Quantum Correlation at Zero-IF: InP HEMT Circuitry Effect

TL;DR

This study analyzes quantum correlations in an InP HEMT-based RF circuit at 4.2 K, revealing that quantum correlations are generated at harmonic frequencies, especially in the zero-IF band, influenced by the nonlinear coupling of oscillators.

Contribution

It introduces a quantum theoretical framework for analyzing quantum correlations in InP HEMT circuits, highlighting the generation of quantum discord at specific harmonic frequencies.

Findings

Quantum correlation appears at 2nd, 3rd, and 5th harmonics.

Quantum correlation is generated in the zero-IF band.

No quantum correlation at oscillator resonance frequencies.

Abstract

The quantum correlation between microwave modes in an RF electronic circuit is analyzed and studied. An open quantum system operating at 4.2 K is designed in which InP HEMT as the nonlinear component couples two external oscillators to each other. The quantum theory is applied to completely analyze the system, by which the related quantum Hamiltonian containing all noise sources is derived. The Lindblad Master equation is used to analyze the time evolution of the expanded closed system that covers the environmental effects. In the following, the state of the system defined is determined in terms of the ensemble average state using the density matrix; then, the ensemble average of the different operators is calculated. Accordingly, the covariance matrix of the quantum system is derived, and the quantum discord as a key quantity to determine the quantum correlation is calculated. As an interesting point, the results show that InP HEMT mixes two coupling oscillator modes so that the quantum correlation is created at different frequency productions such as 2nd, 3rd, and 5th. The harmonics suitable for sampling and digitalization is the zero-IF (downside of 2nd harmonics) band at which the quantum correlation is generated. Another point is that there is no quantum correlation at the frequency resonance of each oscillator coupled to InP HEMT.