Is the spacetime metric Euclidean rather than Lorentzian?

Abstract

My answer to the question in the title is "No". In support of this point of view, we analyze some examples of saddle-point methods, especially as applied to quantum "tunneling" in nonrelativistic particle mechanics and in cosmology. Along the way we explore some of the interrelationships among different ways of thinking about path-integrals and saddle-point approximations to them.

plainTeX, 21 pages, 1 figure (in color). A few minor corrections and some re-wording. A previous version erroneously gave Re(f(z)) rather than Im(f(z)) (Thanks to Adam Brown for this correction.) Most current version is available at http://www.perimeterinstitute.ca/personal/rsorkin/some.papers/134.tunneling.pdf (or wherever my home-page may be)

References in corpus (3)

• Forks in the Road, on the Way to Quantum Gravity
• Quantum Dynamics without the Wave Function
• Instantons and unitarity in quantum cosmology with fixed four-volume

Cited by in corpus (6)

• No Rescue for the No Boundary Proposal
• Evidence for a Phase Transition in 2D Causal Set Quantum Gravity
• Directions in Causal Set Quantum Gravity
• Uses of Complex Metrics in Cosmology
• Action and Observer dependence in Euclidean quantum gravity
• Endeavours in Discrete Lorentzian Geometry; A thesis in five papers