Workshop on QUANTUM MEASUREMENTS AND OPERATIONS FOR CRIPTOGRAPHY AND INFORMATION PROCESSING

Quantum Measurements and Operations for Criptography
and Information Processing
Uncertainty Principle Revisited

aula dottorato  Lunedì 23 Maggio, ore 14.00 

MASANAO
OZAWA, Tohoku University, Sendai, Japan 
>VITAE:
Masanao Ozawa is full professor at Graduate School of Information Sciences,
Tohoku University, formerly professor at Nagoya.
He is well known expert of Quantum Information, Quantum Measurements and
Quantum Open Systems. His realization theorem for instruments is largely
known. 

Abstract 


It has long been accepted that the product of the measurement
noise in measuring A and the disturbance caused on B has a lower bound
determined by the expectation of [A,B]. In the debate on the quantum limit
on gravitational detection, we have experienced that such a reciprocal
relation, called the Heisenberg Uncertainty Principle, is not reliable
as a universally valid relation; Yuen's contractive state measurement
is physically realizable, and yet violates not only the stated limit for
monitoring but also the Heisenberg Uncertainty Principle. Here, we show
an answer to the remaining problem: what is the universally valid relation
for measurement noise and disturbance?
We also discuss the fundamental quantum limit on the accuracy of universal
quantum logic gates derived by the new uncertainty principle in the light
of conservation laws and the nonclassicality of controlling systems.


