Workshop on QUANTUM INFORMATION PROCESSING AND QUANTUM COMMUNICATIONS

Quantum Mechanics: Axiomatics of Measurements
and connections with Computing and Information Retrieval
Information Extraction versus Disturbance in Quantum
Theory: an Information Theoretic Approach

aula DOTTORATO  VENERDI' 2 NOVEMBRE ore 11.00 

FRANCESCO
BUSCEMI , University of Pavia  Italy 
>PRESENTATION:
Francesco Buscemi completed his PhD in Physics at the University of Pavia
in 2006, under the supervision of Prof. G. M. D'Ariano, with the thesis
"Optimization and Realization of Quantum Devices". Since May
2006 he's researcher at the "ERATOSORST Quantum Computation and
Information Project", funded by the Japan Science and Technology
Agency, and is affiliated with the Graduate School of Information Science
at Tokyo University.


Abstract 


We describe the information balance in a general quantum
measuring process, and provide, as a byproduct, a sound informationdisturbance
tradeoff. In particular, we extend the notion of coherent information from
the case of quantum channels to the more general case of quantum measurements,
and show that such a quantity can accurately describe the disturbance that
a quantum measurement unavoidably causes on the input system, whenever some
useful information is extracted. The singleoutcome case, that is, the case
of measurements with postselection, is finally discussed. 

