A programmable five-qubit quantum computer using trapped atomic ions
Dissertation Committee Chair: Prof. Christopher Monroe
Dr. Steve Rolston
Dr. Eite Tiesinga
Dr. Trey Porto
Dr. Andrew Childs
Quantum computers can solve certain problems much more efficiently than conventional classical methods. Driven by this motivation, small scale demonstrations of quantum algorithms have been implemented across several physical platforms where each system have been adapted to run a limited number of instances of a single algorithm. Here, we present the experimental realization of a fully re-configurable quantum computer based on five trapped Yb+ ions that offers the flexibility to be programmed by the user in order to run any quantum algorithm. The computer follows an architecture where high level sequences of standard logic gates are decomposed into fundamental single- and two-qubit quantum gates that are native to the hardware consisting of a linear chain of trapped ions. Each qubit is resolved in space to implement optical addressing for the manipulation and measurement at the single qubit level. By using an array of Raman laser beams that individually address the qubits, a complete set of single-qubit and fully connected two-qubit gates can be implemented where the connectivity between qubits, being defined by the optical fields, can be reconfigured in the software thereby allowing arbitrary gate sequences to be executed. This makes the system a general purpose quantum processor where we implement several algorithms such as the Deutsch-Jozsa and Bernstein-Vazirani algorithm. We further implement a fully coherent five qubit quantum Fourier transform and apply it to solve the quantum period finding and the quantum phase estimation problem. This architecture is also shown to be scalable where the system size can be increased by simply hosting more ions inside a single processor where the number of experimental controls scale favorably.