- Trans-Planckian problem
In black hole physics and inflationary cosmology, the

**trans-Planckian problem**refers to the appearance of quantities beyond thePlanck scale , which raise doubts on the physical validity of some results in these two areas, since one expects the physical laws to suffer radical modifications beyond the Planck scale.In black hole physics, the original derivation of

Hawking radiation involved field modes whose frequencies near the black hole horizon have arbitrarily high frequencies -- in particular, higher than the inversePlanck time , although these do not appear in the final results. A number of different alternative derivations have been proposed in order to overcome this problem.The trans-Planckian problem can be conveniently considered in the framework of

sonic black holes , condensed matter systems which can be described in a similar way as real black holes. In these systems, the analogue of the Planck scale is the interatomic scale, where the continuum description loses its validity. One can study whether in these systems the analogous process to Hawking radiation still occurs despite the short-scale cutoff represented by the interatomic distance.The trans-Planckian problem also appears in inflationary cosmology. The cosmological scales that we nowadays observe correspond to length scales smaller than the

Planck length at the onset of inflation.

*Wikimedia Foundation.
2010.*

### Look at other dictionaries:

**Hawking radiation**— is a thermal radiation with a black body spectrum predicted to be emitted by black holes due to quantum effects. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974, and sometimes also… … Wikipedia**Inflation (cosmology)**— Inflation model and Inflation theory redirect here. For a general rise in the price level, see Inflation. For other uses, see Inflation (disambiguation). Physical cosmology … Wikipedia**Cosmic inflation**— In physical cosmology, cosmic inflation is the idea that the universe passed through a phase of exponential expansion that was driven by a negative pressure vacuum energy density. [Liddle and Lyth (2000) and Mukhanov (2005) are recent cosmology… … Wikipedia**Loop quantum gravity**— Not to be confused with the path integral formulation of LQG, see spin foam. This article is about LQG in its Canonical formulation.. Beyond the Standard Model … Wikipedia**Causal dynamical triangulation**— Beyond the Standard Model Standard Model … Wikipedia**Multiverse**— For other uses, see Multiverse (disambiguation). Physical cosmology … Wikipedia**Inflación cósmica**— La inflación cósmica es un conjunto de propuestas en el marco de la física teórica para explicar la expansión ultrarrápida del universo en los instantes iniciales y resolver el llamado problema del horizonte. Contenido 1 Introducción 2 Motivación … Wikipedia Español**Holographic principle**— Holographic Universe redirects here. For the album, see Holographic Universe (album). For the book by Michael Talbot, see The Holographic Universe. String theory … Wikipedia**Chaotic Inflation theory**— Physical cosmology Universe · Big Bang … Wikipedia**AdS/CFT correspondence**— For the relation of the AdS/CFT correspondence to the general context of string theory, see String theory. The conformal field theory, which may be a gauge theory lies on the conformal boundary of anti deSitter space with quantum gravity. In… … Wikipedia