53 research outputs found
Freudenthal Duality and Generalized Special Geometry
Freudenthal duality, introduced in L. Borsten, D. Dahanayake, M. J. Duff and
W. Rubens, Phys.Rev. D80, 026003 (2009), and defined as an anti-involution on
the dyonic charge vector in d = 4 space-time dimensions for those dualities
admitting a quartic invariant, is proved to be a symmetry not only of the
classical Bekenstein-Hawking entropy but also of the critical points of the
black hole potential. Furthermore, Freudenthal duality is extended to any
generalized special geometry, thus encompassing all N > 2 supergravities, as
well as N = 2 generic special geometry, not necessarily having a coset space
structure.Comment: 1+9 pages; v2: some parts rewritten, Ref. added, to appear in PL
Two-Field Born-Infeld with Diverse Dualities
We elaborate on how to build, in a systematic fashion, two-field Abelian
extensions of the Born-Infeld Lagrangian. These models realize the non-trivial
duality groups that are allowed in this case, namely U(2), SU(2) and U(1)xU(1).
For each class, we also construct an explicit example. They all involve an
overall square root and reduce to the Born-Infeld model if the two fields are
identified, but differ in quartic and higher interactions. The U(1)xU(1) and
SU(2) examples recover some recent results obtained with different techniques,
and we show that the U(1)xU(1) model admits an N=1 supersymmetric completion.
The U(2) example includes some unusual terms that are not analytic at the
origin of field space.Comment: 30 pages. Final version with reference added, typo corrected and
comment added in the Conclusions. To appear in a special Nucl. Phys. B issue
dedicated to the memory of Raymond Stor
Majorana Fermions, Supersymmetry Breaking, and Born-Infeld Theory
This review is devoted to highlight some aspects of the relevance of Majorana
fermions in rigid supersymmetry breaking in four spacetime dimensions. After
introducing some basic facts on spinors, and on their symmetries and reality
properties, we consider Goldstino actions describing partial breaking of rigid
supersymmetry, then focussing on Born-Infeld non-linear theory, its duality
symmetry, and its supersymmetric extensions, also including multi-field
generalizations exhibiting doubly self-duality.Comment: 1+27 pages, 1 Table. Contribution to the Proceedings of the Erice
International School of Subnuclear Physics, 53rd Course : "The Future of Our
Physics Including New Frontiers", and Celebration of the Triumph of Ettore
Majorana, Erice, 24 June-3 July 2015. Dedicated to the memory of Guido
Altarell
Multi-Centered First Order Formalism
We propose a first order formalism for multi-centered black holes with flat
tree-dimensional base-space, within the stu model of N=2, D=4 ungauged
Maxwell-Einstein supergravity. This provides a unified description of first
order flows of this universal sector of all models with a symmetric scalar
manifold which can be obtained by dimensional reduction from five dimensions.
We develop a D=3 Cartesian formalism which suitably extends the definition of
central and matter charges, as well as of black hole effective potential and
first order "fake" superpotential, in order to deal with not necessarily
axisimmetric solutions, and thus with multi-centered and/or (under-)rotating
extremal black holes. We derive general first order flow equations for
composite non-BPS and almost BPS classes, and we analyze some of their
solutions, retrieving various single-centered (static or under-rotating) and
multi-centered known systems. As in the t^3 model, the almost BPS class turns
out to split into two general branches, and the well known almost BPS system is
shown to be a particular solution of the second branch.Comment: 1+22 pages; v2 : some typos fixes and Refs. adde
Supermembrane in D=5: component action
Based on the connection between partial breaking of global supersymmetry,
coset approach, which realized the given pattern of supersymmetry breaking, and
the Nambu-Goto actions for the extended objects, we have constructed on-shell
component action for N=1, D=5 supermembrane and its dual cousins. We
demonstrate that the proper choice of the components and the use of the
covariant (with respect to broken supersymmetry) derivatives drastically
simplify the action: it can be represented as a sum of four terms each having
an explicit geometric meaning.Comment: 14 pages, PACS: 11.30.Pb, 12.60.J
Attractors and first order formalism in five dimensions revisited
The attractor mechanism in five dimensional Einstein-Maxwell Chern-Simons
theory is studied. The expression of the five dimensional rotating black object
potential depending on Taub-NUT, electric and magnetic charges as well as on
all the scalar and gauge fields, is investigated. The first order formalism in
d=5 is constructed and analyzed. We derive a general expression defining the
fake superpotential which is valid for all charge configurations. An explicit
expression for the fake superpotential is constructed, for all very special
geometries, in the case of vanishing Taub-NUT charge. We carry out an analogous
construction in the very special geometries corresponding to and
models, for the most general charge configurations. The attractor flows and
horizon values of all fields are given.Comment: 33 pages, PACS numbers: 04.65.+e, 04.50.Gh, 04.70.Bw, 04.70.Dy,
keywords: five dimensional supergravity, black objects, entropy, attractor
flows, first order formalism, fake superpotential. Several typos corrected;
one reference added; section 6 (conclusions) expande
Generalized Born--Infeld Actions and Projective Cubic Curves
We investigate supersymmetric Born-Infeld Lagrangians with a
second non-linearly realized supersymmetry. The resulting non-linear structure
is more complex than the square root present in the standard Born-Infeld
action, and nonetheless the quadratic constraints determining these models can
be solved exactly in all cases containing three vector multiplets. The
corresponding models are classified by cubic holomorphic prepotentials. Their
symmetry structures are associated to projective cubic varieties.Comment: 17 pages, LaTeX, 1 eps figure. Comments added and misprints
corrected. Final version to appear in Fortschritte der Physik - Progress of
Physic
Noncommutative Coulombic Monopole
We have constructed the appropriate Hamiltonian of the noncommutative
coulombic monopole (i.e. the noncommutative hydrogen atom with a monopole). The
energy levels of this system have been calculated, discussed and compared with
the noncommutative hydrogen atom ones. The main emphasis is put on the ground
state. In addition, the Stark effect for the noncommutative coulombic monopole
has been studied.Comment: 5 pages, PACS numbers: 03.65.-w, 14.80.Hv, 02.40.Gh, 32.60.+
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