Programme

P.60 -- Posters, VCTP-50

Date: Thursday, 7 August 2025

Time: 08:30 - 10:00

Reflection coefficient of a superconducting artificial atom coupled to a mirror

Huyen Tran Thi Thanh (1), Van-Duy Nguyen (2)

(1) Faculty of Physics, Hanoi National University of Education. (2) Phenikaa School of Information Technology and Phenikaa Institute for Advanced Study, Phenikaa University

Qubit readout plays a crucial role in quantum research, as it enables the extraction of fundamental properties such as the qubit’s operating frequency and coherence time through the analysis of reflected and transmitted signals. In the case of superconducting qubits, we consider the Cooper Pair Box model, which functions as an artificial atom coupled to a transmission line—one end of which is open to infinity, while the other is connected to a capacitor that acts as a mirror, reflecting electromagnetic waves. To determine the reflection coefficient of this system, we employ methods from circuit quantum electrodynamics, transmission line theory, and theory of open quantum systems, combined with plotting the reflection coefficient using Python. The analysis is conducted in two regimes: when the artificial atom behaves as a harmonic oscillator and when it exhibits true qubit-like behavior. This allows us to investigate how the position of the artificial atom affects the reflection spectrum.

Presenter: Tran Thi Thanh Huyen