Experimental Demonstration of Swift Analytical Universal Control over Nearby Transitions

TL;DR

This paper demonstrates a fast, high-fidelity quantum control method for closely spaced energy level transitions in a four-level trapped ion system, significantly speeding up operations compared to traditional weak pulse techniques.

Contribution

It introduces and experimentally validates an analytical swift control technique capable of individually or simultaneously manipulating near-degenerate transitions with high fidelity.

Findings

Achieved fidelities between 99.2% and 99.6%.

Realized approximately tenfold speed increase over weak square pulses.

Applicable to quantum systems with crowded spectra.

Abstract

Along with the scaling of dimensions in quantum systems, transitions between the system's energy levels would become close in frequency, which are conventionally resolved by weak and lengthy pulses. Here, we extend and experimentally demonstrate analytically based swift quantum control techniques on a four-level trapped ion system, where we perform individual or simultaneous control over two pairs of spectrally nearby transitions with tailored time-varied drive, achieving operational fidelities ranging from 99.2(3)\% to 99.6(3)\%. Remarkably, we achieve approximately an order of magnitude speed up comparing with the case of weak square pulse for a general control. Therefore, our demonstration may be beneficial to a broad range of quantum systems with crowded spectrum, for spectroscopy, quantum information processing and quantum simulation.