<subfield code="a">We argue that perturbative quantum field theory and string theory can be consistently modified in the infrared to eliminate, in a radiatively stable manner, tadpole instabilities that arise after supersymmetry breaking. This is achieved by deforming the propagators of classically massless scalar fields and the graviton so as to cancel the contribution of their zero modes. In string theory, this modification of propagators is accomplished by perturbatively deforming the world-sheet action with bi-local operators similar to those that arise in double-trace deformations of AdS/CFT. This results in a perturbatively finite and unitary S-matrix (in the case of string theory, this claim depends on standard assumptions about unitarity in covariant string diagrammatics). The S-matrix is parameterized by arbitrary scalar VEVs, which exacerbates the vacuum degeneracy problem. However, for generic values of these parameters, quantum effects produce masses for the nonzero modes of the scalars, lifting the fluctuating components of the moduli.</subfield>
<subfield code="a">A brief overview of hep-th/0201028 prepared for NATO Advanced Study Institute and EC Summer School on Progress in String, Field and Particle Theory, Cargese, Corsica, France, 25 June - 11 July 2002.</subfield>
<subfield code="u">National Technical University of Athens</subfield>
</datafield>
<datafield tag="245" ind1=" " ind2=" ">
<subfield code="a">Quasi-normal Modes of Electromagnetic Perturbations of Four-Dimensional Topological Black Holes</subfield>
</datafield>
<datafield tag="260" ind1=" " ind2=" ">
<subfield code="c">2006</subfield>
</datafield>
<datafield tag="269" ind1=" " ind2=" ">
<subfield code="c">10 Jun 2006</subfield>
</datafield>
<datafield tag="300" ind1=" " ind2=" ">
<subfield code="a">17 p</subfield>
</datafield>
<datafield tag="520" ind1=" " ind2=" ">
<subfield code="a">We study the perturbative behaviour of topological black holes with scalar hair. We calculate both analytically and numerically the quasi-normal modes of the electromagnetic perturbations. In the case of small black holes we find clear evidence of a second-order phase transition of a topological black hole to a hairy configuration. We also find evidence of a second-order phase transition of the AdS vacuum solution to a topological black hole.</subfield>
<subfield code="m">W.-H. Press, S. A. Teukolsky, W. T. Vetterling and B. P. Flannery in Numerical Recipies (Cambridge University Press, Cambridge, England, 1992).</subfield>
</datafield>
<datafield tag="999" ind1="C" ind2="5">
<subfield code="o">[40]</subfield>
<subfield code="m">G. Koutsoumbas, S. Musiri, E. Papantonopoulos and G. Siopsis, in preparation.</subfield>