Quantum systems under frequency modulation

TLDR

Modulating the transition frequency of a quantum system gives rise to phenomena such as Landau–Zener–Stückelberg–Majorana interference, motional averaging, dressed states, and geometric phases, and recent advances in superconducting qubits and ultracold gases have enabled experimental demonstration of these effects. This review surveys these developments across two‑state atoms, harmonic oscillators, and multilevel or many‑particle systems. It focuses on how precise time‑domain control of Hamiltonian parameters and high‑fidelity, non‑destructive readout schemes allow observation and manipulation of the resulting quantum dynamics.

Abstract

We review the physical phenomena that arise when quantum mechanical energy levels are modulated in time. The dynamics resulting from changes in the transition frequency is a problem studied since the early days of quantum mechanics. It has been of constant interest both experimentally and theoretically since, with the simple two-state model providing an inexhaustible source of novel concepts. When the transition frequency of a quantum system is modulated, several phenomena can be observed, such as Landau–Zener–Stückelberg–Majorana interference, motional averaging and narrowing, and the formation of dressed states with the appearance of sidebands in the spectrum. Adiabatic changes result in the accumulation of geometric phases, which can be used to create topological states. In recent years, an exquisite experimental control in the time domain was gained through the parameters entering the Hamiltonian, and high-fidelity readout schemes allowed the state of the system to be monitored non-destructively. These developments were made in the field of quantum devices, especially in superconducting qubits, as a well as in atomic physics, in particular in ultracold gases. As a result of these advances, it became possible to demonstrate many of the fundamental effects that arise in a quantum system when its transition frequencies are modulated. The purpose of this review is to present some of these developments, from two-state atoms and harmonic oscillators to multilevel and many-particle systems.