Zobrazeno 1 - 10
of 4 499
pro vyhledávání: '"Sinn, P."'
We study spurious second-order stationary points and local minima in a nonconvex low-rank formulation of sum-of-squares optimization on a real variety $X$. We reformulate the problem of finding a spurious local minimum in terms of syzygies of the und
Externí odkaz:
http://arxiv.org/abs/2411.02208
We study the Pythagoras numbers $py(3,2d)$ of real ternary forms, defined for each degree $2d$ as the minimal number $r$ such that every degree $2d$ ternary form which is a sum of squares can be written as the sum of at most $r$ squares of degree $d$
Externí odkaz:
http://arxiv.org/abs/2410.17123
We introduce tools for transferring nonnegativity certificates for global sections between line bundles on real algebraic surfaces. As applications, we improve Hilbert's degree bounds on sum-of-squares multipliers for nonnegative ternary forms, give
Externí odkaz:
http://arxiv.org/abs/2409.08834
Every polygon with n vertices in the complex projective plane is naturally associated with its adjoint curve of degree n-3. Hence the adjoint of a heptagon is a plane quartic. We prove that a general plane quartic is the adjoint of exactly 864 distin
Externí odkaz:
http://arxiv.org/abs/2408.15759
The cone of nonnegative polynomials is of fundamental importance in real algebraic geometry, but its facial structure is understood in very few cases. We initiate a systematic study of the facial structure of the cone of nonnegative polynomials $\pos
Externí odkaz:
http://arxiv.org/abs/2407.06017
Autor:
Thévenet, Maxence, Andriyash, Igor A., Fedeli, Luca, Pousa, Ángel Ferran, Huebl, Axel, Jalas, Sören, Kirchen, Manuel, Lehe, Remi, Shalloo, Rob J., Sinn, Alexander, Vay, Jean-Luc
Using realistic laser profiles for simulations of laser-plasma interaction is critical to reproduce experimental measurements, but the interface between experiments and simulations can be challenging. Similarly, start-to-end simulations with differen
Externí odkaz:
http://arxiv.org/abs/2403.12191
Autor:
Myers, Andrew, Zhang, Weiqun, Almgren, Ann, Antoun, Thierry, Bell, John, Huebl, Axel, Sinn, Alexander
AMReX is a software framework for the development of block-structured mesh applications with adaptive mesh refinement (AMR). AMReX was initially developed and supported by the AMReX Co-Design Center as part of the U.S. DOE Exascale Computing Project,
Externí odkaz:
http://arxiv.org/abs/2403.12179
Autor:
Diederichs, Severin, Benedetti, Carlo, Pousa, Angel Ferran, Sinn, Alexander, Osterhoff, Jens, Schroeder, Carl B., Thévenet, Maxence
Linear colliders rely on high-quality flat beams to achieve the desired event rate, while avoiding potentially deleterious beamstrahlung effects. Here, we show that flat beams in plasma accelerators can be subject to quality degradation due to emitta
Externí odkaz:
http://arxiv.org/abs/2403.05871
Publikováno v:
Mathematica Scandinavica, 130(3), 433-466 (2024)
We consider semi-algebraic subsets of the Grassmannian of lines in three-space called tree amplituhedra. These arise in the study of scattering amplitudes from particle physics. Our main result states that tree amplituhedra in ${\rm Gr}(2,4)$ are pos
Externí odkaz:
http://arxiv.org/abs/2402.06527
Autor:
Diederichs, Severin, Benedetti, Carlo, Esarey, Eric, Sinn, Alexander, Osterhoff, Jens, Schroeder, Carl B., Thévenet, Maxence
Preserving the quality of positron beams in plasma-based accelerators, where wakefields are generated in electron filaments, is challenging. These wakefields are characterized by transversely non-linear focusing fields and non-uniform accelerating fi
Externí odkaz:
http://arxiv.org/abs/2311.07402