197 citations · 1k across the 20 of their papers we have counts for
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Differential equations for loop integrals without squared propagators
Jorrit Bosma, Kasper J. Larsen, Yang Zhang
We provide a sufficient condition for avoiding squared propagators in the intermediate stages of setting up differential equations for loop integrals. This condition is satisfied i…
Complete integration-by-parts reductions of the non-planar hexagon-box via module intersections
Janko Boehm, Alessandro Georgoudis, Kasper J. Larsen +2
We present the powerful module-intersection integration-by-parts (IBP) method, suitable for multi-loop and multi-scale Feynman integral reduction. Utilizing modern computational al…
MultivariateResidues - a Mathematica package for computing multivariate residues
Kasper J. Larsen, Robbert Rietkerk
We present the Mathematica package MultivariateResidues, which allows for the efficient evaluation of multivariate residues based on methods from computational algebraic geometry.…
Complete sets of logarithmic vector fields for integration-by-parts identities of Feynman integrals
Janko Boehm, Alessandro Georgoudis, Kasper J. Larsen +2
Integration-by-parts identities between loop integrals arise from the vanishing integration of total derivatives in dimensional regularization. Generic choices of total derivatives…
Differential equations for loop integrals in Baikov representation
Jorrit Bosma, Kasper J. Larsen, Yang Zhang
We present a proof that differential equations for Feynman loop integrals can always be derived in Baikov representation without involving dimension-shift identities. We moreover s…
Azurite: An algebraic geometry based package for finding bases of loop integrals
Alessandro Georgoudis, Kasper J. Larsen, Yang Zhang
For any given Feynman graph, the set of integrals with all possible powers of the propagators spans a vector space of finite dimension. We introduce the package {\sc Azurite} ({\bf…
MultivariateResidues: a Mathematica package for computing multivariate residues
Kasper J. Larsen, Robbert Rietkerk
Multivariate residues appear in many different contexts in theoretical physics and algebraic geometry. In theoretical physics, they for example give the proper definition of genera…
Integration-by-parts reductions from the viewpoint of computational algebraic geometry
Kasper J. Larsen, Yang Zhang
Integration-by-parts reductions play a central role in perturbative QFT calculations. They allow the set of Feynman integrals contributing to a given observable to be reduced to a…
Integration-by-parts reductions from unitarity cuts and algebraic geometry
Kasper J. Larsen, Yang Zhang
We show that the integration-by-parts reductions of various two-loop integral topologies can be efficiently obtained by applying unitarity cuts to a specific set of subgraphs and s…
Cross-Order Integral Relations from Maximal Cuts
Henrik Johansson, David A. Kosower, Kasper J. Larsen +1
We study the ABDK relation using maximal cuts of one- and two-loop integrals with up to five external legs. We show how to find a special combination of integrals that allows the r…
Imaginary parts and discontinuities of Wilson line correlators
Eric Laenen, Kasper J. Larsen, Robbert Rietkerk
We introduce a notion of position-space cuts of eikonal diagrams, the set of diagrams appearing in the perturbative expansion of the correlator of a set of straight semi-infinite W…
Maximal Unitarity for the Four-Mass Double Box
Henrik Johansson, David A. Kosower, Kasper J. Larsen
We extend the maximal-unitarity formalism at two loops to double-box integrals with four massive external legs. These are relevant for higher-point processes, as well as for heavy…
An Overview of Maximal Unitarity at Two Loops
Henrik Johansson, David A. Kosower, Kasper J. Larsen
We discuss the extension of the maximal-unitarity method to two loops, focusing on the example of the planar double box. Maximal cuts are reinterpreted as contour integrals, with t…
Two-Loop Maximal Unitarity with External Masses
Henrik Johansson, David A. Kosower, Kasper J. Larsen
We extend the maximal unitarity method at two loops to double-box basis integrals with up to three external massive legs. We use consistency equations based on the requirement that…
Global Poles of the Two-Loop Six-Point N=4 SYM integrand
Kasper J. Larsen
Recently, a recursion relation has been developed, generating the four-dimensional integrand of the amplitudes of N=4 supersymmetric Yang-Mills theory for any number of loops and l…
Maximal Unitarity at Two Loops
David A. Kosower, Kasper J. Larsen
We show how to compute the coefficients of the double box basis integrals in a massless four-point amplitude in terms of tree amplitudes. We show how to choose suitable multidimens…
MHV, CSW and BCFW: field theory structures in string theory amplitudes
Rutger Boels, Kasper J. Larsen, Niels A. Obers +1
Motivated by recent progress in calculating field theory amplitudes, we study applications of the basic ideas in these developments to the calculation of amplitudes in string theor…
Phases of Thermal N=2 Quiver Gauge Theories
Kasper J. Larsen, Niels A. Obers
We consider large N U(N)^M thermal N=2 quiver gauge theories on S^1 x S^3. We obtain a phase diagram of the theory with R-symmetry chemical potentials, separating a low-temperature…