2,026 research outputs found
Antisymplectic Gauge Theories
A general field-antifield BV formalism for antisymplectic first class
constraints is proposed. It is as general as the corresponding symplectic
BFV-BRST formulation and it is demonstrated to be consistent with a previously
proposed formalism for antisymplectic second class constraints through a
generalized conversion to corresponding first class constraints. Thereby the
basic concept of gauge symmetry is extended to apply to quite a new class of
gauge theories potentially possible to exist.Comment: 13 pages,Latexfile,New introductio
Characteristic classes of gauge systems
We define and study invariants which can be uniformly constructed for any
gauge system. By a gauge system we understand an (anti-)Poisson supermanifold
provided with an odd Hamiltonian self-commuting vector field called a
homological vector field. This definition encompasses all the cases usually
included into the notion of a gauge theory in physics as well as some other
similar (but different) structures like Lie or Courant algebroids. For
Lagrangian gauge theories or Hamiltonian first class constrained systems, the
homological vector field is identified with the classical BRST transformation
operator. We define characteristic classes of a gauge system as universal
cohomology classes of the homological vector field, which are uniformly
constructed in terms of this vector field itself. Not striving to exhaustively
classify all the characteristic classes in this work, we compute those
invariants which are built up in terms of the first derivatives of the
homological vector field. We also consider the cohomological operations in the
space of all the characteristic classes. In particular, we show that the
(anti-)Poisson bracket becomes trivial when applied to the space of all the
characteristic classes, instead the latter space can be endowed with another
Lie bracket operation. Making use of this Lie bracket one can generate new
characteristic classes involving higher derivatives of the homological vector
field. The simplest characteristic classes are illustrated by the examples
relating them to anomalies in the traditional BV or BFV-BRST theory and to
characteristic classes of (singular) foliations.Comment: 23 pages, references added, typos correcte
Loop expansion in Yang-Mills thermodynamics
We argue that a selfconsistent spatial coarse-graining, which involves
interacting (anti)calorons of unit topological charge modulus, implies that
real-time loop expansions of thermodynamical quantities in the deconfining
phase of SU(2) and SU(3) Yang-Mills thermodynamics are, modulo 1PI
resummations, determined by a finite number of connected bubble diagrams.Comment: 15 pages, 2 figures, v5: discussion of much more severely constrained
nonplanar situation included in Sec.
Distinct roles of nonmuscle myosin ii isoforms for establishing tension and elasticity during cell morphodynamics
Nonmuscle myosin II (NM II) is an integral part of essential cellular processes, including adhesion and migration. Mammalian cells express up to three isoforms termed NM IIA, B, and C. We used U2OS cells to create CRISPR/Cas9-based knockouts of all three isoforms and analyzed the phenotypes on homogenously coated surfaces, in collagen gels, and on micropatterned substrates. In contrast to homogenously coated surfaces, a structured environment supports a cellular phenotype with invaginated actin arcs even in the absence of NM IIA-induced contractility. A quantitative shape analysis of cells on micropatterns combined with a scale-bridging mathematical model reveals that NM IIA is essential to build up cellular tension during initial stages of force generation, while NM IIB is necessary to elastically stabilize NM IIA-generated tension. A dynamic cell stretch/release experiment in a three-dimensional scaffold confirms these conclusions and in addition reveals a novel role for NM IIC, namely the ability to establish tensional homeostasis
Asymptotic Conformal Invariance in a Non-Abelian Chern-Simons-Matter Model
One shows here the existence of solutions to the Callan-Symanzik equation for
the non-Abelian SU(2) Chern-Simons-matter model which exhibits asymptotic
conformal invariance to every order in perturbative theory. The conformal
symmetry in the classical domain is shown to hold by means of a local criteria
based on the trace of the energy-momentum tensor. By using the recently
exhibited regimes for the dependence between the several couplings in which the
set of -functions vanish, the asymptotic conformal invariance of the
model appears to be valid in the quantum domain. By considering the SU(n) case
the possible non validity of the proof for a particular n would be merely
accidental.Comment: Latex2e 8 page
Simplifications in Lagrangian BV quantization exemplified by the anomalies of chiral gravity
The Batalin--Vilkovisky (BV) formalism is a useful framework to study gauge
theories. We summarize a simple procedure to find a a gauge--fixed action in
this language and a way to obtain one--loop anomalies. Calculations involving
the antifields can be greatly simplified by using a theorem on the antibracket
cohomology. The latter is based on properties of a `Koszul--Tate differential',
namely its acyclicity and nilpotency. We present a new proof for this
acyclicity, respecting locality and covariance of the theory. This theorem then
implies that consistent higher ghost terms in various expressions exist, and it
avoids tedious calculations.
This is illustrated in chiral gravity. We compute the one--loop anomaly
without terms of negative ghost number. Then the mentioned theorem and the
consistency condition imply that the full anomaly is determined up to local
counterterms. Finally we show how to implement background charges into the BV
language in order to cancel the anomaly with the appropriate counterterms.
Again we use the theorem to simplify the calculations, which agree with
previous results.Comment: 45 page
Odd Scalar Curvature in Anti-Poisson Geometry
Recent works have revealed that the recipe for field-antifield quantization
of Lagrangian gauge theories can be considerably relaxed when it comes to
choosing a path integral measure \rho if a zero-order term \nu_{\rho} is added
to the \Delta operator. The effects of this odd scalar term \nu_{\rho} become
relevant at two-loop order. We prove that \nu_{\rho} is essentially the odd
scalar curvature of an arbitrary torsion-free connection that is compatible
with both the anti-Poisson structure E and the density \rho. This extends a
previous result for non-degenerate antisymplectic manifolds to degenerate
anti-Poisson manifolds that admit a compatible two-form.Comment: 9 pages, LaTeX. v2: Minor changes. v3: Published versio
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