Superconducting microwave cavities and qubits for quantum information systems

Abstract

Superconducting microwave cavities featuring ultrahigh Q-factors, which measure the efficiency of energy storage in relation to energy loss in a system, are revolutionizing quantum computing by providing long coherence times exceeding 1 ms, crucial for the development of scalable multi-qubit quantum systems with low error rates. In this work, we provide an in-depth analysis of recent advances in ultrahigh Q-factor cavities, integration of Josephson junction-based qubits, and bosonic-encoded qubits in 3D cavities. We examine the sources of quantum state dephasing caused by damping and noise mechanisms in cavities and qubits, highlighting the critical challenges that need to be addressed to achieve even higher coherence times. We critically survey the latest progress made in implementing single 3D qubits using superconducting materials, normal metals, and multi-qubit and multi-state quantum systems. Our work sheds light on the promising future of this research area, including novel materials for cavities and qubits, modes with nontrivial topological properties, error correction techniques for bosonic qubits, and new light–matter interaction effects.

Quantum Voting Machine Encoded with Microwave Photons

“…[23] The utilization of microwave fields and photons for quantum state engineering and quantum information processing has garnered considerable recent interest. [24][25][26][27][28][29][30][31][32] As depicted in Fig. 1, the function of the QVM is to determine the total number of voters in favor of the event being voted upon at the conclusion of the voting process.…”