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Building on the idea of numerically integrating differential equations satisfied by Feynman integrals, we propose a novel strategy for handling branch cuts within a numerical framework. We develop an integrator capable of evaluating a basis…

High Energy Physics - Phenomenology · Physics 2025-07-18 Pau Petit Rosàs , William J. Torres Bobadilla

We introduce a new theoretical framework based on Feynman diagrams to compute phase shifts in matter wave interferometry. The method allows for analytic computation of higher order quantum corrections, beyond the traditional semi-classical…

Atomic Physics · Physics 2026-05-14 Jonah Glick , Tim Kovachy

We completely generalize previous results related to the counting of connected Feynman diagrams. We use a generating function approach, which encodes the Wick contraction combinatorics of the respective connected diagrams. Exact solutions…

Mathematical Physics · Physics 2020-05-12 Erick Ramon Castro , Itzhak Roditi

We describe an efficient practical procedure for enumerating and regrouping vacuum Feynman graphs of a given order in perturbation theory. The method is based on a combination of Schwinger-Dyson equations and the two-particle-irreducible…

High Energy Physics - Phenomenology · Physics 2009-11-07 K. Kajantie , M. Laine , Y. Schroder

We describe an algebraic algorithm which allows to express every one-loop lattice integral with gluon or Wilson-fermion propagators in terms of a small number of basic constants which can be computed with arbitrary high precision. Although…

High Energy Physics - Lattice · Physics 2009-10-28 Giuseppe Burgio , Sergio Caracciolo , Andrea Pelissetto

We argue that the Mellin-Barnes representations of Feynman diagrams can be used for obtaining linear systems of homogeneous differential equations for the original Feynman diagrams with arbitrary powers of propagators without recourse to…

High Energy Physics - Theory · Physics 2015-06-05 Mikhail Yu. Kalmykov , Bernd A. Kniehl

We compute the two-loop renormalization functions, in the RI' scheme, of local bilinear quark operators $\bar{\psi}\Gamma\psi$, where $\Gamma$ corresponds to the Vector, Axial-Vector and Tensor Dirac operators, in the lattice formulation of…

High Energy Physics - Lattice · Physics 2009-07-30 A. Skouroupathis , H. Panagopoulos

We present a matrix formalism, inspired by the Minkowski four-vectors of special relativity, useful to solve classical physics problems related to both mechanics and thermodynamics. The formalism turns out to be convenient to deal with…

Classical Physics · Physics 2014-02-11 Julio Güémez , Manuel Fiolhais

Eigenvalue distributions are important dynamical quantities in matrix models, and it is an interesting challenge to study corresponding quantities in tensor models. We study real tensor eigenvalue/vector distributions for real symmetric…

High Energy Physics - Theory · Physics 2022-12-16 Naoki Sasakura

An efficient way to calculate one-loop counterterms within the Feynman diagrammatic approach and dimensional regularization is to expand the propagators in the integrands of the Feynman integrals around vanishing external momentum. In this…

High Energy Physics - Phenomenology · Physics 2019-09-04 Christian F. Steinwachs

An algorithm for calculating two-loop propagator type Feynman diagrams with arbitrary masses and external momentum is proposed. Recurrence relations allowing to express any scalar integral in terms of basic integrals are given. A minimal…

High Energy Physics - Phenomenology · Physics 2009-10-30 O. V. Tarasov

The sign cancellation between scattering amplitudes makes fermions different from bosons. We systematically investigate Feynman diagrams' fermionic sign structure in a representative many-fermion system---a uniform Fermi gas with Yukawa…

Quantum Gases · Physics 2021-03-31 Bao-Zong Wang , Peng-Cheng Hou , Youjin Deng , Kristjan Haule , Kun Chen

We propose and test an algorithm to simulate a lattice system of interacting fermions in two spatial dimensions. The approach is an extension of the entanglement renormalization technique [Phys. Rev. Lett. 99, 220405 (2007)] and the related…

Strongly Correlated Electrons · Physics 2010-03-05 Philippe Corboz , Glen Evenbly , Frank Verstraete , Guifre Vidal

A new integration technique for multi-loop Feynman integrals, called the matrix method, is developed and then applied to the divergent part of the overlapping two-loop quark self-energy function $\,i\Sigma\,$ in the light- cone gauge. It is…

High Energy Physics - Theory · Physics 2009-10-28 George Leibbrandt , Jimmy Williams

In this paper, we analyze a virtual element method (VEM) for solving a non-selfadjoint fourth-order eigenvalue problem derived from the transmission eigenvalue problem. We write a variational formulation and propose a $C^1$-conforming…

Numerical Analysis · Mathematics 2018-03-12 David Mora , Iván Velásquez

We present a new method for numerically computing generic multi-loop Feynman integrals. The method relies on an iterative application of Feynman's trick for combining two propagators. Each application of Feynman's trick introduces a…

High Energy Physics - Phenomenology · Physics 2022-06-30 Martijn Hidding , Johann Usovitsch

A scheme for systematically achieving accurate numerical evaluation of multi-loop Feynman diagrams is developed. This shows the feasibility of a project aimed to produce a complete calculation for two-loop predictions in the Standard Model.…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Passarino

Feynman integrals obey linear relations governed by intersection numbers, which act as scalar products between vector spaces. We present a general algorithm for constructing multivariate intersection numbers relevant to Feynman integrals,…

High Energy Physics - Theory · Physics 2019-11-20 Hjalte Frellesvig , Federico Gasparotto , Manoj K. Mandal , Pierpaolo Mastrolia , Luca Mattiazzi , Sebastian Mizera

We present an iterative algorithm to count Feynman diagrams via many-body relations. The algorithm allows us to count the number of diagrams of the exact solution for the general fermionic many-body problem at each order in the interaction.…

Strongly Correlated Electrons · Physics 2018-08-27 Fabian B. Kugler

Lattice field theory is a useful tool for studying strongly interacting theories in condensed matter physics. A prominent example is the unitary Fermi gas: a two-component system of fermions interacting with divergent scattering length.…

Quantum Gases · Physics 2011-03-23 Olga Goulko , Matthew Wingate