Relative Entropy from Coherent States in Black Hole Thermodynamics and Cosmology

The aim of this work is to study the role of relative entropy in the thermodynamics of black holes and cosmological horizons. We adapt some recent results on the relative entropy of coherent excitations of the vacuum, to find the variation of generalised entropy of static and dynamical black holes and for cosmological horizons. We review the argument for static black holes by Hollands and Ishibashi (2019) with simple modifications. We link the variation of relative entropy to the growth of the horizon using a conservation law for the stress-energy tensor, and we recover the known results. We then study the application of the same framework to the case of dynamical horizons. We study in detail the case of Vaidya spacetime, and we find that a notion of black hole entropy naturally emerges, equals to one-fourth of the area of the dynamical horizon. In the case of dynamical black holes we find an additional term, which is not present in the static case, and that represents the work done on the black hole. We finally show in a simple case that it is possible to follow the same scheme to assign an entropy to the horizons emerging in cosmological scenarios.Comment: Master Thesis, defended on July 2020 at the University of Genova. Thesis supervisor: Nicola Pinamonti and Pierantonio Zangh\`i. Results on the relative entropy for dynamical holes appeared generalised in a subsequent pape

Asymptotic Safety in Lorentzian quantum gravity

We report on a recently introduced Functional Renormalization Group (RG) Equation, and we apply it to quantum gravity in Lorentzian spacetimes. While the RG flow is state-dependent, it is possible to evaluate state and background independent contributions to the flow. Taking into account only these universal terms, the RG flow exhibits a non-trivial fixed point in the Einstein-Hilbert truncation, providing a mechanism for Asymptotic Safety in Lorentzian quantum gravity

Lorentzian Wetterich equation for gauge theories

In a recent paper, with Drago and Pinamonti we have introduced a Wetterich-type flow equation for scalar fields on Lorentzian manifolds, using the algebraic approach to perturbative QFT. The equation governs the flow of the average effective action, under changes of a mass parameter k. Here we introduce an analogous flow equation for gauge theories, with the aid of the Batalin-Vilkovisky (BV) formalism. We also show that the corresponding average effective action satisfies an extended Slavnov-Taylor identity in Zinn-Justin form. We interpret the equation as a cohomological constraint on the functional form of the average effective action, and we show that it is consistent with the flow.Comment: 42 page

Local solutions of RG flow equations from the Nash-Moser theorem

We prove local existence of solutions of a functional Renormalisation Group equation for the effective action of an interacting quantum field theory, when a suitable Local Potential Approximation is considered. To obtain this equation in a Lorentzian setting, a quantum state for the theory is selected, and a regulator consisting in a mass is added to the action. The flow equation for mass rescalings is then studied using the renown Nash-Moser theorem

Decellularized colorectal cancer matrix as bioactive microenvironment for in vitro 3D cancer research

Three-dimensional (3D) cancer models are overlooking the scientific landscape with the primary goal of bridging the gaps between two-dimensional (2D) cell cultures, animal models and clinical research. In this thesis, we describe an innovative tissue engineering approach applied to colorectal cancer (CRC) starting from decellularized human biopsies in order to generate an organotypic 3D bioactive model. This in vitro 3D system recapitulates the ultrastructural environment of native tissue as demonstrated by histology, immunohistochemistry, immunofluorescence and scanning electron microscopy analyses. Mass spectrometry of proteome and secretome confirmed a different stromal composition between decellularized healthy mucosa and CRC in terms of structural proteins (COL1A1, COL1A2, and COL3A1) and secreted proteins such as DEFA3. Importantly, we proved that our 3D acellular matrices retained their biological properties: using CAM assay, we observed a decreased angiogenic potential in decellularized CRC compared with healthy colon mucosa, caused by direct effect of DEFA3. In addition, we demonstrated that following a 5 days of recellularization with HT-29 cell line, the 3D tumor matrices induced an over-expression of IL-8, a DEFA3-mediated pathway and a mandatory chemokine in cancer growth and proliferation, compared with recellularized healthy mucosa and 2D conventional culture model. Given the biological activity maintained by the scaffolds after decellularization, we believe this approach is a powerful tool for future pre-clinical research and screenings

