One of the grand open problems of modern physics is the unification of Einstein’s general relativity and quantum mechanics. This challenge has been approached by the greatest physicists but there is still no complete theory and experimental evidence remains out of reach. The Newton–Schrödinger equation (NSE) offers insight into this puzzle, as it describes a quantum wavefunction under self-gravity dynamics. Having been studied theoretically for decades, optical experiment of this nonlinear model was demonstrated only in 2015. Although the NSE can be generalized to post-Newtonian gravity approximating general relativity, all experiments simulating nonlinear gravity so far have been limited to Newtonian gravity. Here we present experimental emulation of post-Newtonian dynamics by probing a new physical regime of nonlinearity that mimics larger masses in gravity. We find soliton solutions of the post-Newtonian–Schrödinger equations, distinct from their Newtonian counterparts and demonstrate them experimentally. We observe rich beam evolution requiring previously unconsidered nonlinear terms, thereby opening up new experimental capabilities for simulating wavefunction dynamics in the settings of general relativity. An optical emulation experiment of a quantum wave function dynamics under self-induced post Newtonian gravitational potential is presented, including observation of solitons of this system and rich beam evolution due to high-order nonlinear effects.
This is the first in a two-part series in which we extend non-relativistic stochastic mechanics, in the ZSM formulation [1, 2], to semiclassical Newtonian gravity (ZSM-Newton) and semiclassical Newtonian electrodynamics (ZSM-Coulomb), under the assumption that the gravitational and electromagnetic fields are fundamentally classical (i.e., not independently quantized fields). Our key findings are: (1) a derivation of the usual
N-particle Schr{ö}dinger equation for many particles interacting through operator-valued gravitational or Coulomb potentials, and (2) recovery of the `single-body' Schr{ö}dinger-Newton and Schr{ö}dinger-Coulomb equations as mean-field equations valid for systems of gravitationally and electrostatically interacting identical particles, respectively, in the weak-coupling large N limit. We also compare ZSM-Newton/Coulomb to semiclassical Newtonian gravity/electrodynamics approaches based on standard quantum theory, dynamical collapse theories, and the de Broglie-Bohm theory.
The effects of general relativistic gravity on quantum mechanics are thoroughly investigated. The Schr\"odinger equation is derived for a nonrelativistic spinless particle and for a spin-
1/2 particle, with the general relativistic corrections of Earth's gravity up to the first post-Newtonian order,
O(1/c2). The phase differences due to the post-Newtonian corrections in quantum interferometer experiments are also calculated.