Nonminimal Couplings in the Early Universe: Multifield Models of Inflation and the Latest Observations

  • David I. KaiserEmail author
Part of the Fundamental Theories of Physics book series (FTPH, volume 183)


Models of cosmic inflation suggest that our universe underwent an early phase of accelerated expansion, driven by the dynamics of one or more scalar fields. Inflationary models make specific, quantitative predictions for several observable quantities, including particular patterns of temperature anistropies in the cosmic microwave background radiation. Realistic models of high-energy physics include many scalar fields at high energies. Moreover, we may expect these fields to have nonminimal couplings to the spacetime curvature. Such couplings are quite generic, arising as renormalization counterterms when quantizing scalar fields in curved spacetime. In this chapter I review recent research on a general class of multifield inflationary models with nonminimal couplings. Models in this class exhibit a strong attractor behavior: across a wide range of couplings and initial conditions, the fields evolve along a single-field trajectory for most of inflation. Across large regions of phase space and parameter space, therefore, models in this general class yield robust predictions for observable quantities that fall squarely within the “sweet spot” of recent observations.


Scalar Field Cosmic Microwave Background Background Field Einstein Frame Jordan Frame 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



It is a great pleasure to thank Carl Brans for his kind encouragement over the years. I would also like to thank Torsten Asselmeyer-Maluga for editing this Festschrift in honor of Carl’s 80th birthday. I am indebted to Evangelos Sfakianakis for pursuing the research reviewed here with me, along with our collaborators Matthew DeCross, Ross Greenwood, Edward Mazenc, Audrey (Todhunter) Mithani, Anirudh Prabhu, Chanda Prescod-Weinstein, and Katelin Schutz. This research has also benefited from discussions with Bruce Bassett and Alan Guth over the years. This work was conducted in MIT’s Center for Theoretical Physics and supported in part by the U.S. Department of Energy under grant Contract Number DE-SC0012567.


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© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department of Physics, Center for Theoretical PhysicsMassachusetts Institute of TechnologyCambridgeUSA

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