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Harmonic oscillator state synthesis by reservoir engineering

July 25, 2014 - 11:00am
Daniel Kienzler

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 [1], 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

2115 Computer and Space Sciences
College Park, MD 20742

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