Scalar Asymptotic Charges and Dual Large Gauge Transformations

In recent years soft factorization theorems in scattering amplitudes have been reinterpreted as conservation laws of asymptotic charges. In gauge, gravity, and higher spin theories the asymptotic charges can be understood as canonical generators of large gauge symmetries. Such a symmetry interpretation has been so far missing for scalar soft theorems. We remedy this situation by treating the massless scalar field in terms of a dual two-form gauge field. We show that the asymptotic charges associated to the scalar soft theorem can be understood as generators of large gauge transformations of the dual two-form field. The dual picture introduces two new puzzles: the charges have very unexpected Poisson brackets with the fields, and the monopole term does not always have a dual gauge transformation interpretation. We find analogs of these two properties in the Kramers-Wannier duality on a finite lattice, indicating that the free scalar theory has new edge modes at infinity that canonically commute with all the bulk degrees of freedom.Comment: 16 pages, 2 figure

Dynamical Surface Gravity in Spherically Symmetric Black Hole Formation

We study dynamical surface gravity in a general spherically symmetric setting using Painlev\'{e}-Gullstrand (PG) coordinates. Our analysis includes several definitions that have been proposed in the past as well as two new definitions adapted to PG coordinates. Various properties are considered, including general covariance, value at extremality, locality and static limit. We illustrate with specific examples of "dirty" black holes that even for spacetimes possessing a global timelike Killing vector, local definitions of surface gravity can differ substantially from "non-local" ones that require an asymptotic normalization condition. Finally, we present numerical calculations of dynamical surface gravity for black hole formation via spherically symmetric scalar field collapse. Our results highlight the differences between the various definitions in a dynamical setting and provide further insight into the distinction between local and non-local definitions of surface gravity.Comment: Final version to appear in Phys. Rev. D. Slight name change, further improvements to numerics and presentation, 25 pages, 7 figure

Vertex Expansion for the Bianchi I model

A perturbative expansion of Loop Quantum Cosmological transitions amplitudes of Bianchi I models is performed. Following the procedure outlined in [1,2] for isotropic models, it is shown that the resulting expansion can be written in the form of a series of amplitudes each with a fixed number of transitions mimicking a spin foam expansion. This analogy is more complete than in the isotropic case, since there are now the additional anisotropic degrees of freedom which play the role of `colouring' of the spin foams. Furthermore, the isotropic expansion is recovered by integrating out the anisotropies.Comment: 15 pages, 2 figure

Color Fields on the Light-Shell

We study the classical color radiation from very high energy collisions that produce colored particles. In the extreme high energy limit, the classical color fields are confined to a light-shell expanding at $c$ and are associated with a non-linear $\sigma$-model on the 2D light-shell with specific symmetry breaking terms. We argue that the quantum version of this picture exhibits asymptotic freedom and may be a useful starting point for an effective light-shell theory of the structure between the jets at a very high energy collider.Comment: 11 pages, no figure

Polymer quantization, singularity resolution and the 1/r^2 potential

We present a polymer quantization of the -lambda/r^2 potential on the positive real line and compute numerically the bound state eigenenergies in terms of the dimensionless coupling constant lambda. The singularity at the origin is handled in two ways: first, by regularizing the potential and adopting either symmetric or antisymmetric boundary conditions; second, by keeping the potential unregularized but allowing the singularity to be balanced by an antisymmetric boundary condition. The results are compared to the semiclassical limit of the polymer theory and to the conventional Schrodinger quantization on L_2(R_+). The various quantization schemes are in excellent agreement for the highly excited states but differ for the low-lying states, and the polymer spectrum is bounded below even when the Schrodinger spectrum is not. We find as expected that for the antisymmetric boundary condition the regularization of the potential is redundant: the polymer quantum theory is well defined even with the unregularized potential and the regularization of the potential does not significantly affect the spectrum.Comment: 21 pages, LaTeX including 7 figures. v2: analytic bounds improved; references adde

Multiple-event probability in general-relativistic quantum mechanics: a discrete model

