QuCSI

The basic idea here is how do we model processes that emit outputs at continuous points in time? If the process is Markovian (like the spontaneous emission of radiation), then things are easy - as we don't need to track how much time has elapse. But as soon as events turn out to be non-Markovian, ... Read moreSuperior memory efficiency of quantum devices for the simulation of continuous-time stochastic processes (npj Quantum Information 4,18)

There has being a growing interesting in the various features of quantum mechanics that are distinctly non-classical, from entanglement to discord to more recent ideas of coherence. Could these various forms of non-classicality be understood in a unified operation framework? In this piece of we work, we propose a way to do this in the context ... Read moreUnification of non-classicality measures in interferometry (Physical Review A 97, 1, 012331)

The idea here is plug n' play: how can one quantum computer call upon another to perform a subroutine - without assuming anything about how the second computer was physical constructed? This becomes a very important question as the world builds towards scalable quantum computing - where two different parties wishes to work together to ... Read moreQuantum plug n' play: modular computation in the quantum regime (New Journal of Physics, 20, 013004)

It has been established that quantum models can provide a simpler description of most processes than the best possible classical model. However, the extent to which the quantum model can outperform the classical was an open question. In our article, “Provably unbounded memory advantage in stochastic simulation using quantum mechanics,” we answer this question and ... Read moreProvably unbounded memory advantage in stochastic simulation using quantum mechanics (New Journal of Physics 19.10 103009)

Can quantum information fundamentally change the way we perceive what is complex? In our article, “The classical-quantum divergence of complexity in the Ising spin chain,” we generalize a widely-used measure of complexity – the statistical complexity – to the quantum regime. Statistical complexity quantifies the minimal classical information we must store about a process to ... Read moreThe classical-quantum divergence of complexity in the ising spin chain (Quantum 1, 25)

At the heart of complexity and complex systems is the manipulation of patterns – predictable structures – using an internal memory, but the exact structure of this memory is not uniquely defined. In this article,  we consider the thermodynamics involved in this manipulation, such as by living things which exploit patterns in their surroundings, and ... Read moreThermodynamics of Complexity and Pattern Manipulation (Physical Review E 95 4, 042140)

Quantum illumination is a fascinating protocol that allows the improved sensing of distant objects with entanglement - even when the object is encased in so much noise that all entanglement is destroyed. Previously, we were able to show that this phenomenon is related to quantum discord, a more robust notion of quantum correlations. In this ... Read moreOverarching framework between Gaussian quantum discord and Gaussian quantum illumination (Physical Review A 95, 2, 022333)

Can a quantum goldfish exhibit more complex behaviour than a classical dolphin? In omplexity science, the complexity of an input-output process – a system that reacts differently when supplied with different environmental stimuli – can be quantified by the minimal memory needed to reproduce the process’s observed behaviour. This reflects the intuition that a goldfish ... Read moreUsing quantum theory to simplify input–output processes (npj Quantum Information 3, 6)

When it comes to studying transportation systems, stock markets and the weather, quantum mechanics is probably the last thing to come to mind. We have just demonstrated a proof of principle experiment that shows when it comes simulating such complex processes in the macroscopic world, quantum mechanics can provide an unexpected advantage – by drastically ... Read moreExperimentally modelling stochastic processes with less memory by the use of a quantum processor (Science Advances Vol 3, No. 2)