Superconducting Qubits: A Short Review

TL;DR

Superconducting qubits are promising solid-state quantum bits that leverage Josephson junctions, with recent designs improving isolation and coherence, making them suitable for quantum computing applications.

Contribution

This review summarizes recent advances in superconducting qubit designs, focusing on improved isolation from electromagnetic noise and decoherence mitigation strategies.

Findings

New multi-junction designs enhance electromagnetic isolation.

Decoherence is influenced by junction intrinsic noise.

Strategies to improve qubit coherence are discussed.

Abstract

Superconducting qubits are solid state electrical circuits fabricated using techniques borrowed from conventional integrated circuits. They are based on the Josephson tunnel junction, the only non-dissipative, strongly non-linear circuit element available at low temperature. In contrast to microscopic entities such as spins or atoms, they tend to be well coupled to other circuits, which make them appealling from the point of view of readout and gate implementation. Very recently, new designs of superconducting qubits based on multi-junction circuits have solved the problem of isolation from unwanted extrinsic electromagnetic perturbations. We discuss in this review how qubit decoherence is affected by the intrinsic noise of the junction and what can be done to improve it.