1,453 research outputs found
Supersymmetric Yang-Mills theories with local coupling: The supersymmetric gauge
Supersymmetric pure Yang-Mills theory is formulated with a local, i.e.
space-time dependent, complex coupling in superspace. Super-Yang-Mills theories
with local coupling have an anomaly, which has been first investigated in the
Wess-Zumino gauge and there identified as an anomaly of supersymmetry. In a
manifest supersymmetric formulation the anomaly appears in two other
identities: The first one describes the non-renormalization of the topological
term, the second relates the renormalization of the gauge coupling to the
renormalization of the complex supercoupling. Only one of the two identities
can be maintained in perturbation theory. We discuss the two versions and
derive the respective beta function of the local supercoupling, which is
non-holomorphic in the first version, but directly related to the coupling
renormalization, and holomorphic in the second version, but has a non-trivial,
i.e.anomalous, relation to the beta function of the gauge coupling.Comment: References correcte
Coexistence of long-range order for two observables at finite temperatures
We give a criterion for the simultaneous existence or non existence of two
long-range orders for two observables, at finite temperatures, for quantum
lattice many body systems. Our analysis extends previous results of G.-S. Tian
limited to the ground state of similar models. The proof involves an inequality
of Dyson-Lieb-Simon which connects the Duhamel two-point function to the usual
correlation function. An application to the special case of the Holstein model
is discussed.Comment: 12 pages, accepted for publication in J. of Phys.
SU(m|n) supersymmetric Calogero-Sutherland model confined in harmonic potential
In this work, we study a continuous quantum system of a mixture of bosons and
fermions with the supersymmetry SU(m|n). The particles are confined in a
harmonic well and interact with each other through the 1/r2 interaction. The
ground state wavefunction is constructed explicitly for the most general
SU(m|n) case, with the ground state energy given explicitly. The full energy
spectrum of excitations in the SU(m|n) model is also equal spaced. In the
limiting case where there are no bosons in the system, our results reduce to
those obtained previously.Comment: 9 pages, preprint of ETH-Lausanne (August 1996
Finiteness in N=1 SYM Theories
I present a criterion for all-order finiteness in N=1 SYM theories. Three
applications are given; they yield all-order finite N=1 SYM models with global
symmetries of the superpotential.Comment: 3 pages, plain LaTex, no figure
Constructive algebraic renormalization of the abelian Higgs-Kibble model
We propose an algorithm, based on Algebraic Renormalization, that allows the
restoration of Slavnov-Taylor invariance at every order of perturbation
expansion for an anomaly-free BRS invariant gauge theory. The counterterms are
explicitly constructed in terms of a set of one-particle-irreducible Feynman
amplitudes evaluated at zero momentum (and derivatives of them). The approach
is here discussed in the case of the abelian Higgs-Kibble model, where the zero
momentum limit can be safely performed. The normalization conditions are
imposed by means of the Slavnov-Taylor invariants and are chosen in order to
simplify the calculation of the counterterms. In particular within this model
all counterterms involving BRS external sources (anti-fields) can be put to
zero with the exception of the fermion sector.Comment: Jul, 1998, 31 page
Algebraic Properties of BRST Coupled Doublets
We characterize the dependence on doublets of the cohomology of an arbitrary
nilpotent differential s (including BRST differentials and classical linearized
Slavnov-Taylor (ST) operators) in terms of the cohomology of the
doublets-independent component of s. All cohomologies are computed in the space
of local integrated formal power series. We drop the usual assumption that the
counting operator for the doublets commutes with s (decoupled doublets) and
discuss the general case where the counting operator does not commute with s
(coupled doublets). The results are purely algebraic and do not rely on
power-counting arguments.Comment: Some explanations enlarged, references adde
Off-diagonal long-range order and meissner effect for lattice systems
We study some general properties of a strongly correlated electron system defined on a lattice. Assuming that the system exhibits off-diagonal long-range order, we show that this assumption implies the Meissner effect. This extends to lattice systems previous results obtained for the continuous cas
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