PROTECTING SUPERCONDUCTING QUBITS FROM QUASIPARTICLE GENERATED BY COSMIC RAYS
Abstract
Non-equilibrium quasiparticles are a the source of dissipation and decoherence for the superconducting quantum devices, yet the origin of non-equilibrium quasiparticles has been a matter of debate for a long time. Several recent experiments found that cosmic rays and radioactivity may be the dominant source of quasiparticles. The experimental evidence includes the direct measurement of cosmic ray events with superconducting resonators as well as the measurement of the impact of cosmic rays on qubit error rates in quantum processors. Additional results linked quasiparticles to two-level systems which are another dominant source of decoherence for superconducting qubits. In this project, we propose to develop a novel way to protect quantum devices from quasiparticles generated by cosmic rays. We will achieve this goal by fabricating superconducting devices on suspended silicon membranes which will be used as phonon filters rejecting the phonons generated in the substrate by absorption of the cosmic rays (or any other high-energy events). We will use two types of circuits sensitive to quasiparticles for a proof-of-principle demonstration of reduction of the rate of cosmic ray events detected with superconducting microwave resonators and a corresponding reduction of the steady-state number of quasiparticles measured with charge sensitive qubits. Our research will give a better understanding of the link between cosmic rays, phonons and quasiparticles and, if successful, our method can potentially suppress non-equilibrium quasiparticles by several orders of magnitude. As direct shielding from cosmic rays is difficult to implement, our research may be capable to eliminate quasiparticle poisoning as a decoherence source in future fault tolerant superconducting quantum computers.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 20, 2023
- Source ID
- FA23862214049
Entities
People
- Arkady Fedorov
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Queensland