Light switchable molecular qugates

The classical computers we use every day, whether in a PC or a mobile phone or in a tablet, rely on "bits" of information; storing and manipulating data as 0s and 1s. Their speed and capability are limited by the information being stored as one of two states. In a quantum computer the information is stored as 0 and 1 and as superpositions of these two states. This means there is a potential for quantum computers to perform some calculations far faster than a classical computer. These calculations include searching unsorted directories and pattern recognition.

Quantum computers use the quantum mechanical properties of small objects; here our small objects are molecules and the property we will study is the electron spin. Molecules have potential advantages which include atom-by-atom control of the structures via chemistry, allowing exquisite control of the interaction between electron spins. At another level of complexity, many atoms in molecules have nuclear spins which could be used to correct errors that arise when quantum algorithms are performed.

This project is to manipulate the electron spins on different parts of one molecule to perform quantum logic operations. If we can perform certain logic operations - called universal quantum gates - we could then string them together to perform algorithms which could be used in computation. To manipulate the electron spins we will use laser light and microwaves. Our aim is to perform a specific quantum gate which would be the first time such a gate had been reported for a molecular electron spin system. Our ability to control the molecular chemistry combined with expertise in spectroscopy makes the project ambitious and feasible. Within the project, risk is managed by having two distinct and complementary routes to achieve our main goal, and risk mitigation is also present at each stage of the project.