Thermometry at the Nanoscale: Light in Action
L. D. Carlos

Physics Department and CICECO-Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal

The emergence of luminescent nanothermometry during the last decade opened up the possibility of measure thermal flows at spatial scales below 1 μm, unreachable by conventional electrical methods [1]. In fact, diverse phosphors capable of providing a contactless thermal reading through their light emission properties have been examined, e.g., polymers, DNA or protein conjugated systems, organic dyes, quantum dots, and trivalent lanthanide ions incorporated in organic-inorganic hybrids, multifunctional heater-thermometer nanoplatforms, upconverting, downconverting and downshifting nanoparticles.

In the last couple of years, the focus of luminescence thermometry has gradually shifted from the fabrication of more sensitive nanoarchitectures towards the use of the technique as a tool for thermal bioimaging and for the unveiling of properties of the thermometers themselves and of their local surroundings [2-5].

After a general historical perspective of the work done on ratiometric luminescent nanothermometers since the explosion of the field at one decade ago, the lecture will be focused on recent examples illustrating the potential of the technology.

References

1 C. D. S. Brites, A. Millán, L. D. Carlos, in Handbook on the Physics and Chemistry of Rare Earths, J.-C. Bünzli, V. K. Pecharsky, Eds., Amsterdam: Elsevier Science B.V., Vol. 49 (2016), 339–427.
2 R. Piñol et al., ACS Nano 9 (2015) 3134–3142.
3 E. C. Ximendes et al., Nano Lett. 16 (2016) 1695–1703.
4 C. D. S. Brites et al., Nature Nanotech. 11 (2016) 851–857.
5. C. D. S. Brites et al., Nano Lett., 2017, 17, 4746-4752.

Les enjeux de santé publique et de développement durable conduisent à intensifier l’utilisation de protéines végétales notamment dans les secteurs de biens de consommation comme l’industrie pharmaceutique, l’agro-alimentaire et les cosmétiques. La levée récente de certains verrous technologiques permet aujourd’hui la purification industrielle de protéines végétales issues de tourteaux provenant de la production d’huiles végétales. Ces protéines sont valorisables comme substituts aux graisses saturées dans la structuration d’huiles à destination de la consommation humaine. Le manque de texture d’huiles végétales insaturées peut être compensé par ces protéines jouant le rôle de stabilisants et de gélifiants dans les émulsions. Nous nous intéressons aux propriétés fonctionnelles des protéines de blé, de tournesol et de colza, en volume et aux interfaces. Nous avons montré que des gels de protéines de tournesol avec des élasticités modulables sont obtenus par dénaturation thermique. La dynamique de formation de films protéiques aux interfaces fluides a été étudiée en combinant des mesures de tensiométrie, de viscoélasticité dilatationnelle et d’ellipsométrie. Les mesures sur plusieurs ordres de grandeurs en concentrations et en temps mettent en évidence différents régimes de structuration associés à différentes dynamiques d’adsorption pour les trois protéines de blé, de tournesol et de colza étudiées. Nous discutons également le rôle de la flexibilité des protéines dans ces différents régimes de structuration.

Mots clés : Protéines végétales, Gluten, Tournesol, Colza, Interface, Gel, Tension de surface dynamique, Rhéologie, Rhéologie interfaciale, Ellipsométrie.


Challenges of public health and sustainable development trend to intensify the use of vegetables proteins, particularly in consumer goods sectors such as pharmaceutical, food and cosmetics industries. The recent overcome of technical limitation allows the industrial purification of vegetables proteins derived from meal made by vegetable oils production. These proteins are valuable as substitutes for saturated fats in structuring oils for human consumption. The lack of unsaturated vegetable oil texture can be reduced by these proteins acting as stabilizers and gelling agents in emulsions. We are interested in the functional properties of wheat, sunflower and rapeseed proteins, by volume and at interfaces. We have shown that sunflower protein gels with modulable elasticities are obtained by thermal denaturation. In addition, we studied the dynamics of protein film formation at fluid interfaces by combining measurements of tensiometry, dilatational viscoelasticity and ellipsometry. We highlight different structuring regimes and discuss the role of protein flexibility in this structuring.

Keywords: Plant proteins, Gluten, Sunflower, Rapeseed, Interface, Gel, Dynamic surface tension, Rheology, Interfacial Rheology, Ellipsometry.

The nitrogen-vacancy (NV) defect in diamond is a popular system for quantum sensing and imaging, especially for nanoscale magnetometry [1,2]. In this talk, I will present a particular implementation based on ensembles of NV defects in a bulk diamond crystal. I will show that this approach allows wide-field imaging of not only magnetic fields but also electric and strain fields, with access to the full vector/tensor information. I will illustrate these capabilities through three applications: imaging of the current flow in graphene [3]; of surface bend bending in all-diamond devices [4]; and of elastic deformations in carbon microstructures [5]. Finally, I will discuss an anomaly, still unresolved to date, observed in NV magnetometry measurements of the field from current-carrying metallic wires, which seems to suggest that the current density is partly delocalized in the insulating diamond, several microns outside the metal [6].

