In mathematical physics, a caloron is the finite temperature generalization of an instanton.
They describe tunneling between different topological vacuum states of the Minkowski theory.
[1] This is a topologically stable solution to the four-dimensional SU(2) Yang–Mills field equations in Euclidean spacetime (i.e. after Wick rotation).
Finite temperatures in quantum field theories are modeled by compactifying the imaginary (Euclidean) time (see thermal quantum field theory).
The generalization thereof to finite temperature has been found by Harrington and Shepard:[3] where