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Controlling, measuring and displacing the trapped-ion oscillator

Event Details

Event Dates: 

Monday, October 5, 2015 - 2:00pm

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Dr. Jonathan Home

Speaker Affiliation(s): 

ETH Zurich
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Public Seminar

Event Details & Abstract: 

I will describe a range of recent experiments on trapped-ions at ETH Zurich.

In the first, we have engineered spin-oscillator couplings to realize state-engineering, control and diagnostics for the quantum harmonic oscillator . Building upon recent work in which we generated squeezed states by reservoir engineering [1] , we have produced squeezed wavepacket analogues to the well known Schrodinger's cat states, observing re-coherence after separating the entangled wavepackets by up 20 times the ground state r.m.s.

extent, which corresponds to more than 60 times the width of the squeezed wavepacket  [2]. Using a non-squeezed cat, we have demonstrated a measurement-based post-selection scheme to dis-entangle the spin and motion, and reveal the quantum interference between the two separated wavepackets.

Wigner function tomography of the resulting state was performed by driving Jaynes-Cummings physics in a displaced-Fock basis for a range of displacements. I will also describe recent results in which we perform gates on trapped-ion qubits by moving ions through static laser beams. We use these to demonstrate parallel operations in two separated zones of a multi-zone ion trap using a static recycled laser beam, providing a path to scaling trapped-ion quantum processors with reduced optical complexity [3]. The presence of a large first-order Doppler shift led us to devise methods for estimating a time-varying Hamiltonian [4], resulting in a useful method for performing Doppler velocimetry of our ions. In separate work in a cryogenic apparatus, we have demonstrated the ability to control the trapping potentials on nano-second timescales, providing access to the sudden approximation in quantum mechanics, and allowing the demonstration of control of quantum states with up to 10 kilo-quanta [5].


[1] D. Kienzler et al. Science 347, 6217 (2015) [2] H-Y. Lo et al., Nature 521, 7552  (2015) [3] L. deClercq et al. arXiv:1509.06624 (2015) [4] L. deClercq et al. arXiv:1509.07083 (2015) [5] J. Alonso et al. arXiv:1509.06157 (2015)