Speaker
Description
The work describes gravitational wave propagation through a stochastic distribution of weak gravitational lenses beyond the geometric optics limit. The lens distribution is modeled as a static random background field and we formulate the problem in the language of quenched disorder, treating the disorder averaged densitymatrix as the fundamental object from which observables are computed. Using the Schwinger Keldysh formalism, a path-integral representation of the averaged density matrix is constructed and derived explicitly in a perturbatively form for a suitable class of couplings. The result naturally separates into a quadratic exponential term, which governs the suppression of phase sensitive contributions in the averaged description, and a purely oscillatory contribution, which modifies coherent propagation through a disorder-induced correction to the propagation kernel. This provides a unified description of interference, diffraction, and statistical fluctuations of the lens distribution within a single framework. We also identify the physical scales controlling the onset of coherence loss and illustrate the formalism in the case of Gaussian wave packets. More generally, the derivation applies to any system described by the same class of actions, making the framework relevant beyond gravitational wave lensing to wave propagation in disordered media. Insights on future directions will be discussed.