"PhD-student: Active Hysterons and Spiking Neurons for Physical Computing"

We are seeking a motivated PhD-student to join our teams working on bistable elements for in-materia computing, as part of a joint theoretical/experimental program carried out at AMOLF (Amsterdam) and TU/e (Eindhoven). Computing with artificial neurons takes inspiration from nature’s efficient, adaptive use of multistable networks, offering an alternative to energy-intensive digital systems with rigid bits and separated memory and computation. In this project, we aim to design and realize the first networks combining active and passive electronic neurons, using organic electronics for chemical and electrical tunability. This work is based on recent breakthroughs in our groups.

The Van Hecke group recently showed that passive, bistable hysterons excel at sequential tasks such as counting^1,2, whereas the group of van de Burgt has built active electronic neurons that mimic spiking^3,4. Surprisingly, we found that spiking neurons can be described as ‘active’ hysterons, forming a bridge between two distinct frameworks for in-materia computing. Hence, by combining active and passive elements we aim to combine the best of both worlds, endowing passive networks with adaptability and spiking networks with memory and sequencing. We will explore the computational power of these systems and demonstrate it in simple robots. Our work bridges organic neural systems and hysteron computing, and leverages (bio)chemical and electrical feedback to materialize adaptivity and plasticity.

Key questions include: How to realize and design mixed networks of passive and active artificial neurons? How do mixed networks extend the class of realizable computing? Do our networks exhibit spiking, bursting or synchronization, and how to control these behaviors? How to realize targeted sequential and adaptive computations? Can we develop neuronal circuits for maze-solving and sequential adaptation? To answer these questions, the project will involve computational modelling and experimental work, jointly supervised by Martin van Hecke and Yoeri van de Burgt. With this research, we aim to redefine physical computation.

To get an idea of our work, see: [1] Kwakernaak and van Hecke, Counting and Sequential Information Processing in Mechanical Metamaterials, PRL 130 268204 (2023), [2] Liu, Teunisse, Korovin, Vermaire, Jin, Bense and van Hecke, Controlled Pathways and Sequential Information Processing in Serially Coupled Mechanical Hysterons, PNAS 121, e2308414121 (2024), [3] Matrone, van Doremaele, Surendran, Laswick, Griggs, Ye, McCulloch, Santoro, Rivnay and van de Burgt, A modular organic neuromorphic spiking circuit for retina-inspired sensory coding and neurotransmitter-mediated neural pathways, Nat Comm 15, 2868 (2024), [4] Gkoupidenis, Zhang, Kleemann, Ling, Santoro, Fabiano, Salleo and van de Burgt, Organic mixed conductors for bioinspired electronics, Nat Rev Mat 9, 134 (2023), [5] Baconnier, Teunisse and van Hecke, Dynamic self-loops in networks of passive and active binary elements, arXiv:2412.12658.

We seek candidates with a strong background in physics, electrical/mechanical engineering, materials science, or computer science with an interest in complex materials for computing and learning. Excellent candidates with training in any area of science or engineering will be considered. PhD candidates must meet the requirements for an MSc degree. Good verbal and written communication skills in English are required. Other advantageous qualities include experience with coding (Python/Matlab) and numerical methods, as well as familiarity with concepts in complex systems, physical memories or machine learning. We strongly believe in the benefits of an inclusive and diverse research environment, and welcome applicants with any background.

AMOLF is a part of NWO-I and initiate and performs leading fundamental research on the physics of complex forms of matter, and to create new functional materials, in partnership with academia and industry. The institute is located at Amsterdam Science Park and currently employs about 140 researchers and 80 support employees.

The position is intended as full-time (40 hours / week, 12 months / year) appointment in the service of the Netherlands Foundation of Scientific Research Institutes (NWO-I) for the duration of four years. The starting salary is 2.968 Euro’s gross per month and a range of employment benefits. The successful candidate is expected to spend 50% of their time in Amsterdam and 50% of their time in Eindhoven. After successful completion of the PhD research a PhD degree will be granted at a Dutch University. Several courses are offered, specially developed for PhD-students. AMOLF assists any new foreign PhD-student with housing and visa applications and compensates their transport costs and furnishing expenses.