QT Lab Research

Our Research
We're so busy building up our lab and research programs that we've haven't had time to write up a detailed description of our interests. For the moment the insatiably curious will have to be content with the following list of abstracts culled from our grant applications. Apologies for the jargon!
Biomolecular optoelectronic materials and devices The melanins are the molecules in our skin, eyes and hair that provide colour and protection from the sun. In addition to being important bio-molecules, they have properties which make them useful for high tech applications especially in electronics and optoelectronics. Unfortunately, our current understanding of these fascinating materials is poor. In our project we aim to solve this limiting problem. We will develop new science to explain their behaviour, and use this knowledge to create bio-compatible hi-tech materials and devices. We anticipate significant benefits from the perspectives of basic science and utilisation of biomaterials for new green technologies.	Controlling Quantum Technologies We are on the verge of a Quantum Technology revolution, where quantum physics is driving otherwise impossible technological advances. To date, quantum technologies have made little use of the monitoring and feedback that is ubiquitous in everyday industry, keeping planes in the air and robots welding accurately. This project is concerned with learning to actively control finite-size quantum systems and processes, by studying the control of photons - single particles of light. Our experimental and theoretical research will advance the new science of quantum control and have immediate application to quantum technologies such as absolutely secure communication and ultrahigh precision measurement.
Optical Quantum Computing One of the earliest proposals for implementing quantum computation was based on encoding qubits in optical modes, each containing exactly one photon. However it is extremely difficult to couple optical modes containing very few photons. Knill , Laflamme and Milburn (KLM) have proposed a way to circumvent this restriction and implement efficient quantum computation using only passive linear optics, photodetectors, and single photon sources. This efficient optical quantum computing is distinct from all other linear optical schemes which are not efficiently scalable. The objective of this project is to produce a prototype two qubit gate for photons using linear optics, and to develop a blue-print for a multiple qubit device that might be implemented over a longer time scale.	Quantum Holography: encoding quantum information in optical patterns Quantum information applies concepts from quantum mechanics to information tasks such as communication and computation. The fundamental units of quantum information are multi-level quantum systems known as qudits. To date, most experiments have realised only their simplest two-level incarnation, the qubit. In principle, tasks such as quantum cryptography, secret sharing, and dense coding, all benefit from using qudits larger than the qubit. We propose a scheme to realise qudits in practice by encoding them into optical patterns (the transverse spatial modes of the field); to manipulate these qudits via holographic techniques; and to make entangling gates using linear optics and measurement. We will explore a range of quantum phenomena and information protocols that are only accessible with qudits.
High-efficiency Quantum Interrogation (Also known as "interaction-free" measurement). Using the complementary wave- and particle-like natures of photons, the basic particles of light, it is possible to make measurements where the presence of an object can be unambiguously determined without the photons ever interacting with the object. Previous detectors have achieved this with efficiencies of < 80%. In this project we aim to develop a high-efficiency IFM detector, one with efficiencies of 90% or better. Such a detector has great potential for imaging delicate objects, such as biological cells, or quantum systems. An old, but still illuminating, discussion of such measurements can be found here.	Quantum State Engineering Production of non-classically correlated quantum states - entangled states - is now an issue of urgent practical importance. Communication using such states can achieve outcomes impossible with classical systems, such as absolutely secure messaging. We are interested in optically engineering arbitrary quantum states via novel twin-photon sources, and analysing these states via quantum tomography.

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last update 26.09.2007,