title: Frobenius-norm-based measures of quantum coherence and asymmetry.
abstract: We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance.
authors: Microsystems and Terahertz Research Center, China Academy of Engineering Physics, Chengdu, Sichuan 610200, China.|Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang, Sichuan 621999, China.
authors: Yao
authors: Y
authors: Yao
authors: Beijing Computational Science Research Center, Beijing, 100193, China.
authors: G H
authors: GH
authors: Dong
authors: College of Physics and Electronic Information, Gannan Normal University, Ganzhou, Jiangxi 341000, China.
authors: Xing
authors: X
authors: Xiao
authors: Beijing Computational Science Research Center, Beijing, 100193, China.
authors: C P
authors: CP
authors: Sun