Loading in 5 sec....

Gravitational waves and cosmologyPowerPoint Presentation

Gravitational waves and cosmology

- 377 Views
- Updated On :

Gravitational waves and cosmology. P. Binétruy APC, Paris. 6th Rencontres du Vietnam Hanoi, August 2006. At t = 400 000 yrs, the Universe becomes transparent: photons no longer interact with matter. Looking back to the primordial Universe. BIG BANG. Cosmological background

Related searches for transparencies ppt

Download Presentation
## PowerPoint Slideshow about 'transparencies ppt' - victoria

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### Gravitational waves and cosmology

P. Binétruy

APC, Paris

6th Rencontres du Vietnam

Hanoi, August 2006

At t = 400 000 yrs, the Universe becomes transparent: photons no longer interact with matter

Looking back to the primordial Universe

BIG BANG

Cosmological background

T = 3 K = - 270 °C

WMAP satellite

When do graviton decouple? universe

T5

Interaction rate

~ GN2 T5 ~ ----

MPl4

T2

Expansion rate

H ~ ----

(radiation dominated era)

MPl

T3

---- ~ ----

H

MPl3

Gravitons decouple at the Planck era : fossile radiation

But gravitons could be produced after the Planck era. universe

Gravitons of frequency f* produced at temperature T* are observed

at a redshifted frequency

1/6

f = 1.65 10-7 Hz --- ( ----- ) ( ---- )

1

T*

g*

1GeV

100

At production * = H*-1 (or f* = H*/ )

Horizon length

Wavelength

Electroweak phase transition universe

If the transition is first order,

nucleation of true vacuum bubbles

inside the false vacuum

Collision of bubbles production of gravitational waves

Pros and cons for a 1st order EW phase transition:

- in the Standard Model, requires mh < 72 GeV (ruled out)
- in the MSSM, requires a light stop (less and less probable)
- possible to recover a strong 1st order transition by including 6 terms
- in SM potential
- needed to account for baryogenesis at the electroweak scale (out
- of equilibrium dynamics)

E universefalse vac

= ---------

aT*4

h02 GW

radiation energy

at transition

Nicolis

gr-qc/0303084

f in mHz

turbulence

bubble collision

fturb/fcoll~ 0.65 ut/vb

Long wavelength GW produce a universe

redshift on the photons of the CMB

Wavelength outside the horizon at LSS

Wavelength inside the horizon today

CMB polarisation universe

Vacuum fluctuations : de Sitter inflation (constant vacuum energy)

h02GW =10-13(feq/f) 2(H/10-4MPl)2

h02GW =10-13 (H/10-4MPl)2

Fluctuations reenter horizon during matter era radiation era

Cosmic strings energy)

Presence of cusps enhances the production of gravitational waves

Damour-Vilenkin

log h

LIGO

stochastic GW

background

log 50 GN

Loops radiate at

z>1 (MD)

z>1 (RD)

z<1

How to measure a stochastic background? energy)

Cross correlate

ground interferometers

Let LISA move around the Sun

2. Dark energy: in search of standard candles energy)

- Supernovae of type Ia

magnitude versus redshift

mB = 5 log(H0dL) + M - 5 log H0 + 25

- Gamma ray bursts

- Coalescence of black holes : the ultimate standard candle?

Gravitational dynamics energy)

f ~ (G)1/2

R in m

f = 10-4 Hz

space interf.

109

f = 1Hz

ground interf.

f = 104 Hz

104

100

108

M/M

Gravitational dynamics energy)

Schwarzchild radius

R = 2GM/c2

R in m

space interf.

109

ground interf.

black hole line

104

100

108

M/M

Gravitational dynamics energy)

Supermassive BH mergers

R in m

space interf.

109

chirp line

coalesc. in 1 yr

ground interf.

black hole line

104

100

108

M/M

NS-NS coalescence

after B. Schutz

Inspiral phase energy)

(m1 m2)3/5

Key parameter : chirp mass M =

(1+z)

(z)

(m1 + m2)1/5

Amplitude of the gravitational wave:

frequency

f(t) = d/2dt

M(z)5/3 f(t)2/3

h(t) = F (angles) cos (t)

dL

Luminosity distance

Inspiral phase energy)

(m1 m2)3/5

Key parameter : chirp mass M =

(1+z)

(z)

(m1 + m2)1/5

Amplitude of the gravitational wave:

M(z)5/3 f(t)2/3

h(t) = F (angles) cos (t)

dL

Luminosity distance

poorly known in the case of LISA

10 arcmin

1 Hz

~

SNR

fGW

Using the electromagnetic counterpart energy)

Allows both a measure of the direction and of the redshift

0.5%

Holz and Hughes

dL/dL

But limited by weak gravitational lensing!

dL/dLlensing= 1-1/

Conclusions energy)

- LISA will provide complentary ways to identify the geometry
- of the Universe.

- regarding a stochastic background of primordial gravitational
- waves, no detection in the standard inflation scenarios, but many
- alternatives lead to possible signals within reach of advanced
- ground interferometers or LISA.

Download Presentation

Connecting to Server..