Speaker : Cheon Hwa Sung Yonsei University

1. What Can WMAP Tell Us About The Very Early Universe? New Physics as an Explanation of Suppressed Large Scale Power and Running Spectral Index Mar Bastero-Gil, Katherine Freese and Laura Mersimi-Houghton Hep-ph/0306289 Speaker : Cheon Hwa Sung Yonsei University

2. 1.The purpose of this paper • The suppression of low "l" modes (Large angle) in the CMB data and Running of the spectral index of density perturbations can be explained by New physics

3. 1.1 The two modifications to standard cosmology • Modifications to the Friedmann equation • Velocity dependent potentials

4. 1.2 Our purpose • 1)What is the CMB power spectrum ? • 2)What is the Inflation Model? (Horizon, flatness, Relic problem) • 3)Friedmann Equation (Slowly-Rolling Scalar Fields) • 4)What are concerned with between the New physics and these? • 5) RS Model..

5. 2. Introduction of this paper Fig: [astro-ph/0302217] • 1. The suppression of large scale power and the running of the index, can be explained by New Physics • 2. The running of the index can be explained by New Physics The spectral index runs from red on small scales to blue on large scales Last Scattering New Physics!!! New physics is valid beyond, and around the E_c

6. 2.1 The Explanation of the suppression of large scale power From the low “l” suppression of the signal, we could be learning about the initial conditions for the part of inflation • 1) Non trivial topology [astro-ph/0303580, gr-qc/9602039, • Phys. Rev. D58,123006,1998] • 2) Closed Universe[astro-ph/0303245, 03032597, 03303127] 이들 ideas가 Concordance Model과 아주 잘 맞는 Cosmological data의 나머지와 잘 부합할지는 모른다. [astro-ph/0303268] • 3) Double Inflation [phys. Rev. D59(1999)107303, astro-ph/0305020]

7. The conclusion 1 • The initial conditions for the observable universe could be determined by the New Physics, which is the relevant theory valid beyond, and around the cutoff scale E_c of effective low energy theories

8. 2.2 Potential-driven models • We Here consider potential-driven models of Inflation ( 거기서 potential은 우주가 가속하기 위해 우주의 에너지 밀도에 dominate된 Potential이다. ) • Potential의 높이는 GUT scale에 의해 결정되어진다. • Horizon scale 까지 Homogeneous한 우주를 만들기 위해서는 roughly 60 e-folding of inflation이 요청된다.

9. The conclusion 2 • we here consider models in which physics beyond the inflationary scale (e.g. GUT scale) is modified by the introduction of NEW Physics, this NEW Physics can leave imprints in the CMB at scales near and above the Horizon.

10. Conclusion 1, 2에 의해 다음과 같은 결론을 이끌어 낼 수 있다. • Above the 60th e-folding the theory is described by NEW Physics • This is the regime corresponding to all the energy scales above E_c • 이 관점에 의하면, the low “l” feature in CBR 는 Inflation의 initial time에서 차지하는 NEW Physics로 부터 발생되어진다. • E_c 이상의 energy scale에서는 QFT나GR이 적용되지 않는다. 거기서는 NEW Physics가 요청된다. (New physics는 V<E_c에서는 GR, QFT로 approx 할 수 있다. )

11. 이 논문에서는, Standard Cosmology의Formalism에서 두 가지 변경을 고려하였다. • Modification to the Friedmann Equation • The Inflation potential is velocity dependent

12. Modified primordial spectrum CBR spectrum of anisotropies with the modified primordial spectrum fo the Randall Sundrum 점선 : modified 실선 : standard spectrum