We introduce a simple quantum mechanical model in which time and space are discrete and periodic. These features avoid the complications related to continuous-spectrum operators and infinite-norm states. The model provides a tool for discussing the probabilistic interpretation of generally-covariant quantum systems, without the confusion generated by spurious infinities. We use the model to illustrate the formalism of general-relativistic quantum mechanics, and to test the definition of multiple-event probability introduced in a companion paper. We consider a version of the model with unitary time-evolution and a version without unitary time-evolutio

Revisiting the quantum scalar field in spherically symmetric quantum gravity

We extend previous results in spherically symmetric gravitational systems coupled with a massless scalar field within the loop quantum gravity framework. As starting point, we take the Schwarzschild spacetime. The results presented here rely on the uniform discretization method. We are able to minimize the associated discrete master constraint using a variational method. The trial state for the vacuum consists of a direct product of a Fock vacuum for the matter part and a Gaussian centered around the classical Schwarzschild solution. This paper follows the line of research presented by Gambini, Pullin and Rastgoo and a comparison between their result and the one given in this work is made.Comment: 16 page

Chemistry meets Industry and Society A creative showcase conference

Buffalo milk contributes to 13% of the world milk production and is abundantly produced in Southern Italy regions. Buffalo milk is appreciated for its nutritive properties and is highly suitable for the manufacturing of wide range of dairy products. Several studies showed many bioactive peptides in different dairy species such as bovine, ovine and caprine milk, but few studies have been conducted on the buffalo dairy products (1). The present work is focused on the identification of bioactive peptides released after in vitro simulated gastrointestinal digestion of protein fraction isolated from buffalo-milk dairy products by ultra- and nanofiltration pilot plant. The gastrointestinal digests of protein fractions were monitored by RP-UHPLC-DAD, while, the peptide identification was carried out by UHPLC-Orbitrap-based tandem mass spectrometry. 165 peptides were identified in Yoghurt, 152 in Scamorza, 146 in Mozzarella, 136 in Grana and Ricotta and 120 in Ice Cream samples (1). The peptides belong to both buffalo caseins (αs1-, β-, k-CN) and whey proteins (α-LA, β-LG). Six G.I. digests of dairy products were tested in a model of oxidative stress using IEC-6 cells. Among them, buffalo ricotta cheese was the most active. UHPLC-PDA-MS/MS analysis revealed the presence of two abundant β-lactoglobulin peptides (BRP: YVEELKPTPEGDL, f:60-72 and BRP2: SFNPTQL, f:168-174). To confirm the hypothesized chemical structures and study their specific biological activity, the peptides were synthesized by conventional solid-phase peptide synthesis methods. The antioxidant potential of the identified peptides was then evaluated in a model of hydrogen peroxide induced oxidative stress in IEC-6 cell line. The peptides reduce ROS release and increase nuclear factor (erythroid-derived 2)-like 2 activation and the expression of antioxidant cytoprotective factors such as heme oxygenase 1, NAD(P)H: quinone oxidoreductase 1 and superoxide dismutase (2). The bioavailability of β-lactoglobulin peptides was evaluated in intestinal transport studies through Caco-2 cell monolayer. Only BRP2 showed equal bi-directional transport and linear permeability, suggesting that it was mainly absorbed through passive diffusion. In addition to its local effects, administration of BPR2 on mice mesenteric arteries counteracts the Angiotensin II-induced vasoconstriction by Nrf2 nuclear translocation, reduction of active form of Ras-related C3 botulinum toxin substrate 1 (Rac1) and NADPH oxidase activity. The analysis at molecular level of treated vessels showed an induction of Nrf2 translocation to nucleus associated with increased expression of MnSOD and Rac1 deactivation. The data indicate how protein fraction of buffalo ricotta cheese could be an important source of antioxidant compounds, as well as YVEELKPTPEGDL and SFNPTQL peptides could be considered as an “ingredient” for nutraceuticals formulations and functional and personalized foods, in order to prevent the onset of some gastrointestinal pathologies and cardiovascular diseases