Initial entanglement between detectors allows violating Heisenberg's uncertainty relations

7th International Workshop DICE2014 Spacetime – Matter – Quantum Mechanics

物理学;力学

Di Lorenzo, Antonio^1

Universidade Federal de Uberlândia, Uberlândia, MG, Brazil^1

关键词: Arbitrary precision;    Backaction;    Heisenberg;    Heisenberg's uncertainty;    Input state;    Quantum state;    Simultaneous detection;    Statistical noise;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/626/1/012051/pdf
DOI  :  10.1088/1742-6596/626/1/012051

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Physics textbooks introduce an inequality derived by Kennard that concerns the impossibility of preparing a quantum state with well defined momentum and position. However, Heisenberg had formulated two different inequalities: one stating the impossibility of a simultaneous detection of position and momentum with arbitrary precision, and another one imposing a tradeoff between the precision on the measurement of a variable and the backaction on a subsequent measurement of a conjugated variable. Here, we explore the connections among these three inequalities, and we show that the latter can be violated, if the detectors are initially entangled. The results, besides being of fundamental interest, can be useful for building up an ideal momentum, or position, detector (i.e. one that introduces no noise in the measurement, besides the intrinsic statistical noise of the input state).