title: Unsharpness of generalized measurement and its effects in entropic uncertainty relations.
abstract: Under the scenario of generalized measurements, it can be questioned how much of quantum uncertainty can be attributed to measuring device, independent of the uncertainty in the measured system. On the course to answer the question, we suggest a new class of entropic uncertainty relation that differentiates quantum uncertainty from device imperfection due to the unsharpness of measurement. In order to quantify the unsharpness, we suggest and analyze the quantity that characterizes the uncertainty in the measuring device, based on Shannon entropy. Using the quantity, we obtain a new lower bound of entropic uncertainty with unsharpness and it has been shown that the relation can also be obtained under the scenario that sharp observables are affected by the white noise and amplitude damping.
authors.affiliation: Department of Physics, Sogang University, Mapo-gu, Shinsu-dong, Seoul 121-742, Korea.
authors.forename: Kyunghyun
authors.initials: K
authors.lastname: Baek
authors.affiliation: Department of Physics, Sogang University, Mapo-gu, Shinsu-dong, Seoul 121-742, Korea.|University of Oxford, Department of Physics, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Wonmin
authors.initials: W
authors.lastname: Son