Colloquium: Quantum Simplicity: Revisiting Complexity theory from the lens of Quantum Science

ABSTRACT

Complexity and quantum science appear at first to be two fields that bear little relation. One deals with the science of the very large – seeking the understand how unexpected phenomena can emerge in vast systems consisting of many interacting components. Quantum theory, on the other hand, deals with particles at the microscopic level and is usually considered limited to the domain of individual photons and atoms. Yet, different as they appear, there is growing evidence that in interfacing ideas from quantum and complexity science, we may unveil new perspective in either both fields.

In this presentation, I first introduce computational mechanics, a branch of complexity science captures structure by building the simplest causal models of natural observations. I then illustrate how many processes that require complex classical models may be simulated by remarkably simple quantum devices, and describe recent experiments to test this laboratory conditions.  I then survey the potential consequences these developments, highlighting how the indicate that well-established notions of structure, complexity, may change when the quantum properties of information are taken into account

References:

• Quantum mechanics can reduce the complexity of classical models, Nature Communications 3, 762 
• Experimental quantum processing enhancement in modelling stochastic processes, Science Advances Vol. 3, no. 2, e160130.
• Using quantum theory to simplify input–output processes. Nature partner journal: Quantum Information 3, 1
• A practical, unitary simulator for non-Markovian complex processes.  Phys. Rev. Lett. 120, 240502 

BIOGRAPHY

Dr Mile Gu is a National Research Foundation Fellow, and holds dual positions the Complexity Institute at Nanyang Technological University and the Centre for Quantum Technologies. He heads the quantum and complexity science initiative - which seeks to explore how quantum technologies can help us understand the science of complex systems (www.quantumcomplexity.org). Gu past research span the areas of quantum information, complexity theory and optical quantum computation, and has been featured in Science and Natural suite Journals on five separate occasions.  Prior to his current appointment, Gu obtained his Ph.D. at the University of Queensland, and spent three years as faculty at the Institute for Interdisciplinary Information Sciences Tsinghua University.