Technical review of four different quantum systems: comparative analysis of quantum correlation, signal-to-noise ratio, and fidelity

The current paper investigates the different methods and approaches have been used to create microwave modes of quantum correlation. Specifically, we consider the electro-opto-mechanical, optoelectronics, 4-coupled qubits, and InP HEMT coupled with two external oscillator methods, as well as evaluate their effectiveness for quantum applications. Since these systems are open quantum systems, they interact with their own environment medium and thermal bath. To ensure an accurate comparison, we analyzed all of the systems with the same criteria. Thus, at first all systems are introduced briefly, then the total Hamiltonian is theoretically derived, and finally, the system dynamics are analogously analyzed using the Lindblad master equation. We then calculate the quantum correlation function between cavity modes, signal-to-noise ratio, and fidelity for each system to evaluate their performance. The results show that the strength and nature of the calculated quantities vary among the systems. An interesting result is the emergence of mixing behavior in the quantum correlation function and signal-to-noise ratio for systems that use different cavities. Also, it can be identified a significant similarity between the 4-coupled qubits and InP HEMT coupled with external oscillators methods, where an avoided level crossing occurs in the quantum correlation. Additionally, the study results reveal a high consistency between the signal-to-noise ratio and classical discord.