A coupled system of a superconducting transmission line resonator with a semiconductor double quantum dot is analyzed. We simulate the phase shift of the microwave signal in the resonator, which is sensitive to the quantum dot qubit state and manipul
ation. The measurement quality is sufficiently high and the results demonstrate a solid-state quantum processor based on this type of circuit can be envisioned.
Fernando Galve emph{et al.} $[Phys. Rev. Lett. textbf{110}, 010501 (2013)]$ introduced discording power for a two-qubit unitary gate to evaluate its capability to produce quantum discord, and found that a $pi/8$ gate has maximal discording power. Thi
s work analyzes the entangling power of a two-qubit unitary gate, which reflects its ability to generate quantum entanglement in another way. Based on the renowned Cartan decomposition of two-qubit unitary gates, we show that the magic power of the $pi/8$ gate produces maximal entanglement for a general value of purities for two-qubit states.
