ERC FUNDED PROJECTS

In quantum electrodynamics a range of fundamental processes are driven by omnipresent vacuum fluctuations. Photonic crystals can control vacuum fluctuations and thereby the fundamental interaction between light and matter. We will conduct experiments on quantum dots in photonic crystals and observe novel quantum electrodynamics effects including fractional decay and the modified Lamb shift. Furthermore, photonic crystals will be explored for shielding sensitive quantum-superposition states against decoherence. Defects in photonic crystals allow novel functionalities enabling nanocavities and waveguides. We will use the tight confinement of light in a nanocavity to entangle a quantum dot and a photon, and explore the scalability. Controlled ways of generating scalable and robust quantum entanglement is the essential missing link limiting quantum communication and quantum computing. A single quantum dot coupled to a slowly propagating mode in a photonic crystal waveguide will be used to induce large nonlinearities at the few-photon level. Finally we will explore a novel route to enhanced light-matter interaction employing controlled disorder in photonic crystals. In disordered media multiple scattering of light takes place and can lead to the formation of Anderson-localized modes. We will explore cavity quantum electrodynamics in Anderson-localized random cavities considering disorder a resource and not a nuisance, which is the traditional view. The main focus of the project will be on optical experiments, but fabrication of photonic crystals and detailed theory will be carried out as well. Several of the proposed experiments will constitute milestones in quantum optics and may pave the way for all-solid-state quantum communication with quantum dots in photonic crystals.

1 199 648 €

Start date: 2010-12-01, End date: 2015-11-30

The Large Hadron collider (LHC) at CERN will be a milestone for the understanding of fundamental interactions and for the future of high energy physics. Four large experiments at the LHC are complementarily addressing the question of the origin of our Universe by searching for so-called New Physics. The world of particles and their interactions is nowadays described by the Standard Model. Up to now there is no single measurement from laboratory experiments which contradicts this theory. However, there are still many open questions, thus physicists are convinced that there is a more fundamental theory, which incorporates New Physics. It is expected that at the LHC either New Physics beyond the Standard Model will be discovered or excluded up to very high energies, which would revolutionize the understanding of particle physics and require completely new experimental and theoretical concepts. The LHCb (Large Hadron Collider beauty) experiment is dedicated to precision measurements of B hadrons (B hadrons are all particles containing a beauty quark). The analysis proposed here is the measurement of asymmetries between B_s particles and anti-B_s particles at the LHCb experiment. Any New Physics model will change the rate of observable processes via additional quantum corrections. Particle antiparticle asymmetries are extremely sensitive to these corrections thus a very powerful tool for indirect searches for New Physics contributions. In the past, most of the ground-breaking findings in particle physics, such as the existence of the charm quark and the existence of a third quark family, have first been observed in indirect searches. First - still statistically limited - measurements of the asymmetry in the B_s system indicate a 2 sigma deviation from the Standard Model prediction. A precision measurement of this asymmetry is potentially the first observation for New Physics beyond the Standard Model at the LHC. If no hint for New Physics will be found, this measurement will severely restrict the range of potential New Physics models.

1 059 240 €

Start date: 2011-01-01, End date: 2015-12-31

The advent of high-power laser systems in the past two decades has opened a new field of research where astrophysical environments can be scaled down to laboratory dimensions, yet preserving the essential physics. This is due to the invariance of the equations of ideal magneto-hydrodynamics (MHD) to a class of self-similar transformations. In this proposal, we will apply these scaling laws to investigate the dynamics of the high Mach number shocks arising during the formation of the large-scale structure of the Universe. Although at the beginning of cosmic evolution matter was nearly homogenously distributed, today, as a result of gravitational instability, it forms a web-like structure made of filaments and clusters. Gas continues to accrete supersonically onto these collapsed structures, thus producing high Mach number shocks. It has been recently proposed that generation of magnetic fields can occur at these cosmic shocks on a cosmologically fast timescale via a Weibel-like instability, thus providing an appealing explanation to the ubiquitous magnetization of the Universe. Our proposal will thus provide the first experimental evidence of such mechanisms. We plan to measure the self-generated magnetic fields from laboratory shock waves using a novel combination of electron deflectometry, Faraday rotation measurements using THz lasers, and dB/dt probes. The proposed investigation on the generation of magnetic fields at shocks via plasma instabilities bears important general consequences. First, it will shed light on the origin of cosmic magnetic fields. Second, it would have a tremendous impact on one of the greatest puzzles of high energy astrophysics, the origin of Ultra High Energy Cosmic Rays. We plan to assess the role of charged particle acceleration via collisionless shocks in the amplification of the magnetic field as well as measure the spectrum of such accelerated particles. The experimental work will be carried both at Oxford U and at laser facilities.

1 119 690 €

Start date: 2010-12-01, End date: 2015-11-30

From astrophysics to high-energy physics and quantum gravity, black holes (BHs) have acquired an ever increasing role in fundamental physics, and are now part of the terminology of many important branches of theoretical and observational physics. It has been established that supermassive BHs lurk at the center of many galaxies and provide fertile ground for stellar growth and evolution. Millions of stellar-mass BHs populate the galaxies, and power violent processes such as gamma-ray bursts, etc. In high-energy physics, the gauge/gravity duality has created a powerful framework for the study of strongly coupled gauge theories and found applications in connection with the experimental program on heavy ion collisions at RHIC and LHC, among many others. As emphasized by Maldacena and Witten, BHs play a special role in the correspondence: confinement in QCD may be related via the Hawking-Page phase transition to BHs in anti-de Sitter (AdS). Given the central role that BHs have been claiming in physics, a major task for theoreticians is to understand processes in which they are involved. With the advent of techniques to evolve BH spacetimes numerically, the field is undergoing a phase transition from a promising branch of general relativity to one of the most exciting fields in 21st century research that will open up unprecedented opportunities to expand and test our understanding of fundamental physics and the universe. This project aims at evolving numerically BHs in generic backgrounds, in a fully non-linear framework. We intend to generalize all the machinery developed in the last 30 years for asymptotically flat, (3+1) dimensional spacetimes to other geometries and field equations. This allows a number of fundamental questions to be tackled, from tests of the cosmic censorship to an understanding of the stability and phase diagrams of these objects and how different field equations can impact on gravitational-wave emission

915 000 €

Start date: 2010-12-01, End date: 2015-11-30