70,123 research outputs found
Topics in Supersymmetry Breaking and Gauge/Gravity Dualities
No full textThe thesis covers two topics in string theory and quantum field theory. First, we realize metastable vacua in various supersymmetric gauge theories. Specifically, we consider the Coulomb branch of any N = 2 supersymmetric gauge theory, and perturb it by a superpotential and engineer a metastable vacuum at a point. We also study its relation to Kahler normal coordinates and Fayet-Iliopoulos terms. Having studied the metastable construction, we apply this to general gauge mediation. We show how to compute the current correlators when the hidden sector is strongly coupled in specific examples.
Next, we consider gauge/gravity dualities. We apply dualities to the investigation of various strongly coupled field theories. In one example, we construct M-theory supergravity solutions with the nonrelativistic Schroedinger symmetry starting from the warped AdS_5 metric with N = 1 supersymmetry. We impose that the lightlike direction is compact by making it a nontrivial U(1) bundle over the compact space. In another example, we show that, in a gravity theory with a Chern-Simons coupling, the Reissner-Nordstrom black hole in anti-de Sitter space is unstable depending on the value of the Chern-Simons coupling. The analysis suggests that the final configuration is likely to be a spatially modulated phase.</p
"Methodology and Microeconomics in the Early Work of Hyman P. Minsky"
No full textThis paper reviews the recently published Ph.D. thesis of Hyman P. Minsky, summarizing its main contributions to methodology and microeconomics. These were aspects of economics with which Minsky is not usually associated, but which lie at the foundation of his later work. They include critical remarks on Cambridge economics. The paper then draws out some antecedents of Minsky's ideas in the work of Henry Simons, and highlights the Marshallian monetary analysis that he adopted.
Non-topological condensates for the self-dual Chern-Simons-Higgs model
No full textFor the abelian self-dual Chern-Simons-Higgs model we address existence issues of periodic vortex configurations -- the so-called condensates-- of non-topological type as , where is the Chern-Simons parameter. We provide a positive answer to the long-standing problem on the existence of non-topological condensates with magnetic field concentrated at some of the vortex points (as a sum of Dirac measures) as , a question which is of definite physical interest
Multiple membranes in M-theory
No full textJB acknowledges support from the U.S. National Science Foundation, grant NSF-PHY-0910467. NL was supported in part by STFC grant ST/G000395/1. CP is supported by the U.S. Department of Energy under grant DE-FG02-96ER40959
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Capt. Garcia and Sgt. Simons in Italy (photograph)
No full textCapt. Hector P. Garcia standing next to Sgt. Simons, Italia
The quantum theory of Chern-Simons supergravity
No full textWe consider AdS3 N-extended Chern-Simons supergravity (à la Achucarro-Townsend) and we study its gauge symmetries. We promote those gauge symmetries to a BRST symmetry and we perform its quantization by choosing suitable gauge-fixings. The resulting quantum theories have different features which we discuss in the present work.
In particular, we show that a special choice of the gauge-fixing correctly reproduces the Ansatz by Alvarez, Valenzuela and Zanelli for the graphene fermion
Aspects of supersymmetry in multiple membrane theories
No full textPhDThis thesis consists of two parts. In the rst part we investigate the worldvolume
supersymmetry algebra of multiple membrane theories. We begin with a description
of M-theory branes and their intersections from the perspective of spacetime
and worldvolume supersymmetry algebras. We then provide an overview of the
recent work on multiple M2-branes focusing on the Bagger-Lambert theory and
its relation to the Nambu-Poisson M5-brane and the ABJM theory. The worldvolume
supersymmetry algebras of these theories are explicitly calculated and the
charges interpreted in terms of spacetime intersections of M-branes.
The second part of the thesis looks at l3
p corrections to the supersymmetry
transformations of the Bagger-Lambert theory. We begin with a review of the
dNS duality transformation which allows a gauge eld to be dualised to a scalar
eld in 2+1 dimensions. Applying this duality to 02 terms of the non-abelian
D2-brane theory gives rise to the l3
p corrections of the Lorentzian Bagger-Lambert
theory. We then apply this duality transformation to the 02 corrections of the
D2-brane supersymmetry transformations. For the `abelian' Bagger-Lambert theory
we are able to uniquely determine the l3
p corrections to the supersymmetry
transformations of the scalar and fermion elds. Generalising to the `non-abelian'
Bagger-Lambert theory we are able to determine the l3
p correction to the supersymmetry
transformation of the fermion eld. Along the way make a number of
observations relating to the implementation of the dNS duality transformation at
the level of supersymmetry transformations
Scattering Amplitudes of Massive N=2 Gauge Theories in Three Dimensions
No full textWe study the scattering amplitudes of mass-deformed Chern-Simons theories and Yang-Mills-Chern-Simons theories with N=2 supersymmetry in three dimensions. In particular, we derive the on-shell supersymmetry algebras which underlie the scattering matrices of these theories. We then compute various 3 and 4-point on-shell tree-level amplitudes in these theories. For the mass-deformed Chern-Simons theory, odd-point amplitudes vanish and we find that all of the 4-point amplitudes can be encoded elegantly in superamplitudes. For the Yang-Mills-Chern-Simons theory, we obtain all of the 4-point tree-level amplitudes using a combination of perturbative techniques and algebraic constraints and we comment on difficulties related to computing amplitudes with external gauge fields using Feynman diagrams. Finally, we propose a BCFW recursion relation for mass-deformed theories in three dimensions and discuss the applicability of this proposal to mass-deformed N=2 theories
Gravitational Chern-Simons terms and black hole entropy. Global aspects.
No full textWe discuss the topological and global gauge properties of the formula for a
black hole entropy due to a purely gravitational Chern-Simons term. We study under what topological and geometrical conditions this formula is well-defined. To this end we have
to analyze the global properties of the Chern-Simons term itself and the quantization of
its coupling. We show that in some cases the coupling quantization may interfere with the
well-definiteness of the entropy formula
Chern–Simons and Born–Infeld gravity theories and Maxwell algebras type
No full textRecently it was shown that standard odd- and even-dimensional general relativity can be obtained from a -dimensional Chern–Simons Lagrangian invariant under the algebra and from a -dimensional Born–Infeld Lagrangian invariant under a subalgebra , respectively. Very recently, it was shown that the generalized Inönü–Wigner contraction of the generalized AdS–Maxwell algebras provides Maxwell algebras of types which correspond to the so-called Lie algebras. In this article we report on a simple model that suggests a mechanism by which standard odd-dimensional general relativity may emerge as the weak coupling constant limit of a -dimensional Chern–Simons Lagrangian invariant under the Maxwell algebra type , if and only if . Similarly, we show that standard even-dimensional general relativity emerges as the weak coupling constant limit of a -dimensional Born–Infeld type Lagrangian invariant under a subalgebra of the Maxwell algebra type, if and only if . It is shown that when this is not possible for a -dimensional Chern–Simons Lagrangian invariant under the and for a -dimensional Born–Infeld type Lagrangian invariant under the algebra
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