New Developments in Superconducting Quantum Computing with Josephson Junctions

David Pappas
Rigetti Computing, Berkeley, CA
Monday, May 13, 2024
1:30 pm
ISEB 1010

Abstract: Among the myriad of quantum systems being considered for the implementation of quantum computing, superconducting circuits are among the earliest to be developed and most mature. This is likely because they are relatively straightforward and simple to implement, i.e. the fabrication is significantly simpler than typical VLSI circuits as well as the fact that typical VLSI circuits can be leveraged to control and read out the information from the superconducting quantum bits (qubits). However, scaling of the superconducting circuits to large numbers of qubits has been frustrated due to some very basic issues, most significantly the high loss in amorphous materials in the low- power (single photon), low-temperature (10 mK) regime. In that regime, there is a resurgence of loss as parasitic two-level systems settle into their ground state, becoming available to absorb energy and disturb the qubits. This is exacerbated by the fact that the key non-linear component of the qubits, the Josephson junction (JJ), is made using amorphous aluminum oxide. This causes them to be highly variable and have intrinsic decoherence and destabilization effects. In this talk we will present a transformational technique for trimming the JJ’s that is revolutionizing our approach to superconducting quantum information and can be easily transferred to any system that incorporates ionically bonded amorphous materials.

Bill Evans