Dark Energy models

As mentioned in the last blog: "There are many models trying to describe the Accelerating universe problem", the most popular ones are listed as below.

1)Vacuum Energy-Cosmological constant

From Quantum field theory we know that we can relate harmonic oscillator to the vacuum state of QFT(Quantum field Theory)and as we know from the classical mechanics,the ground state of harmonic oscillator has non-zero energy which can contribute to the Dark energy.

In the other way we can easily interpret the energy momentum of vacuum energy as an cosmological constant/which Einstein first proposed before Hubble's discovery to get the static universe and later call it his life's biggest blunder/.

2)Dark Energy models

a)Quintessence

b)k-essence

c)phantom-ghost like fields

d)Pseudo-Nambo-Goldstone bosons

e)Oscillating dark energy models

Dark energy models containing all the subdivisions mention about,are physical models.All proposed a new kind of constitute of universe that has ridiculous equation of state.Usually this exotic entity is related to a scalar field.

3)Failure of General Relativity

a)Gravitation action is a general function of a Ricci scalar , scalars from Ricci and Riemann tensor

b)Scalar-Vector-tensor theories

d)Brane world cosmologies

this models discuss and propose that maybe we do not understand the gravity well and we should change the Einstein-Hilbert action to more general one.

The Brane world cosmologies suggest that in stead of 4D we live in a brane embedded in 5 Dimensions,in this case the gravity leakage to the 5-dimension in contrast to the matter and other force fields that are constrained to live in 4D.the result of this causes modification to the gravity understanded in 4D and causes the accelerating universe.

4)Chamelon models

This models suggest any exotic component of universe with equation of state that in early times behave like dark matter and in late universe is playing the role of dark energy

5)Dark energy,Dark matter interacting models

6)Failure of FRW-assumption.

In this inhomogeneous models the back reaction of structures cause to alter the distances we measure from standard candle SNIa,,and the dark energy is just a miscalculation.

7)Holographic dark energy

In this models our 4d manifold is a hologram of higher dimensional world

8)String theory landscape

In the framework of string theory the cosmological constant solution for accelerating universe is once again proposed and more, the problems of fine tunning and cosmic coincidence is answered by the landscape interpretation.

9)Quantum Geometry

That the space and time is also quantized and are manifestation of a new field.

10)Anthropic principle models

I will blog about it later...

There are other models too!!It seems that really we do not understand the physics of accelerating universe so so much models come to existing.

Let do more physics to found out the mystery.