Environmental Radiation Impact on Lifetimes and Quasiparticle Tunneling Rates of Fixed-Frequency Transmon Qubits

TL;DR

This study investigates how environmental radiation affects the lifetimes and quasiparticle tunneling rates of fixed-frequency transmon qubits, revealing that lifetimes are robust against shielding while tunneling rates are highly sensitive.

Contribution

It provides new insights into the environmental factors influencing qubit performance, especially highlighting the sensitivity of quasiparticle tunneling rates to radiation shielding configurations.

Findings

Qubit lifetimes are stable against shielding variations.

Quasiparticle tunneling rates are highly sensitive to environmental radiation.

Qubit losses are not yet dominated by quasiparticle effects.

Abstract

Quantum computing relies on the operation of qubits in an environment as free of noise as possible. This work reports on measuring the impact of environmental radiation on lifetimes of fixed frequency transmon qubits with various capacitor pad geometries by varying the amount of shielding used in the measurement space. It was found that the qubit lifetimes are robust against these shielding changes until the most extreme limit was tested without a mixing chamber shield in the refrigerator. In contrast, the quasiparticle tunneling rates were found to be extremely sensitive to all configurations tested, indicating these devices are not yet limited by losses related to superconducting quasiparticles.