43 research outputs found
Rotational Graviton Modes in the Brane World
For a brane world embedded in various ten or eleven-dimensional geometries,
we calculate the corrections to the four-dimensional gravitational potential
due to graviton modes propagating in the extra dimensions, including those
rotating around compact directions. Due to additional "warp" factors, these
rotation modes may have as significant an effect as the s-wave modes which
propagate in the large or infinite extra dimension.Comment: 9 pages, LaTe
Black Five-Branes and Fluxbranes on Gravitational Instantons
We apply a U-duality based solution-generating technique to construct
supergravity solutions which describe nonextremal D5-branes and fluxbranes on
various gravitational instantons. This includes an F7-brane wrapped on a
sphere, which remains weakly-coupled in the asymptotic region. We construct
various superpositions of nonextremal D5-branes and fluxbranes that have
angular momentum fixed by the parameters associated with their mass and two
magnetic charges.Comment: 14 pages, added references, an additional commen
Gravitational Lorentz Violations from M-Theory
In an attempt to bridge the gap between M-theory and braneworld
phenomenology, we present various gravitational Lorentz-violating braneworlds
which arise from p-brane systems. Lorentz invariance is still preserved locally
on the braneworld. For certain p-brane intersections, the massless graviton is
quasi-localized. This also results from an M5-brane in a C-field. In the case
of a p-brane perturbed from extremality, the quasi-localized graviton is
massive. For a braneworld arising from global AdS_5, gravitons travel faster
when further in the bulk, thereby apparently traversing distances faster than
light.Comment: 13 pages, 1 figure, LaTeX, references added, minor corrections and
addition
Strongly-Coupled Quarks and Colorful Black Holes
We use the AdS/CFT correspondence to study the behavior of strongly-coupled
quarks in a black hole background. The supergravity background consists of a
six-dimensional Schwarzschild-black string AdS soliton, for which the bulk
horizon extends from the AdS boundary down to an infra-red floor. By going to
higher energy scales, the regime of validity of the classical supergravity
background can be extended closer to the singularity than might be expected
from the four-dimensional perspective. Small black holes potentially created by
the Large Hadron Collider could typically carry color charges inherited from
their parton progenitors. The dynamics of quarks near such a black hole depends
on the curved spacetime geometry as well as the strong interaction with the
color-charged black hole. We study the resulting behavior of quarks and compute
the rate at which a quark rotating around the black hole loses energy. We also
investigate how the interaction between a quark and an antiquark is altered by
the presence of the black hole, which results in a screening length.Comment: Proceedings of the DPF-2011 Conference, 8 pages, 5 figures, added
reference
Brane Resolution Through Fibration
We consider p-branes with one or more circular directions fibered over the
transverse space. The fibration, in conjunction with the transverse space
having a blown-up cycle, enables these p-brane solutions to be completely
regular. Some such circularly-wrapped D3-brane solutions describe flows from
SU(N)^3 N=2 theory, F_0 theory, as well as an infinite family of superconformal
quiver gauge theories, down to three-dimensional field theories. We discuss the
operators that are turned on away from the UV fixed points. Similarly, there
are wrapped M2-brane solutions which describe smooth flows from known
three-dimensional supersymmetric Chern-Simons matter theories, such as ABJM
theory. We also consider p-brane solutions on gravitational instantons, and
discuss various ways in which U-duality can be applied to yield other
non-singular solutions.Comment: 35 pages, additional referenc
Open Wilson Lines and Chiral Condensates in Thermal Holographic QCD
We investigate various aspects of a proposal by Aharony and Kutasov
arXiv:0803.3547 [hep-th] for the gravity dual of an open Wilson line in the
Sakai-Sugimoto model or its non-compact version. In particular, we use their
proposal to determine the effect of finite temperature, as well as background
electric and magnetic fields, on the chiral symmetry breaking order parameter.
We also generalize their prescription to more complicated worldsheets and
identify the operators dual to such worldsheets.Comment: 45 pages, 18 figures; added reference
Singly-spinning black rings in D = 5 U(1)3 supergravity
We construct black ring solutions in five-dimensional U(1)3supergravity which carry three dipole charges, three electric charges and one angular momentum parameter.These solutions are written in a form that is sufficiently compact that their global and thermodynamic properties can be studied explicitly. In particular, we find that the Smarrformula is obeyed regardless of whether or not conical singularities are present, where as the first law of thermodynamics holds only in the absence of conical singularities. We also present black ring solutions with three background magnetic fields
Solar Radiation Pressure and Deviations from Keplerian Orbits
Newtonian gravity and general relativity give exactly the same expression for
the period of an object in circular orbit around a static central mass.
However, when the effects of the curvature of spacetime and solar radiation
pressure are considered simultaneously for a solar sail propelled satellite,
there is a deviation from Kepler's third law. It is shown that solar radiation
pressure affects the period of this satellite in two ways: by effectively
decreasing the solar mass, thereby increasing the period, and by enhancing the
effects of other phenomena, rendering some of them detectable. In particular,
we consider deviations from Keplerian orbits due to spacetime curvature, frame
dragging from the rotation of the sun, the oblateness of the sun, a possible
net electric charge of the sun, and a very small positive cosmological
constant.Comment: 4 pages, minor typo corrected, additional comment
Escape Trajectories of Solar Sails and General Relativity
General relativity can have a significant impact on the long-range escape
trajectories of solar sails deployed near the sun. Spacetime curvature in the
vicinity of the sun can cause a solar sail traveling from 0.01 AU to 2550 AU to
be deflected by as much as one million kilometers, and should therefore be
taken into account at the beginning of the mission. There are a number of
smaller general relativistic effects, such as frame dragging due to the slow
rotation of the sun which can cause a deflection of more than one thousand
kilometers.Comment: 6 pages, 3 figures. Proceedings of the Sixth IAA Symposium on
Realistic Near-Term Advanced Scientific Space Missions. Missions to the Outer
Solar System and Beyond, pp. 67-72, Aosta, Italy, 6-9 July, 200