SAIP2014

Aliasing in Atomic Clocks

9 Jul 2014, 11:30

20m

D Les 104

Oral Presentation Track G - Theoretical and Computational Physics Theoretical

Speaker

Dr Ismail Akhalwaya (University of Johannesburg)

Description

Atomic clocks execute periodic corrections of a 'classical' quartz crystal oscillator, by comparison to an atomic quantum reference, namely a precise hyperfine transition frequency. This periodic calibration has a surprising noise-inducing effect called aliasing. In fact, this sampling effect is mathematically identical to visual digital aliasing. Many of the standard visual anti-aliasing techniques are not applicable to the atomic clock problem or experimentally tenable. A new technique is proposed where previous samples are incorporated to boost correction on certain portions of the noise spectral density and dampen sensitivity on the aliased portion. We find scenarios for realistic parameters where our multiple window technique improves the accuracy of the atomic clock correction by reducing aliasing. Ultimately, this may help your GPS tell you to "turn right now" more accurately.

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

PhD

Main supervisor (name and email)<br>and his / her institution

Francesco Petruccione, petruccione@ukzn.ac.za, Quantum Research Group, School of Physics, University of KwaZulu-Natal

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

No

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Atomic clocks execute periodic corrections of a 'classical' quartz crystal oscillator, by comparison to an atomic quantum reference, namely a precise hyperfine transition frequency. This periodic calibration has a surprising noise-inducing effect called aliasing. In fact, this sampling effect is mathematically identical to visual digital aliasing. Many of the standard visual anti-aliasing techniques are not applicable to the atomic clock problem or experimentally tenable. A new technique is proposed where previous samples are incorporated to boost correction on certain portions of the noise spectral density and dampen sensitivity on the aliased portion. We find scenarios for realistic parameters where our multiple window technique improves the accuracy of the atomic clock correction by reducing aliasing. Ultimately, this may help your GPS tell you to "turn right now" more accurately.