Observation of coherent oscillation in single-passage Landau-Zener transitions

TL;DR

This paper investigates the coherent oscillations in single-passage Landau-Zener transitions, revealing errors caused by finite energy ranges and emphasizing the importance of transient dynamics in quantum state control.

Contribution

It demonstrates that finite energy ranges cause significant errors in LZT due to coherent oscillations, supported by experimental data and numerical simulations.

Findings

Finite energy ranges induce errors in LZT.

Coherent oscillations affect transition probabilities.

Numerical simulations align with experimental results.

Abstract

Landau-Zener transition (LZT) has been explored in a variety of physical systems for coherent population transfer between different quantum states. In recent years, there have been various proposals for applying LZT to quantum information processing because when compared to the methods using ac pulse for coherent population transfer, protocols based on LZT are less sensitive to timing errors. However, the effect of finite range of qubit energy available to LZT based state control operations has not been thoroughly examined. In this work, we show that using the well-known Landau-Zener formula in the vicinity of an avoided energy-level crossing will cause considerable errors due to coherent oscillation of the transition probability in a single-passage LZT experiment. The data agree well with the numerical simulations which take the transient dynamics of LZT into account. These results not only provide a closer view on the issue of finite-time LZT but also shed light on its effects on the quantum state manipulation.