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Jason Hogan June 26, 2014

Gravitational wave detection using atom interferometry. Frontiers of New Physics: Colliders and Beyond. Jason Hogan June 26, 2014. Gravitational Wave Detection. frequency. L (1 + h sin( ω t )). Megaparsecs …. strain. Why study gravitational waves? New carrier for astronomy

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Jason Hogan June 26, 2014

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  1. Gravitational wave detection using atom interferometry Frontiers of New Physics: Colliders and Beyond Jason Hogan June 26, 2014

  2. Gravitational Wave Detection frequency L (1 + h sin(ωt)) Megaparsecs… strain Why study gravitational waves? New carrier for astronomy Tests of gravity Cosmology

  3. Laser Interferometer Detectors Gound-based detectors: LIGO, VIRGO, GEO (> 10 Hz) Space-based detector concept: LISA (1 mHz – 100 mHz)

  4. Gravitational Wave Detection Why consider atoms? Neutral atoms are excellent proof masses Atom interferometry to measure geodesic Atoms are excellent clocks

  5. Atom interference Light interferometer Light fringes Beamsplitter Atom fringes Atom interferometer Beamsplitter Mirror Atom http://scienceblogs.com/principles/2013/10/22/quantum-erasure/ http://www.cobolt.se/interferometry.html

  6. Light Pulse Atom Interferometry Long duration Large wavepacket separation 4 cm

  7. 10 m Drop Tower Apparatus < 3 nK

  8. Interference at long interrogation time Wavepacket separation at apex (this data 50 nK) 2T = 2.3 sec Near full contrast 6.7×10-12 g/shot (inferred) Demonstrated statistical resolution: ~5 ×10-13g in 1 hr (87Rb) Interference (3 nK cloud) Dickerson, et al., PRL 111, 083001 (2013).

  9. Large momentum transfer atom optics Sequences of optical pulses can be used to realize large separations between interferometer arms. Example interferometer pulse sequence Chiow, PRL, 2011

  10. Preliminary LMT in 10 m apparatus LMT using sequential Raman transitions with long interrogation time. 6 ħk 4 cm wavepacket separation 10 ħk 7 cm wavepacket separation LMT demonstration at 2T = 2.3 s (unpublished)

  11. Single Baseline Gravitational Wave Detection frequency L (1 + h sin(ωt)) strain Are multiple baselines required? Motivation Formation flying: 2 vs. 3 spacecraft Reduce complexity, potentially cost Laser interferometer GW detector

  12. Measurement Concept Essential Features Atoms are good clocks Light propagates across the baseline at a constant speed Atom Clock Atom Clock L (1 + h sin(ωt))

  13. Simple Example: Two Atomic Clocks Atom clock Atom clock Phase evolved by atom after time T Time

  14. Simple Example: Two Atomic Clocks Atom clock Atom clock GW changes light travel time Time

  15. Phase Noise from the Laser The phase of the laser is imprinted onto the atom. Laser phase noise, mechanical platform noise, etc. Laser phase is common to both atoms – rejected in a differential measurement.

  16. Single Photon Accelerometer Three pulse accelerometer “Two level” atom Long-lived single photon transition (e.g. clock transition in Sr, Yb, Ca, Hg, etc.) Graham, et al., PRD 78, 042003, (2008). Yu, et al., GRG 43, 1943, (2011).

  17. Two-photon vs. single photon configurations 1 photon transitions 2 photon transitions Sr Rb How to incorporate LMT enhancement? Graham, et al., PRD 78, 042003, (2008). Yu, et al., GRG 43, 1943, (2011).

  18. Laser frequency noise insensitive detector Excited state Pulses from alternating sides allow for sensitivity enhancement (LMT atom optics) Laser noise is common Graham, et al., arXiv:1206.0818, PRL (2013)

  19. LMT enhancement with single photon transition Example LMT beamsplitter (N = 3) Each pair of pulses measures the light travel time across the baseline. Excited state Graham, et al., arXiv:1206.0818, PRL (2013)

  20. Reduced Noise Sensitivity Leading order kinematic noise sources: 1. Platform acceleration noise da 2. Pulse timing jitter dT 3. Finite duration Dt of laser pulses 4. Laser frequency jitter dk Differential phase shifts (kinematic noise) suppressed by Dv/c < 3×10-11

  21. Satellite GW Antenna Common interferometer laser Atoms Atoms L ~ 100 - 1000 km

  22. Potential Strain Sensitivity Possible sensitivity on ground JH, et al., GRG 43, 7 (2011).

  23. Stochastic GW Sensitivity AGIS Requires correlation among multiple independent baselines

  24. Technology development for GW detectors • Large wavepacket separation (meter scale) • Laser frequency noise mitigation strategies • Ultra-cold atom temperatures (picokelvin) • Long interferometer time (>10 seconds) • Spatial wavefront of laser

  25. Atom Lens Cooling Optical Collimation: position time Atom Cooling:

  26. 2D Atom Refocusing Lens Without Lens Transverse dipole potential approximately harmonic With Lens Laser beam profile

  27. Vary Focal Length North West

  28. Extended free-fall on Earth Launch  Lens  Relaunch  Detect Lens Image of cloud after 5 seconds total free-fall time Launched to 9.375 meters Relaunched to 6 meters Towards T > 10 s interferometry (?)

  29. Sr compact optical clock 6 liter physics package As built view with front panel removed in order to view interior. 408-735-9500 AOSense.com Sunnyvale, CA AOSense

  30. Future GW work Single photon AI gradiometer proof of concept Ground based detector prototype work 10 m tower studies MIGA; ~1 km baseline (Bouyer, France)

  31. Collaborators Stanford Mark Kasevich (PI) Susannah Dickerson Alex Sugarbaker Tim Kovachy Christine Donnelly Chris Overstreet Theory: SavasDimopoulos Peter Graham SurjeetRajendran Former members: Sheng-weyChiow David Johnson Visitors: Philippe Bouyer (CNRS) Jan Rudolph (Hannover) NASA GSFC BabakSaif Bernard D. Seery Lee Feinberg RitvaKeski-Kuha AOSense Brent Young (CEO)

  32. Phase shear readout Phase Shear Readout (PSR) F = 2 (pushed) F = 1 g F = 1 F = 2 (pushed) g 1 cm 1 cm ≈ 4 mm/s Single-shot interferometer phase measurement Mitigates noise sources: • Pointing jitter and residual rotation readout • Laser wavefront aberration in situ characterization

  33. Phase shear readout Phase Shear Readout (PSR) F = 2 (pushed) F = 1 g F = 1 F = 2 (pushed) g 1 cm 1 cm ≈ 4 mm/s Single-shot interferometer phase measurement Mitigates noise sources: • Pointing jitter and residual rotation readout • Laser wavefront aberration in situ characterization

  34. Phase shear readout Phase Shear Readout (PSR) F = 2 (pushed) F = 1 g F = 1 F = 2 (pushed) g 1 cm 1 cm ≈ 4 mm/s Single-shot interferometer phase measurement Mitigates noise sources: • Pointing jitter and residual rotation readout • Laser wavefront aberration in situ characterization

  35. Phase shear readout Phase Shear Readout (PSR) F = 2 (pushed) F = 1 g F = 1 F = 2 (pushed) g 1 cm 1 cm ≈ 4 mm/s Single-shot interferometer phase measurement Mitigates noise sources: • Pointing jitter and residual rotation readout • Laser wavefront aberration in situ characterization

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