Low frequency Rabi spectroscopy for a dissipative two-level system

TL;DR

This paper investigates how a dissipative two-level quantum system responds to simultaneous high and low frequency excitation, revealing resonance phenomena useful for low frequency Rabi spectroscopy across various physical systems.

Contribution

It introduces a method for low frequency Rabi spectroscopy applicable to diverse two-level systems, including nuclear spins and superconducting qubits.

Findings

Resonance at the Rabi frequency with damping-dependent width

Undamped low frequency oscillations near the level separation

Application potential in NMR, quantum dots, and superconducting qubits

Abstract

We have analyzed the interaction of a dissipative two level quantum system with high and low frequency excitation. The system is continuously and simultaneously irradiated by these two waves. If the frequency of the first signal is close to the level separation the response of the system exhibits undamped low frequency oscillations whose amplitude has a clear resonance at the Rabi frequency with the width being dependent on the damping rates of the system. The method can be useful for low frequency Rabi spectroscopy in various physical systems which are described by a two level Hamiltonian, such as nuclei spins in NMR, double well quantum dots, superconducting flux and charge qubits, etc. As the examples, the application of the method to a nuclear spin and to the readout of a flux qubit are briefly discussed.