ERC Advanced Grants for Laserlab Researchers

Majed Chergui (FERMI): X-ray spectroscopy of molecular chirality in solutions

Majed Chergui, founder of the LACUS centre at EPFL, has recently won an ERC Advanced Grant for his project “CHIRAX: X-ray spectroscopy of molecular chirality in solutions”, which aims at implementing steady-state and time-resolved X-ray circular dichroism to resolve molecular structures and their evolution with element specificity. The research will in addition further develop new tools using the orbital angular momentum of X-ray light to perform helical dichroism studies.

Morgan Mitchell (ICFO): Field sensors with exceptional energy resolution

Morgan Mitchell has recently been awarded an ERC Advanced Grant for the project “Field-SEER: Field Sensors with Exceptional Energy Resolution”. In this project, he will develop magnetic sensors with combined spatial, temporal, and field resolution beyond what is possible with existing sensing approaches. Ultra-high-coherence media, including Bose-Einstein condensates and optically-addressed nuclear spin ensembles, will be developed as sensors for application in fundamental physics and bio-magnetism.

Niek van Hulst (ICFO): Photons and electrons on the move

Niek van Hulst received his third ERC Advanced Grant for his project entitled “FastTrack: Photons and electrons on the move”. In this new project, he will investigate the dynamic organisation of the natural light-harvesting membrane architecture, its packing order, diffusion, and re-organisation in response to light stress. The research will address questions related to which pathways are taken to charge separation and the role of fluctuations, coherences, input-spectra and vibrations.

Nathalie Picqué (MPQ): Precision measurements in molecules with frequency combs

With her ERC Advanced Grant, Nathalie Picqué explores a new concept of precision measurements with frequency combs. A revolutionary spectrometer will simultaneously achieve broad spectral coverage, Doppler-free resolution and extreme accuracy for precise studies of small molecules. The unprecedented degree of control of frequency combs achieved in this way could also open up new experimental possibilities for the study of highly non-linear phenomena in strong-field and attosecond physics.
For more than ten years, Nathalie Picqué has developed pioneering methods using frequency combs in high-resolution molecular  spectroscopy. These provide essential information about the structure and dynamics of molecules and open numerous new applications in chemistry, biology and environmental sciences, but also in fundamental physics, for example for precision measurements
of fundamental constants.

Olga Smirnova (MBI): Ultrafast molecular chirality: twisting light to twist electrons on ultrafast time scale

Chiral molecules exist in pairs of non-superimposable “mirror twins” called enantiomers. The specific stereo arrangements of their nuclei underlie their key functions in chemistry and biology. Yet, little is known about chiral molecular interactions at the level of electrons, occurring on ultrafast time scales. Developing extremely enantio-sensitive, ultrafast and all-optical approaches to track electronic dynamics is an important unsolved challenge.
The ERC Advanced Grant supports the multidisciplinary project ULISSES. It aims to address this challenge by taking advantage of chiral electronic currents that arise naturally when chiral molecules interact with sufficiently intense light. The project applies light with polarisation structured both in space and in time, endowing such light with local chiral and global topological properties. It aims to induce new optical effects being orders of magnitude more enantio-sensitive than the traditional optical techniques, gaining access to the ultrafast electron dynamics and physical  mechanisms underlying chiral functions.

Anne L’Huillier (LLC): Quantum Physics with Attosecond Pulses

Using attosecond laser pulses as a "camera flash", it is possible to study the fundamental interactions of our physical world, such as the motion of an electron as an atom is ionised. With her new ERC Advanced Grant, Anne L'Huillier intends to push this incredible technique even further, by characterising the quantum properties of the electron (or electrons) ionised by absorption of attosecond pulses. This is the third time that Anne L’Huillier has received an ERC Advanced Grant. Instead of photons, atoms or ions as in conventional quantum optics, the new project will study electron "wave packets", generated by absorption of attosecond laser pulses. The aim of the project is to characterise the quantum state of these wavepackets, to realise multiple slit experiments in the temporal domain, and to study entangled two-electron wavepackets. It is hoped that this will shed new light in quantum physics given the originality of the studied systems and the versatility of the experimental tools, enabling four-dimensional information (momentum and time) for one or two particles. “I am very pleased. It is a very, very nice feeling to be awarded this grant. It will be both demanding and exciting”, says Anne L’Huillier.

