There are already experiments (and simulations) which show Raychaudhuri focusing and Einstein lensing in purely-quantum analog gravity (see e.g. <https://scitec

There are already experiments (and simulations) which show Raychaudhuri focusing and Einstein lensing in purely-quantum analog gravity (see e.g. <https://scitechdaily.com/bridging-quantum-theory-and-relativity-curved-spacetime-in-a-quantum-simulator/ https://scitechdaily.com/bridging-quantum-theory-and-relativ...> for something moderately accessible that allows for attaching a causal cone at each point in a relevant analog spacetime), so > no; I'm saying that if you apply QM as it exists today to describe the motion of light beams around the sun, you will not get any effect similar to gravitational lensing falls down because we can describe such an effect purely quantum mechanically. Also, I think you should be put to proof with respect to a claim against quantum perturbative or canonical methods in the solar-mass lensing regime in which perturbation theory works great for classical GR, taking into account all sorts of beyond-leading-order (classical) effects like noncircularity, backreaction, helicity, you name it. The sun is a fixed enough background that it's a linearized gravity problem. What exactly in "QM as it exists today" breaks (or is broken by) this? > ... if you used the formulae of GR to compute the motion of photons passing through a double-slit experiment ... GR is also wrong. How exactly does taking the fully Lorentz-invariant QED or Standard Model to local Lorentz-invariance (with the radius of curvature significantly larger than the laboratory experiment) break the picture? We are nowhere near needing to consult Birrell & Davies. What do you think needs doing here if "you used the formulae of GR", beyond solving the EFEs and the geodesic equations for the whole (region of) spacetime, and then wondering what geodesic any given photon will couple to? What do you think the scale of the correction from Minkowskian geodesics will be? And how much of that do you impute to the apparatus?