People, Texts and Artefacts: Cultural Transmission in the Norman Worlds of the Eleventh and Twelfth Centuries

This volume is based on two international conferences held in 2013 and 2014 at Ariano Irpino, and at Emmanuel College, Cambridge. It contains essays by leading scholars in the field. Like the conferences, the volume seeks to enhance interdisciplinary and international dialogue between those who work on the Normans and their conquests in northern and southern Europe in an original way. It has as its central theme issues related to cultural transfer, treated as being of a pan-European kind across the societies that the Normans conquered and as occurring within the distinct societies of the northern and southern conquests. These issues are also shown to be an aspect of the interaction between the Normans and the peoples they subjugated, among whom many then settled

A Finite element model of tactile flow for softness perception

Touch is an extremely dynamic sense. To take into account this aspect, it has been hypothesized that there are mechanisms in the brain that specialize in processing dynamic tactile stimuli, in a way not too dissimilar from what happens for optical flow in dynamic vision. The concept of tactile flow, related to the rate of expansion of isostrain volumes in the human fingerpad, was used to explain some perceptual illusions as well as mechanisms of human softness perception. In this paper we describe a computational model of tactile flow, and apply it to a finite element model of interaction between deformable bodies. The shape and material properties of the bodies are modeled from those of a human fingertip interacting with specimens with different softness properties. Results show that the rate of expansion of isostrain volumes can be used to discriminate different materials in terms of their softness characteristics

Intrinsic and Extrinsic Modulators of the Epithelial to Mesenchymal Transition: Driving the Fate of Tumor Microenvironment

The epithelial to mesenchymal transition (EMT) is an evolutionarily conserved process. In cancer, EMT can activate biochemical changes in tumor cells that enable the destruction of the cellular polarity, leading to the acquisition of invasive capabilities. EMT regulation can be triggered by intrinsic and extrinsic signaling, allowing the tumor to adapt to the microenvironment demand in the different stages of tumor progression. In concomitance, tumor cells undergoing EMT actively interact with the surrounding tumor microenvironment (TME) constituted by cell components and extracellular matrix as well as cell secretome elements. As a result, the TME is in turn modulated by the EMT process toward an aggressive behavior. The current review presents the intrinsic and extrinsic modulators of EMT and their relationship with the TME, focusing on the non-cell-derived components, such as secreted metabolites, extracellular matrix, as well as extracellular vesicles. Moreover, we explore how these modulators can be suitable targets for anticancer therapy and personalized medicine

Correlated-photon imaging at 10 volumetric images per second

The correlation properties of light provide an outstanding tool to overcome the limitations of traditional imaging techniques. A relevant case is represented by correlation plenoptic imaging (CPI), a quantum-inspired volumetric imaging protocol employing spatio-temporally correlated photons from either entangled or chaotic sources to address the main limitations of conventional light-field imaging, namely, the poor spatial resolution and the reduced change of perspective for 3D imaging. However, the application potential of high-resolution imaging modalities relying on photon correlations is limited, in practice, by the need to collect a large number of frames. This creates a gap, unacceptable for many relevant tasks, between the time performance of correlated-light imaging and that of traditional imaging methods. In this article, we address this issue by exploiting the photon number correlations intrinsic in chaotic light, combined with a cutting-edge ultrafast sensor made of a large array of single-photon avalanche diodes (SPADs). This combination of source and sensor is embedded within a novel single-lens CPI scheme enabling to acquire 10 volumetric images per second. Our results place correlated-photon imaging at a competitive edge and prove its potential in practical applications.Comment: 13 pages, 6 figure