Quantum State Tomography of Spin Qubits

James Medford, J. Beil, Jacob M. Taylor +7 more

Dan Cogan, Giora Peniakov, Zu-En Su +1 more

Semiconductor quantum dots are the preferred choice for interfacing anchored matter spin qubits and flying photonic qubits. They are particularly attractive for generating highly entangled hybrid spin-multiphoton entangled cluster and graph states. These highly entangled multiqubit states are required for measurement-based quantum communication and computing. Here, the authors develop a novel all-optical method for conducting full tomography of the confined electronic spin qubits. This method is essential for characterization and benchmarking these hybrid entangled spin-multiphoton cluster and graph states.

Naser Karimi, Marziyeh Yahyavi

Naser Karimi, Marziyeh Yahyavi

Jonathan Home, M J McDonnell, D M Lucas +7 more

We have implemented a universal quantum logic gate between qubits stored in the spin state of a pair of trapped 40 Ca ions. An initial product state was driven to a maximally entangled state deterministically, with 83% fidelity. We present a general approach to quantum state tomography which achieves good robustness to experimental noise and drift, and use it to measure the spin state of the ions. We find the entanglement of formation is 0.54.

Jonathan Home, McDonnell, M.J., Lucas, D.M. +7 more

We have implemented a universal quantum logic gate between qubits stored in the spin state of a pair of trapped 40Ca ions. An initial product state was driven to a maximally entangled state deterministically, with 83% fidelity. We present a general approach to quantum state tomography which achieves good robustness to experimental noise and drift, and use it to measure the spin state of the ions. We find the entanglement of formation is 0.54.