Life after charge noise: recent results with transmon qubits

TL;DR

The paper reviews recent theoretical and experimental advances in transmon qubits, highlighting their reduced charge noise sensitivity, long coherence times, and successful implementation in various quantum computing experiments.

Contribution

It provides a comprehensive overview of how increased Josephson to charging energy ratio improves transmon performance and confirms experimental results align with theoretical predictions.

Findings

Transmons exhibit coherence times up to 3 microseconds.

Charge noise sensitivity is exponentially suppressed in transmons.

Experimental results are consistent with theoretical models.

Abstract

We review the main theoretical and experimental results for the transmon, a superconducting charge qubit derived from the Cooper pair box. The increased ratio of the Josephson to charging energy results in an exponential suppression of the transmon's sensitivity to 1/f charge noise. This has been observed experimentally and yields homogeneous broadening, negligible pure dephasing, and long coherence times of up to 3 microseconds. Anharmonicity of the energy spectrum is required for qubit operation, and has been proven to be sufficient in transmon devices. Transmons have been implemented in a wide array of experiments, demonstrating consistent and reproducible results in very good agreement with theory.