Presentation on theme: "The Fit and the Pendulum Quantum Mechanics and New Clocks M. Crescimanno Department of Physics and Astronomy Youngstown State University & R. Walsworth,"— Presentation transcript:
The Fit and the Pendulum Quantum Mechanics and New Clocks M. Crescimanno Department of Physics and Astronomy Youngstown State University & R. Walsworth, D. Phillips, Irina Novikova and Christine Wang Harvard -Smithsonian Center for Astrophysics
Need to shine some dark on this clock... (Use interference) Fountain Clocks (Reduce time atoms spend in cavity) CPT Clock
Coherent Population Trapped Clock = optical pumping to a superposition hyperfine ground states bc ac |a> |c> |b> ab Atomic population's dipole vanishes "Dark State" No microwave cavity Small Size Simple construction Low light readout
CPT = Electromagnetically Induced Transparency Static Solution (exact) Im(rho_01) = probe beam absorption Little spike of transparency in middle... Dispersion: Large index of refraction = slow- and stopped light
EIT window CPT clock : lock to center of EIT window
CPT clock : Elements 2 Lasers Shield Photodetector
Schematic of "All-Optical" Atomic Clock cell oven solenoid shields bc ac |a> |c> |b> ab (Source: D. Phillips, R. Walsworth) isolator power level = +17 dBm freq=6.834 GHz x2 Multplier VCXO 12 GHz photodetector cell oven solenoid shields 6.84 GHz LO 3.42 GHz drive 3.42 GHz EOM DC feedback signal laser diode
Why so good? " Environmental susceptibility (Data from I. Novikova) " Medium Term stability at the Level
Simulation vapor cell inputs: gas, pressure, laser power, beam diameter diffusion coefficient, line shifts, broadenings... bc ac |a> |c> |b> ab 3-level density matrix solver average over velocities, diffusion dv v output lineshapes calculations performed in C/GSL/IDL parameters chosen to match experimental conditions from literature and our measurements Detection
Simulatio n Doppler effect + Motional Averaging (Lamb-Dicke) Analytic solution for steady state AC Stark Effect due to carrier Lockin detection modulation dependent effects - (EIT line asymmetry) Includes...
Preliminary Comparisons So many knobs to twist ! DATA THEORY
DATA THEORY Detuning Slope w1/w0 ~ 10 mHz/MHZ Slope is negative !
Dependence on Modulation DATA THEORY
Carrier Intensity Stark Effect DATA THEORY
CONCLUSIONS: CPT clock may be promising Experiment and QO theory are converging QO theory informing design compromises