Gijs Wuite (LLAMS): Mechanically mapped chromosomes

Optical tweezers are a tool for manipulating micro- scopic objects using a beam of light. When the light diffracts through the object, it imparts a force which acts to center it in the beam. This has enabled extremely precise manipulation of microscopic objects, which can be combined with precision microscopy to give new insight into their exact shape. Gijs Wuite has used this technique to attach microscopic spheres to specific points on complex molecules, such as DNA which has been extracted from a cell and kept in physiological buffer, enabling them to be moved and deformed in very precise ways. Chromosomes (the compact organisation of DNA just before cells divide) are found in every cell, and in diseased cells (cancer in particular) they will have an abnormal composition and structure. By imaging and mechanically mapping chromosomes, it is possible to learn about these abnormal structures. Wuite plans to use his new ERC Advanced Grant to expand his research group to address this question. “There are currently only two of us working on this project. The grant gives us the opportunity to hire five extra researchers and considerably expand our line of biophysics of chromosome research.”

Maciej Lewenstein (ICFO): New applications of quantum simulators

Quantum simulators are experimental systems mimicking complex models of, for example, condensed matter and high-energy physics. Such quantum simulators can be realised on various platforms, ranging from ultracold atoms and ions to Josephson junctions or superconducting qubits.
Maciej Lewenstein’s third ERC Advanced Grant project, NOQIA, aims at introducing quan- tum simulators to two novel areas: physics of ultrafast phenomena and attoscience on one side, and quantum machine learning and neural networks on the other. The project will, for example, address the question whether in- tense laser physics may serve as a tool to detect topologi- cal effects in solid state and strongly correlated systems (such as graphene), and whether ultracold atoms can mimic such phenomena. In addition, the aim is to design and analyse quantum neural network devices that will employ topology in order to achieve robust quantum memory or robust quantum information processing.

Theo Kitsopoulos (IESL-FORTH):Slice imaging to understand catalysis

Catalysis and catalytic processes account, directly or indirectly, for 20-30 % of world gross domestic product. In order to optimise these important chemical processes, knowledge of elementary chemical reaction mechanisms in heterogeneous catalysis (where molecules in different states of aggregation interact with each other) is needed to construct comprehensive kinetic models.
In his ERC Advanced Grant project, Theo Kitsopoulos will use the slice imaging technique developed at IESL- FORTH to measure catalytic rates for site-specific elementary reactions. Originally, this slice imaging technique, was developed to study gas phase processes such as laser photodissociation or crossed-beam reactive scattering. In collaboration with the Max Planck Institute of Biophysical Chemistry, Kitsopoulos’ methodology was extended to measurements of the kinetics of catalysis in the microsec- ond regime, at industrially relevant temperatures of 200 to 1000 Kelvin. His intention is to focus on elementary reactions involving carbon, hydrogen, oxygen, and nitrogen, as these are important in many key industrial processes.

Thomas Elsaesser (MBI): Probing DNA and RNA charge dynamics

Biological macromolecules exist in an environment of water molecules and solvated ions, where electric water dipoles and charged ions exert electric forces on the biomolecules and, thus, strongly influence their structure and biological function. Understanding such interactions at the molecular level is a major scientific challenge; presently, their strengths, spatial range and interplay with other non-covalent interactions are barely known.
In his second ERC Advanced Grant project, Thomas Elsaesser will try to map these molecular forces on sub-nanometer length scales and at terahertz frequencies. He will do this by measuring the vibrational response of the biomolecules DNA and RNA to the charge dynamics and local electric fields, using multidimensional vibrational spectroscopy on a femtosecond timescale. As a ground- breaking open problem, the role of magnesium and other ions in DNA and RNA structure definition and folding will be addressed. Beyond RNA research, the present approach holds potential for fundamental insight in transmembrane ion and water channels.

Antonio Acín (ICFO): Certification of quantum information systems

Currently, complex many-body quantum systems are prepared in many labs worldwide, and quantum information technologies are making the transition to real applications. The concept of quantum certification covers the questions of ensuring entanglement, randomness, and security of these quantum information systems, as well as whether the performed quantum calculations are indeed correct.
Antonio Acín’s ERC Advanced Grant project aims at bringing quantum certification to the next level, focussing on tools to identify quantum properties of many-body quantum systems; characterising networks in the quantum regime, and constructing cryptography protocols offering certified security. Expected outcomes of this project include new protocols to benchmark quantum simulators and annealers, first methods to characterise quantum causality, and new protocols exploiting simple network geometries.

Jens Limpert (HIJ): Compact lasers as alternative to synchrotron facilities

High-quality radiation in the terahertz and mid-infrared spectral range can, for example, be used for non-destructive investigation of complex materials and detection of diseases in the human body, respectively. However, the radiation provided by current laser-based sources is not yet of sufficiently high quality for these practical applications. At the moment, large-scale research facilities such as synchrotrons are still needed for this kind of
research.
With his ERC Advanced Grant, Jens Limpert intends to develop a high-performance fibre laser system to generate coherent laser pulses in the infrared, terahertz and soft X- ray range. Since direct emission of coherent radiation with the wavelength agility and performance of a synchrotron is not possible with conventional lasers, Limpert and his team in Jena are adopting a different approach. They first generate laser pulses of a different frequency and focus them through a non-linear medium, which shifts the frequency into the desired range. In order to achieve signifi cantly longer wavelengths, they will – among other things – use thulium-doped ultrafast fibre lasers.

