1,466 research outputs found
PP-wave String Interactions from String Bit Model
We construct the string states ,
and in the Hilbert space of the quantum
mechanical orbifold model so as to calculate the three point functions and the
matrix elements of the light-cone Hamiltonian from the interacting string bit
model. With these string states we show that the three point functions and the
matrix elements of the Hamiltonian derived from the interacting string bit
model up to order precisely match with those computed from the
perturbative SYM theory in BMN limit.Comment: 20 pages, no figure, LaTeX, some changes made and references adde
Non-Abelian BIonic Brane Intersections
We study "fuzzy funnel" solutions to the non-Abelian equations of motion of
the D-string. Our funnel describes n^6/360 coincident D-strings ending on n^3/6
D7-branes, in terms of a fuzzy six-sphere which expands along the string. We
also provide a dual description of this configuration in terms of the world
volume theory of the D7-branes. Our work makes use of an interesting non-linear
higher dimensional generalization of the instanton equations.Comment: 17 pages uses harvmac; v2: small typos corrected, refs adde
Dependent Types for Pragmatics
This paper proposes the use of dependent types for pragmatic phenomena such
as pronoun binding and presupposition resolution as a type-theoretic
alternative to formalisms such as Discourse Representation Theory and Dynamic
Semantics.Comment: This version updates the paper for publication in LEU
PP-wave and Non-supersymmetric Gauge Theory
We extend the pp-wave correspondence to a non supersymmetric example. The
model is the type 0B string theory on the pp-wave R-R background. We explicitly
solve the model and give the spectrum of physical states. The field theory
counterpart is given by a sector of the large N SU(N) x SU(N) CFT living on a
stack of N electric and N magnetic D3-branes. The relevant effective coupling
constant is g_{eff}=g_sN/J^2. The string theory has a tachyon in the spectrum,
whose light-cone energy can be exactly computed as a function of g_{eff}. We
argue that the perturbative analysis in g_{eff} in the dual gauge theory is
reliable, with corrections of non perturbative type. We find a precise
state/operator map, showing that the first perturbative corrections to the
anomalous dimensions of the operators have the behavior expected from the
string analysis.Comment: 19 pages. Revised versio
[μ-1,1′-Bis(diphenylphosphino)ferrocene-κ2 P:P′]bis[chloridogold(I)]–chloroform–hexane (2/2/1)
In the title mixed solvate, [Au2Fe(C17H14P)2Cl2]·CHCl3·0.5CH3(CH2)4CH3, the hexane solvent molecule is disposed about an inversion centre. The Au atoms exist within nearly ideal linear coordination defined by P,Cl-donor sets, and when viewed down the P⋯P axis the Au atoms are gauche to each other. In the crystal structure, the chloroform solvent molecule is associated with the complex via a C—H⋯Cl contact, and the hexane solvent molecules occupy voids defined by the remaining components of the structure
Holographic QCD and Pion Mass
To realize massive pions, we study variations of the holographic model of
massless QCD using the D4/D8/anti-D8 brane configuration proposed by Sakai and
Sugimoto. We propose deformations which break the chiral symmetry explicitly
and compute the mass of the pions and vector mesons. The observed value of the
pion mass can be obtained. We also argue a chiral perturbation corresponding to
our deformation.Comment: 23pages, minor changes, references adde
A uniqueness theorem for the adS soliton
The stability of physical systems depends on the existence of a state of
least energy. In gravity, this is guaranteed by the positive energy theorem.
For topological reasons this fails for nonsupersymmetric Kaluza-Klein
compactifications, which can decay to arbitrarily negative energy. For related
reasons, this also fails for the AdS soliton, a globally static, asymptotically
toroidal spacetime with negative mass. Nonetheless, arguing from
the AdS/CFT correspondence, Horowitz and Myers (hep-th/9808079) proposed a new
positive energy conjecture, which asserts that the AdS soliton is the unique
state of least energy in its asymptotic class. We give a new structure theorem
for static spacetimes and use it to prove uniqueness of the AdS
soliton. Our results offer significant support for the new positive energy
conjecture and add to the body of rigorous results inspired by the AdS/CFT
correspondence.Comment: Revtex, 4 pages; Matches published version. More detail in Abstract
and one equation corrected. For details of proofs and further results, see
hep-th/020408
Non-perturbative effects in the BMN limit of N=4 supersymmetric Yang-Mills
One-instanton contributions to the correlation functions of two
gauge-invariant single-trace operators in N=4 SU(N) Yang-Mills theory are
studied in semi-classical approximation in the BMN limit. The most
straightforward examples involve operators with four bosonic impurities. The
explicit form for the correlation functions, which determine the anomalous
dimensions, follows after integration over the large number of bosonic and
fermionic moduli. Our results demonstrate that the instanton contributions
scale appropriately in the BMN limit. We find impressive agreement with the
D-instanton contributions to mass matrix elements of the dual plane-wave IIB
superstring theory, obtained in a previous paper. Not only does the dependence
on the scaled coupling constants match, but the dependence on the mode numbers
of the states is also in striking agreement.Comment: 52 pages, no figures, latex; V2: minor change
Mesons in gauge/gravity dual with large number of fundamental fields
In view of extending gauge/gravity dualities with flavour beyond the probe
approximation, we establish the gravity dual description of mesons for a
three-dimensional super Yang-Mills theory with fundamental matter. For this
purpose we consider the fully backreacted D2/D6 brane solution of Cherkis and
Hashimoto in an approximation due to Pelc and Siebelink. The low-energy field
theory is the IR fixed point theory of three-dimensional N=4 SU(N_c) super
Yang-Mills with N_f fundamental fields, which we consider in a large N_c and
N_f limit with N_f/N_c finite and fixed. We discuss the dictionary between
meson-like operators and supergravity fluctuations in the corresponding
near-horizon geometry. In particular, we find that the mesons are dual to the
low-energy limit of closed string states. In analogy to computations of
glueball mass spectra, we calculate the mass of the lowest-lying meson and find
that it depends linearly on the quark mass.Comment: 19 pages, LaTeX, 6 figures, v2: fig. 4 added, refs. adde
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