YQI Colloquium - Simone Gasparinetti - Chalmers University of Technology

Event time: 
Friday, December 17, 2021 - 12:00pm to 1:00pm
YQI Researchers
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Event description: 

Robust preparation of Wigner-negative states with optimized SNAP-displacement sequences

Hosting non-classical states of light in three-dimensional microwave cavities has emerged as a promising paradigm for continuous-variable quantum computation. I will present the experimental, high-fidelity generation of a range of Wigner-negative states useful for computation, based on sequences of interleaved selective number-dependent arbitrary phase (SNAP) gates and displacements. Among the generated states are Schrödinger-cat states, binomial states, Gottesman-Kitaev-Preskill (GKP) states, as well as cubic phase states. Our state preparation is based on a two-step optimization process. First we use a gradient-descent algorithm to optimize the parameters of the SNAP and displacement gates. Then we optimize the envelope of the pulses implementing the SNAP gates. This approach to state preparation is robust to fluctuations of the system parameters such as the qubit frequency and the dispersive shift, and offers a valid alternative to direct optimization of the control pulses.

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