Institute for Theoretical Physics, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
Phys Rev Lett. 2013 Jul 12;111(2):023601. doi: 10.1103/PhysRevLett.111.023601. Epub 2013 Jul 9.
Blackbody radiation around hot objects induces ac Stark shifts of the energy levels of nearby atoms and molecules. These shifts are roughly proportional to the fourth power of the temperature and induce a force decaying with the third power of the distance from the object. We explicitly calculate the resulting attractive blackbody optical dipole force for ground state hydrogen atoms. Surprisingly, this force can surpass the repulsive radiation pressure and actually pull the atoms against the radiation energy flow towards the surface with a force stronger than gravity. We exemplify the dominance of the "blackbody force" over gravity for hydrogen in a cloud of hot dust particles. This overlooked force appears relevant in various astrophysical scenarios, in particular, since analogous results hold for a wide class of other broadband radiation sources.
热物体周围的黑体辐射会引起附近原子和分子能级的斯塔克位移。这些位移与温度的四次方成正比，并产生与物体距离的立方成反比的力。我们明确计算了基态氢原子产生的引力黑体光偶极力。令人惊讶的是，这种力可以超过辐射压力，并实际将原子拉向辐射能流，使其朝向表面的力超过重力。我们以热尘埃粒子云中的氢为例，说明了“黑体力”对重力的优势。这种被忽视的力在各种天体物理场景中似乎很重要，特别是因为类似的结果也适用于广泛的其他宽带辐射源。
