MARC 主機 00000nam 2200313 4500
001 AAI3251267
005 20080111103839.5
008 080111s2007 eng d
035 (UMI)AAI3251267
040 UMI|cUMI
100 1 Ernebjerg, Morten
245 10 Field theory methods in two-dimensional and heterotic
string theories
300 151 p
500 Source: Dissertation Abstracts International, Volume: 68-
02, Section: B, page: 1039
500 Adviser: Andrew Strominger
502 Thesis (Ph.D.)--Harvard University, 2007
520 This thesis has three parts. In the first, we study the
Das-Jevicki collective field description of arbitrary
classical solutions in the c = 1 matrix model, which are
believed to describe nontrivial spacetime backgrounds in
2D string theory. Our analysis naturally includes the case
of a Fermi droplet cosmology. We cast the droplet
collective field theory in standard coordinates and
comment on the form of the interactions
520 In the second part, we prove the existence of topological
rings in (0, 2) theories containing non-anomalous left-
moving U(1) currents by which they may be twisted. While
the twisted models are not topological, their ground
operators form a ring under non-singular OPE which reduces
to the (a,c) or (c,c) ring at (2, 2) points and define a
quantum sheaf cohomology. In the special case of Calabi-
Yau compactifications, these rings are shown to exist
globally on the moduli space in many cases
520 In the third part, we construct worldsheet descriptions of
heterotic flux vacua as the IR limits of N = 2 gauge
theories. Spacetime torsion is incorporated via a 2D Green
-Schwarz mechanism in which a doublet of axions cancels a
one-loop gauge anomaly. Manifest (0, 2) supersymmetry and
the compactness of the gauge theory instanton moduli space
suggest that these models, which include Fu-Yau models,
are stable against worldsheet instantons
590 School code: 0084
590 DDC
650 4 Physics, Elementary Particles and High Energy
690 0798
710 2 Harvard University
773 0 |tDissertation Abstracts International|g68-02B
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