1. 1/35 Fundamental physics in our time Gerhard Schäfer Institute of Theoretical Physics from quantum to cosmos(2), bremen, june 10 - 13, 2007

2. 2/35 from quantum to cosmos In 1968 J. Schwinger formulated empirical scaling laws that interconnect the cosmos, the laboratory, and the atoms, Does the quantum stabilize the cosmos?

3. 3/35 from quantum to cosmos empirical law (Zel`dovich 1967/68):

4. 4/35 goals of fundamental physics (FP)  FP is exploring the basic aspects of Nature  Space and time  Particles and fields  FP aims at  Finding more comprehensive concepts and laws  Testing the existing ones  Resolving basic inconsistencies  FP includes  Unification of the fundamental forces  Discovery of new particles and fields  Test of GR and of the equivalence principle  Verification and exploration of black holes  Detection and observation of gravitational waves

5. 5/35 current problems in FP Conceptual problems  Dark Energy & Dark Matter  Big Bang & Inflation  Black Holes  Irreversibility of phys. proc. Mathematical problems   Grav. waves astrophysics   Global aspects of spacetime   Unification of all forces   Phase transitions Experimental problems   Gravitational Waves   Black Holes   Big Bang & Inflation   Dark Energy & Dark Matter Need for Space Missions

6. 6/35 Why missions in space?  Space conditions  Infinitely long gravity-free environment  Large gravitational potential differences  Large velocity differences  Quiet environment  Straight view to the Universe

7. 7/35 frame theories  Special Relativity Einstein 1905  General Relativity Einstein 1915  Quantum Theory Heisenberg 1925 Schrödinger 1926 Dirac 1927 non-relativistic relativistic

8. 8/35 special relativity (SR)  Fundamental principle: constancy of speed of light c = universal constant  Unification of space and time: spacetime  Poincare´ group; causality cone  Proper time and action

9. 9/35 general relativity (GR)  Fundamental principle: Equivalence Principle  Unification of inertia and gravity: curved spacetime  Group of coordinate transformations; horizons  Proper time and spacetime metric universally constant

10. 10/35 quantum theory (QT)  Fundamental principle: Superposition Principle  Unification of particles and waves: probability amplitudes  Unitary group; coherence  Antimatter

11. 11/35 Spin in SR & GR & QT  SR: min. transvers. extension of body with mass m and spin S  GR: radius of ring singularity of Kerr BH  QT: Compton wavelength  QT: transversal extension of massless particle

12. 12/35 dynamical theories  electrodynamics [U(1)]: photon quarks, leptons (charged) infinite range  weak int. th. [SU(2)]: Z-, W-bosons quarks, leptons  chromodynamics [SU(3)]: gluon quarks  U(1) x SU(2) - unified theory [Higgs boson]  GR [GL(4)]: gravitation infinite range

13. 13/35 from microphysics to macrophysics  Transition from coherence to incoherence  Transition from time to temperature:  Arrow of time:  No quantization of time: negative prob.

14. 14/35 GR and the quantum  Unification of gravity with electro-weak and strong interaction  Observation: General Relativity  is effective theory (low-energy limit): : vacuum-expectation value of fundamental field at present epoch  - term is of vacuum-energy type with pressure

15. 15/35 GR and the quantum  Unification-Ansatze: String and brane theories in higher-dimensional spacetimes with non-trivial topologies  However, the effective cosmological constant is infinitesimal by particle-physics standards  Quintessence scenarios

16. 16/35 cosmology  Curvature  Hubble parameter  Deceleration parameter t A A A A B B B B

17. 17/35 cosmology

18. 18/35

19. 19/35 Energy and Matter in the Universe accelerated expansion at present epoch

20. 20/35 inflation area

21. 21/35 inflation - inflaton  action of massive scalar field  action of 3-dimensional spaces (space-slices)

22. 22/35 `´square root`´ of GR  square root of metric: tetrad field invariance group: local Lorentz group [S0(3,1),SL(2,C)]  connection to SUSY (unification of fermions and bosons)

23. 23/35 string theory  action of point particle (m = m[i] = m[pg] = m[ag])  action of global part of 3-dimensional spaces  action of string

24. 24/35 the structure of gravity  Foundations of GR Einstein‘s Equivalence Principle Univ. free fall Lorentz invariance Univ. grav. red shift Constancy of fund. const. metric gravity Matter Grav. field Geodetic eqn Einstein field eqn

25. 25/35 equivalence principle (EP)  Why testing the EP in Space?  The EP is deduced from experimental facts by `infinite‘ extrapolation.  Present fundamental physics framework is incomplete.  The most sensitive low-energy tests of new, gravity- related theories are those involving the EP.  There exist theoretical models which predict a violation of the EP at a level that is smaller than the presently tested level of about 10 -13 but could be within reach of a Space experiment.

26. 26/35 universality of free fall  Action of point mass:  Violation of EP: fundamental field  Acceleration of mass 1:  cosmological value g

27. 27/35 test of EP – the concept  Why testing the EP in Space?

28. 28/35 the structure of gravity  Framework: PPN-formalism (variable G included) Metric gravity

29. 29/35 the structure of gravity  Non-cosmological effects of the gravitational field Perihelion shift Perihelion shift Deflection of light Deflection of light Grav. redshift Grav. redshift Time delay Time delay Gravitomagnetism Gravitomagnetism Black holes Black holes Gravitational waves Gravitational waves

30. 30/35 the binary pulsar  Hulse-Taylor pulsar (PSR B1913 + 16)

31. 31/35 polarization of gravit. wave in GR

32. 32/35 gravitational wave detectors in space  Fundamental Physics with gravitational-wave detectors in space  Gravitational waves  Black holes/strong-field GR direct confirmation of existence of Black Holes Measurement of Lense-Thirring effect better than 1%  Cosmological background: Direct signature of cosmic strings and/or inflation Observation of conditions close to Big Bang  Measurement of total density of the Universe, determination of all dark matter

33. 33/35 black holes Schwarzschild radius Horizon

34. 34/35 Einstein-Rosen bridge

35. 35/35 Schwarzschild geometry

36. 36/35 GR and the quantum W. Israel in 2003: You can pick anyone off the street and say `Einstein´. They will at once write. But if you ask what this formula means, the response will be quite different. At best, you may get some mumbling about `atomic bomb´. It is sobbering that after a quarter-century we are in a hardly better position regarding the formula

37. 37/35 missions & main FP objectives ASTROD, Bepi-Col., Gaia, LATOR, Cassini, GP-B, LAGEOS: PPN-metric ACES/PHARAO: PPN-metric, foundations of GR GG, MICROSCOPE, POEM, STEP: equivalence principle LISA: gravitational waves, black holes, big bang Constellation-X: black holes, dark matter Planck: dark matter, dark energy GAUGE: unification of forces