https://doi.org/10.1140/epjqt/s40507-015-0026-0
Research
Improved mirror position estimation using resonant quantum smoothing
1
School of Engineering and Information Technology, UNSW Australia, Canberra, ACT, 2600, Australia
2
Centre for Quantum Computation & Communication Technology, Australian Research Council, Canberra, Australia
3
Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
4
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
5
Research School of Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT, 2600, Australia
* e-mail: t.wheatley@adfa.edu.au
Received:
26
February
2015
Accepted:
23
April
2015
Published online:
20
May
2015
Quantum parameter estimation, the ability to precisely obtain a classical value in a quantum system, is very important to many key quantum technologies. Many of these technologies rely on an optical probe, either coherent or squeezed states to make a precise measurement of a parameter ultimately limited by quantum mechanics. We use this technique to theoretically model, simulate and validate by experiment the measurement and precise estimation of the position of a cavity mirror. In non-resonant systems, the achieved estimation enhancement from quantum smoothing over optimal filtering has not exceeded a factor two, even when squeezed state probes were used. Using a coherent state probe, we show that using quantum smoothing on a mechanically resonant structure driven by a resonant forcing function can result significantly greater improvement in parameter estimation than with non-resonant systems. In this work, we show that it is possible to achieve a smoothing improvement by a factor in excess of three times over optimal filtering. By using intra-cavity light as the probe we obtain finer precision than has been achieved with the equivalent quantum resources in free-space.
PACS: Codes – 42.50.Dv / Codes – 03.65.Ta / Codes – 03.67.-a
Key words: quantum smoothing / quantum parameter estimation / cavity mirror position
© Wheatley et al.; licensee Springer., 2015
