Experimental Demonstration of Swift Analytical Universal Control Over Nearby Transitions

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)%. We achieve approximately an order of magnitude speed up compared with the case of a 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.

Automated summary

In this study, we extended and experimentally demonstrated analytically based swift quantum control techniques on a four-level trapped ion system. By using tailored time-varied drive, we achieved individual or simultaneous control over two pairs of spectrally nearby transitions, with high operational fidelities. We achieved approximately an order of magnitude speedup compared with the conventional weak square pulse control.