New Phases of Magnetic Quantum Matter Studied by Neutrons and Photons

Friday 16 November at 2.00 p.m. Chadwick Amphitheatre, ILL 4

Prof. Dr. Christian Rüegg
Division Research with Neutrons and Muons, Paul Scherrer Institute and Department of Quantum Matter Physics

University of Geneva, Switzerland


Materials made of arrays of quantum spins forming well-defined lattices serve as model systems to study the phases of correlated magnetic quantum matter like spin Luttinger-liquids, magnon Bose-Einstein condensates, or spin super-solids. Neutron and X-ray scattering are unique tools for high-precision studies of such phases and of their correlations and excitations with high energy and momentum resolution and under multi-extreme conditions. Our results for a selection of low-dimensional and frustrated quantum magnets will be discussed in the context of recent developments in neutron instrumentation and computational physics, and exciting new opportunities that free electron lasers will offer to study the time-dependence and out-of-equilibrium dynamics of such systems.

B. Wehinger et al. Phys. Rev. Lett. 120, 117201 (2018).
M. Kubus et al. Inorg. Chem. 57, 4934 (2018).
M. Skoulatos et al. Phys. Rev. B 96, 235154 (2017).
M. Zayed et al., Nature Physics 13, 962 (2017).
S. Ward et al. Phys. Rev. Lett. 118, 177202 (2017).
A. Biffin et al. Phys. Rev. Lett. 118, 067205 (2017).

Self-Assemblies Bridging the Length Scales for Biomimetic and Functional Materials

Friday 7 september at 2.00 p.m. Chadwick Amphitheatre, ILL 4

Prof. Olli Ikkala

Aalto University,
Department of Applied Physics, Molecular materials
Puumiehenkuja 2, P.O. Box 15100,
00076 Aalto, Espoo, Finland

Self-assemblies have extensively been used towards well-defined structures and functional materials. An overarching challenge is to bridge the different length scales to transfer the local structures to useful macroscopic materials properties. This talk addresses selected examples thereof using colloids and polymers. Inspired by the attractive mechanical properties of nacre, we show that aligned clay nanosheets, self-assembled with polymer layers, allow nacre-mimetic bulk materials with strength of 220 MPa and fracture toughness of 3.4 MPa m1/2, approaching those of nacre (1). The fracture processes can be followed by laser speckle methods (2). Then reasons are discussed why atomically precise metallic nanoclusters decorated by ligands mediating hydrogen bonds lead to 2D colloidal hexosome-like sheets and hollow virus-like capsids (3,4). Nanocelluloses are colloidal rods or nanofibers with extraordinarily good mechanical properties. Directed polymer self-assemblies on their surfaces are discussed to facilitate "brushes on brushes", architecturally resembling proteoglycans (5). Nanocelluloses allow porous films towards efficient light scattering media (6), mimicking white beetles. Finally, complex block copolymer self-assemblies are discussed. Diblock copolymer micelles lead to tunable photonic fluids and photonic crystals, once the micellar coronae become super-stretched by their promoted repulsion by charging (7). Upon involving more blocks, complex self-assemblies are obtained (8-9). The challenges in the phase identification are discussed.
[1] M. Morits, T. Verho, J. Sorvari, V. Liljeström, M. Kostiainen, A. Gröschel, O. Ikkala, Adv. Funct. Mater. 27, 1605378, 2016; [2] T. Verho, P. Karppinen, A. Gröschel, O. Ikkala, Adv. Sci, 1700635, 2017; [3] Nonappa, T. Lahtinen, J. Haataja, T.-R. Tero, H. Häkkinen, O. Ikkala, Angew. Chem., Int Ed., 55, 16035, 2016; [4] Nonappa, J. Haataja, J. Timonen, S. Malola, P. Engelhardt, N. Houbenov, M. Lahtinen, H. Häkkinen, O. Ikkala, Angew. Chem., Int Ed. 56, 6473, 2017; [5] J.-M. Malho, M. Morits, T. Löbling, N. Nonappa, J. Majoinen, F. Schacher, O. Ikkala, A. Gröschel, ACS Macro Lett. 5, 1185, 2016; [6] M. S. Toivonen, O. D. Onelli, G. Jacucci, V. Lovikka, O. J. Rojas, O. Ikkala, S. Vignolini, Adv. Mat, 2018, in press; [7] M. Poutanen, G. Guidetti, T. Gröschel, O. Borisov, S. Vignolini, O. Ikkala, A. H. Gröschel, ACS Nano, 2018, in revision; [8]    Löbling, T. I.; Borisov, O.; Haataja, J. S.; Ikkala, O.; Gröschel, A. H.; Müller, A. H. E. Nature Comms,  7, 12097, 2016; [9] J. S. Haataja, N. Houbenov, V. Aseyev, P. Fragouli, H. Iatrou, R. Sougrat, N. Hadjichristidis, O. Ikkala, Chem. Comm. 54, 1085, 2018.

