Promotor: Prof.dr. E. R. Eliel, Co-Promotor: M.J.A. de Dood

We study the interplay of topology and geometry with chirality for several passive and active systems, employing both analytical and numerical methods.

Promotor: E.R. Eliel, Co-Promotor: M.J.A. de Dood

During my PhD research, I studied the photon statistics of light emitted by a microcavity that contains a single quantum dot (QD) on resonance.

Promotor: Prof.dr. C.W.J. Beenakker

We investigate how radiation pressure can be used to influence the mechanical motion of a micro-mirror suspended from springs.

Promotores: Prof.dr. D. Bouwmeester, Prof.dr. A. Fiore (TU Eindhoven)

Promotor: J. Zaanen, Co-Promotor: V. Juricic

My PhD research is devoted to studies of the conjectural cluster-algebraic symmetry in the theory of topological string, which is the simplest, however already non-trivial sector in the theory of string.

Geometric phases lead to a nontrivial interference result when an electron's different quantum mechanical paths choices encircle a magnetic coil in an Aharonov-Bohm experiment.

This thesis consists of three papers that are centered around the common theme of Hausdorff uo-Lebesgue topologies and convergence structures on vector lattices and on vector lattices and vector lattice algebras of order bounded operators.

Promotor: S.M. Verduyn Lunel, Co-promotoren: M.F.E. de Jeu, S.D. Silvestrov

In this thesis we investigated the ability of two-photon multifocal microscopy for single-molecule microscopy in live cells and organisms.

This thesis covers various applications of topology in condensed matter physics and quantum information.

Promotor: P. Stevenhagen, Co-promotor: R.M. van Luijk

The key characteristic of active matter is the motion of an emergent collection (such as a flock of birds), which is driven by the consumption of energy by its active components (i.e. individual birds).

Topology is an emerging field within many scientific disciplines, even leading to a Physics Nobel Prize in 2016. Leiden physicist Marcello Caio and his colleagues have now discovered the existence of topological currents in analogy to electric currents. Publication in Nature Physics on January 14th.

The main focus of this thesis is the behaviour of two-dimensional materials, namely (anti)-ferromagnetic materials in the first two chapters, which show topological phases, and energetic square ice in the third and fourth chapter.

Wiskunde en Natuurwetenschappen, Leiden Academic Centre for Drug Research (LACDR)

Promotor: Jan van der Greef; Co-promotors: Mei Wang; Eduard van Wijk

Gold nanorods are biocompatible nanoparticles that present an excellent two-photon signal that can be used to get high spatial resolution inside living cells. Gold nanorods are photostable and therefore can be followed inside cells for long time, with possible applications as trackers in live cells.

Promotor: J. van der Greef; Co-promotor: E. van Wijk, M. Wang

This thesis aims to improve the detection from ultra-weak single emitter by enhancing their emission properties with plasmonic nanostructures. We exploit the wet-chemically synthesized single crystalline gold nanorods (GNRs) as our basic frameworks in the whole studies, simply because of their unique…

Leiden physicists have developed a way to address how accurately a superconducting single photon detector (SSPD) can be characterized by detector tomography. SSPDs are not fully understood, and tomography is a key element to determine how these devices detect light. A better understanding of these detectors…

The thesis mainly contributes to the characterization of Majorana fermions as they appear in the Condensed Matter context.

The team of Alireza Mashaghi at the Leiden Academic Centre for Drug Research has found a way to determine and classify the shape of proteins. Their new theory defines the topology of proteins as a simple and precise barcode that allows the identification of all types of folds. ‘This barcode enables…

Press coverage for the Nature Physics-paper about topological materials by Anne Meeussen, Erdal Oğuz, Yair Shokef and Martin van Hecke

Leiden physicists have created a light source that emits individual particles in an identical state through optical fibers. Using this setup, their measurements can last longer and are more efficient, meaning they can perform more in-depth research on bizarre quantum effects, such as interference and…

The Leiden Institute of Physics (LION) is the coordinating partner in the Qluster research project, which was awarded a 2,9 million euro FET Open grant by the European Union. The three-year project, which started on 1 December 2019, aims to produce many photon entanglement to aid quantum communication…

Leiden physicists are helping Wageningen plant researchers to study unpredictable plant embryos. For this, they are using a novel two-photon fluorescence microscope, aided by a 30 thousand euro ZonMW grant.

Scientists need individual photons for quantum cryptography and quantum computers. Leiden physicists have now experimentally demonstrated a new production method. Publication in Physical Review Letters on July 23rd.

Promotor: C. W. J. Beenakker, Co-promotor: J. K. Asboth

The quantum nature of matter and light has grown into a broad and fruitful research field for theorists and experimentalists alike. It combines foundational research with toward applications, the most well known of which is the quantum computer.

The CIGR brings together a diverse range of unique expertise in genome research rooted in biology, chemistry and physics. Members of the CIGR investigate genome folding and genome transactions. An important aspect is direct as well as long term relevance for medicine.

With the help of quantum mechanics, digital quantum hardware may be able to tackle some of the problems that are too difficult for ordinary computers. But despite these expectations and the ongoing effort of the research community, reliable quantum computers are not yet realized in a lab setting.

Electrons in a crystal lattice have properties that may differ from those of a free electron in vacuum.

The CIGR brings together a diverse range of unique expertise in genome research rooted in biology, chemistry and physics. Members of the CIGR investigate genome folding and genome transactions. An important aspect is direct as well as long term relevance for medicine. The available expertise extends…

A new computer simulation shows the promising possibilities of the booming field of topology. Smartly designed mechanical structures carry sound exclusively one way and are immune to fabrication errors. Publication on 17 July in Nature Physics.

This month, a paper was published in Nanoscale by scientists from Dr. Alireza Mashaghi group at the Systems Biomedicine and Pharmacology Division in collaboration with the group of Dr. Sander Tans from TU Delft/AMOLF. In this paper, the authors studied how nanoscale spatial confinement affects the fold…

In unconventional high temperature superconductors, supercurrent vortices are known to spoil the Landau levels. In this thesis the emergence of Landau levels is studied in different types of superconductors: Weyl superconductors, and the Fu-Kane heterostructure.

Promotor: C.W.J. Beenakker, Co-promotor: M.T. Wimmer

A specifically designed collection of gears is soft on one end and rigid on the other. These are robust properties of the system that hold even in the presence of manufacturing imperfections. This emerging research area may lead to new ways of designing geared devices like satellite trackers or watches.…

Gold nanoparticles show surprisingly strong interactions with light in the visible range, which can be divided into scattering, absorption, and photoluminescence.

Majorana fermions in superconductors are the subgap quasiparticle excitations that are their own antiparticles.

Errors are everywhere, and mechanical failures are especially common: buckled grain silos and cracked support columns are, justly, seen as an issue to be avoided.

Key publications of the Medical Systems Biophysics and Bioengineeringgroup (Mashaghi Lab)

Our group explores the larger domain of quantum measurement. In particular we investigate two themes that are closely connected: The detection of specially prepared quantum states of light and understanding and characterizing quantum photon detectors.