Iman Rosignoli

Brachistochrones in conformal Kerr spacetimes: control domain, exterior separatrices, and adiabatic response

What is the fastest constrained worldline when the spacetime not only evolves but rotates? We study this for the controlled-rail brachistochrone—the time-optimal worldline reaching a fixed target at a free arrival clock—in Thakurta–Kerr, the conformal Kerr geometry $g=A(\eta)^2 g...

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...