More information about John Hefele

Surface plasmons (SPs) are surface waves at the interface between a dielectric and a good metal, and are formed by the interaction between light and the free electrons at the metal-dielectric interface. They provide strong field confinement for optical fields, opening new possibilities for enhanced…

This thesis presents insights from our study of various correlated electron systems with a scanning tunneling microscope (STM). In ordinary metals, electron-electron interactions exist, but get substantially screened due to the sheer number of electrons.

The thesis describes the use of electron paramagnetic resonance (EPR) spectroscopy, in continuous wave and pulse modes, to address the interaction of α-Synuclein (αS) with membranes and the aggregation of αS.

In condensed matter systems electron-electron interactions, negligible in everyday metals, can dramatically alter the electronic behavior of the system. Examples of such altered behavior include high-temperature superconductivity and modulation of the electron density.

In this thesis, we show how MRFM can usefully contribute to the field of condensed-matter.

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n this PhD thesis, the recombination of different atomic lattices in stacked 2D materials such as twisted bilayer graphene is studied. Using the different possibilities of Low-Energy Electron Microscopy (LEEM), the domain forming between the two atomic layers with small differences is studied.

Toll-like receptors (TLRs) are central components of the innate immune system, functioning as pattern recognition receptors that detect microbial- and damage-associated molecular patterns and initiate antimicrobial and inflammatory responses.

The war in Ukraine is leading not only to human suffering. Ukraine's cultural heritage is also experiencing the consequences of the war: museums are being bombed and 'Russification' in the occupied territories means children no longer learn Ukrainian. Researcher Evelien Campfens was commissioned by…

Researchers from eLaw, the Center for Law and Digital Technologies, published a new book on EU data protection law.

More than 5,000 exoplanets have been found over the past couple of decades. These exoplanets show a tremendous diversity, ranging from scorching hot Jupiters, common super-Earths, to widely separated super-Jupiters on the planet/brown dwarf boundary.

On Tuesday 11 February, the European Data Protection Supervisor, Mr. Wojciech Wiewiórowski, visited eLaw, - center for Law and Digital Technologies at Leiden Law School to give a lecture on facial recognition systems and data protection in Europe.

SALTSWAT -- a project which combines the Spaces for Active Learning & Teaching and the Support wtih Active Teaching -- began in Mid-2019 and is running in pilot until the summer of 2020. The purpose of the project is to find answers to the question of how to systematically accelerate 'active teaching…

Prof. Dr. Richard Gill has recently joined as a member of the Foundational Questions Institute (FQXi). FQXi is an international association of scientists who explore the foundations of physics and cosmology.

Joon Hyung Lee is a researcher in quantum computing algorithms and probabilistic combinatorics.

In the spirit of 'unity in diversity', our objective is to promote insight into and appreciation for the wonder that the same physical laws and mathematical concepts apply to the whole of nature, from the largest to the smallest energy and length scales. We strive for the application of abstract theoretical…

Violent conflicts all over the world pose a great threat. Not only to the region’s inhabitants, but also to the cultural heritage in the area. This is the subject of the Europe Lecture in The Hague on 13 June.

Political scientist Tom Theuns (Leiden University) has been awarded a Veni grant from the Dutch Research Council (NWO). This means that he is recognised as a promising researcher and that he will receive support to develop his ideas further for a period of three years. Theuns will focus on the role…

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.

Inspectors say the William Schrikker Foundation, a leading Dutch youth protection agency, is failing in its duties. Mariëlle Bruning, Professor of Child Law, told public broadcaster NOS: ‘It's deeply concerning that there's insufficient oversight of children’s safety.’

One of the most important correlation functions in physics, especially in cosmology, is the energy density, which describes how much energy is present at each point in spacetime due to matter fields. A key contribution to the energy density of the primordial universe comes from gravitational waves (GWs),…

On 15 February 2018, Simone van der Hof gave a keynote lecture entitled 'Data Protection and Children's Rights - the reasoning behind the protective provisions for children in the GDPR' at the International School of Amsterdam conference on Strategic marketing & communications for international scho…

Farmers do not love them all. Microbes can cause tragic consequences for crops. Even the presence of just one pathogenic fungus or bacterium can drastically reduce yields. Still, there are exceptions. In that case, a pathogenic microbe is present in the soil, but does not cause any harm. Adam Ossowicki…

The Dutch cabinet will allocate a total of 40 million euros extra for institutions providing youth protection and youth rehabilitation over the next four years. Local councils must make the same amount available. Will that be enough to solve the problems?

From surface science towards industrial practice using high-pressure scanning tunneling microscopy.

Systems with local constraints is a new finding in recent researches on complex systems. The heterogeneous spatial interactions and the temporal dependencies among those numerous units make it difficult to describe by traditional statistical physics.

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You’ve been accepted! Leiden University looks forward to welcoming you as a new student. Your next step is to prepare for your studies. Below you can find some tips to help you get a head start as you embark on your studies at Leiden University.

In a new study, we found that when we are exposed to potential harm to the other person, it improves our automatic attentional processes to avoid harm to that person.

This paper addresses the gap that explores how agencies might allocate their personnel so as to maximise performance with the personnel they have.

PhD defence