Low dimensional nano-systems are promising candidates for manipulating, controlling and capturing photons with large sensitivities and low-noise. If quantum engineered to tailor the energy of the localized electrons across the desired frequency range, they can allow devising efficient quantum sensors across any frequency domain. Here, we exploit the rich few-electrons physics to develop millimeter-wave nanodetectors employing as sensing element an InAs/InAs0.3P0.7 quantum-dot nanowire, embedded in a single electron transistor. Once irradiated with light the deeply localized quantum element exhibits an extra electromotive force driven by the photothermoelectric effect, which is exploited to efficiently sense radiation at 0.6 THz with a noise equivalent power < 8 pWHz-1/2 and almost zero dark current. The achieved results open intriguing perspectives for quantum key distributions, quantum communications and quantum cryptography at terahertz frequencies.

Euclidean D-branes wrapped on non-trivial cycles of a Calabi-Yau threefold are known to affect the metric on the hypermultiplet moduli space determining the effective action of type II strings on such manifolds. After reviewing the existing results on the instanton corrected metric following from a combination of constraints imposed by supersymmetry and dualities, I'll show how the D-instanton effects can be computed by a direct worldsheet approach. It required solving several conceptual and technical problems and can now be extended to compactifications with lower supersymmetry. The talk is based on joint work with A. Sen and B. Stefanski.

The last decade has seen a spectacular development of genomic physics both in bacteria and eukaryotes. This is due in large part to the development of experimental techniques, which allow to probe (i) the motion of nucleic acids (chromosomal DNA and RNA) in vivo by means of microscopy techniques and (ii) the interactions of these nucleic acids with other actors of the cell (like proteins and molecular motors) by means of high-throughput sequencing techniques. I will focus on three different processes : (i) the modeling of translation with a ballistic model describing the motion of ribosomes on messenger RNA, (ii) the physical mechanism of liquid-liquid phase separation, which is found to be universally spread in the cells to increase, locally and transiently, the concentration of a molecular actor (proteins, RNA etc.). We illustrate this process with the example of the bacterial DNA segregation where liquid-liquid phase separation is used to increase the local concentration in order to catalyze ATP hydrolysis. Finally (iii) I give a general framework on how polymer physics can help to infer the organization of DNA in vivo from microscopy and high-throughput sequencing experiments and apply it to the modeling of bacterial DNA in Escherichia coli and to the epigenetic regulation via polycomb domains in Drosophila.

Zinc is often regarded as an alternative to magnesium p-type dopants in gallium nitride. However, besides many theoretical predictions, at present, there are poor data on experimentally revealed p-type conductivity and evaluation of Zn activation energy by means of electrical transport measurements. In this paper, ammonothermal crystallization of bulk GaN:Zn monocrystals is reported. Despite a high doping level of Zn (up to 2 × 1020 cm−3), p-type conductivity with hole concentration as low as of 4 × 1015 cm−3 at room temperature and mobility about 3 cm2/V s was observed. A deep nature of the Zn acceptor was proved, as the ionization energy can exceed 260 meV. In addition, conduction in the impurity band appeared at temperatures as high as room temperature