Neutron Interferometry Search for Strongly- Coupled Chameleons W.M. Snow (Indiana University) M. Arif, M. Huber, D.L. Jacobson (NIST) D. Pushkin (Institute for Quantum Computing) What is a neutron interferometer? Use for chameleon search: recent developments Thanks to G. Pignol, P. Brax
Perfect Crystal Neutron Interferometer 5 - 15 cm in length and 2 - 10 cm in width Blades are typically 0.5 to 3 mm thick Dimensional tolerance: A few micro-meters Typical neutron transit is time 50-100 micro-sec
Neutron Interferometer and Optics Facility (NIOF) Contrast > 90% 0.25 o / day (best value) Phase Stability: Monochromator: PG (002), Parallel double crystal geometry Beam Intensity: 2.10 5 n/cm 2 .sec (at the interferometer) < 10 -7 g Vibration : Stability: < 2 micro-meter (linear) < 1 micro-rad (rotation) < 0.1 o C Temperature: Polarizer: Super mirror transmission type Polarization: > 98 %
How a neutron interferometer works Neutron wave function coherently split by Δε Top View Bragg diffraction. Interferometer δ H-beam Neutron m a e b m a e b - O Phase Sample shifter Sample Incident Sample Outgoing wave front wave front 1000 D λ λ / n λ 500 V opt Visibility Δφ λ λ λ Δφ 0 -2 -1 0 1 2 Phase Shifter Angle (deg) Visibility > 90% Only neutron optics device Δφ = − λΝ bD which can directly measure the phase shift.
Setup for measuring scattering length of gas samples 1 cm n - beam Si (111) phase shifter vacuum cell gas cell quartz alignment cell out cell in flag Temp A Temp B 3 He detectors
Neutron interferometry Chameleon bubble Brax-Pignol, to appear. One of the beams traverses a chamber where the chameleon leads to a change of the phase vacuum Chameleon bubble
Interferometry is competitive with current bouncing neutron experiments. Interferometry vs GRANIT
CHASE constraints on V ( φ ) = M 4 Λ (1 + M Λ /φ ) 1e+18 1e+18 1e-1 1e-1 1e+17 1e+17 colliders (CLEO, precision EW) colliders (CLEO, precision EW) 1e-2 1e-2 1e+16 1e+16 1e-3 1e-3 photon coupling β γ photon coupling β γ g γ = β γ / M Pl [GeV -1 ] g γ = β γ / M Pl [GeV -1 ] 1e+15 1e+15 torsion pendulum torsion pendulum 1e-4 1e-4 1e+14 1e+14 1e-5 1e-5 afterglow afterglow 1e+13 1e+13 1e-6 1e-6 (GammeV-CHASE) (GammeV-CHASE) 1e+12 1e+12 1e-7 1e-7 1e+11 1e+11 GRANIT GRANIT qBounce qBounce 1e-8 1e-8 1e+10 1e+10 helioscope helioscope neutrons neutrons 1e-9 1e-9 (Grenoble) (Grenoble) 1e+09 1e+09 1e-10 1e-10 1e+08 1e+08 1 1 10000 10000 1e+08 1e+08 1e+12 1e+12 1e+16 1e+16 matter coupling β m matter coupling β m Theory: AU, Steffen, Chou, PRD 86 :035006(2012)[arXiv:1204.5476] , AU, Steffen, Weltman, PRD 81 :015013(2010)[arXiv:0911.3906] Experiment: Steffen, AU, Baumbaugh, Chou, Mazur, Tomlin, Weltman, Wester, PRL 105 :261803(2010)[arXiv:1010.0988] Amol Upadhye Testing gravity in the laboratory 16
Future neutron interferometry experiments for Chameleons Repeat with dedicated experiment: straightforward, can get ~1 order of magnitude improvement Sensitivity can be improved significantly using neutron Fabry-Perot cavities and larger-area interferometers Technical developments also of interest for quantum computing research
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