April 2009 testing point for Bojowald et al (bounce QC)

[marcus]

Bojowald (and other bounce QC researchers) are approaching a kind of 'moment of truth' with the April 2009 scheduled launch of Planck and Herschel satellites.

The nonsingular Quantum Cosmology models they are developing are expected to make predictions about structure formation in the early universe. The new ESA instruments will have unprecedented ability to detect and record the process of structure formation.

Some preliminary indefinite suggestions of things to look for have been made (for example Bojowald Skirzewski 0808.0701). The bounce QC people have an important opportunity to derive and state more precise predictions.

People in several different research lines talk with apparent confidence about quantum fluctuations seeding structure in an assumed homogeneous-isotropic universe. I get the impression that it isn't clearly understood how inflation is supposed to have amplified and realized these fluctuations---how the shift from quantum to classical occurred and how the observed spectrum of spatial variation was determined.

Quantum cosmology is specifically equipped to study this in detail, and you can see them approaching these issues in the 0808.0701 paper.

The opportunity would be to predict aspects of structure which can be looked for by Planck and Herschel satellites, when they go into operation starting around April.

Planck will look at CMB wavelengths 0.35 mm to 10 mm.
Herschel will look at protogalaxy wavelengths possibly from 0.05 mm to 0.7 mm (I didn't find consistent information about this yet)

Roughly speaking the CMB is at redshift z = 1000 (more exactly 1090) and the protogalaxies are more like z = 10 to z = 100 (very roughly an order of magnitude less redshift, and therefore an order of magnitude shorter wavelengths).

The hope would be, I surmise, that bounce quantum cosmology models will be better than classical models at explaining and predicting early structure formation in the cosmic microwave background and the protogalaxies.

Whether or not this will prove true, we of course do not know

 

[marcus]

Both Planck and Herschel will be at L2 orbits. They will be about 1.5 million km further from the sun than the Earth is. Both will oscillate around the L2 point. Both will be launched by the same Arianne rocket. Here is a website of the ESA (Euro Space Agency).

http://www.rssd.esa.int/index.php?project=Planck

here are some links to science goals and specs
http://www.rssd.esa.int/index.php?project=PLANCK&page=science_top
this gives detailed specs
http://www.rssd.esa.int/index.php?project=PLANCK&page=perf_top
It says Planck low frequency instrument detects 30-70 GHz and high frequency instrument detects 100-857 GHz
Lumping that together it seems like a range from 30 to 857, which is maybe where they get 0.35 mm to 10 mm
in wavelength terms.

Let's see what we can find for Herschel
http://www.esa.int/esaSC/120390_index_0_m.html
http://en.wikipedia.org/wiki/Herschel_Space_Observatory

 

[marcus]

0808.0701

Bojowald and coworkers are gearing up to make predictions about what will be seen in the early universe--I suppose by these new instruments like Planck.
We talked about this in Nominations for the "MIP" (most important paper) poll.

I will add one by Bojowald which addresses the problem of testing bounce cosmology models (LQC) by observations of structure formation in the early universe. Here's the list of papers nominated for this quarter.
...
...

http://arxiv.org/abs/0808.0701
Effective theory for the cosmological generation of structure
Martin Bojowald, Aureliano Skirzewski
8 pages, 1 figure, Advanced Science Letters 1 (2008) 92-98
(Submitted on 5 Aug 2008)

"The current understanding of structure formation in the early universe is mainly built on a magnification of quantum fluctuations in an initial vacuum state during an early phase of accelerated universe expansion. One usually describes this process by solving equations for a quantum state of matter on a given expanding background space-time, followed by decoherence arguments for the emergence of classical inhomogeneities from the quantum fluctuations. Here, we formulate the coupling of quantum matter fields to a dynamical gravitational background in an effective framework which allows the inclusion of back-reaction effects. It is shown how quantum fluctuations couple to classical inhomogeneities and can thus manage to generate cosmic structure in an evolving background. Several specific effects follow from a qualitative analysis of the back-reaction, including a likely reduction of the overall amplitude of power in the cosmic microwave background, the occurrence of small non-Gaussianities, and a possible suppression of power for odd modes on large scales without parity violation."

The actual poll, if you want to register your prediction of what will be the most valuable paper from third quarter (July-Sept ) 2008 is here:
https://www.physicsforums.com/showthread.php?t=260947