Families of Lorentzian problems on the Heisenberg group
Yu. Sachkov
TL;DR
This work analyzes two Lorentzian optimal control families on the Heisenberg group. The first family, with metric $g=-\omega_1^2+\omega_2^2+\omega_3^2/\varepsilon^2$, yields invariant sets, explicit normal and abnormal extremals, conjugate-point scarcity for $h_3\neq0$, a diffeomorphic exponential map, and complete characterizations of attainable sets and Lorentzian spheres, together with a detailed limit analysis as $\varepsilon\to0$ toward a sub-Lorentzian problem. The second family, with a reversed cone orientation, is globally controllable but admits no length-maximizing optimizers due to a periodic timelike trajectory, and it provides explicit normal and abnormal extremals and conjugate-point structure, with implications for general left-invariant problems on the Heisenberg group. Overall, the paper illuminates how cone geometry and the placement of the commutant influence optimality, controllability, and semiclassical convergence in Lorentzian and sub-Lorentzian Heizberg-type systems.
Abstract
We consider two families of Lorentzian problems on the Heisenberg group and their asymptotic behaviour as the parameter of a family tends to a limit.
