How to detect an anti-spacetime

Abstract

Is it possible, in principle, to measure the sign of the Lapse? We show that fermion dynamics distinguishes spacetimes having the same metric but different tetrads, for instance a Lapse with opposite sign. This sign might be a physical quantity not captured by the metric. We discuss its possible role in quantum gravity.

Article awarded with an "Honorable Mention" from the 2012 Gravity Foundation Award. 6 pages, 8 (pretty) figures

References in corpus (4)

• Towards Spinfoam Cosmology
• The Ponzano-Regge model
• Stepping out of Homogeneity in Loop Quantum Cosmology
• Parity and reality properties of the EPRL spinfoam

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• Dimensional crossover of effective orbital dynamics in polar distorted 3He-A: Transitions to anti-spacetime
• Varying Newton constant and black hole to white hole quantum tunneling
• Coupled intertwiner dynamics: A toy model for coupling matter to spin foam models
• Negative temperature for negative lapse function
• Comment to the CPT-symmetric Universe: Two possible extensions
• Two roads to antispacetime in polar distorted B phase: Kibble wall and half-quantum vortex
• Taming Fluctuations for Gaussian States in Loop Quantum Cosmology