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We present a very simple algorithm for computing Pfaffians which uses no division operations. Essentially, it amounts to iterating matrix multiplication and truncation. Its complexity, for a $2n\times 2n$ matrix, is $O(nM(n))$, where $M(n)$…

Data Structures and Algorithms · Computer Science 2023-02-24 Adam J. Przezdziecki

We show that cluster algorithms for quantum models have a meaning independent of the basis chosen to construct them. Using this idea, we propose a new method for measuring with little effort a whole class of Green's functions, once a…

Statistical Mechanics · Physics 2015-06-25 R. Brower , S. Chandrasekharan , U. -J. Wiese

This paper introduces a new Windowed Green Function (WGF) method for the numerical integral-equation solution of problems of electromagnetic scattering by obstacles in presence of dielectric or conducting half-planes. The WGF method, which…

Computational Physics · Physics 2015-08-05 Oscar Bruno , Mark Lyon , Carlos Perez-Arancibia , Catalin Turc

In this paper, we present a numerical algorithm for the accurate and efficient computation of the convolution of the frequency domain layered media Green's function with a given density function. Instead of compressing the convolution…

Numerical Analysis · Mathematics 2020-06-16 Min Hyung Cho , Jingfang Huang

In this article we derive the lattice Green Functions (GFs) of graphene using a Tight Binding Hamiltonian incorporating both first and second nearest neighbour hoppings and allowing for a non-orthogonal electron wavefunction overlap. It is…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 James A. Lawlor , Mauro S. Ferreira

We derive the (matrix-valued) Feynman rules of the mass perturbation theory and use it for the resummation of the $n$-point functions with the help of the Dyson-Schwinger equations. We use these results for a short review of the complete…

High Energy Physics - Theory · Physics 2009-07-24 C. Adam

This is the 4-th paper in the series devoted to a systematic study of the problem of mathematically correct formulation of the rules needed to manage an effective field theory. Here we consider the problem of constructing the full set of…

High Energy Physics - Theory · Physics 2009-11-10 A. Vereshagin , V. Vereshagin

We present a method for the computation of hepta-cuts of two loop scattering amplitudes. Four dimensional unitarity cuts are used to factorise the integrand onto the product of six tree-level amplitudes evaluated at complex momentum values.…

High Energy Physics - Phenomenology · Physics 2012-04-18 Simon Badger , Hjalte Frellesvig , Yang Zhang

By building upon the recent theory that established the connection between implicit generative modeling (IGM) and optimal transport, in this study, we propose a novel parameter-free algorithm for learning the underlying distributions of…

Machine Learning · Statistics 2019-06-12 Antoine Liutkus , Umut Şimşekli , Szymon Majewski , Alain Durmus , Fabian-Robert Stöter

When we consider a finite abelian group acting linearly on a polynomial ring, we can find monomial generators for the subring of invariants. By Noether's degree bound and Hilbert's finiteness theorem, we know that there are finitely many…

Commutative Algebra · Mathematics 2026-05-20 Sasha Arasha , Marcus Cassell , Mal Dolorfino , Francesca Gandini , Gordie Novak , Daniel Qin , Sumner Strom

In this paper, a new inversion model for 2D microwave imaging is introduced by means of a convenient rewriting of the usual Lippmann Schwinger integral scattering equation. Such model is derived by decomposing the Greens function and the…

Signal Processing · Electrical Eng. & Systems 2021-03-01 Martina T. Bevacqua , Tommaso Isernia

We derive a method to efficiently compute the Green function of on arbitrary Hamiltonians defined on semi-infinite and periodic quasi-one-dimensional lattices. Computing the Green function is the backbone of quantum transport, electronic…

Mesoscale and Nanoscale Physics · Physics 2021-05-18 Pablo San-Jose

Reflection and transmission of waves in piecewise constant layered media are important in various imaging modalities and have been studied extensively. Despite this, no exact time domain formulas for the Green's functions have been…

Combinatorics · Mathematics 2013-05-20 Peter C. Gibson

We extend earlier constructions of the effective action for neutrino-photon scattering, using the connection between low-energy neutrino-photon and photon-photon scattering together with the known effective Lagrangian describing low-energy…

High Energy Physics - Phenomenology · Physics 2009-10-31 Y. Aghababaie , C. P. Burgess

Recently we introduced the chirality-flow formalism, a method which builds on the spinor-helicity formalism and is inspired by the color-flow idea in QCD. With this formalism, Feynman rules and diagrams are simplified to the extent that it…

High Energy Physics - Phenomenology · Physics 2022-07-06 Andrew Lifson , Malin Sjodahl , Zenny Wettersten

It is a classical problem to compute a minimal set of invariant polynomial generating the invariant ring of a finite group as an algebra. We present here an algorithm for the computation of minimal generating sets in the non-modular case.…

Commutative Algebra · Mathematics 2012-10-25 Simon King

We present a new algorithm to rapidly and optimally compute power spectra. This new algorithm is based on a generalization of iterative multigrid, and has computational cost O(N log N), compared to the standard brute force approach which…

Astrophysics · Physics 2009-11-07 Ue-Li Pen

We present a numerically stable Quantum Monte Carlo algorithm to calculate zero-temperature imaginary-time Green functions $ G(\vec{r}, \tau) $ for Hubbard type models. We illustrate the efficiency of the algorithm by calculating the…

Condensed Matter · Physics 2009-10-28 F. F. Assaad , M. Imada

The Fermi surface symmetric mass generation (SMG) is an intrinsically interaction-driven mechanism that opens an excitation gap on the Fermi surface without invoking symmetry-breaking or topological order. We explore this phenomenon within…

Strongly Correlated Electrons · Physics 2023-07-25 Da-Chuan Lu , Meng Zeng , Yi-Zhuang You

We present an alternative to the Higgs mechanism to generate masses for non-abelian gauge fields in (3+1)-dimensions. The initial Lagrangian is composed of a fermion with current-current and dipole-dipole type self-interactions minimally…

High Energy Physics - Theory · Physics 2009-10-28 Didier Caenepeel , Martin Leblanc