24,446 research outputs found
Physical States and String Symmetries
It is shown that if the momenta belong to an integral lattice, then every
physical state of string theory leads to a symmetry of the scattering
amplitudes. We discuss the role of this symmetry when the momenta are those
provided by the usual D.D.F construction and show that the string compactified
on the torus associated with the self-dual Lorentzian lattice,
possess the Fake Monster Lie algebra as a symmetry.Comment: 14 pages, ( Some references are added.
M-Theory and Hypercharge
We discuss the possibility that the electro-weak and strong interactions
arise as the low energy effective description of branes in M-theory. As a step
towards constructing such a model we show how one can naturally obtain
SU(N_1)\times SU(N_2)\times U(1) gauge theories from branes, including matter
in the bi-fundamental representation of SU(N_1)\times SU(N_2) which are
fractionally charged under U(1).Comment: 29 pages Phyzzx. Two figure
G+++ and Brane Solutions
We demonstrate that the very extended G+++ group element of the form
describes the usual BPS, electric, single brane solutions found in G+++
theories.Comment: One new equation, added references, corrected typos and minor
changes, 42 pages, 6 figures, LaTeX2
Chiral Green's Functions in Superconformal Field Theory
By solving the Ward identities in a superconformal field theory we find the
unique three-point Green's functions composed of chiral superfields for N =
1,2,3,4 supersymmetry. We show that the N=1 four-point function with R-charge
equal to one is uniquely determined by the Ward identities up to the
specification of four constants. We discuss why chiral Green's functions above
three-points, with total R-charge greater than N, are not uniquely determined.Comment: 32 pages, no figures, LaTeX2e forma
The Threebrane Soliton of the M-Fivebrane
We discuss the supersymmetry algebra of the M theory fivebrane and obtain a
new threebrane soliton preserving half of the six-dimensional supersymmetry.
This solution is dimensionally reduced to various D-p-branes.Comment: 10 pages, phyzz
A New Massive Type IIA Supergravity From Compactification
We consider the most general form for eleven dimensional supersymmetry
compatible with on-shell superfields. This allows for the introduction of a
conformal Spin(1,10) connection. In eleven dimensional Minkowski space this
modification is trivial and can be removed by a field redefinition, however,
upon compactification on S^1 it is possible to introduce a non-trivial `Wilson
line'. The resulting ten dimensional supergravity has massive 1-form and 3-form
potentials and a cosmological constant. This theory does not possess a
supersymmetric eightbrane soliton but it does admit a supersymmetric non-static
cosmological solution.Comment: 13 pages, phyzzx. The introduction is clarifed and a reference adde
Duality Symmetries and G^{+++} Theories
We show that the non-linear realisations of all the very extended algebras
G^{+++}, except the B and C series which we do not consider, contain fields
corresponding to all possible duality symmetries of the on-shell degrees of
freedom of these theories. This result also holds for G_2^{+++} and we argue
that the non-linear realisation of this algebra accounts precisely for the form
fields present in the corresponding supersymmetric theory. We also find a
simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables
corrected, other minor changes, one appendix added, refs. added. Version
published in Class. Quant. Gra
M-Theory Through the Looking Glass: Tachyon Condensation in the E_8 Heterotic String
We study the spacetime decay to nothing in string theory and M-theory. First
we recall a nonsupersymmetric version of heterotic M-theory, in which bubbles
of nothing -- connecting the two E_8 boundaries by a throat -- are expected to
be nucleated. We argue that the fate of this system should be addressed at weak
string coupling, where the nonperturbative instanton instability is expected to
turn into a perturbative tachyonic one. We identify the unique string theory
that could describe this process: The heterotic model with one E_8 gauge group
and a singlet tachyon. We then use worldsheet methods to study the tachyon
condensation in the NSR formulation of this model, and show that it induces a
worldsheet super-Higgs effect. The main theme of our analysis is the
possibility of making meaningful alternative gauge choices for worldsheet
supersymmetry, in place of the conventional superconformal gauge. We show in a
version of unitary gauge how the worldsheet gravitino assimilates the goldstino
and becomes dynamical. This picture clarifies recent results of Hellerman and
Swanson. We also present analogs of R_\xi gauges, and note the importance of
logarithmic CFT in the context of tachyon condensation.Comment: 36 pages, 1 figur
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