1,274 research outputs found

### Axions in gravity with torsion

We study a scenario allowing a solution of the strong charge parity problem
via the Peccei-Quinn mechanism, implemented in gravity with torsion. In this
framework there appears a torsion-related pseudoscalar field known as
Kalb-Ramond axion. We compare it with the so-called Barbero-Immirzi axion
recently proposed in the literature also in the context of the gravity with
torsion. We show that they are equivalent from the viewpoint of the effective
theory. The phenomenology of these torsion-descended axions is completely
determined by the Planck scale without any additional model parameters. These
axions are very light and very weakly interacting with ordinary matter. We
briefly comment on their astrophysical and cosmological implications in view of
the recent BICEP2 and Planck data.Comment: 7 pages, no figures, comments and references added, published versio

### N-dimensional geometries and Einstein equations from systems of PDE's

The aim of the present work is twofold: first, we show how all the
$n$-dimensional Riemannian and Lorentzian metrics can be constructed from a
certain class of systems of second-order PDE's which are in duality to the
Hamilton-Jacobi equation and second we impose the Einstein equations to these
PDE's

### On a certain formulation of the Einstein equations

We define a certain differential system on an open set of $R^6$. The system
locally defines a Lorentzian 4-manifold satisfying the Einstein equations. The
converse statement is indicated and its details are postponed to the
furthcoming paper.Comment: 7 pages, Late

### An Introduction to Pure Spinor Superstring Theory

In these lecture notes presented at the 2015 Villa de Leyva Summer School, we
give an introduction to superstring theory. We begin by studying the particle
and superparticle in order to get a better understanding on the superstring
side. Afterwards, we review the pure spinor formalism and end by computing the
scattering amplitude for three gravitons at tree-level.Comment: Villa de Leyva Summer School 2015 proceedings, 28 pages, 2 figure

### Localization of Energy in General Relativity

In the framework of the teleparallel equivalent of general relativity the
energy density of asymptoticaly flat gravitational fields can be naturally and
unambiguously defined. Upon integration of the energy density over the whole
three dimensional space we obtain the ADM energy. We use this energy density to
calculate the energy inside a Schwarzschild black hole.Comment: 12 pages, LaTex file, no figure

### A three-qubit interpretation of BPS and non-BPS STU black holes

Following the recent trend we develop further the black hole analogy between
quantum information theory and the theory of extremal stringy black hole
solutions. We show that the three-qubit interpretation of supersymmetric black
hole solutions in the STU model can be extended also to include
non-supersymmetric ones. First we show that the black hole potential can be
expressed as one half the norm of a suitably chosen three-qubit entangled state
containing the quantized charges and the moduli. The extremization of the black
hole potential in terms of this entangled state amounts to either supressing
bit flip errors (BPS-case) or allowing very special types of flips transforming
the states between different classes of non-BPS solutions. We are illustrating
our results for the example of the D2-D6 system. In this case the bit flip
errors are corresponding to sign flip errors of the charges originating from
the number of D2 branes. After moduli stabilization the states depending
entirely on the charges are maximally entangled graph states (of the triangle
graph) well-known from quantum information theory. An N=8 interpretation of the
STU-model in terms of a mixed state with fermionic purifications is also given.Comment: 35 page

### The Motion of a Body in Newtonian Theories

A theorem due to Bob Geroch and Pong Soo Jang ["Motion of a Body in General
Relativity." Journal of Mathematical Physics 16(1), (1975)] provides the sense
in which the geodesic principle has the status of a theorem in General
Relativity (GR). Here we show that a similar theorem holds in the context of
geometrized Newtonian gravitation (often called Newton-Cartan theory). It
follows that in Newtonian gravitation, as in GR, inertial motion can be derived
from other central principles of the theory.Comment: 12 pages, 1 figure. This is the version that appeared in JMP; it is
only slightly changed from the previous version, to reflect small issue
caught in proo

### Geometrical Interpretation of BRST Symmetry in Topological Yang-Mills-Higgs Theory

We study topological Yang-Mills-Higgs theories in two and three dimensions
and topological Yang-Mills theory in four dimensions in a unified framework of
superconnections. In this framework, we first show that a classical action of
topological Yang-Mills type can provide all three classical actions of these
theories via appropriate projections. Then we obtain the BRST and anti-BRST
transformation rules encompassing these three topological theories from an
extended definition of curvature and a geometrical requirement of Bianchi
identity. This is an extension of Perry and Teo's work in the topological
Yang-Mills case. Finally, comparing this result with our previous treatment in
which we used the ``modified horizontality condition", we provide a meaning of
Bianchi identity from the BRST symmetry viewpoint and thus interpret the BRST
symmetry in a geometrical setting.Comment: 16 pages, LaTeX fil

### Quantum Mechanics in Non-Inertial Frames with a Multi-Temporal Quantization Scheme: II) Non-Relativistic Particles

The non-relativistic version of the multi-temporal quantization scheme of
relativistic particles in a family of non-inertial frames (see hep-th/0502194)
is defined. At the classical level the description of a family of non-rigid
non-inertial frames, containing the standard rigidly linear accelereted and
rotating ones, is given in the framework of parametrized Galilei theories. Then
the multi-temporal quantization, in which the gauge variables, describing the
non-inertial effects, are not quantized but considered as c-number generalized
times, is applied to non relativistic particles. It is shown that with a
suitable ordering there is unitary evolution in all times and that, after the
separation of center of mass, it is still possible to identify the inertial
bound states. The few existing results of quantization in rigid non-inertial
frames are recovered as special cases

### Formal rigidity of the Witt and Virasoro Algebra

The formal rigidity of the Witt and Virasoro algebras was first established
by the author in [4]. The proof was based on some earlier results of the author
and Goncharowa, and was not presented there. In this paper we give an
elementary proof of these facts.Comment: 5 page

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