420 research outputs found
Rational foundation of GR in terms of statistical mechanic in the AdS/CFT framework
In this article, we work out the microscopic statistical foundation of the
supergravity description of the simplest 1/2 BPS sector in the AdS(5)/CFT(4).
Then, all the corresponding supergravity observables are related to
thermodynamical observables, and General Relativity is understood as a
mean-field theory. In particular, and as an example, the Superstar is studied
and its thermodynamical properties clarified.Comment: 13 pages, 6 eps figures, latex, some improvements introduced,
reference added, typos correcte
Minisuperspace Quantization of "Bubbling AdS" and Free Fermion Droplets
We quantize the space of 1/2 BPS configurations of Type IIB SUGRA found by
Lin, Lunin and Maldacena (hep-th/0409174), directly in supergravity. We use the
Crnkovic-Witten-Zuckerman covariant quantization method to write down the
expression for the symplectic structure on this entire space of solutions. We
find the symplectic form explicitly around AdS_5 x S^5 and obtain a U(1)
Kac-Moody algebra, in precise agreement with the quantization of a system of N
free fermions in a harmonic oscillator potential, as expected from AdS/CFT. As
a cross check, we also perform the quantization around AdS_5 x S^5 by another
method, using the known spectrum of physical perturbations around this
background and find precise agreement with our previous calculation.Comment: 22 Pages + 2 Appendices, JHEP3; v3: explanation of factor 2 mismatch
added, references reordered, published versio
Complex Matrix Model and Fermion Phase Space for Bubbling AdS Geometries
We study a relation between droplet configurations in the bubbling AdS
geometries and a complex matrix model that describes the dynamics of a class of
chiral primary operators in dual N=4 super Yang Mills (SYM). We show rigorously
that a singlet holomorphic sector of the complex matrix model is equivalent to
a holomorphic part of two-dimensional free fermions, and establish an exact
correspondence between the singlet holomorphic sector of the complex matrix
model and one-dimensional free fermions. Based on this correspondence, we find
a relation of the singlet holomorphic operators of the complex matrix model to
the Wigner phase space distribution. By using this relation and the AdS/CFT
duality, we give a further evidence that the droplets in the bubbling AdS
geometries are identified with those in the phase space of the one-dimensional
fermions. We also show that the above correspondence actually maps the
operators of N=4 SYM corresponding to the (dual) giant gravitons to the droplet
configurations proposed in the literature.Comment: 27 pages, 6 figures, some clarification, typos corrected, published
versio
Bubbling Orientifolds
We investigate a class of 1/2-BPS bubbling geometries associated to
orientifolds of type IIB string theory and thereby to excited states of the
SO(N)/Sp(N) N=4 supersymmetric Yang-Mills theory. The geometries are in
correspondence with free fermions moving in a harmonic oscillator potential on
the half-line. Branes wrapped on torsion cycles of these geometries are
identified in the fermi fluid description. Besides being of intrinsic interest,
these solutions may also occur as local geometries in flux compactifications
where orientifold planes are present to ensure global charge cancellation. We
comment on the extension of this procedure to M-theory orientifolds.Comment: 25 pages, 11 figures. v2: few references adde
Bosonization of non-relativstic fermions in 2-dimensions and collective field theory
We revisit bosonization of non-relativistic fermions in one space dimension.
Our motivation is the recent work on bubbling half-BPS geometries by Lin, Lunin
and Maldacena (hep-th/0409174). After reviewing earlier work on exact
bosonization in terms of a noncommutative theory, we derive an action for the
collective field which lives on the droplet boundaries in the classical limit.
Our action is manifestly invariant under time-dependent reparametrizations of
the boundary. We show that, in an appropriate gauge, the classical collective
field equations imply that each point on the boundary satisfies Hamilton's
equations for a classical particle in the appropriate potential. For the
harmonic oscillator potential, a straightforward quantization of this action
can be carried out exactly for any boundary profile. For a finite number of
fermions, the quantum collective field theory does not reproduce the results of
the exact noncommutative bosonization, while the latter are in complete
agreement with the results computed directly in the fermi theory.Comment: references added and typos corrected; 21 pages, 3 figures, eps
Singularities and closed time-like curves in type IIB 1/2 BPS geometries
We study in detail the moduli space of solutions discovered in LLM relaxing
the constraint that guarantees the absence of singularities. The solutions fall
into three classes, non-singular, null-singular and time machines with a
time-like naked singularity. We study the general features of these metrics and
prove that there are actually just two generic classes of space-times - those
with null singularities are in the same class as the non-singular metrics.
AdS/CFT seems to provide a dual description only for the first of these two
types of space-time in terms of a unitary CFT indicating the possible existence
of a chronology protection mechanism for this class of geometries.Comment: 34 pages, 7 figures, LaTeX. References adde
Economics of preceding crops and nitrogen application rates for canola and barley production in western Canada
Non-Peer ReviewedThe objective of this study was to evaluate the economic effects of a range of legume and non-legume preceding crops and N rates on costs and net revenue (NR) of canola (Brassica napus L.), barley (Hordeum vulgare L.) and canola-barley rotation under various environmental conditions. Legumes such as field pea (Pisum sativum L.) and lentil (Lens culinaris Medik.) as preceding crop generated higher net revenues for the following crops canola and barley than when wheat (Triticum aestivum L.) and canola were the preceding crops. Although faba bean (Vicia faba L.) grown as a green manure produced the highest annual net revenues for the following crops canola and barley, this contribution was not enough to compensate for the loss of income during the green manure production year. Therefore, growing faba bean as a green manure was not economical. Response of net revenue to N rates was mainly linear or quadratic, and N was optimal at 60 to 90 kg ha-1 at most sites. The results indicate that growing legumes for seed prior to canola can increase net revenues of canola and subsequent barley
Contribution of legume preceding crops to improve economic and non-renewable energy use efficiency of canola production
Non-Peer Reviewe
From Gravitons to Giants
We discuss exact quantization of gravitational fluctuations in the half-BPS
sector around AdSS background, using the dual super Yang-Mills
theory. For this purpose we employ the recently developed techniques for exact
bosonization of a finite number of fermions in terms of bosonic
oscillators. An exact computation of the three-point correlation function of
gravitons for finite shows that they become strongly coupled at
sufficiently high energies, with an interaction that grows exponentially in
. We show that even at such high energies a description of the bulk physics
in terms of weakly interacting particles can be constructed. The single
particle states providing such a description are created by our bosonic
oscillators or equivalently these are the multi-graviton states corresponding
to the so-called Schur polynomials. Both represent single giant graviton states
in the bulk. Multi-particle states corresponding to multi-giant gravitons are,
however, different, since interactions among our bosons vanish identically,
while the Schur polynomials are weakly interacting at high enough energies.Comment: v2-references added, minor changes and typos corrected; 24 pages,
latex, 3 epsf figure
- …