Quantum observations
(Tutorial lectures)
Vladimír Bužek
Research Center for Quantum Information, Slovak Academy of Sciences, Bratislava
In my tutorial lectures I will briefly outline some epistemological as well as operational
problems associated with the quantum theory of measurement. I will address several
topics including:
Basic concepts - Why quantum measurements are so much different from classical
observations?
Maximum entropy principle - I will discuss how states of quantum systems can be
reconstructed from incomplete experimental data when meanvalues of a limited
number of the system observables are available from a measurement.
Quantum “clickology” - I will show how information can be extracted from finitesize ensembles of identically prepared quantum systems. I will discuss the role of
resources available in measurement. In particular, I will present quantum version of
the Bayesian inference method.
Recycling of quantum information - I will address a question whether one can
extract some useful information from a quantum system that has already been
measured.
Reconstruction of quantum channels - I will also show how quantum channels can
be reconstructed from incomplete experimental data.
Compression of quantum information – I will analyse how classical information
can be efficiently compressed and encoded into quantum systems.