Physicists Use Particle Physics Link to Study Hawking Radiation

Physicists have identified a new approach to study Hawking radiation, the faint particle emission associated with black holes, by using a mathematical link between gravity and particle physics. The connection, known as the double copy, draws an equivalence between equations in general relativity and those in the standard model of particle physics.

It allows calculations in one framework to be translated into the other, sometimes revealing new insights or simplifying computations. The double copy was discovered in 2010 and has since been applied to various gravitational phenomena. Hawking radiation, proposed by physicist Stephen Hawking in 1974, cannot be observed directly because it is extremely faint.

As black holes emit this radiation, they lose mass and eventually evaporate. The process raises questions about what happens to information that falls into a black hole, given that quantum physics holds information cannot be destroyed. Three teams of physicists have now found a standard model counterpart for Hawking radiation using the double copy.

In one paper accepted to the Journal of High Energy Physics, researchers determined that Hawking radiation corresponds mathematically to a charged particle scattering off a spherical shell of charged matter collapsing in on itself. Two other teams reached essentially the same conclusion in papers published in February in Physical Review Letters.

The work shows that certain physics intrinsic to black holes can be found within the standard model of particle physics.

The finding is notable because Hawking radiation connects physics at vastly different scales, with large black holes emitting tiny particles. The double copy had not previously been shown to bridge those scales for this phenomenon. One physicist not involved in the research described the identification of a standard model analog as a major advance for the technique.

Researchers hope to extend the approach to other black hole features. In particular, they aim to find a standard model equivalent for the event horizon, the boundary beyond which nothing can escape. One physicist not involved in the studies said the papers provide tools that could be used to address that question.

Hawking radiation is viewed as a key problem for advancing understanding of gravity through the double copy. By examining its translated form in the standard model, physicists may gain fluency in connecting the two theoretical frameworks. The work offers a new route into long-standing puzzles without requiring direct observation of the radiation itself.