1. Interacting Dark Energy Xinmin Zhang Institute of High Energy Physics Beijing Outline of the talk I. Current constraints on Dark Energy a. Constraints from SN Ia b. Global analysis with WMAP, SDSS and SN Ia II. Interacting Dark Energy and mass varying Neutrinos III. Summary

2. Dark Energy: * Negative pressure:  * Smoothly distributed, (almost ) not clustering Candidates: * Cosmological constant (or vacuum Energy) cosmological constant problem! * Dynamical Field: Quintessence, K-essence, Phantom etc

3. Constraints on the Dark Energy A quantity characterizing the property of Dark Energy: Equation of state: w(Z)=P/ρ For example : * Vacuum Energy: w=-1 * Quintessence: * Phantom: Using the recent 157 Supernova data published by Riess et al. astro-ph/0402512 ) * Within 2 σ, the cosmological constant fits well the data * Data mildly favors a running of the W across -1 Model independent analysis with the following parameterization ： 1 ， w(z)=w_0 + w_1* z 2 ， w(z)=w_1 + w_a*z/(1+z)

5. Feng, Wang & Zhang Astro-ph/0404224 Huterer & Cooray Astro-ph/0404062 z w

6. Implication in model building of dark energy If the running of w(Z), especially a transition across –1, confirmed in the future, big challenge to the model building * Vacuum : w=-1 * Quintessence: ( 精质 ) * Phantom: （幽灵） * K-essence: or but cannot across -1 A new scenanio of Dark Energy : Quintom （精灵） (Zhang et al. Astro-ph/0404224) For ex: single scalar: multi-scalar:

7. astro-ph/0407259, Steen Hannestad,Steen Hannestad Edvard Mortsell Adding CMB,LSS data

8. Include DE perturbation when parametrizing the EOS Seljak et al Astro-ph/0407372 Ch. Yeche et al Astro-ph/0507170 Neglect DE perturbations Including DE perturbation only when w>-1 BIASED!!

9. Constrains on dark energy with SN Ia (Riess) + SDSS + WMAP-1 Observing dark energy dynamics with supernova, microwave background and galaxy clustering Jun-Qing Xia, Gong-Bo Zhao, Bo Feng, Hong Li and Xinmin Zhang Phys.Rev.D73, 063521, 2006

10. Jun-Qing Xia, Gongbo Zhao, Bo Feng, Hong Li and Xinmin Zhang Phys.Rev.D73, 063521, 2006 WMAP+SDSS+Riess WMAP+SDSS+SNLS Comparision of global fitting results with SN Ia (Riess) and SNLS

11. Constrain on dark energy by WMAP group (importance of perturbation)

16. Current constrains on dark energy 1.Cosmological constant fit the data well 2.Dynamical model are not ruled out 3.Quintom is mildly favored Short summary :

17. Features of Quintom ( “ 精灵 ” ) Dark Energy Model I.A lot of recent studies on the models of Dark Energy with equation of state across -1 II.Implications in CMB: III.Different from cosmological constant, Quintessence and Phantom in the determination of the evolutions and the fate of the universe Oscillating Quintom

18. Oscillating Quintom and the Recurrent Universe: astro-ph/0407432 Bo Feng, Minzhe Li, Yunsong Piao, Xinmin Zhang

19. Parameterization: Astro-ph / 0605366

20. “Offline” analysis of the first 2 years - Search the previous year imaging data for likely SNe either missed or not spectred for various reasons - Search the previous year imaging data for likely SNe either missed or not spectred for various reasons - get z from host galaxy spectro (either by us or other projects) or get photo-z from imaging - get z from host galaxy spectro (either by us or other projects) or get photo-z from imaging - photo-id the SN - photo-id the SN - add Ia to the Hubble diagram (in red) - add Ia to the Hubble diagram (in red) very preliminary very preliminary Z=1.2 ! Z=1.2 ! From Reynald Pain ’ s Hangzhou talk (May, 2006)

21. Precise Hubble diagram from SNe Ia From Dr. Xiao Feng Wang ’ s Hangzhou talk ( May, 2006) Precise Hubble diagram from SNe Ia From Dr. Xiao Feng Wang ’ s Hangzhou talk ( May, 2006)

22. Interacting Dark Energy Current data favors Quintom Quintom Dark Energy is described by dynamical scalar fields Expected also to interact with the matter directly. Open new possibilities for the detection. * Direct coupling with ordinary matter Constraint from the limits on the long-range force * Interacting with DM (Peebles et al ) * Interacting with neutrinos

23. Xinmin Zhang etal. PRD68, 087301 (2003) Dark Energy and neutrinos ： Any connection between Dark Energy and neutrinos? 1.ΛCDM: 2.QCDM: If yes, very interesting: 2 of the biggest discoveries in the recent years Predictions : neutrino masses vary and cosmological CPT violation Derivative couplings: Quintessential Leptogenesis -M. Li, X. Wang, B. Feng, X. Zhang Phys.Rev. D65 (2002) 103511

24. M.Li, X.Wang, B.Feng, X. Zhang PRD65,103511 (2002) M.Li & X. Zhang ， PLB573,20 (2003) In thermo equilibrium   Quintessential Baryo(Lepto)genesis Cohen & Kaplan The value of depends on the model of Quintessence Cosmological CPT violation!

25. Where, Corresponding the formula for the neutrino mass upper limit now is:

26. Astro-ph/0309800

27. New features of neutrino Dark Energy model: I.Unlike the ordinary matter the massive neutrino has equation of state II.Neutrino plays an improtant role in the evolution of the universe III.Mass varying neutrinos effects on CMB, LSS IV.Testing mass varying neutrinos with GRB V.Testing mass varying with neutrino oscillations

28. Cosmological evolution of Interacting Dark Energy models with massvarying neutrinos hep/ph/0412002 -Xiaojun Bi, Bo Feng, Hong Li, Xinmin Zhang

29. Astro-ph/0503349

30. Testing mass varying neutrino with short GRB -Hong Li, Zigao Dai, Xinmin Zhang: hep-ph/0411228

31. Neutrino oscillation probes of Dark Energy D.B. Kaplan et al., PRL 93,091801 (2003); V. Barger et al., hep-ph/0502196; M. Cirelli et al., hep-ph/0503028. Basic idea ： given by Neutrino oscillation Solar Neutrino oscillation ：

32. Summary I.Quintom Dark Energy Models: Current data consistant with the cosmological constant but mildly favour the Quintom: a dynamical dark energy with Equation of state evolving and crossing -1 need more data and model building of Quintom dark energy II. The massive neutrino might have connection with dark energy; open up a possibility of detecting dark energy non-gravitationally need more study

33. Thanks !