Workshop on Transplanckian Physics

Stockholm, 7 November 2002

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Workshop on Transplanckian Physics

Uppsala, 24-26 october 2002

http://www.teorfys.uu.se/PEOPLE/domert/nordic/index.html


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Review ofStandard Big Bang

Cosmology


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Standard BB Cosmology

• Hubble Law (20’s) and redshift

• CMBR (60’s and today)

• Nucleosynthesis

• Age of the Universe

• Expansion Models

• Dark Matter/Energy

• Other models: steady state model, …


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History of the Universe (with Inflation)


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CMBR angular power spectrum

Dipole anisotropy(Conklin, 1969)


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CMBR Anisotropy

http://www.astro.ucla.edu/~wright/CMB-DT.html


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Why Transplanckian Physics?

Standard BB cosmology presents some open issues:

• The Flatness Problem• The Entropy Problem• The Horizon Problem• Structure formation + CMBR inhomogeneities• matter/antimatter asimmetry, dark matter, ...


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Workshop on Transplanckian Physics

Uppsala, 24-26 october 2002

http://www.teorfys.uu.se/PEOPLE/domert/nordic/index.html


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ProgramU. Danielsson Can Planck see transplanck?O. Elgaroey Neutrino properties from the 2dF Galaxy Redshift SurveyM. Giovannini The pre-big bang scenario confronts observationsD. Grasso Cosmology with gravitational wave detectorsF. Hassan 1. Introduction to the Theory of Cosmological Perturbations

2. Introduction to the Trans-Planckian Problem in Inflationary Cosmology

A. Jokinen Baryogenesis through Affleck-Dine mechanismN. Kaloper Inflation and Short-Distance PhysicsE. K.Vakkuri Cosmological toy models in string theoryM. Laine Higher dimension induced domain wall defects in our worldJ. Niemeyer Models and Signatures of Short Distance Physics in InflationS. Räsänen The ekpyrotic scenario/cyclic model: status reportM. Sloth Transplanckian effects in inflationary cosmology and the

modified uncertainty principleA. Starobinsky Trans-Planckian particle creation now and in the pastI. Wehus Scalar field potential in 5-dimensional Kaluza-Klein theory


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Theories vs Experiments (1)• Theories / Toy models:

– Standard Big Bang Cosmology (starting point)

– Inflation– Theory of Cosmological Perturbations– Pre-Big Bang scenario– Ekpyrotic scenario / cyclic model– ...


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Theories vs Experiments (2)• Typical signatures• Look for theories with a ”good” footprint• Experiments:

– Gravitational waves detectors– Supernova Project– CMBR survey– Neutrino studies– UHECR– PAMELA, ...


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Some formalism + Inflation

Friedmann eq.

FRW line element:

Einstein eq.

During inflation: a(t) ~ exp[H(t)·t]

Typical numbers: 60 e-foldings; 10-33sec (start:10-37 after BB)

”These numbers are like George Bush military budget...”


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Theory of Cosmological Perturbations

• Standard Big Bang formalism & theory

• Perturbation theory

• Density inhomogeneities amplified by gravity (ex. / ~ 10-5 after 300000 yrs may explain structure formation)

Riotto, hep-ph/0210162Inflation and the theory of cosmological perturbations


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Trans-planckian Problem in Inflationary Cosmology

In most current models of inflation, the period of exponential expansion lasts so long that at the beginning of inflation, scales of cosmological interest today had a physical wavelength much smaller than the Planck length, and the theories used to compute the spectrum of fluctuations are known to break down on these scales.


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The pre-big bang scenario confronts observations

Massimo Giovannini,University of Lausanne

Abstract: “The key features of the pre-big bang scenario will be presented in light of its possible phenomenological relevance. Recent developments will also be discussed with particular attention to possible implications for CMB physics and relic GW backgrounds. A personal view of the speaker on the future (possible) directions of this scenario will also be given.”


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Pre Big-bang Scenario

Figures from: http://www.ba.infn.it/~gasperin/

Inflation after BB Inflation

before BB


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Cosmology with gravitational wave detectors

Abstract: “The new generation of gravitational waves detectors under construction/project may be able to detect stochastic backgrounds of cosmological origin. A short panoramic on the most promising sources and the characteristics of the expected signals will be given.”

Dario Grasso, Scuola Normale Superiore, Pisa


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GW Production• GW background from amplification of

vacuum fluctuations– Standard inflation– Pre-Big Bang cosmology– Other models

• Known astrophysical sources• Noise (unresolved astrophysical

sources)On Earth: Seismic noise


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GW from a Pre-BB Model

http://www.ba.infn.it/~gasperin/


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VIRGO Sensitivity


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VIRGO

http://wwwlapp.in2p3.fr/virgo/gwf.html


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Ekpyrotic Scenario

• One visible 3-D brane + one 3-D hidden brane in a 11-D space

• Brane oscillations induce energy transfer (BB in our brane)

• Old, new + cyclic scenario (all: 2001)

Figures from:

http://www.sciencenews.org/20010922/bob9.asp


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The Stringy Uncertainty Principle

Hyphotesis: there is a minimum resolution xmin = ½

xp ½( 1 + (p)² + ... )

[x, p] = i(1+p²)

xp ½

[x, p] = i

Classical uncertainty principle & commutation relation Modified uncertainty principle

J. Niemeyer, Models and Signatures of short distance physics in inflationM.Sloth, Transplanckian effects in inflationary cosmology and the modified uncertainty principle


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Sentences of the Day

“If a matematician would look at what we are doing, he wouldn’t be happy!”

“They are never happy”

“...then a miracle occurs...”

In case a singularity appears in the theory:

Workshop on Transplanckian Physics

Documents