Invited Session 09:量子概率与信息
49
组织者:骆顺龙,中国科学院数学与系统科学研究院
Gaussian states as minimum uncertainty states
Shuangshuang Fu, 傅双双
University of Science and Technology Beijing shuangshuang.fu@ustb.edu.cn
Abstract
Gaussian distributions and Gaussian states are fundamental and ubiquitous in
probability theory and quantum theory. In bosonic fields, Gaussian states constitute a rather
wide family of states including coherent states, squeezed states, thermal states, etc., and have
many classical-like features, which are usually defined from the mathematical perspective in
terms of characteristic functions. It is well known that some special Gaussian states, such as
coherent states, are minimum uncertainty states for the conventional Heisenberg uncertainty
relation involving canonical pair of position and momentum observables. A natural question
arises as whether all Gaussian states can be characterized as minimum uncertainty states. In
this work, we show that indeed Gaussian states coincide with minimum uncertainty states for
an information-theoretic refinement of the conventional uncertainty relation. This
characterization puts Gaussian states on a novel basis of physical significance.
From asymmetry to correlations
Nan Li, 李楠
AMSS, Chinese Academy of Sciences linan@amss.ac.cn
Abstract
Symmetry, as well as the dual concept of asymmetry, are essential, powerful and
ubiquitous in physics and nature. Motivated by the original Wigner-Yanase skew information
and its extension by Dyson (Wigner E. P. and Yanase M. M., Proc. Natl. Acad. Sci. U.S.A.,
49 (1963) 910), which quantifies the information content of a quantum state skew to a
conserved observable and may be reinterpreted as asymmetry of a state with respect to an
observable, we address the issue of quantifying asymmetry and symmetry of states with
respect to Lie groups and Lie algebras. We elucidate that correlations arise naturally from the
difference between asymmetries of global and local states. This provides a fundamental
insight into correlations. The idea is further illustrated by several examples.