A Wick rotation deforms a time or energy contour from real to imaginary values, converting suitable Minkowski integrals into Euclidean integrals while respecting pole prescriptions.
A Wick rotation from real time to imaginary time replaces the oscillatory weight by . For a real scalar with positive kinetic normalization, . Positivity of its kinetic term does not ensure convergence if the potential is unbounded below. Fermionic integrals instead use independent Grassmann fields and need not define a positive measure.
Articles by others on the same topic
Wick rotation is a mathematical technique used primarily in quantum field theory and statistical mechanics to relate problems in particle physics to problems in statistical physics. Named after the physicist Giovanni Wick, this technique involves a transformation of the time coordinate in a Minkowski spacetime formulation from real to imaginary values.