Covert quantum sensing work presented at ISIT
Recent work on covert quantum sensing by Christos and Animesh is today being presented at the IEEE International Symposium on Information Theory in Aachen (ISIT 2017) by collaborator Boulat Bash. Typically parameter estimation benefits from the use of high energy probe states which use many photons to obtain a high-precision estimate of an unknown parameter. However such probes can easily be detected by an adversary who can recognise an attempt to probe this system by detecting these probe photons. In order to prevent the target itself or any third-parties from observing an attempt at sensing it is necessary to devise covert methods, hiding the probe state photons among thermal photons from the environment, which restrict the attainable precision. To quantify this restriction, a covertness constraint is derived which imposes a limitation on the probe state energy. While the mean square error scales, in general, with the number of repeated channel uses; these new results show that the improvement cannot exceed the square root of n without compromising the covertness of the measurement when using an n-mode state or making n uses of the channel.
The paper can be found at arXiv:1701.06206 and will appear in the ISIT 2017 Proceedings.