Julien Fuchs (LULI): Extreme neutrons for nucleosynthesis

The heaviest elements found in our Solar System and in stars are believed to have been formed by what is known as the “r-process” of nucleosynthesis, where multiple neutrons are squeezed into a nucleus at the same time. At present, however, there are large discrepancies between the observed element abundances in stars and those found in simulations. It is speculated that this problem stems from the uncertainties in nuclear parameters, particularly in the plasma environment. These parameters have not been verified experimentally, because the flux of current neutron facilities is insufficient, and there is as yet no means to create on-site hot and dense plasmas.

In his ERC Advanced Grant project GENESIS, Julien Fuchs will aim to perform the first direct measurements of neutron capture and beta-decay rates related to the r-process, exploiting the upcoming generation of multipetawatt lasers. Those lasers could be used to generate neutron beams of extreme brightness, with a flux comparable to that found in Supernovae.

Maria García-Parajo (ICFO): Mechanical forces inside the cell membrane

Through evolution, cells have developed the exquisite abil- ity to sense, transduce and integrate mechanical and biochemical signals (i.e. mecha- nobiology) to generate appropriate responses. These key events are rooted at the molecular and nanoscale levels, a size regime difficult to access, hindering our progress towards mechanistic understanding of mechanobiology. Recent evidence shows that the lateral nanoscale organisation of mechanosensitive membrane receptors and signalling molecules is crucial for cell function. Yet, current models of mechanosensing are based on force-induced molecular conformations, completely overlooking the chief role of mechanical forces on the nanoscale organisation of the plasma membrane.

The goal of Maria García-Parajo’s ERC Advanced Grant project NANO-MEMEC is to provide understanding on the role of mechanical and biochemical stimuli in the remodelling of adhesion mechanisms at the cell membrane. To overcome the technical challenges of probing these processes at the relevant length- and timescales, she will exploit cutting-edge biophysical and nanophotonic tools exclusively developed in her lab, which combine super-resolution optical nanoscopy and single-molecule dynamics in conjunction with simultaneous mechanical stimulation of living cells.

Javier García de Abajo (ICFO): Free electrons as ultrafast nanoscale probes

According to the laws of quantum mechanics, the principles of nanophotonics can be extended from photons to electrons. This means that the wave nature of electrons can be exploited to gain in spatial resolution (because electrons have a much smaller wavelength than photons), and use can be made of the stronger, even non-linear interactions mediated by Coulomb fields.

In his ERC Advanced Grant project eNANO, Javier García de Abajo intends to start the new field of free-electron nanoelectronics, where electrons evolving in the vacuum regions defined by nanostructures will be generated, guided, and sampled at the nanoscale. In this way, these free electrons will act as probes to excite, detect, image, and spectrally resolve so-called polaritonic modes (i.e., quantum phenomena such as plasmons, optical phonons, and excitons) with atomic precision over sub-femtosecond timescales.

He will develop the theoretical and computational tools required to investigate this unexplored scenario, covering a wide range of free-electron energies, their elastic interactions with the material’s atomic structures, and their inelastic coupling to nanoscale dynamical excitations. The project will bring together a multidisciplinary theory group, in close collaboration with leading experimentalists, aimed at pursuing a radically new approach to study and control the nanoworld.

Jens Biegert (ICFO): Real-time observation of transformations and transitions

The ability to synthesise and to tailor substances and ma- terials with specific function has huge impact on modern society. In this context, a firm understanding of structural transformations of molecules and phase transitions of solids is vital, as they are omnipresent, e.g. as formation and breakage of molecular bonds, proton motion and isomerisation, and as collective phenomena in phase transitions.

In Jens Biegert’s ERC Advanced Grant project TRANS - FORMER, he aims to provide unprecedented insight into the real-time electronic and nuclear dynamics of molecular transformations and phase transitions. The project will exploit attosecond soft X-ray spectroscopy (XAFS) and laser- induced electron diffraction (LIED) to pinpoint in real-time which electronic states participate at which nuclear configuration.

Employing the two methods, he aims to establish the boundaries for space-time imaging of isolated molecules with application to molecular isomerisation. In condensed phase, attosecond X-rays will be used to study effects such as the metal-to-insulator phase transition. Simultaneous and real-time electronic and nuclear information will be extracted, in order to gain insight into the underlying many-body quantum correlations.

