1. STE-QUEST M4 Peter Wolf STE-QUEST M4 core team: K. Bongs(UK), P. Bouyer(F), C. Braxmaier (D), D. Calonico (I), M. Cruise (UK), N. Gaaloul (D), L. Iess(I), P. Jetzer(CH), W. von Klitzing (GR), S. Lecomte (CH), E. Rasel(D), M. Rothacher (CH) S. Schiller(D), C. Sopuerta (E), G. Tino(I), P. Tuckey(F), P. Wolf(F), M. Zelan (S)

2. Motivation General Relativity is a classical theory, difficult to reconcile with quantum field theory and the standard model of particle physics. Most unification models predict modifications of gravitational phenomena at some small (generally unknown) level. Dark energy and dark matter may indicate deviations from our known laws of gravitation. Many modified gravitational theories and corresponding cosmological models contain long range scalar fields. Higgs boson is the first known fundamental scalar field (short range). Low energy tests of fundamental gravitational physics can provide pieces of the puzzle that are complementary to cosmological observation or high energy physics in accelerators (LHC).

3. Astronomy & Cosmology (CMB, Planck, EUCLID, …) Low energy (LLR, lab-tests, ACES,  -scope, …) High energy (CERN-LHC, Fermilab, DESY, …) Scientific Context

4. Local Lorentz Invariance Universality of Clock Rates (LPI) Universality of Free Fall (WEP) GR Theory of gravitation Theory of electromagne- tic interaction Theory of weak interaction Theory of strong interaction Standard Model Lorentz Invariance CPT - Symmetry exactly valid? Unified theories string theory, quantum loop gravity,... ? ? (courtesy S. Schiller) Scientific Context

5. STE-QUEST Space-Time Explorer and Quantum Equivalence Space Test Elliptic orbit, 2500x33600 km, 63° inclination 3.5 yrs mission lifetime 41 K- 87 Rb double atom interferometer MWL for intercontinental ground clock comparisons Fundamental physics: Tests of all aspects of the EEP (Quantum WEP, LPI, LLI) Geodesy: Unification of reference frames (SLR, VLBI, GNSS), Clock based geodesy Time/Frequency metrology: Intercontinental clock comparisons at 10 -18 level

6. L. Catani, "Galileo performs the experiment of the motion of weights from the Tower of Pisa in the presence of the Grand Duke", Gallery of Modern Art of the Pitti Palace, Florence 41 K 87 Rb “STE-QUEST performs the experiment of the motion of Rb and K in a quantum superposition” Quantum test of UFF/WEP at 10 -15, based on matter wave interference using BECs Quantum superpositions: “Largest Atoms in the Universe”: 24 cm (10 2 x larger than individual wave packets) De Broglie wavelength 10 21 x larger than for macroscopic test masses Exploring the interface between Gravitation and Quantum Mechanics Universality of Free Fall (WEP)

7. Measured GRACE vibration PSD [Flury2008], and differential K-Rb sensitivity function for T K = 5 s and two different values of T Rb WEP performance (1)

8. WEP performance (2) There exists no principle that states: c.f. Ehrenfest!!

9. To sun Ground-to-satellite links allow terrestrial clock comparisons in common-view Test for anomalous coupling between source (sun/moon) gravity and clock fields Measurement does not require operation of atomic clock on satellite U = const.  The time-independent signal allows a determination of the geopotential difference U Earth ( r 1 ) – U Earth ( r 2 ) Precise test of Sun gravitational time dilation: (courtesy S. Schiller) Universality of Clock Rates (LPI)

10. LPI performance Visibility for Torino, Tokyo, BoulderMC simulation result for 10 days

11. ObjectiveSTE-QUESTOther UCR/LPI Sun2x10 -6 10 -2 (Krisher 1993) 10 -4 (ACES 2016) UCR/LPI Moon4x10 -4 10 -2 (ACES 2016) UFF/WEP2x10 -15 10 -7 (Fray 2004, Schlippert 2014, Tarallo 2014) 7x10 -9 (Peters 2001, Merlet 2010) 2x10 -13 (Schlamminger 2008) 10 -15 (  -scope 2016) Other science objectives: Lorentz Invariance: Improvements by > factor 10 expected on several SME parameters. Geodesy: Unification of Reference Frames. Clock based geodesy at cm level. T/F metrology: Distant clock comparisons at 10 -18 level after a few days integration: Essential for next generation ground clocks (at present 6x10 -18 accuracy, 2x10 -18 stability). Summary of Science objectives