We study the phenomenon of absorption refrigeration, where refrigeration is achieved by heating instead work, in two different setups: a minimal set up based on coupled qubits, and non-linearly resonators. Considering ZZ interaction between we outline basic ingredients required to achieve cooling. Using local as well global master equations, observe that inclusion XX type term qubit-qubit coupl...

A temperature below 100 µK is achieved in a customized cryogen-free dilution refrigerator with copper-nuclear demagnetization stage. The lowest of conduction electrons the stage as measured by using pulsed platinum nuclear magnetic resonance thermometer, and can remain for over 10 h. field up to 9 T research 12 be controlled independently, provided coaxial room-temperature-bore magnet.