875 research outputs found
3D gauged supergravity from SU(2) reduction of 6D supergravity
We obtain Yang-Mills gauged supergravity in three dimensions
from group manifold reduction of (1,0) six dimensional supergravity
coupled to an anti-symmetric tensor multiplet and gauge vector multiplets in
the adjoint of . The reduced theory is consistently truncated to 3D
supergravity coupled to bosonic and fermionic propagating degrees of freedom. This is in contrast to the
reduction in which there are also massive vector fields. The scalar manifold is
, and there is a gauge group. We then
construct Chern-Simons three dimensional gauged supergravity with scalar
manifold and
explicitly show that this theory is on-shell equivalent to the Yang-Mills
gauged supergravity theory obtained from the reduction,
after integrating out the scalars and gauge fields corresponding to the
translational symmetries .Comment: 24 pages, no figures, references added and typos correcte
On Subleading Contributions to the AdS/CFT Trace Anomaly
In the context of the AdS/CFT correspondence, we perform a direct computation
in AdS_5 supergravity of the trace anomaly of a d=4, N=2 SCFT. We find
agreement with the field theory result up to next to leading order in the 1/N
expansion. In particular, the order N gravitational contribution to the anomaly
is obtained from a Riemann tensor squared term in the 7-brane effective action
deduced from heterotic - type I duality. We also discuss, in the AdS/CFT
context, the order N corrections to the trace anomaly in d=4, N=4 SCFTs
involving SO or Sp gauge groups.Comment: 25 pages, LaTeX, v2: references adde
On the perturbative corrections around D-string instantons
We study -threshold corrections in an eight dimensional S-dual
pair of string theories, as a prototype of dual string vacua with sixteen
supercharges. We show that the orbifold CFT description of D-string instantons
gives rise to a perturbative expansion similar to the one appearing on the
fundamental string side. By an explicit calculation, using the Nambu-Goto
action in the static gauge, we show that the first subleading term agrees
precisely on the two sides. We then give a general argument to show that the
agreement extends to all orders.Comment: 12 page
Duality Symmetries in N=2 Heterotic Superstring
We review the derivation and the basic properties of the perturbative
prepotential in N=2 compactifications of the heterotic superstring. We discuss
the structure of the perturbative monodromy group and the embedding of rigidly
supersymmetric monodromies associated with enhanced gauge groups, at both
perturbative and non-perturbative level.Comment: Based on talks presented at several conferences. 12 pages, LaTe
Do we need a hybrid law of contract? Why Hugh Collins is wrong and why it matters
In Regulating Contracts Hugh Collins takes up the challenge presented by 40 years of empirical studies which show that business people make little use of contract law in settling disputes, preferring instead to rely on trust and various non-legal sanctions to organise their transactions. Indeed, business parties often actively avoid the use of law because of its expense, inconvenience and tendency to harm business relationships. These findings pose a challenge to traditional doctrinal scholars. If business parties do not make much use of contract law, one has to ask what role it does play and whether the attention that is paid to it by orthodox legal scholars is misplaced. Regulating Contracts takes on this challenge directly and is the most substantial attempt made so far to explain the role of contract law in light of the questions raised as to its usefulness.John Gava and Janey Green
AdS/CFT correspondence and D1/D5 systems in theories with 16 supercharges
We discuss spectra of supergravities, arising in the near horizon
geometry of D1/D5 systems in orbifolds/orientifolds of type IIB theory with 16
supercharges. These include models studied in a recent paper (hep-th/0012118),
where the group action involves also a shift along a transversal circle, as
well as IIB/, which is dual to IIB on . After appropriate
assignements of the orbifold group eigenvalues and degrees to the supergravity
single particle spectrum, we compute the supergravity elliptic genus and find
agreement, in the expected regime of validity, with the elliptic genus obtained
using U-duality map from (4,4) CFTs of U-dual backgrounds. Since this U-duality
involves the exchange of KK momentum and D1 charge , it allows us to
test the (4,4) CFTs in the and regimes by two different
supergravity duals.Comment: 28 pages, no figure
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