67 citations · 528 across the 47 of their papers we have counts for
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Semi-Differential Operators and the Algebra of Operator Product Expansion of Quantum Fields
Nikolay M. Nikolov
We introduce a symmetric operad whose algebras are the Operator Product Expansion (OPE) Algebras of quantum fields. There is a natural classical limit for the algebras over this op…
Renormalization of Massless Feynman Amplitudes in Configuration Space
Nikolay M. Nikolov, Raymond Stora, Ivan Todorov
A systematic study of recursive renormalization of Feynman amplitudes is carried out both in Euclidean and in Minkowski configuration space. For a massless quantum field theory (QF…
Renormalization theory of Feynman amplitudes on configuration spaces
Nikolay M. Nikolov
In a previous paper "Anomalies in Quantum Field Theory and Cohomologies of Configuration Spaces" (arXiv:0903.0187) we presented a new method for renormalization in Euclidean config…
Cohomological analysis of the Epstein-Glaser renormalization
Nikolay M. Nikolov
A cohomological analysis of the renormalization freedom is performed in the Epstein-Glaser scheme on a flat Euclidean space. We study the deviation from commutativity between the r…
Pole structure and biharmonic fields in conformal QFT in four dimensions
N. M. Nikolov, K. -H. Rehren, I. Todorov
Imposing Huygens' Principle in a 4D Wightman QFT puts strong constraints on its algebraic and analytic structure. These are best understood in terms of ``biharmonic fields'', whose…
Infinite dimensional Lie algebras in 4D conformal quantum field theory
B. Bakalov, N. M. Nikolov, K. -H. Rehren +1
The concept of global conformal invariance (GCI) opens the way of applying algebraic techniques, developed in the context of 2-dimensional chiral conformal field theory, to a highe…
Harmonic bilocal fields generated by globally conformal invariant scalar fields
Nikolay M. Nikolov, Karl-Henning Rehren, Ivan Todorov
The twist two contribution in the operator product expansion of phi_1(x_1) phi_2(x_2) for a pair of globally conformal invariant, scalar fields of equal scaling dimension d in four…
Partial wave expansion and Wightman positivity in conformal field theory
N. M. Nikolov, K. -H. Rehren, I. T. Todorov
A new method for computing exact conformal partial wave expansions is developed and applied to approach the problem of Hilbert space (Wightman) positivity in a non-perturbative fou…
Elliptic Thermal Correlation Functions and Modular Forms in a Globally Conformal Invariant QFT
Nikolay M. Nikolov, Ivan T. Todorov
Global conformal invariance (GCI) of quantum field theory (QFT) in two and higher space-time dimensions implies the Huygens' principle, and hence, rationality of correlation functi…
Vertex Algebras in Higher Dimensions and Globally Conformal Invariant Quantum Field Theory
Nikolay M. Nikolov
We propose an extension of the definition of vertex algebras in arbitrary space-time dimensions together with their basic structure theory. An one-to-one correspondence between the…
Globally conformal invariant gauge field theory with rational correlation functions
Nikolay M. Nikolov, Yassen S. Stanev, Ivan T. Todorov
Operator product expansions (OPE) for the product of a scalar field with its conjugate are presented as infinite sums of bilocal fields V_k (x_1, x_2) of dimension (k,k). For a {\i…
Global Conformal Invariance and Bilocal Fields with Rational Correlation Functions
Nikolay M. Nikolov, Yassen S. Stanev, Ivan T. Todorov
The singular part of the \textit{operator product expansion} (OPE) of a pair of \textit{globally conformal invariant} (GCI) scalar fields of (integer) dimension can be writ…
Four Dimensional CFT Models with Rational Correlation Functions
Nikolay M. Nikolov, Yassen S. Stanev, Ivan T. Todorov
Recently established rationality of correlation functions in a globally conformal invariant quantum field theory satisfying Wightman axioms is used to construct a family of soluble…
Rationality of conformally invariant local correlation functions on compactified Minkowski space
Nikolay M. Nikolov, Ivan T. Todorov
Rationality of the Wightman functions is proven to follow from energy positivity, locality and a natural condition of global conformal invariance (GCI) in any number D of space-tim…