Quantum frictionless trajectories versus geodesics

TL;DR

The paper identifies special non-geodesic trajectories around stars and black holes where particles experience no quantum friction due to a balance of Doppler and gravitational shifts, with potential implications for buoyancy effects.

Contribution

It introduces quantum frictionless trajectories that balance Doppler and gravitational shifts, providing a new perspective on particle motion near stars and black holes.

Findings

Quantum frictionless trajectories exist outside stars.

These trajectories have acceleration obeying an inverse square law.

In black hole scenarios, they suggest possible buoyancy effects.

Abstract

Moving particles outside a star will generally experience quantum friction caused by the Unruh radiation reaction. There exist however radial trajectories that lack this effect (in the outgoing radiation sector, and ignoring backscattering). Along these trajectories, observers perceive just stellar emission, without further contribution from the Unruh effect. They turn out to have the property that the variations of the Doppler and the gravitational shifts compensate each other. They are not geodesics, and their proper acceleration obeys an inverse square law, which means that it could in principle be generated by outgoing stellar radiation. In the case of a black hole emitting Hawking radiation, this may lead to a buoyancy scenario. The ingoing radiation sector has little effect and seems to slow down the fall even further.