Entropy Production of Doubly Stochastic Quantum Channels

We study the entropy increase of quantum systems evolving under primitive, doubly stochastic Markovian noise and thus converging to the maximally mixed state. This entropy increase can be quantified by a logarithmic-Sobolev constant of the Liouvillian generating the noise. We prove a universal lower bound on this constant that stays invariant under taking tensor-powers. Our methods involve a new comparison method to relate logarithmic-Sobolev constants of different Liouvillians and a technique to compute logarithmic-Sobolev inequalities of Liouvillians with eigenvectors forming a projective representation of a finite abelian group. Our bounds improve upon similar results established before and as an application we prove an upper bound on continuous-time quantum capacities. In the last part of this work we study entropy production estimates of discrete-time doubly-stochastic quantum channels by extending the framework of discrete-time logarithmic-Sobolev inequalities to the quantum case.Comment: 24 page

Rapid high-resolution mid-IR imaging for molecular spectral histopathological diagnosis of oesophageal cancers

This thesis is written as part of Marie-Curie international training network called Mid-TECH. Mid-TECH is devoted to improve mid-infrared (MIR) technologies and consists of 15 PhD projects across European universities. This thesis aims to evaluate new technologies and concepts developed by the project partners for their applicability in a biomedical setting. The clinical problem to diagnose oesophageal cancers serves as an example case for this. The thesis consists of three projects all aimed to further the understanding of MIR hyperspectral imaging. The first project discussed in chapter 5 demonstrates the use of an new design of the United States Airforce resolution test chart. The new test chart is developed to evaluate spatial resolution of MIR hyperspectral imaging systems. The use of different materials is discussed and the new iteration of the thes chart is evaluated using a state of the art MIR imaging system. The second project discussed in chapter 6 evaluates the technical differences and their practical implications of discrete frequency MIR imaging systems compared to continuum source systems. A comparison of the two system types is drawn for imaging paraffin embedded sections of oesophageal tissue. Furthermore the effect of chemically removing the paraffin from the sample is compared to a mathematical correction algorithm. The system performance is compared based on their ability to differentiate healthy from cancerous tissue. The third project discussed in chapter 7 evaluates the potential of a new MIR detection scheme called upconversion in combination with a novel MIR laser source. It is a prove of concept study demonstrating that those two technologies can be deployed to do hyperspectral imaging in the MIR.European Commissio

Relative Entropy Convergence for Depolarizing Channels

We study the convergence of states under continuous-time depolarizing channels with full rank fixed points in terms of the relative entropy. The optimal exponent of an upper bound on the relative entropy in this case is given by the log-Sobolev-1 constant. Our main result is the computation of this constant. As an application we use the log-Sobolev-1 constant of the depolarizing channels to improve the concavity inequality of the von-Neumann entropy. This result is compared to similar bounds obtained recently by Kim et al. and we show a version of Pinsker's inequality, which is optimal and tight if we fix the second argument of the relative entropy. Finally, we consider the log-Sobolev-1 constant of tensor-powers of the completely depolarizing channel and use a quantum version of Shearer's inequality to prove a uniform lower bound.Comment: 21 pages, 3 figure

Characterization of Skin-Resident Microbiota in Inflammatory Cutaneous Disease

The skin is the largest organ in the human body, approximately 1.5 to 2 m2 in area, and serves as a crucial physical and immune barrier from our environment. Yet, the skin is home to billions of microorganisms inhabiting a multitude of folds, invaginations, and specialized niches that sustain microscopic life (Grice and Segre, 2011; Scharschmidt and Fischbach, 2013). We are not teeming with bugs so much as we are irrevocably intertwined with microbiota such that, throughout evolutionary history, these bacteria, fungi, and viruses have become invaluable parts of our physiology, cooperatively acting as a hidden organ. The microbiota colonizing the skin, their genetic material, and their microenvironments are collectively referred to as the skin microbiome (Marchesi and Ravel, 2015). Most microorganisms are not pathogens. Rather, the majority of microorganisms living on their hosts are benign and, in some cases, beneficial, performing functions vital for host physiology and homeostasis. Scientists are beginning to unravel how the skin microbiome is interfacing with different physiological processes of the mammalian host. Microbiota living on us, but also residing within deeper layers of the skin, contribute to host inflammation, epidermal barrier function, and immunity through feedback mechanisms with our immune cells (Grice and Segre, 2011). Microbiota even contribute to host defense through the production of bactericidal factors (Iacob et al., 2018; Jacobs et al., 2017; Nakatsuji et al., 2017; Zheng et al., 2020). Microbiome researchers are interested in understanding these mechanisms that link commensal microbes with host biology and how these interactions contribute to host health or disease. This thesis aims to characterize resident skin microbiota communities the context of inflammatory cutaneous disease

Looking at Shadows: Four French Texts in English Translation

This project present four French texts in English translation that share the theme of loss. This theme is perhaps one of the most poignant and relevant; loss is an experience that every human will encounter, and as people we continue across time to grapple with what it means for us and how to deal with it. These four texts will bring the perspectives of four authors to light in English. When we study how other countries and cultures deal with common human issues, we are able to gain new views on these issues. This project will make these texts accessible to English speakers and allow them to study the messages contained in them. I have chosen four texts from different time periods, by different writers, and of different styles to give the reader a greater sampling of this theme across French literature. The texts to be translated are: Demain dès l’aube by Victor HUGO Le Pont Mirabeau by Guillaume APOLLINAIRE La Folle by Guy de MAUPASSANT La Maison face à la mer by Marie-Célie AGNAN

New insight on the Sivers transverse momentum dependent distribution function

Polarised Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes allow to study Transverse Momentum Dependent partonic distributions (TMDs), which reveal a non trivial three dimensional internal structure of the hadrons in momentum space. One of the most representative of the TMDs is the so-called Sivers function that describes the distribution of unpolarized quarks inside a transversely polarized proton. We present a novel extraction of the Sivers distribution functions from the most recent experimental data of HERMES and COMPASS experiments. Using suitable parametrizations, within the TMD factorization scheme, and a simple fitting strategy, we also perform a preliminary exploration of the role of the proton sea quarks.Comment: Talk delivered by M. Boglione at SPIN2010, September 27-October 2, 2010, Juelich, Germany. Left panel of Fig. 5 replace