We prove that the Boltzmann-Grad limit of the Lorentz gas with periodic distribution of scatterers cannot be described with a linear Boltzmann equation. This is at variance with the case of a Poisson distribution of scatterers, for which the convergence to the linear Boltzmann equation was proved by Gallavotti [Phys. Rev. (2) 185, 308 (1969)]. The arguments presented here complete the analysis ...

A theoretical model of computation is proposed based on Lorentz quantum mechanics. Besides the standard qubits, this has an additional bit, which we call hyperbolic bit (or hybit in short). set basic logical gates are constructed and their universality proved. As application, a search algorithm designed for computer found to be exponentially faster than Grover’s algorithm.

We show that maximal causal curves for a Lipschitz continuous Lorentzian metric admit $\mathcal{C}^{1,1}$-parametrization and they solve the geodesic equation in sense of Filippov this parametrization. Our proof shows are either everywhere lightlike or timelike. Furthermore, demonstrates an $\alpha$-H\"older $\mathcal{C}^{1,\frac{\alpha}{4}}$-parametrization.