Quantum harmonic oscillator state synthesis by reservoir engineering

Engineering a shelter for quantum protection In isolation, quantum states of matter can be stable entities. These states are often seen as useful when they can be made to interact in a controlled way. However, those interactions and the unavoidable interactions with their environment often correlate with decoherence and eventual loss of the quantum state. Kienzler et al. show that they can engineer the interactions between a quantum system (a trapped ion) and the environment to prepare stable quantum states. The generality of the technique implies applications for other interacting quantum systems. Science, this issue p. 53 Engineering the interactions between a quantum system and its environment leads to stable quantum states. The robust generation of quantum states in the presence of decoherence is a primary challenge for explorations of quantum mechanics at larger scales. Using the mechanical motion of a single trapped ion, we utilize reservoir engineering to generate squeezed, coherent, and displaced-squeezed states as steady states in the presence of noise. We verify the created state by generating two-state correlated spin-motion Rabi oscillations, resulting in high-contrast measurements. For both cooling and measurement, we use spin-oscillator couplings that provide transitions between oscillator states in an engineered Fock state basis. Our approach should facilitate studies of entanglement, quantum computation, and open-system quantum simulations in a wide range of physical systems.