Events at Physics
Can a harmonic oscillator ever be truly at rest? It may seem strange, but according to Heisenberg’s uncertainty principle, the answer is: “no!” Even at a temperature of absolute zero, in its lowest possible energy state or “ground state”, the oscillator must still exhibit quantum fluctuations of its position and momentum. Can we unambiguously detect motion of a purely quantum origin? I will discuss a unique experiment that can unequivocally observe the quantum fluctuations of a mechanical oscillator near its ground state of motion. To do this, we have created a hybrid system that merges a microwave opto-mechanical element with a superconducting quantum bit (or qubit). Parametric coupling between the electrical and the mechanical oscillators allows us to cool the mechanics to its ground state and then amplify the intrinsic quantum fluctuations in both oscillators into real energy quanta that can then be detected by the qubit, which effectively acts as an ideal single photon or phonon detector. Operated in reverse, this system could be used to prepare complex quantum states of mechanical motion or to generate entanglement between the mechanical phonons and the electrical microwave photons. Controlling the quantum states of long-lived mechanical oscillators is important for applications in quantum information and for providing new, powerful quantum-enhanced detection methods for unbeatable precision measurements.