We have been awarded a new grant to develop radio-frequency quantum amplifiers that can withstand magnetic fields.
The most sensitive radio-frequency amplifiers exploit a phenomenon known as kinetic inductance in superconductors. However, these amplifiers do not currently work well in magnetic fields because the kinetic inductance is affected in unpredictable ways (or even eliminated, in the case of Josephson-junction amplifiers). If quantum-limited amplifiers could be developed that withstand high-fields, this would open many new applications including measuring spin qubits and searching for dark matter.
Our new amplifier proposal uses a quantum paraelectric material as the active element. Our immediate goal is to create an amplifier that works in a magnetic field and to test it in the QSHS axion search experiment. We will then study whether the amplifier can reach quantum-limited sensitivity or create non-classical photon states.