Fundamental limitation on qubit operations due to the Bloch-Siegert Oscillation

TL;DR

This paper reveals a fundamental limitation in qubit operations caused by Bloch-Siegert oscillations when the rotating wave approximation fails, impacting precise quantum control.

Contribution

It introduces the effect of Bloch-Siegert oscillations on qubit operations and proposes an experimental scheme to observe this phenomenon.

Findings

Extra oscillation appears when Rabi frequency is comparable to Bohr frequency.

Sensitivity to field phase constrains precise quantum rotations.

Scheme for observing Bloch-Siegert oscillation in atomic beams.

Abstract

We show that if the Rabi frequency is comparable to the Bohr frequency so that the rotating wave approximation is inappropriate, an extra oscillation is present with the Rabi oscillation. We discuss how the sensitivity of the degree of excitation to the phase of the field may pose severe constraints on precise rotations of quantum bits involving low-frequency transitions. We present a scheme for observing this effect in an atomic beam.