1,298 research outputs found
Constructing Classical and Quantum Superconformal Algebras on the Boundary of AdS_3
Motivated by recent progress on the correspondence between string theory on
anti-de Sitter space and conformal field theory, we address the question of
constructing space-time N extended superconformal algebras on the boundary of
AdS_3. Based on a free field realization of an affine SL(2|N/2) current
superalgebra residing on the world sheet, we construct explicitly the Virasoro
generators and the N supercurrents. N is even. The resulting superconformal
algebra has an affine SL(N/2) \otimes U(1) current algebra as an internal
subalgebra. Though we do not complete the general superalgebra, we outline the
underlying construction and present supporting evidence for its validity.
Particular attention is paid to its BRST invariance. In the classical limit
where the free field realization may be substituted by a differential operator
realization, we discuss further classes of generators needed in the closure of
the algebra. We find sets of half-integer spin fields, and for N>4 these
include generators of negative weights. An interesting property of the
construction is that for N>2 it treats the supercurrents in an asymmetric way.
Thus, we are witnessing a new class of superconformal algebras not obtainable
by conventional Hamiltonian reduction. The complete classical algebra is
provided in the case N=4 and is of a new and asymmetric form.Comment: 29 pages, LaTeX, extends hep-th/990518
Conformal higher-spin symmetries in twistor string theory
It is shown that similarly to massless superparticle, classical global
symmetry of the Berkovits twistor string action is infinite-dimensional. We
identify its superalgebra, whose finite-dimensional subalgebra contains
superalgebra. In quantum theory this infinite-dimensional
symmetry breaks down to one.Comment: 20 pages, LaTeX. v2: section 3 undergone major revision, others -
minor improvements including correction of typos. Version accepted to Nuclear
Physics
Nonlinear superconformal symmetry of a fermion in the field of a Dirac monopole
We study a longstanding problem of identification of the fermion-monopole
symmetries. We show that the integrals of motion of the system generate a
nonlinear classical Z_2-graded Poisson, or quantum super- algebra, which may be
treated as a nonlinear generalization of the . In the
nonlinear superalgebra, the shifted square of the full angular momentum plays
the role of the central charge. Its square root is the even osp(2|2) spin
generating the u(1) rotations of the supercharges. Classically, the central
charge's square root has an odd counterpart whose quantum analog is, in fact,
the same osp(2|2) spin operator. As an odd integral, the osp(2|2) spin
generates a nonlinear supersymmetry of De Jonghe, Macfarlane, Peeters and van
Holten, and may be identified as a grading operator of the nonlinear
superconformal algebra.Comment: 13 pages; comments and ref added; V.3: misprints corrected, journal
versio
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