Iman Rosignoli

Controlled-rail brachistochrones in non-stationary spacetimes: conformal symmetry, Kodama energy, and Vaidya dynamics

What is the fastest constrained worldline in a spacetime that is itself evolving? In a stationary spacetime the relativistic brachistochrone reduces to Fermat/Randers optics with a conserved rail energy supplied by a timelike Killing vector; in a dynamical spacetime no such conse...

Controlled-rail brachistochrones in non-stationary spacetimes: conformal symmetry, Kodama energy, and Vaidya dynamics

What is the fastest constrained worldline in a spacetime that is itself evolving? In a stationary spacetime the relativistic brachistochrone reduces to Fermat/Randers optics with a conserved rail energy supplied by a timelike Killing vector; in a dynamical spacetime no such conse...

Relativistic Brachistochrones in Conformal Kerr Spacetimes: Adiabatic Theory, Ergosphere Transitions and Hyperelliptic Closed Forms

We develop the relativistic controlled-rail brachistochrone — the fastest constrained worldline reaching a fixed spatial target at a free arrival clock — in the rotating, axisymmetric Thakurta–Kerr spacetime, the conformal Kerr geometry \(g = A(\eta)^2 g_{Kerr}\). The controlled-...