Not all Probability Density Functions are Tomograms

arXiv (Cornell University)

Abstract

This paper delves into the significance of the tomographic probability density function (pdf) representation of quantum states, shedding light on the special classes of pdfs that can be tomograms. Instead of using wave functions or density operators on Hilbert spaces, tomograms, which are the true pdfs, are used to completely describe the states of quantum systems. Unlike quasi-pdfs, like the Wigner function, tomograms can be analysed using all the tools of classical probability theory for pdf estimation, which can allow a better quality of state reconstruction. This is particularly useful when dealing with non-Gaussian states where the pdfs are multi-mode. The knowledge of the family of distributions plays an important role in the application of both parametric and non-parametric density estimation methods. We show that not all pdfs can play the role of tomograms of quantum states and introduce the conditions that must be fulfilled by pdfs to be "quantum".

Authors 3

1. Liubov A. Markovich
2. Justus Urbanetz Aachen Institute Lorentz

   Leiden University

   Affiliation as printed

   Institute-Lorentz , University Leiden , P.O. Box 9506 , 2300 RA Leiden , The Netherlands

3. Vladimir I. Man’ko

   Russian Academy of Sciences · P.N. Lebedev Physical Institute of the Russian Academy of Sciences · Russian Quantum Center

   Affiliation as printed

   Lebedev Physical Institute , Russian Academy of Sciences , Leninskii Prospect 53 , Moscow 119991 , Russia

   Russian Quantum Center , Skolkovo , Moscow 121205 , Russia