Harmonic oscillator state synthesis by reservoir engineering
I will describe the creation of quantum states of a trapped-ion harmonic oscillator by reservoir engineering. This generalizes the standard methods of sideband cooling , allowing us to pump the
system into quantum superpositions directly with the desired state arising as the dark state of a dissipative process [2,3]. The >spin-oscillator coupling Hamiltonians used for the pumping are
generalized versions of the Jaynes-Cummings Hamiltonian which act on a basis rotated from the usual energy eigenstates. We have implemented Hamiltonians with coherent and squeezed ground states. Using a spin-motion coupling involving the creation operator for the engineered basis, we are able to directly transfer state information in this basis into the spin, resulting in a significant reduction in measurement overhead. Addtionally I present a new diagnostic technique to directly measure the quadratures of a squeezed state via the creation of a squeezed Schroedinger cat state.
Our results provide new tools for open-system quantum simulations and the characterization of many-body systems of harmonic oscillators, such as those found in continuous-variable quantum computation. These techniques should facilitate quantum state engineering and measurement
in a wide range of spin-oscillator systems where engineered couplings are available, including superconducting circuits and nano-mechanics.
Host: Chris Monroe