References
[1] L. Rondin, J.-P. Tetienne, T. Hingant, J.-F. Roch, P. Maletinsky, V. Jacques, “Magnetometry with NV centers in diamond”, Reports on Progress in Physics 77, 056503 (2014).
[2] J.-P. Tetienne, T. Hingant, J.-V. Kim, L. Herrera Diez, J.-P. Adam, K. Garcia, J.-F. Roch, S. Rohart, A. Thiaville, D. Ravelosona, V. Jacques, “Nanoscale imaging and control of domain wall hopping with a nitrogen-vacancy center microscope”, Science 344, 1366 (2014).
[3] J.-P. Tetienne, N. Dontschuk, D. A. Broadway, A. Stacey, D. A. Simpson, L. C. L. Hollenberg, “Quantum imaging of current flow in graphene”, Science Advances 3:e1602429 (2017).
[4] D. A. Broadway, N. Dontschuk, A. Tsai, S. E. Lillie, C. T.-K. Lew, J. C. McCallum, B. C. Johnson, M. W. Doherty, A. Stacey, L. C. L. Hollenberg, J.-P. Tetienne, “Spatial mapping of band bending in semiconductor devices using in situ quantum sensors”, Nature Electronics 1, 502 (2018).
[5] D. A. Broadway, B. C. Johnson, M. S. J. Barson, S. E. Lillie, N. Dontschuk, D. J. McCloskey, A. Tsai, T. Teraji, D. A. Simpson, A. Stacey, J. C. McCallum, J. E. Bradby, M. W. Doherty, L. C. L. Hollenberg, J.-P. Tetienne, “Microscopic imaging of elastic deformation in diamond via in-situ stress tensor sensors”, arXiv:1812.01152 (2018).
[6] J.-P. Tetienne, N. Dontschuk, D. A. Broadway, S. E. Lillie, T. Teraji, D. A. Simpson, A. Stacey, L. C. L. Hollenberg, “Apparent delocalization of the current density in metallic wires observed with diamond nitrogen-vacancy magnetometry”, Physical Review B 99, 014436 (2019).

We will develop geometric techniques for counting BPS states in five-dimensional gauge theories engineered by M theory on a toric Calabi-Yau threefold. The problem is approached by studying framed 3d-5d wall-crossing in presence of a single M5 brane wrapping a special Lagrangian submanifold L. The spectrum of 3d-5d BPS states is encoded by the geometry of the manifold of vacua of the 3d-5d system, which further coincides with the mirror curve describing moduli of the Lagrangian brane. The information about the BPS spectrum is extracted from the geometry of the mirror curve by construction of a nonabelianization map for the exponential networks. We will start by reviewing exponential networks, sketch the computation for a particular toric Calabi-Yau threefold. Finally, we will finish by remarking about several aspects of enumerative invariants for the Calabi-Yau threefolds.

Condensed He-4 is a fascinating system because it exhibits quantum properties at the macroscopic scale. The most famous of these is probably the transition of the liquid into a so called superfluid state when cooled down below 2.17 K at vapor pressure. I will present and discuss experiments investigating the metastable phases of liquid and solid He-4. Achieving a metastable phase of (for instance) liquid 4 He consists in bringing a sample of liquid 4 He at a temperature and a pressure (or density) where the thermal equilibrium phase is not the liquid phase but rather the solid one or the gaseous one. We experimentally realize these states by focusing an acoustic wave (pressure/density wave) in the bulk of the liquid (solid). We measure the local density within the metastable state thanks to an optical time-resolved interferometric method. In both metastable liquid and solid He-4, we have observed instabilities at densities which are not compatible with theoretical predictions. These results are interesting because metastable liquid He-4 is a model system to study homogeneous cavitation and because solid metastable solid He-4 is a potential candidate for a hypothetical (not yet discovered) supersolid state of matter.

$T^3$ in Grande Ourse*

*tea/coffee/biscuits break around 4pm

Vivian will entertain us pedagogically with The Hubble Tension:
Local measurements of the Hubble parameter (the current expansion rate of our
Universe) from type 1a supernovae disagree at 4.4sigma with the value inferred from a
ΛCDM fit to the cosmic microwave background (CMB), with local measurements
suggesting a higher value. This discrepancy is not easily circumvented by any obvious
systematic effect in either measurement, and so increasing attention is given to the
possibility that this “Hubble tension” indicates new physics beyond ΛCDM. In this tea-time talk, I
would like to (pedagogically) review how one can measure the Hubble constant thanks to
the classical ``distance ladder’’ and the CMB. I will argue that discrepancy in the
Hubble parameter should be interpreted as a tension between our understanding
of the early and late universe cosmology, rather than a tension between two
datasets. I will then explain why it is not trivial (and therefore interesting) to solve this
discrepancy and discuss promising solutions (Early Dark Energy, additional
relativistic degrees of freedom, phantom dark energy...).