5 citations · 5 across the 13 of their papers we have counts for
15 papers
Towards a Floer theory for Mars II -- Floer Hessian field almost extends
Urs Frauenfelder, Joa Weber
In part I, \cite{Frauenfelder:2026c}, we showed that collisional periodic orbits of twisted Zeeman systems can be detected variationally by a non-local Hamiltonian action functiona…
Towards a Floer theory for Mars I -- Twisted Zeeman systems
Urs Frauenfelder, Joa Weber
In this article we study periodic orbits of an electron attracted by a proton subject to Lorentz, electric, and Euler forces where each of them is allowed to depend periodically on…
The kei word metric on the transvection group and its unit ball
Urs Frauenfelder, Lei Zhao
We define a bi-invariant word metric on a group using keis. We discuss whether such a word metric is trivial or non-trivial in various examples coming from group theory, dynamical…
Merry-go-round and time-dependent symplectic forms
Urs Frauenfelder, Joa Weber
In the merry-go-round fictitious forces are acting like centrifugal force and Coriolis force. Like the Lorentz force Coriolis force is velocity dependent and, following Arnold, can…
The Linearized Floer Equation in a Chart
Urs Frauenfelder, Joa Weber
In this article, we are considering the Hessian of the area functional in a non-Darboux chart. This does not seem to have been considered before and leads to an interesting new mat…
Loop space blow-up and scale calculus
Urs Frauenfelder, Joa Weber
In this note we show that the Barutello-Ortega-Verzini regularization map is scale smooth.
A variational approach to time-dependent planar two-center Stark-Zeeman systems
Urs Frauenfelder, Seongchan Kim
We study periodic orbits in a time-dependent two-center Stark-Zeeman system, which models the motion of a charged particle attracted by two fixed Coulomb centers and subject to ext…
Hilbert manifold structures on path spaces
Urs Frauenfelder, Joa Weber
In Floer theory one has to deal with two-level manifolds like for instance the space of loops and the space of loops. Gradient flow lines in Floer theory are th…
Periodic orbits in time-dependent planar Stark-Zeeman systems
Urs Frauenfelder
Time-dependent Stark-Zeeman systems describe the motion of an electron attracted by a proton subject to a magnetic and a time-dependent electric field. For instance the study of th…
Floerfolds and Floer functions
Urs Frauenfelder, Joa Weber
In this article we introduce the notion of Floer function which has the property that the Hessian is a Fredholm operator of index zero in a scale of Hilbert spaces. Since the Hessi…
On the spectral flow theorem of Robbin-Salamon for finite intervals
Urs Frauenfelder, Joa Weber
In this article we consider operators of the form where lies in an interval and is continuous. Without boundary conditions these op…
On Kepler's geometric approach to consonances
Urs Frauenfelder
Kepler's thinking is highly original and the inspiration for discovering his famous third law is based on his rather curious geometric approach in his Harmonices mundi for explaini…
Growth of eigenvalues of Floer Hessians
Urs Frauenfelder, Joa Weber
In this article we prove that the space of Floer Hessians has infinitely many connected components.
Local gluing
Urs Frauenfelder, Joa Weber
In the local gluing one glues local neighborhoods around the critical point of the stable and unstable manifolds to gradient flow lines defined on a finite time interval f…
The regularized free fall I -- Index computations
Urs Frauenfelder, Joa Weber
Main results are, firstly, a generalization of the Conley-Zehnder index from ODEs to the delay equation at hand and, secondly, the equality of the Morse index and the clockwise nor…