arXiv:1711.04566 · Physical Review A
Multidimensional entropic uncertainty relation based on a commutator matrix in position and momentum spaces
Anaelle Hertz, Luc Vanbever, Nicolas J. Cerf
Abstract
The uncertainty relation for continuous variables due to Bya\l{}inicki-Birula and Mycielski [I. Bia\l{}ynicki-Birula and J. Mycielski, Commun. Math. Phys. 44, 129 (1975)] expresses the complementarity between two $n$-tuples of canonically conjugate variables $({x}_{1},{x}_{2},...,{x}_{n})$ and $({p}_{1},{p}_{2},...,{p}_{n})$ in terms of Shannon differential entropy. Here we consider the generalization to variables that are not canonically conjugate and derive an entropic uncertainty relation expressing the balance between any two $n$-variable Gaussian projective measurements. The bound on entropies is expressed in terms of the determinant of a matrix of commutators between the measured variables. This uncertainty relation also captures the complementarity between any two incompatible linear canonical transforms, the bound being written in terms of the corresponding symplectic matrices in phase space. Finally, we extend this uncertainty relation to R\'enyi entropies and also prove a covariance-based uncertainty relation which generalizes the Robertson relation.