Presentation (pdf - 4.35 Mi)


Atomic nuclei as building blocks of the interdisciplinary quantum many-body science

Monday, 2 July 2018, at 2:00 p.m. Chadwick Amphitheatre, ILL 4

Prof. Gianluca Colo
Dipartimento di Fisica, Universita` degli Studi and I.N.F.N.
Milano - Italy


Atomic nuclei are relevant for applications, and at the same time, they constitute a formidable intellectual challenge for scientists who are still striving to answer the fundamental question: how do the complex nuclear phenomena emerge from the interactions between the neutrons and protons? The nuclear many-body problem has many similarities with the electronic many-body problem, as recognised already long ago.

In this Colloquium, I will try to update this vision. I will first give a brief survey of the status of nuclear structure theory, and emphasise the role of Density Functional Theory (DFT) as the framework in which the mutual cross-fertilization between nuclear physics and physics of matter, or chemistry, may work at best. I will also discuss some applications of the most recent DFT-based theoretical models to the global ground-state properties of nuclei.

Then, I will focus on nuclear excitations and single out a few specific aspects. I will discuss the low-lying nuclear spectra, that play an important role to identify relevant nuclear correlations like those related to the coupling between single-particle motion and the vibrations or rotations of the nucleus as a whole. The comparison with the electron-phonon coupling in superconductors will be stressed.

Moving to the high-lying nuclear excitations, or giant resonances, I will discuss their importance to deduce from the experiment the so-called nuclear equation of state (EoS), that is, the relationship between pressure and density in nuclear matter. This also connects nuclear physics and the physics of a gas or a liquid.

Finally, a link will be set with the macroscopic scale of those "nuclei" that have dimensions of km, namely neutron stars. In neutron stars, the many-body physics under extreme conditions (high density) manifests itself. They are also good laboratories to study superfluidity, and matter under the highest magnetic fields that have been identified so far.

Presentation (pdf - 4.52 Mi)


Supra-molecular and Biomaterial Chemistry

Monday, 11 June 2018 at 2.00 pm in ILL Chadwick amphitheatre

Prof. Luisa De Cola
Professor at Institut de Science et d'Ingénierie Supramoléculaires, Strasbourg and KIT-INT, Karlsruhe, Germany

Despite the substantial progress that has been made in biomaterials synthesis and functionalization, the challenge of delivery in vivo in desired organs biomolecules or drugs and to mimic the ECM with implants that are able to reduce immunoresponse is still unmet.
Towards this aim, we reported a novel biocompatible hydrogel with the ability to release a migration-inducing factor, for the recruitment of stem cells [1]. The hydrogel is a composite made of breakable container –type materials able to respond to an external stimulus. In particular in the last 5 years we devoted much effort in the creation of “containers’ able to break in small fragments (<5 nm) by a redox reactions,[2] enzymatic degradation,[3] and pH. They can also be capsules in which large biomolecules such as enzymes and proteins can be entrapped and release on demand [4]. The hydrogels that contain such containers are formed in physiological conditions, without any catalyst and at room or at body temperature. They are perfectly biocompatible and can be made degradable. Cells are able to populate and proliferate in the matrices and even stem cells are able to grow and differentiate . Interestingly these soft materials can be injected as liquid and are able to solidify in few seconds or even in milliseconds in different tissues and organs.
Finally I wish to close my talk showing novel capsules that can be realized using a unique approach to template virus proteins to reconstruct virus-like particles. We use luminescent Pt(II)-complex amphiphiles, able to form supramolecular structures in water solutions, that can act as templates of viruses capsid proteins. The platinum assemblies can have different morphologies and extremely high emission of which the color depends on the assembly. Interestingly we are able to change the size and shape of the particles even though we use the same natural proteins. The obtained virus-like particles can be visualized by their intense emission at room temperature, generated by the self-assembly of the Pt(II)-complexes inside the capside [5].

