Microstrip filters for measurement and control of superconducting qubits

TL;DR

This paper presents a compact distributed transmission line filter design that effectively reduces noise at GHz frequencies, enhancing the measurement and control of superconducting qubits at millikelvin temperatures.

Contribution

Introduction of a novel, compact distributed transmission line filter that can be anchored at low temperatures for improved superconducting qubit measurements.

Findings

Filters cut off exponentially at GHz frequencies

Suitable for filtering multiple bias lines simultaneously

Enhances coherence measurements in superconducting circuits

Abstract

Careful filtering is necessary for observations of quantum phenomena in superconducting circuits at low temperatures. Measurements of coherence between quantum states requires extensive filtering to protect against noise coupled from room temperature electronics. We demonstrate distributed transmission line filters which cut off exponentially at GHz frequencies and can be anchored at the base temperature of a dilution refrigerator. The compact design makes them suitable to filter many different bias lines in the same setup, necessary for the control and measurement of superconducting qubits.