arXiv subjects

R. Celechovsky

Publications and source records attributed to R. Celechovsky.

3 recordsLinked to original sources

arXiv2009

Full tomography from compatible measurements

We put forward a reconstruction scheme prompted by the relation between a von Neumann measurement and the corresponding informationally complete measurement induced in a relevant reconstruction subspace. This method is specially suited for the full tomography of complex quantum systems, where the intricacies of the detection part of the experiment can be greatly reduced provided some prior information is available. In broader terms this shows the importance of \sugg{this often-disregarded} prior information in quantum theory. The proposed technique is illustrated with an experimental tomography of photonic vortices of moderate dimension.

quant-ph↗

arXiv2007

Experimental test of uncertainty relations for quantum mechanics on a circle

We rederive uncertainty relations for the angular position and momentum of a particle on a circle by employing the exponential of the angle instead of the angle itself, which leads to circular variance as a natural measure of resolution. Intelligent states minimizing the uncertainty product under the constraint of a given uncertainty in angle or in angular momentum turn out to be given by Mathieu wave functions. We also discuss a number of physically feasible approximations to these optimal states. The theory is applied to the orbital angular momentum of a beam of photons and verified in an experiment that employs computer-controlled spatial light modulators both at the state preparation and analyzing stages.

quant-ph↗

arXiv2006

Minimum uncertainty measurements of angle and angular momentum

The uncertainty relations for angle and angular momentum are revisited. We use the exponential of the angle instead of the angle itself and adopt dispersion as a natural measure of resolution. We find states that minimize the uncertainty product under the constraint of a given uncertainty in angle or in angular momentum. These states are described in terms of Mathieu wave functions and may be approximated by a von Mises distribution, which is the closest analogous of the Gaussian on the unit circle. We report experimental results using beam optics that confirm our predictions.

quant-ph↗