Cosmological constant—the weight of the vacuum

By Thanu Padmanabhan. 2002

2,777 citations recorded by the source corpus.

Recent cosmological observations suggest the existence ofa positive cosmological constantwith the magnitude � (G˝=c 3 ) ≈ 10 −123 . This review discusses several aspects ofthe cosmological constant both f rom the cosmological (Sections 1- 6) and .eld theoretical (Sections 7-11) perspectives. After a brief introduction to the key issues related to cosmological constant and a historical overview, a summary ofthe kinematics and dynamics ofthe standard Friedmann model ofthe universe is provided. The observational evidence for cosmological constant, especially from the supernova results, and the constraints from the age of the universe, structure formation, Cosmic Microwave Background Radiation (CMBR) anisotropies and a few others are described in detail, followed by a discussion of the theoretical models (quintessence, tachyonic scalar .eld, :::) from di4erent perspectives. The latter part of the review (Sections 7-11) concentrates on more conceptual and f aspects ofthe cosmological constant like some alternative interpretations ofthe cosmological constant, relaxation mechanisms to reduce the cosmological constant to the currently observed value, the geometrical structure ofthe de Sitter spacetime, thermodynamics ofthe de Sitter universe and the role of string theory in the cosmological constant problem. c

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

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Citations in the corpus

Low surface brightness galaxy rotation curves in the low energy limit of Rn gravity: no need for dark matter? (2006, background): “…the ground (from a scalar field rolling down a suitably chosen self interaction potential to phantom fields and unified models of dark energy and dark matter), we refer the interested reader to the enlightening reviews available in literature (see, e.g., Peebles & Rathra 2003 and Padmanabhan 2003).”
Dark Energy and the Accelerating Universe (2008, neutral): “A number of useful reviews target different aspects of the subject, including theory (Copeland, Sami & Tsujikawa 2006, Padmanabhan 2003), cosmology (Peebles & Ratra 2003), the physics of cosmic acceleration (Uzan 2007), probes of dark energy (Huterer & Turner 2001), dark energy reconstruction…”
Transition redshift: new kinematic constraints from supernovae (2008, background): “However, independent theoretical observational analyzes points to more general models whose basic ingredient is a negativepressure dark energy component (for review see, Padmanabhan 2003; Peebles & Ratra 2003; Lima 2004; Copeland et al. 2006).”
f(R) Theories (2010, background): “The unknown component giving rise to this latetime cosmic acceleration is called dark energy [310] (see [517, 141, 480, 485, 171, 32] for reviews).”