Thesis defended on November 19, 2025
Abstract
Robust manipulation and control of quantum systems require a fast and efficient way to read out their state. After cavity quantum electrodynamics (cavity QED) pioneered the manipulation of neutral atoms and ions with light, circuit quantum electrodynamics (circuit QED) became the dominant readout paradigm for artificial atoms such as su perconducting circuits, with dispersive readout widely adopted for its stability and efficiency. Recently, longitudinal readout has emerged as a potentially faster readout protocol, but relies on sophisticated parametric modulation, whose underlying mechanisms have remained unclear so far. We devise a unifying Floquet theory to establish a universal connection between AC Stark shift, longitudinal coupling and dispersive readout in cQED.
Inspired by cQED’s readout capabilities in single qubit measurements, we address many-body state readout in quantum simulators. Since the dynamical structure factor (DSF) encodes key information about density excitations in quantum systems, we propose Many-Body Admittance Spectroscopy (MADS) as a weakly invasive method to probe the DSF by analyzing the transmission coefficients of microwave signals coupled to the quantum simulator.
Direction: Yann-Michel NIQUET
Deputy: Michele FILIPPONE
Keywords
Circuit Quantum Electrodynamics; readout; Floquet theory; many-body physics