Granular Aluminum Parametric Amplifier for Low-Noise Measurements in Tesla Fields

Area of Science:

• Quantum Computing
• Microwave Engineering
• Materials Science

Background:

• Josephson junction parametric amplifiers are crucial for quantum circuit readout but are sensitive to magnetic fields.
• This magnetic field sensitivity restricts their application in areas like spin qubits and dark matter searches.
• Kinetic inductance materials, like granular aluminum (grAl), offer a promising alternative due to inherent magnetic field resilience.

Purpose of the Study:

• To develop a novel nondegenerate amplifier utilizing granular aluminum (grAl) resonators.
• To demonstrate the amplifier's resilience to in-plane magnetic fields up to 1 Tesla.
• To characterize the amplifier's performance, including gain, noise, gain-bandwidth product, and saturation power.

Main Methods:

• Fabrication of a nondegenerate amplifier based on two coupled grAl resonators.
• Testing the amplifier's performance under varying in-plane magnetic field strengths up to 1T.
• Measurement of key performance metrics: gain, added noise, gain-bandwidth product, and input saturation power.

Main Results:

• The grAl resonator amplifier exhibits resilience to in-plane magnetic fields up to 1T.
• Achieved 20 dB of gain with noise levels near the quantum limit.
• Demonstrated a gain-bandwidth product of 28 MHz and an input saturation power of -110 dBm.

Conclusions:

• Granular aluminum (grAl) resonators provide a viable alternative for building magnetic field resilient parametric amplifiers.
• The developed amplifier meets critical performance benchmarks for quantum information processing and sensitive measurements.
• This technology advances the development of robust readout systems for quantum circuits operating in challenging magnetic environments.