Dark Energy

J.P. Ostriker and P.J. Steinhardt

The observational case for low-density universe with a non-zero cosmological constant,
Nature 377 (1995) 600

First definitive empirical case for dark energy (three yrs prior to SNe data) and introduction of “cosmic concordance” (combining different evidence) in cosmology

P.J. Steinhardt

Cosmological challenges for the 21st century
in Critical Problems in Physics , ed. by V. L. Fitch and D. R. Marlow, (Princeton University Press, 1997)

Overview of open issues for the 21st century including an early discussion of the possibility of time-varying dark energy (the term “quintessence” had not be invented yet).

R. R. Caldwell, R. Dave, P.J. Steinhardt

Cosmological imprint of an energy component with general equation of state
Phys. Rev. Lett. 80, 1582

Paper that introduced the concept (and the term) “quintessence,” referring a time-varying form of dark energy

P.J. Steinhardt

A quintessential introduction to dark energy
Phil. Trans. R. Soc. Lond. A361 (2003) 2497

Review of case for quintessence dark energy circa 2003

D. Shlivko and P.J. Steinhardt

Assessing observational contraints on dark energy 
Phys.Lett . B855 (2024) 138826

The current conventional approach for parameterizing observational constraints on time-varying dark energy give the misleading impression that null energy condition violation at large redshift is favored. This paper exposes the flaws in this parameterization and shows that quintessence models satisfying the null energy condition fit the observations equally well.

A. Bedroya, Q. Lu and P.J. Steinhardt

TCC in the interior of moduli space and its implications for the string landscape and cosmology 
arXiv:2407.08793 (2024).

The case for the Transplanckian Censorship Conjecture (TCC) is strengthened, implying a new set of complex and highly nonlinear constraints across the entire string landscape which may make inflation impossible and restricts the ways dark energy can be incorporated in quantum gravity.

C. Deffayet, B.A. Ovrut and P.J. Steinhardt

Stable Vacua with Realistic Phenomenology and Cosmology in Heterotic M-theory Satisfying Swampland Conjectures 
JHEP07, 288 (2024).

In this paper, we elucidate, in detail, the mathematical and computational methods required to utilize the protocol described in the paper listed below. These methods are then applied to a realistic heterotic M-theory model, the B−L MSSM, whose observable sector is consistent with all particle physics requirements. It is shown that the dilaton and universal moduli can be completely stabilized at values compatible with every phenomenological and mathematical constraint — as well as with ΛCDM cosmology. We also show that the heterotic M-theory vacua are consistent with all well-supported Swampland conjectures.

C. Deffayet, B.A. Ovrut and P.J. Steinhardt

Moduli axions, stabilizing moduli and the large field Swampland conjecture in Heterotic M-theory 
Phys.Rev. D109, 12, 126004 (2024).

We compute the potential energy for the dilaton, complex structure and Kahler moduli and search of realistic vacua of heterotic M-theory compactified on Calabi-Yau threefolds. We present a protocol for deriving the potential that combines the non-perturbative complex structure, gaugino condensate and worldsheet instanton superpotentials in theories in which the hidden sector contains an anomalous U(1) structure group. We obtain explicit examples in which potential has a global minimum at negative or zero vacuum density or a metastable minimum with positive vacuum density.

A. Agrawal, G. Obied, P.J. Steinhardt and C. Vafa

On the Cosmological Implications of the String Swampland 
Phys.Lett. B784, 271-6 (2018).

Although a cosmological constant  may not be compatible with string theory if the Swampland picture is correct, quintessence may be compatible.

D. Wesley and P.J. Steinhardt

Dark Energy, Inflation and Extra Dimensions 
Phys. Rev. D79 (2008) 104026

and

Exploring extra dimensions through observational tests of dark energy and varying Newton’s constant
Preprint (2010)

Two papers exploring why cosmic acceleration in the form of quintessence may be the most plausible form of dark energy in theories with extra spatial dimensions.