitational Waves, held in Sydney, Australia from 8-14 July 2007. Accepted
to J. Phys.: Conf. Se
Gauge Invariant Lagrangians for Free and Interacting Higher Spin Fields. A Review of the BRST formulation
We give a detailed review of the construction of gauge invariant Lagrangians
for free and interacting higher spin fields using the BRST approach developed
over the past few years.Comment: Extended version of the contribution to the volume dedicated to the
60th birthday of Prof I.L. Buchbinder; 58 pages. v2 References added, some
typos fixed, a couple of clarifications added. v3 To appear in International
journal of Modern Physics A (pubished version), some typos fixed, references
adde
Mixed-symmetry tensor conserved currents and AdS/CFT correspondence
We present the full list of conserved currents built of two massless spinor
fields in Minkowski space and their derivatives multiplied by Clifford algebra
elements. The currents have particular mixed-symmetry type described by Young
diagrams with one row and one column of arbitrary lengths and heights. Along
with Yukawa-like totally antisymmetric currents the complete set of constructed
currents exactly matches the spectrum of AdS mixed-symmetry fields arising in
the generalized Flato-Fronsdal theorem for two spinor singletons. As a
by-product, we formulate and study general properties of primary fields and
conserved currents of mixed-symmetry type.Comment: 17 pages; v2: typos corrected, clarifications and refs added; v3:
more explanations and refs added; contribution to the J.Phys.A special volume
on "Higher Spin Theories and AdS/CFT" edited by Matthias Gaberdiel and
Mikhail Vasilie
Topological Cigar and the c=1 String : Open and Closed
We clarify some aspects of the map between the c=1 string theory at self-dual
radius and the topologically twisted cigar at level one. We map the ZZ and FZZT
D-branes in the c=1 string theory at self dual radius to the localized and
extended branes in the topological theory on the cigar. We show that the open
string spectrum on the branes in the two theories are in correspondence with
each other, and their two point correlators are equal. We also find a
representation of an extended N=2 algebra on the worldsheet which incorporates
higher spin currents in terms of asymptotic variables on the cigar.Comment: 37 pages, 2 figures, corrections to section 3.1, references adde
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