Research Interest of Masaki Shigemori

      Publication 1: Nonsupersymmetric Brane/Antibrane Configurations in Type IIA and M Theory (URL)
      Publication 2: Spinning strings as small black rings (URL)
      Publication 3: Massless black holes and black rings as effective geometries of the D1-D5 system (URL)

    URL of Research: N/A

Statement of Interest:


  I am interested in string theory, including nonsupersymmetric metastable
states in string theory and gauge theory.  Recently, it was realized
that nonsupersymmetric metastable states are ubiquitous in gauge theory
and string theory.  Our universe being nonsupersymmetric, studies of
such nonsusy configurations are of essential importance.  In work with
J. Marsano and K. Papadodimas to appear very soon (hopefully this week
or the next), we studied nonsupersymmetric states in type IIA/M-theory
obtained by suspending D4-branes and anti-D4-branes between NS5-branes.
We found that, by lifting to a nonholomophic M5-brane/NS5-brane curve,
this nonsupersymmetric system can be studied in a reliable way in
various parameter regimes of type IIA/M-theory.  In particular, when the
numbers of branes and antibranes are the same, we obtained the exact
nonholomorphic M5/NS5 curve.  In addition, this IIA/M vantage point
sheds lights on and deepens understanding of the IIB system studied by
Vafa et al. in hep-th/0610249 and hep-th/0702077, which is the T-dual of
our system in the weak coupling IIA limit.  Our explicit M-theory curves
also help us to better understand the subtlety regarding boundary
conditions raised by Bena et al. in hep-th/0608157.  Our formalism can
readily be generalized to many other systems which have been mainly
studied in supersymmetric contexts only, such as ADE quiver gauge
theories.  These nonsupersymmetric IIA/M configurations are expected to
be useful local modules in constructing realistic models in
phenomenology/cosmology.