Controlling entropic uncertainty bound through memory effects

¹ Turku Center for Quantum Physics, Department of Physics and Astronomy, University of Turku FI-20014, Turun yliopisto, Finland
² Faculdade de Ciências, UNESP - Universidade Estadual Paulista - Bauru, SP, 17033-360, Brazil

^(a) goktug.karpat@utu.fi

Received: 16 June 2015
Accepted: 22 August 2015

Abstract

One of the defining traits of quantum mechanics is the uncertainty principle which was originally expressed in terms of the standard deviation of two observables. Alternatively, it can be formulated using entropic measures, and can also be generalized by including a memory particle that is entangled with the particle to be measured. Here we consider a realistic scenario where the memory particle is an open system interacting with an external environment. Through the relation of conditional entropy to mutual information, we provide a link between memory effects and the rate of change of conditional entropy controlling the lower bound of the entropic uncertainty relation. Our treatment reveals that the memory effects stemming from the non-Markovian nature of quantum dynamical maps directly control the lower bound of the entropic uncertainty relation in a general way, independently of the specific type of interaction between the memory particle and its environment.