Suppressing Charge Noise Decoherence in Superconducting Charge Qubits

TL;DR

This paper reports the experimental realization of the transmon qubit, which significantly reduces charge noise sensitivity, leading to longer coherence times and improved performance for quantum computing applications.

Contribution

The paper demonstrates the experimental verification of exponential suppression of charge noise sensitivity in transmon qubits, advancing superconducting qubit technology.

Findings

Charge noise sensitivity is exponentially suppressed in transmons.

Relaxation and dephasing times reach microsecond range.

Excellent agreement between theory and experimental data.

Abstract

We present an experimental realization of the transmon qubit, an improved superconducting charge qubit derived from the Cooper pair box. We experimentally verify the predicted exponential suppression of sensitivity to 1/f charge noise [J. Koch et al., Phys. Rev. A 76, 042319 (2007)]. This removes the leading source of dephasing in charge qubits, resulting in homogenously broadened transitions with relaxation and dephasing times in the microsecond range. Our systematic characterization of the qubit spectrum, anharmonicity, and charge dispersion shows excellent agreement with theory, rendering the transmon a promising qubit for future steps towards solid-state quantum information processing.