1,533 research outputs found
On the Six-dimensional Kerr Theorem and Twistor Equation
The Kerr theorem is revisited as part of the twistor program in six
dimensions. The relationship between pure spinors and integrable 3-planes is
investigated. The real condition for Lorentzian spacetimes is seen to induce a
projective property in the space of solutions, reminiscent of the quaternionic
structure of the 6-dimensional Lorentz group. The twistor equation (or Killing
spinor equations generically) also has an interpretation as integrable null
planes and a family of Einstein spacetimes with this property are presented in
the Kerr-Schild fashion.Comment: JHEP style, 19 pages, minor corrections. Matches printed versio
Isomonodromy, Painlev\'e Transcendents and Scattering off of Black Holes
We apply the method of isomonodromy to study the scattering of a generic
Kerr-NUT-(A)dS black hole. For generic values of the charges, the problem is
related to the connection problem of the Painlev\'e VI transcendent. We review
a few facts about Painlev\'e VI, Garnier systems and the Hamiltonian structure
of flat connections in the Riemann sphere. We then outline a method for
computing the scattering amplitudes based on Hamilton-Jacobi structure of
Painlev\'e, and discuss the implications of the generic result to black hole
complementarity.Comment: 40 pages, 4 figures, JHEP styl
Scalar quasinormal modes of Kerr-AdS
An analytic expression for the scalar quasinormal modes of the generic,
spinning Kerr- black holes was previously proposed by the
authors in ref. 1, in terms of transcendental equations involving the
Painlev\'e VI (PVI) function. In this work, we carry out a numerical
investigation of the modes for generic rotation parameters, comparing
implementations of expansions for the PVI function both in terms of
conformal blocks (Nekrasov functions) and Fredholm determinants. We compare the
results with standard numerical methods for the subcase of Schwarzschild black
holes. We then derive asymptotic formulas for the angular eigenvalues and the
quasinormal modes in the small black hole limit for generic scalar mass and
discuss, both numerically and analytically, the appearance of superradiant
modes.Comment: JHEP style, 42 pages, 3 figures, 3 tables; Updated discussion on the
superradiant mode
A Note on Tachyon Moduli and Closed Strings
The collective behavior of the SL(2,R) covariant brane states of non-critical
c=1 string theory found in a previous work, is studied in the Fermi liquid
approximation. It is found that such states mimick the coset WZW model, whereas
only by further restrictions one recovers the double-scaling limit which was
purported to be equivalent to closed string models. Another limit is proposed,
inspired by the tachyon condensation ideas, where the spectrum is the same of
two-dimensional string theory. We close by noting some strange connections
between vacuum states of the theory in their different interpretations.Comment: PDFLaTeX, 17 pages, 2 figures; Section 2 rewritten, several fixes
throughout the text to improve clarit
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