1. Atom-interferometry constraints on dark energy Philipp Haslinger Müller group University of California Berkeley

2. 1.„A brief history of time“ 2.Search for dark energy 3.Screened scalar fields as dark energy 4.Atom interferometry limits dark energy theories 5. Future research with atom interferometry Outline

3. Evidence ESA/Planck SDSS SCP + + =

4. Known unknowns ESA/Planck

5. Publications on dark energy theories G. Pignol (2015) arXiv:1503.03317

6. Scalar dark energy Simple scalar models lead to equivalence principle violations in conflict with solar system tests and fifth force searches. What if scalar field effects are somehow reduced in normal matter? Only two ingredients needed for screening 1)Scalar field self-potential 2)Coupling to local matter density Khoury, Weltman Phys. Rev. D 69, 044026

7. Chameleon fields Khoury, Weltman Phys. Rev. D 69, 044026 The “chameleon” as a model screened scalar field Self-potential Coupling to local density Self-potential

8. Chameleon screening Unscreened Screened Only a thin shell contributes in macroscopic objects 1 cm 1 nm Chameleon field acts as a potential for objects

9. Screened force Unscreened force can be much stronger than gravity

10. The idea Probing Dark Energy with Atom Interferometry C. Burrage, E. J. Copeland, E. A. Hinds JCAP 1503 (2015) 03, 042 Realization: Single atom’s small size in ultra high vacuum makes it ideal test mass which evades screening

11. Screened force Unscreened force can be much stronger than gravity C. Burrage, E. J. Copeland, E. A. Hinds JCAP 1503 (2015) 03, 042

12. Atom interferometry Time 0 T 2T Height

13. Detection Optically push one state to side before imaging Fluorescence detection of two output states Sphere moved in and out with translation stage 3 mm

14. Cavity interferometer 4 lasers, 2 optical cavities 7 frequency and phase locks Upper Mirror Lower Mirror 3D MOT 2D MOT For more information:

15. Gravimetry fringes Height Time

16. Results Red = sphere near Blue = sphere far Difference between sphere near/far P. Hamilton, M. Jaffe, P. Haslinger, Q. Simmons, H. Müller, J. Khoury arXiv:1502.03888

17. Dark energy limits T. Jenke et al. PRL 112, 151105 (2014) H. Lemmel et al. Phys. Lett. B 743 (2015) 310-314 β M =M Pl /M Amol Upadhye Phys. Rev. D 86, 102003 (2012)

18. Atom interferometry does not need photon coupling Photon coupling comparison GammeV collaboration J. Steffen et al. PRL 105, 261803 (2010) CAST- arxiv:1503.04561

19. The future 3-4 orders of magnitude improvement reaches Planck Mass couplings

20. Dark energy / optical cavity interferometer Atom-interferometry constraints on dark energy P. Hamilton, M. Jaffe, P. Haslinger, Q. Simmons, H. Müller, J. Khoury arXiv:1502.03888

21. Exclusion plot regions Large for: small source radius small atom mass vacuum pressure Source, test mass screened Large for: large vacuum chamber small source radius small atom mass Source, test mass screened Large for: large vacuum chamber small source radius independent atom mass Source mass screened