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Gravitational Waves- Implications in our lives. Roxanne Radpour Miranda Pihlaja. Talk Outline. Theoretical basis for Gravitational Waves Einstein’s Theory of Relativity Cosmological Sources Detection efforts Generations of ‘gravity telescopes’ How close are we ? Implications
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Gravitational Waves-Implications in our lives Roxanne Radpour Miranda Pihlaja
Talk Outline • Theoretical basis for Gravitational Waves • Einstein’s Theory of Relativity • Cosmological Sources • Detection efforts • Generations of ‘gravity telescopes’ • How close are we? • Implications • What do gravitational waves tell us?
Basis for Gravitational Waves • Einstein’s Theory of Relativity postulates the existence of gravitational waves • Weak field limit of Einstein’s field equation: • Make up <<1% of the energy density of the universe • Strongest evidence for GW’s • Binary pulsar system • Energy dissipated
Cosmological Sources Inflation Phase Transitions Topological Defects all contributors to the Stochastic GW Background (SBGW) Random noise of GW’s 4
C.S.’s: Phase Transitions 1st order phase transitions Discontinuities-> violent events Symmetry breaking process Bubbles! Different vacua Expansion/Collision
C.S.’s: Topological Defects Phase transitions from symmetry breaking form these defects Different topology can make different defects: domain walls monopoles hybrid effects strings** 7
T.D.’s: Cosmic Strings Small & Large Loops decay through emission of GW’s oscillate relativistically from tension Depending on size, can create larger amplitudes of GW spectra
C.S.’s: Inflation Mechanisms in preheating Excited modes-> inhomogeneous Universe-> GWs! Symmetry breaking at end of inflation Bubbles!
Detection • Generations of gravity telescopes • Bar detectors- sensitivity issues • Interferometers- use light as the measuring stick • Ground-based detectors have noisy neighbors-everything • Space-based interferometers- the vacuum is free • LIGO - the plane version
The Friends and Family Version Trampoline, bowling ball, and marble Vibrations Noise canceling headphones Ants sneezing Marbles on a plate on a boat Paris cafe
Again… why do we care? Gives us picture into early universe - why? gravity is weakest force decoupling of graviton at very early times -> GW’s Thermal equilibrium: Γ ~ H > Tdec ~ Mpl (Mpl ~ 1019 GeV) > tpl ~ 10-44 s Γ ~ (G2N ) T5 H ~ T2/Mpl
Implications These relic GW’s maintain spectrum, frequency, intensity Probe Inflationary physics Explore HEP ex: String Theory (allows for a measurable spectrum)
References • Cosmological Sources of Stochastic Gravitational-Wave Background, V. Mandic • Phys.Rept. 331 (2000) 283-367, M. Maggiore • Gravitational Waves, IoP Series, Ciufolini, et al.