Project title: Experimental demonstration of optimal control of trapped ion quantum gates

Supervisors: Richard Thompson and Florian Mintert

Project description:
Ions trapped with electric and magnetic fields can be carefully addressed with laser fields in order to create and manipulate the quantum state of a logical qubit. This physical system is one of the most promising for the implementation of quantum algorithms and quantum simulations.

The fidelity of quantum gates with trapped ions is limited when gates are performed in shorter times or in smaller traps, which are both desired features for the realisation of a scalable quantum computer. These limitations are mostly due to motional heating during the gate operation and the excitation of unwanted off-resonant transitions in ions.

Our group is working on the realisation of optimal control schemes that take into account these sources of experimental errors to improve the fidelity of two qubit gates.

My project includes the realisation of a linear Paul trap with intrinsically low heating rates such that optimal control schemes can be implemented in a carefully controlled environment. Part of the project includes also the development and experimental realisation of fast two qubit gates by working outside the Lamb-Dicke regime. This can be done by the development of optimal control schemes that take into account off-resonant transitions that would otherwise limit the gate fidelity.