Erik Nibbering (MBI): Soft-X-ray spectroscopy of acids and bases

How acids and bases react in water is a question raised since the pioneering days of modern chemistry. Recent decades have witnessed an increased effort in elucidating the microscopic mechanisms of proton exchange between acids and bases and the important mediating role of water in this. Using ultrafast spectroscopy it has been shown that the elementary steps in aqueous proton transfer occur on femtosecond to picosecond time scales. Aqueous acid-base neutralisation predominantly proceeds in a sequential way via water bridging acid and base molecules. Complementing spectroscopy in the ultraviolet to infrared range, soft-X-ray absorption spectroscopy (XAS), probing transitions from inner-shell levels to unoccupied molecular orbitals, can be used to monitor electronic structure with chemical element specificity.

Within his ERC Advanced Grant project, Erik Nibbering aims to develop steady-state and time-resolved soft-X-ray spectroscopy of acids and bases. Here novel liquid flatjet technology is utilised with soft-X-ray sources at synchrotrons as well as table-top laser-based high-order harmonic systems. Resolving the electronic structural dynamics of elementary steps of aqueous proton transport will furthermore elucidate the role of mediating water in bulk solution, and in specific conditions such as hydrogen fuel cells or trans-membrane proteins.

Erwin Peterman (LLAMS): Fluorescence microscopy to study cilia in live worms

Many cells in our body are equipped with cilia, antenna-like protuberances that are used to detect chemical, mechanical or optical signals from the environment. In the past few years, quite a few diseases, so-called ciliopathies, have been found where cilia play a central role. In his ERC Advanced Grant project, Erwin Peterman will study the relation between the cilium’s function, its structure and a specific continuous transport mechanism inside the cilium. Peterman’s group already found that this intraflagellar transport is intricately connected to the length of the cilium and to signal detection. By studying the taste cilia of the roundworm C. elegans he will try to further elucidate how cilia are able to extract information from their environment. His team will use advanced fluorescence microscopy in live worms to follow structural dynamics, such as intraflagellar transport. With these optical techniques individual receptors can be visualised in live worms and their location will be followed over time. The worms will be exposed to several different chemicals in order to see how the worms, cilia, and intraflagellar transport respond to external stimuli. This approach should yield quantitative information which could hopefully be used to address ciliopath

Thomas Udem (MPQ): High Resolution Extreme Ultraviolet Laser Spectroscopy

At the precision frontier of Quantum Electrodynamics (QED), comparisons between theory and experiment have so far been performed almost ex clusively with atomic hydrogen. According to Thomas Udem, it is of fundamental importance to proceed to other, hydrogen- like systems that can be computed with very good accuracy. In his ERC Advanced Grant project, Udem therefore proposes to study singly ionised helium (He + ) with high resolution laser spectroscopy. In addition of representing a hitherto unexplored system, he argues, He + allows for a far better test than atomic hydrogen due to the QED power series expansion of its energy levels in terms of Zα. With the nuclear charge Z and the fine structure constant α, the disputed terms are of the order of (Zα) 6 . Unlike ordinary hydrogen, He + can be readily stored in an ion trap and sympathetically cooled by co-stored ions with an accessible cooling transition. This approach eliminates essentially all dominating experimental uncer - tainties that are faced with ordinary hydrogen today. The 1S-2S resonance is the sharpest and hence most interest - ing transition. Its observation requires highly coherent ex - treme ultraviolet radiation at 60.8 nm, which can be gener - ated through high-order harmonics from a mode-locked laser. The resulting frequency comb is most suitable for a two-photon transition, as photons from pairs of modes can combine to deliver the excitation energy. According to Udem, other applications of such a new laser source are foreseeable as well.

Ignacio Cirac (MPQ): Quantum Emitters in Non-conventional Baths

The coupling of two-level quantum emitters to a zero temperature electromagnetic reservoir (or bath) is a central problem in quantum optics. For a single emitter, the bath, having infinite degrees of freedom, may induce dissipation (via spon- taneous emission), and other basic phenomena of Quantum Electrodynamics, like Lamb shifts. For many emitters, it may lead to collective phenomena, such as superradiance and dipole-dipole interactions. If the electromagnetic bath has some structure – meaning it has a non-linear dispersion relation, with gaps at certain energy intervals – new and intriguing phenomena may arise. This holds even more so for a bath with a tailored dispersion relation for the electromagnetic field. These unconventional baths can be found, for instance, in photonic crystals made of dielectric materials, where the (quasi)periodic structure gives rise to dispersion relations in the bath akin to those occurring in solid state physics. Thanks to the advances in nano-fabrication, it is possible nowadays to build photonic crystals with arbitrary patterns, and thus to tailor the dispersion relations. In his Advanced Grant project, Ignacio Cirac will develop new theoretical techniques in order to investigate the physics of emitters coupled to these unconventional baths. In addition, specific physical setups will be proposed and analysed, starting with atoms close to photonic crystals.