1,830 research outputs found
Harmonic Superspaces from Superstrings
We derive harmonic superspaces for N=2,3,4 SYM theory in four dimensions from
superstring theory. The pure spinors in ten dimensions are dimensionally
reduced and yield the harmonic coordinates. Two anticommuting BRST charges
implement Grassmann analyticity and harmonic analyticity. The string field
theory action produces the action and field equations for N=3 SYM theory in
harmonic superspace.Comment: 14 pp. Harvma
No saturation of the quantum Bogomolnyi bound by two-dimensional supersymmetric solitons
We reanalyse the question whether the quantum Bogomolnyi bound is saturated
in the two-dimensional supersymmetric kink and sine-Gordon models. Our starting
point is the usual expression for the one-loop correction to the mass of a
soliton in terms of sums over zero-point energies. To regulate these sums, most
authors put the system in a box with suitable boundary conditions, and impose
an ultraviolet cut-off. We distinguish between an energy cut-off and a mode
number cut-off, and show that they lead to different results. We claim that
only the mode cut-off yields correct results, and only if one considers exactly
the same number of bosonic and fermionic modes in the total sum over
bound-state and zero-point energies. To substantiate this claim, we show that
in the sine-Gordon model only the mode cut-off yields a result for the quantum
soliton mass that is consistent with the exact result for the spectrum as
obtained by Dashen et al. from quantising the so-called breather solution. In
the supersymmetric case, our conclusion is that contrary to previous claims the
quantum Bogomolnyi bound is not saturated in any of the two-dimensional models
considered.Comment: 23 pages, LATe
BRS symmetry versus supersymmetry in Yang-Mills-Chern-Simons theory
We prove that three-dimensional supersymmetric Yang-Mills-Chern-Simons
theory is finite to all loop orders. In general this leaves open the
possibility that different regularization methods lead to different finite
effective actions. We show that in this model dimensional regularization and
regularization by dimensional reduction yield the same effective action.
Consequently, the superfield approach preserves BRS invariance for this model.Comment: 27 pages, 2 figures, latex2e, uses epsfi
Consistent boundary conditions for supergravity
We derive the complete orbit of boundary conditions for supergravity models
which is closed under the action of all local symmetries of these models, and
which eliminates spurious field equations on the boundary. We show that the
Gibbons-Hawking boundary conditions break local supersymmetry if one imposes
local boundary conditions on all fields. Nonlocal boundary conditions are not
ruled out. We extend our analysis to BRST symmetry and to the Hamiltonian
formulation of these models.Comment: 37 pages, v2: references added, v3: misprint correcte
Superstrings and WZNW Models
We give a brief review of our approach to the quantization of superstrings.
New is a covariant derivation of the measure at tree level and a path integral
formula for this measure.Comment: 12 pp, LaTeX, Contribution to the QTS3 Conference Proceeding
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