Superconducting Quantum Circuits: Loss Mechanisms and Potential Mitigation Strategies

Abstract
In the last twenty years, the emergence of quantum information science has intensified research
toward building a quantum computer capable of performing computations beyond the capabilities
of classical modern supercomputers. Superconducting qubits are among the most promising
candidates in the race to build scalable and fault-tolerant quantum computers. However,
functionalizing superconducting materials for applications in quantum information science
necessarily requires exchanging information with the classical world through electromagnetic
signals, creating decoherence channels for the devices. In this talk I will explore interplay between
decoherence mechanism and material/ nanofabrication for superconducting quantum circuits. I will
demonstrate how a combination of multimode resonator and participation ratio modeling can play
a critical role in determining the contribution of individual loss channels affecting performance of
superconducting quantum circuits . By selectively choosing several thin film/ substrate
combinations, we show that the fabrication process and surface treatments can substantially
impact loss factors of quantum circuits.

Bio:
Dr. Archan Banerjee did his PhD from Glasgow University where he worked on superconducting thin
films and Superconducting Nanowire Single Photon Detectors. He did postdoctoral work at the
University of California, Berkeley following which he has been working as a Research Scientist at
Yale University in the Schoelkopf Lab.