The theoretical explanation of cosmic acceleration is nowadays one of the biggest puzzles in cosmology.

What are the 'dark' components of the universe?

The focus of the dissertation

Ten years after its introduction, the controversial idea of Erik Verlinde on gravity is still a hotly debated topic, and is still surrounded by a cloud of scepticism. Scepticism in which the media have played a major role, theoretical physicst Koenraad Schalm says in an article by NWO. ‘The media simply…

In this thesis, classes of strongly interacting quantum field theories, have been studied.

Of all the mass in our Universe, 80% is thought to consist of a hypothetical and invisible substance called dark matter (DM).

In this thesis we study the landscape of gravitational models which modify GR by introducing an additional scalar degree of freedom (d.o.f.) to source Cosmic Acceleration.

Lecture

Lecture

Lecture

PhD Defence

We are cosmologists, in other words we use physics to study the Universe, how it started and evolved into the structure that we observe around us.

How can citizen science be used to communicate and provide data for social network analysis?

Promotores: Prof.dr. F. van Lunteren, Prof.dr. F.S. Gaastra

Promotor: Richard D. Gill

Why are not all children equally responsive to variations in the social environment?

Promotores: Prof.dr. J. Zaanen & Prof.dr. K.E. Schalm

German scientists and NASA have developed a bacteria-killing coating for space toilets. With this coating they hope to protect astronauts in space stations from pathogens. Professor of Biological chemistry Nathaniel Martin sheds light on the discovery: 'You don't expect nasty bacteria up there, but…

For centuries, astronomers have studied the universe by collecting light signals. Since 2015, the confirmation of an important prediction of Einstein allows us to explore the universe in a new way: through gravitational wave radiation. Astronomy PhD candidate Valeriya Korol proposes to use these gravitational…

On Wednesday September 26th, theoretical physicist Sean Carroll will give an Ehrenfest colloquium. It is part of a lecture series that has been running since 1912 and was founded by physicist Paul Ehrenfest.

On November 21, theoretical physicist Juan Maldacena gives the Ehrenfest Colloquium. Maldacena is known worldwide as the inventor of AdS/CFT correspondence, which might be key to a theory of quantum gravity. Maldacena is winner of the prestigious Dirac Prize and the Breakthrough Prize in Fundamental…

The 2017 Nobel Prize in Physics has been awarded to Rainer Weiss, Barry Barish and Kip Thorne for their work on the measurement of gravitational waves. Thorne was Lorentz Professor in 2009 in Leiden. Physicist Jan Willem van Holten explains why this is such an important discovery. ‘A new branch of astrophysics…

As an alternative to the diving board shaped force sensor, we are now developing a magnetically levitated small superconducting particle – or ‘Lead Zeppelin'' – as our mechanical resonator. We explore routes towards detection of gravity between small objects.

In the early universe, the dynamics of the Higgs field can give rise to many interesting phenomena.

In this lecture professor Harding considered the implications of Asia's 21st-century rise for its legal systems and our approaches to studying them in the new situation we confront in the early 21st century.

Do humans and zebra finches share cognitive mechanisms that are important for speech perception?

A remarkable population of short period transiting rocky exoplanets with equilibrium temperatures on the order of 2,000 K has recently been discovered.

On 9 May 2018, Roy van Keulen defended his doctoral thesis 'Digital Force: Life, Liberty & Livelihood in the Information Age'. The doctoral research was supervised by Prof. dr. A. Ellian.

How does FoxP1 affect auditory perception on a behavioural and genomic level?

We explore the possibilities to combine magnetic resonance techniques with atomic force microscopy together in a single microscope: the MRI-AFM, also called Magnetic Resonance Force Microscopy (MRFM).

Lecture

The Dutch Black Holes Consortium receives 4.9 million euros from NWO for unravelling the mysteries of black holes and other mysteries of the universe. The Astronomy and Society group at Leiden Observatory is affiliated to use the leading research to introduce people of all ages and background, and children…

An international team of astronomers has found an unexpected link between dark matter and visible stars in stellar systems. This discovery may even cause us to reconsider our understanding of gravity. They published on their discovery in 'Nature' on 1 October.

The life of a fibroblast is heavy, but PhD student Julia Eckert makes it 19.5 times heavier, using the Large Diameter Centrifuge at the ESTEC space research centre in Noordwijk.

Mathematical and computational analysis of the dynamics of polar transport of the plant hormone auxin.

1. What is the exact role of PIN proteins in PAT? 2. How is PIN polarity established, and how is it modulated by AGC kinase-mediated phosphorylation? 3. What is the role of the AGC kinase, as modulators of PAT, in translating environmental signals, such as gravity, light or mechanical stress, to plant…

Simulations of galaxies help researchers understand astronomical observations better. The EAGLE simulation, a large project in which Leiden astronomers play a leading role, shows the evolution of the Universe, from just after the Big Bang to the present day.

Researchers at Leiden Observatory study the fundamental physics that creates structure in the Universe. These processes collect matter into galaxies and gas into stars. With the use of powerful telescopes and advanced calculations and computer simulations, Leiden astronomers seek to understand the origin,…

Researchers at Leiden Observatory study the fundamental physics that creates structure in the Universe. These processes collect matter into galaxies and gas into stars. With the use of powerful telescopes and advanced calculations and computer simulations, Leiden astronomers seek to understand the origin,…

‘AI can’t do half as much as people think,’ says computer scientist and psychologist Roy de Kleijn. He tries to teach robots seemingly easy things, and keeps on discovering how smart human intelligence really is. Three things that computers are no way near doing.

It must be there. We just cannot see it: mysterious dark matter and dark energy in the universe. Henk Hoekstra is one of the many cosmologists who would love to know what exactly these substances consist of. He has received a European research grant of 1.3 euro million to find out.

Astronomers led by Pieter van Dokkum have discovered a galaxy that barely contains any dark matter, which actually proves that dark matter does indeed exist. The research results will be published this week in Nature.

The Leiden physics institute LION has bought a painting by the American physicist Gregory Horndeski, who wrote a brilliant article about gravity in 1974. After being ignored for 35 years, Horndeski's paper became a huge hit among cosmologists, unbeknownst to Horndeski himself, who had made a career…

On Wednesday February 7th, Professor Ed Copeland from the University of Nottingham will give the Colloquium Ehrenfestii.

Depression has traditionally been linked to increased inflammation. Innovative research by psychologist Eiko Fried refutes this popular assumption. He shows that specific depression symptoms such as sleeping problems explain this relationship. Publication in Psychological Medicine .

Many astronomers suspect that most of the matter in the universe is invisible. So how can you weigh dark matter if you can't actually see it? Professor Henk Hoekstra is looking for a solution. Inaugural lecture 25 June.

Cosmologists have many possible models for the Universe, of which only one can be true. A new flowchart will eliminate some of them when two specific Universe features are accurately measured. Publication in Physical Review D on 7 November.

How did British scholars and scientists in the period of discipline formation envision, experience and resist scholarly temptations?

Quantum computers deserve their own quantum internet. This is a network that dispatches information not in the form of bits - ones and zeros - but rather as qubits, just like in the quantum computer itself. In the view of Dirk Bouwmeester, a professor in Leiden’s Quantum Matter & Optics research group,…

In his guest lecture on 22 January André Kuipers took school pupils and students on trip through space. His mission was to interest his young listeners in science and technology.