Editing General relativity (section)

=== Quantum field theory in curved spacetime ===
{{Main|Quantum field theory in curved spacetime}}
Ordinary [[quantum field theory|quantum field theories]], which form the basis of modern elementary particle physics, are defined in flat Minkowski space, which is an excellent approximation when it comes to describing the behavior of microscopic particles in weak gravitational fields like those found on Earth.<ref>{{Harvnb|Ramond|1990}}, {{Harvnb|Weinberg|1995}}, {{Harvnb|Peskin|Schroeder|1995}}; a more accessible overview is {{Harvnb|Auyang|1995}}</ref> In order to describe situations in which gravity is strong enough to influence (quantum) matter, yet not strong enough to require quantization itself, physicists have formulated quantum field theories in curved spacetime. These theories rely on general relativity to describe a curved background spacetime, and define a generalized quantum field theory to describe the behavior of quantum matter within that spacetime.<ref>{{Harvnb|Wald|1994}}, {{Harvnb|Birrell|Davies|1984}}</ref> Using this formalism, it can be shown that black holes emit a blackbody spectrum of particles known as [[Hawking radiation]] leading to the possibility that they [[Black hole evaporation|evaporate]] over time.<ref>For Hawking radiation {{Harvnb|Hawking|1975}}, {{Harvnb|Wald|1975}}; an accessible introduction to black hole evaporation can be found in {{Harvnb|Traschen|2000}}</ref> As briefly mentioned [[#Horizons|above]], this radiation plays an important role for the thermodynamics of black holes.<ref>{{Harvnb|Wald|2001|loc=ch. 3}}</ref>