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Viewing upcoming talks containing the keyword: 8
Physics and Astronomy Colloquia
Speaker: Professor Isabelle Ledoux-Rak (Laboratoire de Photonique Quantique et MolÃ©culaire, Ecole Normale SupÃ©rieure de Cachan, France)
2015 Holweck Prize Lecture
Joint Physics/Chemistry Colloquium
The emergence of molecular photonics at the cross-roads of physics, chemistry and device engineering has being triggered by increasing demand in various fields such as high bitrate telecommunications, sensors, and bio-imaging. The wealth of molecular structures and the exploitation of their functional and structural flexibility opens-up new, exciting horizons for this area of research. Designing highly efficient molecules with optimised photonic properties remains a major challenge after 50 years of continuous development, based on fruitful and interdisciplinary cooperation between chemists and physicists.
In this lecture, the principles of molecular engineering for quadratic nonlinear optics will be discussed, with an emphasis on metal complexes and lanthanide derivatives, on nonlinear optical characterization methods. This will be followed by a review of intermolecular interactions and various orientation methods, in order to bridge the gap between molecules to materials, towards a wide range of applications. Finally, perspectives will be provided on molecular photonics towards device–rel.
On: September 16, 2015 From: 17h15 To: 18h30View talk
Physics and Astronomy Colloquia
Speaker: Prof James F Scott (University of St Andrews)
Multiferroics are crystals that simultaneously exhibit ferromagnetism and ferroelectricity (and usually ferroelasticity, which is hysteretic stress/strain). In some cases the ferromagnetism is actually created by the ferroelectricity, by causing the spins to cant [via Dzyaloshinskii-Moriya anisotropic exchange: P.(L x M)]. These materials have become very popular in part due to the interesting new physics, previously neglected because the effects require very low crystal symmetry, and because they offer the promise of new kinds of memory devices, including voltage-tunable magnetic tunnel junctions and four-state memories (+P,+M; +P,-M; -P,+M; -P,-M) which would be vastly superior to the usual binary (0,1) Boolean algebra. At St. Andrews I am experimentally studying GaFeO3 and Pb[Fe(1/2)Ta(1/2)]y[Ti(1/2)Zr(1/2)(1-y)]O3.
On: September 25, 2015 From: 10h00 To: 11h00View talk
Speaker: Dr Roger De Souza (RWTH Aachen)
There is renewed interest in the behaviour of point defects in bulk SrTiO3 and at its extended defects due to the material's possible application in all-oxide electronics and as a memristive device. The combination of 18O/16O exchange and Secondary Ion Mass Spectrometry (SIMS) analysis constitutes a powerful tool for probing the behaviour of oxygen vacancies in oxides. In this contribution, after a brief introduction to the technique and its capabilities and limitations, I demonstrate the application of this method to investigating the behaviour of oxygen vacancies in SrTiO3 and at its extended defects (dislocations, surfaces, hetero-interfaces). Three systems will be examined: (1) single crystal SrTiO3 substrates; (2) low-angle grain boundaries in SrTiO3 comprising periodic arrays of edge dislocations; and (3) thin films samples. In general, I will emphasize the need to combine experimental and computational approaches, and I will draw attention to current challenges and outstanding problems.
On: September 30, 2015 From: 15h30 To: 16h30View talk
Cond Mat Seminars
Speaker: Graham Bruce (St Andrews)
Single-atom-resolved detection of ultracold atoms in optical lattices using quantum-gas microscopes has enabled a new generation of experiments in the field of quantum simulation. While such devices have been realised with bosonic species, a fermionic quantum-gas microscope has proven more challenging. We recently demonstrated single-site- and single-atom-resolved florescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope setup using electromagnetically-induced-transparency cooling . We detected on average 1000 fluorescence photons from each single atom within 1.5 s, while keeping them close to the vibrational ground state of the optical lattice.
Our fermionic quantum-gas microscope will provide the possibility to probe quantities that are difficult to access directly, such as spin-spin-correlation functions or string-order. It would allow the study of out-of-equilibrium dynamics, the spreading of correlations and the build-up of entanglement in many-particle fermionic quantum systems. It could perform quantum simulation of the Fermi-Hubbard model, which is conjectured to capture the key mechanism behind high-temperature superconductors.
 E. Haller, J. Hudson, A. Kelly, D. Cotta, B. Peaudecerf, G. D. Bruce, and S. Kuhr, Single-atom imaging of fermions in a quantum-gas microscope, Nature Physics 11, 738-742 (2015)
On: September 30, 2015 From: 13h00 To: 14h00View talk
Physics and Astronomy Colloquia
Speaker: Professor Caroline Terquem (University of Oxford)
As of today, about 2000 objects have received the label of "confirmed" extrasolar planets. Recent observations indicate that a significant number of the Jupiter-type planets with very short periods are on an orbit which is inclined with respect to the equatorial plane of their host star. This is difficult to explain in the context of planets forming in a protostellar disc assumed to lie in that plane. In this talk, I will review different mechanisms that have been proposed to account for the observed orbital inclinations. I will then focus on the case of an orbit inclined with respect to the disc, and will discuss the interaction between the planet and the disc in this context and the subsequent orbital evolution.
On: October 2, 2015 From: 10h00 To: 11h00View talk
Proline conformation in intrinsically unfolded proteins : sense or nonsense? (Video Conference from Edinburgh)
Speaker: Guy Lippens (University of Lille)
The conformational state of distinct prolines can determine the folding of a protein but equally other biological processes when coupled to a conformation sensitive secondary reaction. The importance of proline conformation is underscored by the interaction of many of those proteins with different prolyl cis/trans isomerases.
We will present our results on the proline conformation in two examples, the neuronal protein Tau and the non-structural protein NS5A of the HCV virus. For Tau, a number of molecular diseases including Alzheimer’s disease (AD) and Traumatic Brain injury (TBI) were recently qualified as “cistauois” (Kondo et al. 2015) and would imply a cis conformation for the pThr213-Pro232 prolyl bond. For NS5A, the molecular interaction between NS5A and the host cyclophilin is essential for the viral RNA replication, and implies a small motif centered on a particular proline residue (Dujardin et al., 2015).
Using NMR spectroscopy as an analytical tool, we have investigated the conformational aspects of the different prolines in both systems, and will discuss the possible interaction with prolyl cis/trans isomerases such as Pin1and FKBP52 (Giustiniani et al., PNAS 2014).
Dujardin et al., A Proline-Tryptophan Turn in the Intrinsically Disordered Domain 2 of NS5A Protein Is Essential for Hepatitis C Virus RNA Replication. , J Biol Chem. 2015 Jul 31;290(31):19104-20.
Kondo et al., Antibody against early driver of neurodegeneration cis P-tau blocks brain injury and tauopathy., Nature. 2015 Jul 23;523(7561):431-6.
Giustiniani et al., Immunophilin FKBP52 induces Tau-P301L filamentous assembly in vitro and modulates its activity in a model of tauopathy. Proc Natl Acad Sci U S A. 2014 Mar 25;111(12):4584-9.
On: October 7, 2015 From: 15h30 To: 16h30View talk