Allowable Complex Scalars from Kaluza-Klein Compactifications and Metric Rescalings

J. M. Bardeen, “Gauge Invariant Cosmological Perturbations,” Phys. Rev. D

1905

Earlier work this paper cites.

G. W. Gibbons and S. W. Hawking, “Action Integrals and Partition Functions in Quantum Gravity,” Phys. Rev. D

1977

Earlier work this paper cites.

K. S. Stelle, “Classical Gravity with Higher Derivatives,” Gen. Rel. Grav

1978

Earlier work this paper cites.

E. Cremmer, B. Julia, and J. Scherk, “Supergravity Theory in Eleven-Dimensions,” Phys. Lett. B

1978

Earlier work this paper cites.

S. R. Coleman and F. De Luccia, “Gravitational Effects on and of Vacuum Decay,” Phys. Rev. D

1980

Earlier work this paper cites.

A. A. Starobinsky, “A New Type of Isotropic Cosmological Models Without Singularity,” Phys. Lett. B

1980

Earlier work this paper cites.

E. Witten, “Instability of the Kaluza-Klein Vacuum,” Nucl. Phys. B

1982

Earlier work this paper cites.

J. B. Hartle and S. W. Hawking, “Wave Function of the Universe,” Phys. Rev. D

1983

Earlier work this paper cites.

M. J. Duff, B. E. W. Nilsson, and C. N. Pope, “Kaluza-Klein Supergravity,” Phys. Rept

1986

Earlier work this paper cites.

G. W. Lyons, “Complex solutions for the scalar field model of the universe,” Phys. Rev. D

1992

Earlier work this paper cites.

J. Louko and R. D. Sorkin, “Complex actions in two-dimensional topology change,” Class. Quant. Grav

1997

Cited alongside, same era.

J. B. Hartle, S. W. Hawking, and T. Hertog, “The Classical Universes of the No-Boundary Quantum State,” Phys. Rev. D

Original

2008

Cited alongside, same era.

C. Jonas and J.-L. Lehners, “No-boundary solutions are robust to quantum gravity corrections,” Phys. Rev. D

Original

2008

Cited alongside, same era.

O. Janssen, “Slow-roll approximation in quantum cosmology,” Class. Quant. Grav

Original

2009

Cited alongside, same era.

A. De Felice and S. Tsujikawa, “f(R) theories,” Living Rev. Rel

Original

2010

S. V. Ketov and H. Nakada, “Inflation from ( R + γ ​ R n − 2 ​ Λ ) (R+\gamma R^{n}-2\Lambda) Gravity in Higher Dimensions,” Phys. Rev. D

Original

2017

Later among the works it cites.

S. P. Otero, F. G. Pedro, and C. Wieck, “ R + α ​ R n R+\alpha R^{n} Inflation in higher-dimensional Space-times,” JHEP

Original

2017

Later among the works it cites.

A. Hebecker, T. Mikhail, and P. Soler, “Euclidean wormholes, baby universes, and their impact on particle physics and cosmology,” Front. Astron. Space Sci

Original

2018

Later among the works it cites.

J.-L. Lehners, “Small-Field and Scale-Free: Inflation and Ekpyrosis at their Extremes,” JCAP

Original

2018

Later among the works it cites.

M. Kontsevich and G. Segal, “Wick Rotation and the Positivity of Energy in Quantum Field Theory,” Quart. J. Math. Oxford Ser