Analytical Solutions to the Wheeler-DeWitt Equation in Rosen-Lagrangian Cosmology via the Eisenhart Lift

Abstract

The Rosen Lagrangian framework promotes the cosmological constant to a scale-factor-dependent quantity, $Λ(a)=Λ_{0}a^λ$, thereby providing a dynamical dark energy scenario for $λ\neq 0$. In the special case $λ=0$, the model naturally reduces to the standard $Λ$CDM cosmology. Within this framework, the conformal Killing equations are employed to determine the conformal factor $\mathcal{F}(a)$, which is expressed in terms of the effective potential $V_{\rm eff}$ and its derivative $V'_{\rm eff}$. Furthermore, the Eisenhart lift formalism introduces an additional field $χ$, allowing the cosmological dynamics to be reformulated through a purely kinetic lifted action. This geometrical construction provides a powerful approach to quantum cosmology by transforming the Wheeler-DeWitt equation into a tractable form that admits analytic solutions. Such solutions are particularly relevant in cosmological epochs dominated by the cosmological constant, including both the inflationary era of the early Universe and the late-time accelerated expansion. Consequently, this framework offers a promising avenue for connecting geometrical methods, quantum cosmology, and dynamical dark energy within a unified description.