CPM Seminar

Quantum information and quantum optics with superconducting devices

Adrian Lupascu

Institute for Quantum Computing & Department of Physics and Astronomy
University of Waterloo

At low temperatures, nanoscale electrical circuits are well described by a small number of degrees of freedom, and their properties can be tailored by circuit design. These “artificial” atoms have potential applications as basic units of quantum information (qubits) and provide a testbed for the study of light-matter interaction.

In the first part of my talk I will discuss a new type of two-qubit quantum logic gate. Two-qubit gates form, together with single-qubit gates, the required elements of a quantum computer. Our gate applies to a generic type of coupling between qubits and is minimal in terms of resources � it requires the same resources as needed for single-qubit control. I will discuss the first experimental implementation for two coupled qubits. I will also present recent experimental results on the application of this method to a system formed by a few qubits.

In the second part of the talk I will focus on a different line of research, namely the interaction of artificial atoms with microwave fields. I will present our work on using strong non-linear interactions for detection of single photons, which can be done without photon absorption.

Finally, I will discuss work in progress on hybrid devices formed by combining superconductors and semiconductors. I will show how coupling quantum dots to high-quality superconducting resonators opens new prospects for studying spin dynamics and has applications in quantum information.