Dear all,

Kei-ichi Maeda - Wednesday 27th June - 4.30pm QMUL Maths 103

This week our Relativity and Cosmology seminar will be given by
Kei-ichi Maeda from Waseda University on "Black Holes in a Universe
from higher dimensions". The abstract is below.

As usual the seminar will start at 4.30pm in the Maths Seminar Room
103 on the Mile End Campus.
More information is available on our wiki at http://cosrel.maths.qmul.ac.uk .


Best wishes,

Ian

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Dr Ian Huston

Postdoctoral Researcher
Cosmology and Relativity Group
Astronomy Unit, School of Physics and Astronomy
Queen Mary, University of London

[log in to unmask]
http://ph.qmul.ac.uk/i.huston
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Black Holes in a Universe from higher dimensions

Kei-ichi Maeda

An exact solution representing black holes in an expanding universe is
found.  The black holes are maximally charged and the universe is
expanding with arbitrary equation of state.  It is an exact solution
of the Einstein-scalar-Maxwell system, in which we have two
Maxwell-type U(1) fields coupled to the scalar field. The potential of
the scalar field is an exponential. The solution depends on two
parameters, the charge Q and one parameter (the ratio of the energy
density of U(1) fields to that of the scalar field). We find a regular
horizon, which is static because of the balance on the horizon between
gravitational attractive force and U(1) repulsive force acting on the
scalar field. We also calculate the black hole temperature. For the
case without a potential, we can derive such a solution from a
time-dependent intersecting M-brane solution in eleven dimensions by
the dimensional reduction.