Abstract:

Modern digital computers have changed our lives in a variety of ways, but the technology on which they are built is rapidly reaching a hard limit due to inherent quantum effects. Two of the main pillars of our modern digital computers are the electronic transistor and the von-Neumann computer architecture. While the von-Neumann architecture established the physical separation of computing tasks like storage and processing, transistors are the fundamental building blocks in digital computers. The drive for faster and more powerful computers can be realised by increasing the number of transistors in a processor and the clock frequency. However, Moore’s law will soon come to an end, whilst the breakdown of Dennard’s scaling law means that clock frequencies have remain unchanged since 2006. This leads to the pressing quest to develop new kinds of transistors and alternative computing architectures that could one day allow us to solve currently intractable problems. 

In our labs, we combine state-of-the-art photonic structures and light emitting semiconductor materials in which light and matter fuse to form new types of particles called polaritons. In a sense, polaritons bridge the fields of electronics and photonics by controlling the amount of light vs matter in these hybrid particles. At high densities, polaritons undergo ‘condensation’ forming micron scale droplets of liquid-light, with all particles within the droplet being coherent and indistinguishable from one another. In this seminar, I will describe the fundamental properties of such liquid-light droplets, aka polariton condensates, and their applications both in analogue (simulators) [1-4] and digital (logic) computing [5-6].

[1] Synthetic band-structure engineering in polariton crystals with non-Hermitian topological phases, Nature Comm 11, 4431 (2020)

[2] Geometric frustration in polygons of polariton condensates creating vortices of varying topological charge, Nature Comm 12 2120 (2021)

[3] Quantum fluids of light in all-optical scatterer lattices, Nature Comm. 12, 5571 (2021)

[4] Quantum vortex formation in the “rotating bucket experiment with polariton condensates, Sci. Adv. 9, eadd1299 (2023)

[5] A room-temperature organic polariton transistor, Nature Photonics 13, 378–383 (2019)

[6] Single-photon nonlinearity at room temperature, Nature 597 (7877), 493-497 (2021)