[1] F. Fiorini, L. De Cola et al. Small, 2016, 12, 4881
[2] L. Maggini, L. De Cola  et al. Nanoscale, 2016, 8, 7240
[3] L. Maggini,  L. De Cola et al. Chem. Eu. J., 2016, 22, 3697
[4] E.A. Prasetyanto, L. De Cola et al. Angew. Chem. Int. Ed. 2016, 55, 3323.
[5] S. Sinn, L. De Cola et al. J. Am. Chem. Soc. 2018, DOI 10.1021/jacs.7b12447

Presentation (pdf - 19.14 Mi)

Diamond Light Source

Monday, 23 April 2018 at 2.00 pm, Chadwick Amphitheatre

Prof. Andrew Harrison
Chief Executive
Diamond Light Source
Harwell Science and Innovation Campus,
Didcot, Oxfordshire, OX11 0DE, UK

Diamond Light Source, the UK’s national synchrotron facility, will complete its third phase of construction later in 2018 with 32 operational beamlines. The new experimental capabilities of some of the recent additions to the beamline portfolio will be presented, together with complementary, integrated facilities for Cryo-EM and high-resolution TEM, and high throughput sample delivery systems developed for both macromolecular crystallography beamlines and XFEL endstations around the world. The rapid pace of development of all aspects of enabling technology for synchrotrons means that it is vital to have long-term plans to remain competitive. Diamond is planning a very significant upgrade to its machine, has a rolling upgrade programme for its beamlines, and is developing a strategy to address the increasing challenge of ‘big’ - and complex – data.  These developments will be outlined together with the broader challenge of ensuring the long-term sustainability both of Diamond and the increasing number of large-scale research infrastructures across Europe.

Presentation (pdf - 6.55 Mi)

Quantum Biology

Friday 6 April 2018 at 2.00, Chadwick Amphitheatre

Prof. Johnjoe McFadden
University of Surrey
Professor of Molecular Genetics, Associate Dean (International)
BSc (Biochemistry), PhD (Biochemistry)

Quantum mechanics and molecular biology were the two revolutionary scientific disciplines that grew out of the twentieth century. Quantum biology can be said to have been initiated by a physicist, Erwin Schrödinger, in his lecture, essay and book entitled “What in Life” (published in 1944) in which he proposed that heredity was based on non-trivial aspects of quantum mechanics. The book was very influential to molecular biology pioneers, such as James Watson and Francis Crick, who speculated that quantum tunnelling may be the driver for mutation in DNA. This idea was given a firm theoretical foundation by the Swedish physicist Per-Olov Löwdin in the 1960’s; but thereafter the field of quantum biology largely languished; albeit with occasional bursts of interest, such as the speculation that consciousness is based on quantum mechanics, stimulated by Roger Penrose’s book, “The Emperor’s New Mind” in 1989. However, the twenty-first century has seen a revival of quantum biology with the arrival of new experimental evidence of quantum mechanical effects in a range of biological phenomena such as photosynthesis and enzyme action. In this talk I will provide an introduction to quantum biology, returning to Schrödinger’s original insight that quantum phenomena may be found in biological processes that involve very small numbers of molecules. I will review the kinds of biological phenomena that may be subject to these quantum stochastic effects and present some recent experimental evidence that proton tunnelling is involved in mutation as well as highlighting areas for future research.

Presentation (pdf - 5.38 Mi)

SmartGrids: Stakes, Research Needs and Opportunities for Energy Transition

Friday, 23 March 2018 at 2.00 pm, Chadwick Amphitheatre

Prof. Nourredine Hadj-Said
Director GIE-IDEA - G2Elab
Grenoble Electrical Engineering
UGA Saint Martin d'Hères

Among the technical objectives of the SmartGrid concept, one can mention an increased integration and management of distributed generation as well as PHEV (Plug-in Hybrid and Electric Vehicles) in the best economical and security conditions, an increased participation of consumers (concept of active consumer and optimization of consumption), a reduced environmental impact of the whole electricity supply system (reducing losses, improving energy efficiency, among others), and an improved power quality and overall system security for examples.  The field of expected achievements is as broad as efficient devices/structures for interconnecting DGs (Distributed Generation), control and supervision, energy chain optimization, reduction of peak consumption, anticipation of equipment failures and self-healing to manage outages and improve network resilience, etc.

The extent of technologies to be developed for reaching these objectives encompasses several areas that include generating and storage technologies, information and communication technologies, new monitoring and control devices, smart equipment for fault management, advanced forecasting tools, etc. For the various technologies, some specific technology enablers in the process of innovation and expected breakthroughs play a key role in SmartGrids.  Examples of the key roles for the advanced energy materials are PV (Photovoltaic), storage technologies, power electronics components and new generation of sensors needed to enhance distribution grids monitoring.

The presentation will address the advent of SmartGrids, solutions being developed to meet the increasing complexity of the whole electrical system and the opportunities offered for the energy transition. It will cover both up to date research and development in the field of SmartGrids and industrial applications including some examples on large scale pilot projects for SmartGrids.

Presentation (pdf - 18.84 Mi)