The paper presents a method to cool the motion of a micromechanical oscillator to its quantum ground state using sideband cooling techniques. The authors achieve this by embedding a thin aluminum membrane into a superconducting microwave resonant circuit, creating a cavity optomechanical system. This setup allows for strong coupling between the mechanical motion and the electromagnetic field, enabling efficient cooling. The system is operated at a temperature of 15 mK, and the authors demonstrate near-quantum-limited measurement of the microwave field, resolving the membrane motion with a factor of 5.1 from the Heisenberg limit. The device also exhibits strong coupling between the microwave photons and mechanical phonons, allowing for coherent exchange. The combination of ground-state preparation, strong coupling, and near quantum-limited detection sets the stage for advanced control and detection of non-classical states of motion, potentially enabling quantum information processing and testing quantum theory in larger systems.The paper presents a method to cool the motion of a micromechanical oscillator to its quantum ground state using sideband cooling techniques. The authors achieve this by embedding a thin aluminum membrane into a superconducting microwave resonant circuit, creating a cavity optomechanical system. This setup allows for strong coupling between the mechanical motion and the electromagnetic field, enabling efficient cooling. The system is operated at a temperature of 15 mK, and the authors demonstrate near-quantum-limited measurement of the microwave field, resolving the membrane motion with a factor of 5.1 from the Heisenberg limit. The device also exhibits strong coupling between the microwave photons and mechanical phonons, allowing for coherent exchange. The combination of ground-state preparation, strong coupling, and near quantum-limited detection sets the stage for advanced control and detection of non-classical states of motion, potentially enabling quantum information processing and testing quantum theory in larger systems.