1. 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

2. $$$ : ONR, NASA, Research Corporation, Cluster Ohio Program, YSU PACER funds

3. "No one can serve two masters; for a slave will either hate one and love the other or be devoted to the one and despise the other."

4. IDEAL CLOCK Bright : need good SNR to "split" the line. Dark : period needs to be immune from environment. Based on regularity of periodic behavior must be:

5. Gerard David "Rest on the Flight into Egypt" 1512(?)

6. A Brief History of Time......Measurement Mercury Ion Stability 10 3-4 10 4-6 10 7-10 10 14 Size/Cost Rooms Table Quarter ?

7. Why Small Atomic Clocks? " Cell Phone Repeaters " GPS System

8. Rb Atomic Clock 6.8 GHz 87 Rb microwave cavity Optical table: lasers, optics and magnetic shields Q L = 15,000 • split endplate design for double bulb • mechanical tuning • access for fiber optical detector (Source: D. Phillips)

9. Level Scheme What the experimentalist knows... Level Scheme Simplified What the theorist thinks...

10. Atomic Clock: Traditional Maser Good: Bad: Simple, Bright Light shifts, environment couplings large, bulky Microwave Cavity Shield Light RF Pickup

11. Need to shine some dark on this clock... (Use interference) Fountain Clocks (Reduce time atoms spend in cavity) CPT Clock

12. 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

13. CPT = Electromagnetically Induced Transparency Light Collisions,... RWA o1

14. 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

15. EIT window CPT clock : lock to center of EIT window

16. CPT clock : Elements 2 Lasers Shield Photodetector

17. 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

18. Why so good? " Environmental susceptibility (Data from I. Novikova) " Medium Term stability at the 10 12 Level

19. 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

20. 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...

21. Preliminary Comparisons So many knobs to twist ! DATA THEORY

22. DATA THEORY Detuning Slope w1/w0 ~ 10 mHz/MHZ Slope is negative !

23. Dependence on Modulation DATA THEORY

24. Carrier Intensity Stark Effect DATA THEORY

25. CONCLUSIONS: CPT clock may be promising Experiment and QO theory are converging QO theory informing design compromises