Zapata Nicolas, Takmakov Ivan, Günzler Simon, Geisert Simon, Ihssen Soeren, Field Mitchell, Nambisan Ameya, Rieger Dennis, Reisinger Thomas, Wernsdorfer Wolfgang, Pop Ioan M
Karlsruhe Institute of Technology, IQMT, 76131 Karlsruhe, Germany.
Karlsruhe Institute of Technology, PHI, 76131 Karlsruhe, Germany.
Phys Rev Lett. 2024 Dec 31;133(26):260604. doi: 10.1103/PhysRevLett.133.260604.
Josephson junction parametric amplifiers have become essential tools for microwave quantum circuit readout with minimal added noise. Even after improving at an impressive rate in the past decade, they remain vulnerable to magnetic fields, which limits their use in many applications such as spin qubits, Andreev and molecular magnet devices, dark matter searches, etc. Kinetic inductance materials, such as granular aluminum (grAl), offer an alternative source of nonlinearity with innate magnetic field resilience. We present a nondegenerate amplifier made of two coupled grAl resonators resilient to in-plane magnetic fields up to 1T. It offers 20 dB of gain close to the quantum limit of added noise, with a gain-bandwidth product of 28 MHz and -110 dBm input saturation power.
