Employing computer algorithms to automate the engineering of quantum states

Dr Paul Knott
Research Fellow 2017

Dr Paul Knott
University of Nottingham

This project will tackle a key challenge in the quantum technology revolution by designing computer algorithms that automate the engineering of useful quantum states. These algorithms will enable the design of novel experiments to bring forward the development of new technologies such as quantum computing, communications and metrology.

Any physical object that is described using quantum mechanics, including an atom, an electron, or the light from a laser, can be expressed as a “quantum state”. These quantum states can exhibit bizarre and counter-intuitive properties, such as being in two places simultaneously (a superposition) or containing correlations simply not possible with every day “classical” objects (entanglement). If these properties can be controlled, then they can be exploited in quantum technologies to dramatically transform computing, enable secure cryptography, and unlock new ways of observing the universe.

A requirement of any experiment involving quantum mechanics is that the quantum state of the system is engineered (i.e. designed, prepared and manipulated) with extreme precision and control. But the counter-intuitive nature of the quantum world, whilst enabling disruptive new technologies, also makes it particularly challenging to design quantum experiments that can engineer useful states – our usual intuitions can fail us here. To overcome this Paul recently pioneered an automated technique: the quantum state engineering algorithm (QSEA), which in essence uses computer algorithms to design quantum experiments.

“will tackle a key challenge in the quantum technology revolution by designing computer algorithms that automate the engineering of useful quantum states”

The QSEA shuffles through different combinations of experimental equipment to find arrangements that can produce quantum states of light with specific properties, which can be used for a given task. Paul’s computer algorithm found numerous solutions that surpass the previous results in the literature whilst involving surprising experimental arrangements quite different from the human designs.

The Fellowship will enable Paul to extend this technique by incorporating recent developments in evolutionary algorithms and artificial intelligence to explore uncharted regions of the quantum state space (the abstract mathematical space containing all possible quantum states) to find new classes of quantum states. He will use QSEAs to design experiments, which his collaborators will subsequently implement, to produce these quantum states; and he will extend his approach to additional physical systems, including spin systems (e.g. electrons/nuclei) and optical circuits (the optical equivalent of an electronic circuit).

Paul’s algorithms will revolutionise the way that quantum states and experiments are designed and optimised, and will find quantum states for use in quantum computing, fundamental physics experiments, high-precision measurements, and many more applications.