....Alternatives to Inflation in Primordial Power Spectrum

Click For Summary
SUMMARY

The discussion centers on the exploration of alternatives to the cosmic inflation theory in the context of the primordial power spectrum. It introduces a mechanism where massive fields act as standard clocks, imprinting oscillatory signals in density perturbations that reflect the scale factor of the primordial universe, a(t). This approach aims to provide a model-independent identification of primordial universe scenarios. The absence of detectable primordial gravitational waves has led to increased interest in these alternative theories of cosmogenesis.

PREREQUISITES
  • Understanding of primordial power spectrum
  • Familiarity with quantum fluctuations in cosmology
  • Knowledge of density perturbations in the universe
  • Basic concepts of cosmic inflation theory
NEXT STEPS
  • Research the implications of massive fields as standard clocks in cosmology
  • Study the methods for analyzing density perturbations in the primordial power spectrum
  • Explore the detection techniques for primordial gravitational waves
  • Investigate alternative cosmogenesis theories and their observational signatures
USEFUL FOR

Astronomers, cosmologists, and researchers interested in the origins of the universe and alternative theories to cosmic inflation.

Spinnor
Gold Member
Messages
2,227
Reaction score
419
Unique Fingerprints of Alternatives to Inflation in the Primordial Power Spectrum

"Massive fields in the primordial universe function as standard clocks and imprint clock signals in the density perturbations that directly records the scale factor of the primordial universe as a function of time, a(t). A measurement of such signals would identify the specific scenario of the primordial universe in a model-independent fashion. In this Letter, we introduce a new mechanism through which quantum fluctuations of massive fields function as standard clocks. The clock signals appear as scale-dependent oscillatory signals in the power spectrum of alternative scenarios to inflation."

From, https://arxiv.org/abs/1809.02603

From, https://www.quantamagazine.org/a-new-test-for-the-leading-big-bang-theory-20180911/

"The leading hypothesis about the universe’s birth — that a quantum speck of space became energized and inflated in a split second, creating a baby cosmos — solves many puzzles and fits all observations to date. Yet this “cosmic inflation” hypothesis lacks definitive proof. Telltale ripples that should have formed in the inflating spatial fabric, known as primordial gravitational waves, haven’t been detected in the geometry of the universe by the world’s most sensitive telescopes. Their absence has fueled underdog theories of cosmogenesis in recent years. And yet cosmic inflation is wriggly. In many variants of the idea, the sought-after ripples would simply be too weak to observe."
Universe_lede1300.jpg


An all-sky map of the local universe derived from the 2MASS Extended Source Catalog of more than 1.5 million galaxies. The Milky Way is shown at the center, and other galaxies are color-coded by their distances, obtained from several different galaxy surveys.

See also, https://dailygalaxy.com/2018/09/the...xes-the-big-bang-todays-top-science-headline/
 

Attachments

  • Universe_lede1300.jpg
    Universe_lede1300.jpg
    95 KB · Views: 813
Space news on Phys.org
Potentially interesting, but for now it's just a data analysis methods paper. I'll be curious to see it applies to actual data, to see if the signal is actually detectable given reasonable models.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
12
Views
2K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 13 ·
Replies
13
Views
6K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 0 ·
Replies
0
Views
475
  • · Replies 1 ·
Replies
1
Views
3K