Physics of Frost Heaving
When a soil is subject to low temperatures, the freezing of water can lead to an upward forces and the deformation of the soil with the growth of ice. This phenomena, called frost heaving can lead to catastrophic destruction of roads or buildings in cold regions as shown in figure above. The most obvious explanation … Read more
Detector Research and Development for LHC experiments and beyond
The Large Hadron Collider (LHC) at CERN in Geneva seeks to answer fundamental questions about elementary particles and our universe. Protons or heavy ions are collided at nearly the speed of light to study the tiniest building blocks of nature. To increase the amount of data taken by the LHC experiments in the future, many … Read more
A trapped-ion quantum sensor for the search for new physics
The Standard Model of physics is still far from complete: there is an unexplained asymmetry between matter and antimatter in the universe, gravity is not included and dark matter and dark energy are not understood. Quantum sensors have become strong tools to search for effects stemming from physics beyond the Standard Model. I am searching for 1-2 … Read more
Diamond is forever?
At the Advanced Research Center for Nanolithography (ARCNL) we carry out exciting fundamental physics research at the highest possible level with relevance to key technologies in nanolithography. We contribute to the production of ever smarter and smaller electronics, while at the same time pushing the boundaries of our fundamental insight into the workings of nature. … Read more
Magnonic spectrum of a metallic altermagnet: CrSb
In the same way that a photon can be seen as the quasiparticle that carries the energy of an electromagnetic wave, magnons are quasiparticles that propagate the energy of a spin wave. Spin waves are low-energy excitations that arise from the correlated motion of electron-hole pairs with opposite spins. Theoretically, they can be studied within … Read more
3D Printing on Earth and in Space
3D printing has proven to be a game-changer in space exploration and has revolutionized the way astronauts and space agencies approach problems in space. With 3D printing, it is possible to produce complex components and parts on demand, reducing the need for large inventories and saving space and weight on spacecraft. It also enables the … Read more
Robotic swarms as a model for dense active matter
Can we use robots to study biological materials like tissues? We think we can! We are developing experimental and computational platforms to study the dense population of moving cells using robots. To this end, we program the robots about the size of a 2-Euro coin to move like cells. We then explore how robots move … Read more
Active Dynamics in Plants – the Physics of Chloroplast Motion
When plant face different light conditions they have to adapt, sometimes the light is too strong and they get a “sun burn” which destroys the biochemical machinery for photosynthesis. If the light is too weak they “starve” because photosynthesis does not work well. Plants seem like very calm organisms, but if you zoom into their … Read more
3D-PRINTED ACTIVE MATTER
Active Matter refers to a class of physical systems made up of self-propelled, interacting entities, such as living organisms or synthetic particles, that exhibit collective behavior and can produce forces and fluxes at the macroscopic scale. Active matter systems can generate directed motion, spontaneous pattern formation, and display emergent properties that are not present in … Read more
Designing New Materials with Computations
Many industries and technological developments benefit by designing new materials to optimized performances and save energy. For instance, cosmetic or food industries significantly benefit from materials that have engineered mechanical properties. Designing material in the lab is however expensive and require many steps. Here we aim to use computational fluid dynamics to explore emergent behaviour … Read more
A memory of heat
We are witnessing a truly remarkable moment: the birth of an artificial intelligence. Large language models, machine learning and deep fakes are all running on distributed computing networks that use a tremendous amount of energy. For example, the training of chat-GPT used up approximately 1 GWh of energy. The projections are that at the current … Read more
The surprising effect of nothing
In 2015, a team in Strasbourg made an amazing (and controversial) claim: The electrical conductivity of a material can be dramatically enhanced by embedding it in a tailored photonic environment. Remarkably, light was not involved. The enhancement was due to the coupling of electron-hole pairs to the vacuum field, i.e., to nothing. The team recently … Read more
Measuring transient violations of the 2nd law
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The mysterious normal state of TiSe2
The layered material TiSe2 is famous for several reasons, one of which is the discovery of a new state of matter “excitonium” [1]. This state involves the spontaneous formation and Bose-Einstein condensation of excitons, resulting in an elemental electronic crystal in which excitons play the role of atoms. The formation of excitonium has been … Read more
Quantifying excitonic light scattering in 2D nanophotonic metasurfaces
Supervisors: Thomas Bauer and Jorik van de Groep Monolayer 2D semiconductors exhibit uniquely strong light-matter interactions in the visible spectral range due to quantum mechanical exciton resonances. When patterned on the nanoscale, light can be confined into these atomically thin layers of material and pick up a scattering phase and amplitude that is dictated by … Read more
Excitonic light-matter interactions in heterostructure 2D solar cells (joint project)
Supervisors: Tom Hoekstra, Peter Schall, and Jorik van de Groep Since the isolation of graphene in 2004, more than two thousand layered 2D materials have been identified. These materials can be exfoliated from bulk down to atomically thin monolayers, which exhibit unique optical and electronic properties, including stable excitons at room temperature. By employing a … Read more
Superlubric particles for friction and wear reduction
Supervisors: Abhishek Gupta and Peter Schall Friction between moving parts and the associated wear are responsible for about 25% of the world’s energy consumption. Superlubricity is a new mechanism of ultralow friction between solid surfaces, achieved with 2D materials such as graphene when sliding along incommensurate lattice directions (see image below). In this project, we … Read more
Solarfoil: Nanocrystal spectral converters for green economy
Supervisors: Ina Flaucher and Peter Schall Despite many years of photosynthesis research, the photosynthetic efficiency remains low. One reason is that plants use only limited spectral regions for photosynthesis; the solar spectrum, however is much broader, containing much more energy. We develop highly efficient nanocrystal layers to “shape” the solar spectrum into an optimum spectrum … Read more
Active Photonic Metasurfaces
Includes a 3-4 months internship at: Osaka University, Japan (Prof. Dr. Fujiwara) Supervisors: N. de Gaay Fortman, F. Koenderink, P. Schall Metasurfaces are 2D arrangements of nanostructures that resonantly scatter and jointly can act as analogue signal processing components: upon reflection or transmission of light, they can encode a complex optical function, programmed as an … Read more
AI-assisted nanophotonic inverse design of optical sensors
Nanomaterials have optical properties that strongly depend on their geometry and are therefore are often used as tunable signal transducers in optical sensors. For example, palladium nanoparticles are capable of detecting H2 gas by absorbing hydrogen within its metallic lattice, leading to a modified electronic structure and optical appearance. Recently, we have shown that periodic … Read more