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Attempts to explain CMB Large-scale Anomalies Kin-Wang Ng ( 吳建宏 ) Academia Sinica, Taiwan NTU String Group, June 18, 2010 Thanks: Hsien-Chun Wu, I-Chin Wang, Da-Shin Lee, Wolung Lee, Hing-Tong Cho,Yeo-Yie Charng, Shang-Yung Wang
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7 o resolution
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WMAP3 CMB sky map
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WMAP1 WMAP3 Low quadrupole
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South-North Power Asymmetry Eriksen et al 04 Park 04 North pole (80 o,57 o ) northern hemisphere southern hemisphere full sky
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“Axis of Evil” Land & Magueijo 05 l=2, quadrupole l=3, octopole
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Foreground problem??
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At last scattering surface, 400,000 yrs after big-bang Size of a casually connected region (horizon -- distance travelled by light in 400,000 yrs) is about 1 o now COBE DMR MAP 7 o angular scale Each 7 o pixel contains many 1 o regions Measuring super-horizon temperature fluctuations So smooth (1 in 10 5 )!! Why?? Primordial density fluctuations that seed large scale structures l = 180 degrees /
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Inflation and Primordial Density Fluctuations
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WMAP3 and chaotic inflation r : tenor/scalar m ~ 10 13 GeV
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Inflation and Primordial Density Fluctuations roughness of H inflation starts here periodic universe, more…..
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H
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A Challenge to Standard Slow-roll inflation!? Slow-roll kinematics Quantum fluctuations Slow-roll conditions violated after horizon crossing (Leach et al) General slow-roll condition (Steward) |n-1|~|dn/dlnk| Multi-field (Vernizzi, Tent, Rigopoulos, Yokoyama et al) etc Chaotic inflation – classical fluctuations driven by a white noise (Starobinsky) or by a colored noise (Liguori, Matarrese et al.) coming from high-k inflaton Driven by a colored noise from interacting quantum environment (Wu et al) Others
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Our Inflaton-Scalar Interacting Model Single-field inflation 〈 σ 〉 = 0 (Wu et al 07)
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Trace out sigma field to obtain : Colored, dependent on history Dissipation Noise imaginary partreal part Feynman & Vernon 1963 Influence Functional Method semi-classical
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Start of inflation
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Dominant passive fluctuations and low CMB quadrupole assuming no active de Sitter quantum fluctuations
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Conclusion I We propose a new dynamical source for density perturbation: Colored Quantum Noise - give a low CMB quadrupole Can be applied to trapped inflation (Green et al. 09) Working on running spectral index and non- Gaussianity, both are natural with colored noise Relative large three-point functions nsns Dissipation?
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A black hole in inflation Cho, Ng, Wang 09 Schwarzschild-de Sitter M - black hole mass H - Hubble parameter Static ------> Planar
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Inflaton fluctuations Expansion parameter where the source term
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Solutions Zero order First order
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Power spectrum de Sitter quantum fluctuations End of inflation → 0
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Possible effects to CMB anisotropy Carroll, Tseng, & Wise 08 preferred point, line, or plane Inflation present universe early universe e.g. black holes formed via thermal fluctuations Chen, Gruber, Ng, Scardigli 10
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Conclusion II Hints from WMAP data on beyond standard slow-roll inflation !? A fine tuning – physics just at 60 e-foldings Maybe there is a window to see the first few e-foldings of inflation !? From homogeneous to directional effects Or we are all fooled by probability – it is indeed a Gaussian quantum process Nongaussianity is an important check
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Speculations Is it possible not to fine tune inflation duration to 60 efolds? Then there must be something happening during slow-roll inflation Formation rate must not be far below the expansion rate of inflation
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String Landscape 10 500 de Sitter vacua Metastable, bubble nucleation via tunneling Barriers of string scale, slow tunneling rate The spacetime is a hierachy of de Sitter vacuum bubbles Most part in eternal inflation Some regions tunnel down to flat potential for slow-roll infaltion We sit in a vacuum with a small cosmological constant today
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Efficient and rapid tunneling slow-roll inflation in a de Sitter vauum Will these bubbles collapse into black holes? Tye, Shiu,… Λ1Λ1 Λ2Λ2
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Motion of the bubble wall surface tension bubble radius
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