It is shown that in some regions of X-state space the measurement-dependent one-way quantum deficit \Delta as a function of measurement angle \theta\in[0,\pi/2] exhibits a bimodal behavior inside the open interval (0,\pi/2), i.e., it has two interior extrema: one minimum and one maximum. Moreover, cases are found when the interior minimum of such a bimodal function \Delta(\theta) is less than that one at the endpoint with \theta=0 or \theta=\pi/2. This refutes the result of Ye et al. [Int. J. Theor. Phys. {\bf 55}, 2237 (2016)] which was intended for obtaining the one-way quantum deficit of general two-qubit X states.It is shown that in some regions of X-state space the measurement-dependent one-way quantum deficit \Delta as a function of measurement angle \theta\in[0,\pi/2] exhibits a bimodal behavior inside the open interval (0,\pi/2), i.e., it has two interior extrema: one minimum and one maximum. Moreover, cases are found when the interior minimum of such a bimodal function \Delta(\theta) is less than that one at the endpoint with \theta=0 or \theta=\pi/2. This refutes the result of Ye et al. [Int. J. Theor. Phys. {\bf 55}, 2237 (2016)] which was intended for obtaining the one-way quantum deficit of general two-qubit X states.

Jun 9, 20171 citation

Jumps of optimal measurement angle and fractures on the curves of quantum correlation functions

Mikhail A. Yurischev

The one-way quantum work deficit, a measure of quantum correlation, exhibits the regions with the bimodal behavior of post-measurement entropy versus the measurement angle θ ε (0, π/2). Under certain conditions this can lead to the finite jumps Δν> 0 of optimal measurement angle ν from the endpoint 0 or π/2 to the interior minimum and vice versa. In turn, such sudden jumps lead to the fractures, i.e., non-analytical points on the dependencies of quantum correlation upon the state parameters. We examine a possibility to experimentally observe these phenomena on an example of three-component mixture consisting of one pair of Bell-diagonal states and a basis state orthogonal to the Bell ones. Observation of named effects, beyond their intrinsic interest, could demonstrate the experimental ability in controlling and manipulating the quantum states.The one-way quantum work deficit, a measure of quantum correlation, exhibits the regions with the bimodal behavior of post-measurement entropy versus the measurement angle θ ε (0, π/2). Under certain conditions this can lead to the finite jumps Δν> 0 of optimal measurement angle ν from the endpoint 0 or π/2 to the interior minimum and vice versa. In turn, such sudden jumps lead to the fractures, i.e., non-analytical points on the dependencies of quantum correlation upon the state parameters. We examine a possibility to experimentally observe these phenomena on an example of three-component mixture consisting of one pair of Bell-diagonal states and a basis state orthogonal to the Bell ones. Observation of named effects, beyond their intrinsic interest, could demonstrate the experimental ability in controlling and manipulating the quantum states.

International Conference on Micro- and Nano-Electronics (ICMNE)Mar 15, 20190 citations