Quintessence (physics)

Quintessence or quintessence is a model of dark energy in physics , which is used as an explanation for an accelerating expansion of the universe .

The term was introduced by RR Caldwell, Rahul Dave and Paul J. Steinhardt in 1998. Investigations into such temporally variable cosmological scalar fields have been carried out since the 1980s ( Bharat Ratra , James Peebles 1988).

According to theoretical ideas, quintessence is a dynamic (time-changing), self-interacting scalar field . If w denotes the ratio of pressure p to energy density ρ : w = p / ρ , this is negative for the quintessence (negative pressure), as well as for the cosmological constant , in contrast to all known forms of matter. In contrast to the cosmological constant, which has w = −1, the quintessence changes over time, so that it can also have developed from a positive value in the early days of the universe (the value of w results from the ratio of potential and kinetic energy of the quintessence field).

Many models that contain quintessence have a sequence scheme ( tracker behavior), which partially solves the problem of cosmological constants (Ratra / Peebles 1988, Steinhardt et al. 1999). In these models, the quintessence field has a density that follows the radiation density (but remains a little lower) until equilibrium between radiation and matter occurs. From this point on, Quintessence acts as dark energy that determines the development of the universe in the long term.

Special cases of quintessence are phantom energy with w <−1 and K-essence (kinetic essence) with a non-standard form of kinetic energy.

literature

Lawrence Krauss : Quintessence - the mystery of missing mass in the universe. Basic Books, New York 2000, ISBN 0-465-03740-2 .
Sidney Bludman: What We Already Know About Quintessence , bibcode : 2003astro.ph.12450B

Web links

Dark Energy dominates the Universe - Martin Kilbinger, Marco Hetterscheidt, University of Bonn 12/2003
The quintessence of the universe - Jeremiah P. Ostriker , Paul Steinhardt , Spectrum of Science 03/2001

References and comments

↑ Caldwell, Dave, Steinhardt, Cosmological Imprint of an Energy Component with General Equation of State , Phys. Rev. Lett., Vol. 80, 1998, pp. 1582-1585.
↑ Ratra, Peebles: Cosmological Consequences of a rolling homogeneous scalar field . In: Physical Review D , Volume 37, 1988, p. 3406 ff. ( Abstract ).
↑ Caldwell, Dave, Steinhardt considered values in their original work , which corresponded best to the observations at the time. ${\ displaystyle -1 <w <0}$
↑ I. Zlatev, L. Wang, PJ Steinhardt, Quintessence, Cosmic Coincidence, and the Cosmological Constant, Phys. Rev. Lett., Vol. 82, 1999, pp. 896-899.

[1] Caldwell, Dave, Steinhardt, Cosmological Imprint of an Energy Component with General Equation of State , Phys. Rev. Lett., Vol. 80, 1998, pp. 1582-1585.

[2] Ratra, Peebles: Cosmological Consequences of a rolling homogeneous scalar field . In: Physical Review D , Volume 37, 1988, p. 3406 ff. ( Abstract ).

[3] Caldwell, Dave, Steinhardt considered values in their original work , which corresponded best to the observations at the time. ${\ displaystyle -1 <w <0}$

[4] I. Zlatev, L. Wang, PJ Steinhardt, Quintessence, Cosmic Coincidence, and the Cosmological Constant, Phys. Rev. Lett., Vol. 82, 1999, pp. 896-899.