17 research outputs found
Modified convex hull pricing for fixed load power markets
We consider fixed load power market with non-convexities originating from
start-up and no-load costs of generators. The convex hull (minimal uplift)
pricing method results in power prices minimizing the total uplift payments to
generators, which compensate their potential profits lost by accepting
centralized dispatch solution, treating as foregone all opportunities to supply
any other output volume allowed by generator internal constraints. For each
generator we define a set of output volumes, which are economically and
technologically feasible in the absence of centralized dispatch, and propose to
exclude output volumes outside the set from lost profit calculations. New
pricing method results in generally different set of market prices and lower
(or equal) total uplift payment compared to convex hull pricing algorithm.Comment: v.3 (section on comparison with convex hull pricing extended,
references added
Topological Disorder Operators in Three-Dimensional Conformal Field Theory
Many abelian gauge theories in three dimensions flow to interacting conformal
field theories in the infrared. We define a new class of local operators in
these conformal field theories which are not polynomial in the fundamental
fields and create topological disorder. They can be regarded as
higher-dimensional analogues of twist and winding-state operators in free 2d
CFTs. We call them monopole operators for reasons explained in the text. The
importance of monopole operators is that in the Higgs phase, they create
Abrikosov-Nielsen-Olesen vortices. We study properties of these operators in
three-dimensional QED using large N_f expansion. In particular, we show that
monopole operators belong to representations of the conformal group whose
primaries have dimension of order N_f. We also show that monopole operators
transform non-trivially under the flavor symmetry group, with the precise
representation depending on the value of the Chern-Simons coupling.Comment: 24 pages, latex. v2: a reference to prior work has been adde
Monopole operators and mirror symmetry in three dimensions
We study vortex-creating, or monopole, operators in 3d CFTs which are the infrared limit of N = 2 and N = 4 supersymmetric QEDs in three dimensions. Using large-N-f expansion, we construct monopole operators which are primaries of short representations of the superconformal algebra. Mirror symmetry in three dimensions makes a number of predictions about such operators, and our results confirm these predictions. Furthermore, we argue that some of our large-N-f results are exact. This implies, in particular, that certain monopole operators in N = 4 d = 3 SQED with N-f = 1 are free fields. This amounts to a proof of 3d mirror symmetry in a special case
Monopole operators in three-dimensional N=4 SYM and mirror symmetry
We study non-abelian monopole operators in the infrared limit of
three-dimensional SU(N_c) and N=4 SU(2) gauge theories. Using large N_f
expansion and operator-state isomorphism of the resulting superconformal field
theories, we construct monopole operators which are (anti-)chiral primaries and
compute their charges under the global symmetries. Predictions of
three-dimensional mirror symmetry for the quantum numbers of these monopole
operators are verified.Comment: 23 pages, LaTex; v2: section 3.4 modified, section 3.5 extended,
references adde
Belinfante Tensors Induced by Matter-Gravity Couplings
We show that any generally covariant coupling of matter fields to gravity
gives rise to a conserved, on-shell symmetric energy-momentum tensor equivalent
to the canonical energy-momentum tensor of the flat-space theory. For matter
fields minimally coupled to gravity our algorithm gives the conventional
Belinfante tensor. We establish that different matter-gravity couplings give
metric energy-momentum tensors differing by identically conserved tensors. We
prove that the metric energy-momentum tensor obtained from an arbitrary gravity
theory is on-shell equivalent to the canonical energy-momentum tensor of the
flat-space theory.Comment: 10 pages, LaTex; misprints corrected, references added; to appear in
Physical Review
Non-supersymmetric deformations of the dual of a confining gauge theory
We introduce a computational technique for studying non-supersymmetric
deformations of domain wall solutions of interest in AdS/CFT. We focus on the
Klebanov-Strassler solution, which is dual to a confining gauge theory. From an
analysis of asymptotics we find that there are three deformations that leave
the ten-dimensional supergravity solution regular and preserve the global
bosonic symmetries of the supersymmetric solution. Also, we show that there are
no regular near-extremal deformations preserving the global symmetries, as one
might expect from the existence of a gap in the gauge theory.Comment: 18 pages, latex, published as JHEP 0305 (2003) 03
Monopole Operators and Mirror Symmetry in Three-Dimensional Gauge Theories
Many gauge theories in three dimensions flow to interacting conformal field theories in the infrared. We define a new class of local operators in these conformal field theories that are not polynomial in the fundamental fields and create topological disorder. They can be regarded as higher-dimensional analogs of twist and winding-state operators in free 2-D CFTs. We call them monopole operators for reasons explained in the text. The importance of monopole operators is that in the Higgs phase, they create Abrikosov-Nielsen-Olesen vortices. We study properties of these operators in three-dimensional gauge theories using large N_f expansion. For non-supersymmetric gauge theories we show that monopole operators belong to representations of the conformal group whose primaries have dimension of order N_f. We demonstrate that these monopole operators transform non-trivially under the flavor symmetry group.
We also consider topology-changing operators in the infrared limits of N=2 and N=4 supersymmetric QED as well as N=4 SU(2) gauge theory in three dimensions. Using large N_f expansion and operator-state isomorphism of the resulting superconformal field theories, we construct monopole operators that are primaries of short representation of the superconformal algebra and compute their charges under the global symmetries. Predictions of three-dimensional mirror symmetry for the quantum numbers of these monopole operators are verified. Furthermore, we argue that some of our large-N_f results are exact. This implies, in particular, that certain monopole operators in N=4 3-D SQED with N_f=1 are free fields. This amounts to a proof of 3-D mirror symmetry in these special cases.</p