25.04.2017 - Iñigo Arrazola - Fast and Robust Phase Gates and Digital-Analog Quantum Simulation with Trapped Ions

On the first part of my talk, I will present a proposal for generating fast and robust quantum phase gates between two microwave-driven hyperfine ions, making use of a pulsed dynamical decoupling protocol. The scheme consists of a series of pi-pulses that are applied individually to each ion, whose internal level act as a qubit. Unlike previous proposals, this gate uses both axial vibrational modes as the quantum bus between both qubits. In this way, we are able to achieve a higher gate speed. In addition, I will argue that the proposed gate is robust against most harmful noise sources, related with fluctuations of the Rabi frequency or the magnetic field. Our numerical simulations show that with state-of-the-art ion trap technology, entangling gates with fidelities above 99.9% can be produced in tens of microseconds.
On the second part of my talk, I will present a novel method to simulate spin models in trapped ions using a digital-analog approach, consisting in a suitable gate decomposition in terms of analog blocks and digital steps. In this way, we show that the quantum dynamics of an enhanced variety of spin models could be implemented with substantially less number of gates than a fully digital approach. Typically, analog blocks are built of multipartite dynamics providing the complexity of the simulated model, while the digital steps are local operations bringing versatility to it. I will finally describe a possible experimental implementation in a trapped-ion quantum platform.