115 citations · 181 across the 20 of their papers we have counts for
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No Rescue for the No Boundary Proposal
Job Feldbrugge, Jean-Luc Lehners, Neil Turok
In recent work, we introduced Picard-Lefschetz theory as a tool for defining the Lorentzian path integral for quantum gravity in a systematic semiclassical expansion. This formulat…
No smooth beginning for spacetime
Job Feldbrugge, Jean-Luc Lehners, Neil Turok
We identify a fundamental obstruction to any theory of the beginning of the universe, formulated as a semiclassical path integral. Hartle and Hawking's no boundary proposal and Vil…
Lorentzian Quantum Cosmology
Job Feldbrugge, Jean-Luc Lehners, Neil Turok
We argue that the Lorentzian path integral is a better starting point for quantum cosmology than the Euclidean version. In particular, we revisit the mini-superspace calculation of…
Caustic Skeleton & Cosmic Web
Job Feldbrugge, Rien van de Weygaert, Johan Hidding +1
We present a general formalism for identifying the caustic structure of an evolving mass distribution in an arbitrary dimensional space. For the class of Hamiltonian fluids the ide…