Comments on Critical Electric and Magnetic Fields from Holography

We discuss some aspects of critical electric and magnetic fields in a field theory with holographic dual description. We extend the analysis of arxiv:1109.2920, which finds a critical electric field at which the Schwinger pair production barrier drops to zero, to the case of magnetic fields. We first find that, unlike ordinary weakly coupled theories, the magnetic field is not subject to any perturbative instability originating from the presence of a tachyonic ground state in the W-boson spectrum. This follows from the large value of the 't Hooft coupling \lambda, which prevents the Zeeman interaction term to overcome the particle mass at high B. Consequently, we study the next possible B-field instability, i.e. monopole pair production, which is the S-dual version of the Schwinger effect. Also in this case a critical magnetic field is expected when the tunneling barrier drops to zero. These Schwinger-type criticalities are the holographic duals, in the bulk, to the fields E or B reaching the tension of F1 or D1 strings respectively. We then discuss how this effect is modified when electric and magnetic fields are present simultaneously and dyonic states in the spectrum can be pair produced by a generic E - B background. Finally, we analyze finite temperature effects on Schwinger criticalities, i.e. in the AdS-Schwarzshild black hole background.Comment: 33 pages, 4 figures; v2: refs added; v3: typos corrected, to appear on JHE

Virtual reconstruction from scan to VR of architecture and landscape of a monumental park

The Monza Park, with its more than 7 square meters of green area divided between lawn and woods, its 110,000 tall trees, its 13 farmhouses, 3 historic villas, 13 m of fences and 90,000 visitors on spring Sundays, represents an irreplaceable source of wellness and sustainability for those who live near it. The pandemic situation of the 20s and 21s by reducing the movements and the possibility of coexistence of a large public in an open space has suggested the possibility of new forms of use and interaction of the same, even remotely, reproducing Virtual and Augmented Reality experiences. With this paper, the authors intend to illustrate a workflow from Scan to VR and AR applications, taking advantage of the opportunity to explore digital acquisitions and additional materials available and functional to convey the values and importance of open space and historical monuments immersed in them. The VR/AR experiences have been structured for navigation from the scale of architectural detail to the environmental one, which effectively ensures the fruition of one of the most significant and large historical walled parks in Europe. An unprecedented and still unique park made up of woods, meadows, cultivated fields, the Lambro, the farmhouses and villas, the mills inserted in an apparently natural but carefully designed environment

Stable vs Unstable Vortices in SQCD

We give a topological classification of stable and unconfined massive particles and strings (and some instantons) in worldvolume theories of M5-branes and their dimensional reductions, generalizing Witten's classification of strings in SYM. In particular 4d N=2 SQCD softly broken to N=1 contains torsion (Douglas-Shenker) Z_N-strings and nontorsion (Hanany-Tong) Z-strings. Some of the former are stable when the flavor symmetry is gauged, while those that are not stable confine quarks and in some vacua even dyons into baryons. The nontorsion strings are stable if and only if all colors are locked to flavors, which is weaker than the BPS condition. As a byproduct unstable string decay modes and approximate lifetimes are found. Cascading theories have no vortices stabilized by the topological charges treated here and in particular Gubser-Herzog-Klebanov axionic strings do not carry such a charge.Comment: 32 pages, 6 figure

CULTURAL HERITAGE DISSEMINATION: BIM MODELLING AND AR APPLICATION FOR A DIACHRONIC TALE

The research purpose is to present a project of cultural dissemination and enhancement of the “Madonna della Pace” Sanctuary at Rocchetta di Airuno (Lecco - Italy), based on an immersive experience of knowledge of the history and places that characterize not only the sanctuary but also the “Cammino di Sant’Agostino” (of which it is one of the stages). The research goal focuses on the direct employment and exploitation of HBIM models for the digital fruition project. An integrated digital survey based on a terrestrial laser scanner and photogrammetry was conducted to provide a complete geometrical representation of the sanctuary and its surroundings. Both output point clouds were employed as metric and geometric references to create the reality-based parametric model. Specifically, the work focuses on creating a three-dimensional chronological model of the sanctuary, which not only represents the current state of the cultural asset but is also enriched through the definition of different evolutionary phases of the architectural artifact based on an indepth study of the photographic and bibliographic documentations. Four Project Phasing has been identified to represent the most significant transformations of the building and were managed using the time parameter in the same BIM project. The sanctuary geometric and parametric models were displayed and navigable thanks to the aid of Virtual and Augmented Reality applications. A VR environment was defined to display in the first person the textured model. Finally, an AR smartphone app prototype was developed to show tourists the sanctuary’s historical transformation over time

Perceived Psychological Restorativeness in Relation to Individual and Environmental Variables: A Study Conducted at Poetto Beach in Sardinia, Italy

This study examines how objective, social, and perceived environmental conditions in a blue space are associated with the perception of psychological restorativeness. We collected data between April 2021 and February 2022 at Poetto Beach in Sardinia, Italy. The participants (N = 255) completed a survey about perceived environmental quality, stress, weather, and restorativeness during their stay at the beach. We used linear models to evaluate the association between psychological restorativeness and social, environmental, and weather parameters. We also analyzed the nature of the association between temperature and restorativeness by viewing this relation as both linear and non-linear and by evaluating the differences in restorativeness between winter, springtime, and summer. The results suggested that the participants viewed the beach as psychologically restorative, especially during the winter season. We also found that the number of people that participants came with was negatively associated with perceived restorativeness. Finally, the results from the correlation analysis revealed that people are less stressed if they go to the beach more frequently

Degeneracy Between the Regge Slope of Mesons and Baryons from Supersymmetry

We consider the degeneracy between the Regge slope of mesons and baryons in QCD. We argue that within the "orientifold large-N approximation" asymptotically massive mesons and baryons become supersymmetric partners and hence degenerate. To this end, we generalize QCD by a SU(N) theory with a quark in the two-index antisymmetric representation. We show that in this framework the meson is represented by an oriented bosonic QCD-string and the baryon is represented by an un-oriented fermionic QCD-string. At large-N, due to an equivalence with super Yang-Mills, the tensions of the bosonic and the fermionic strings coincide. Our description of mesons and baryons as oriented and un-oriented bosonic and fermionic QCD-strings is in full agreement with the spectra of open strings in the dual type 0' string theory.Comment: v2: extended version. Appendices and references adde

Enhanced Interaction Experience for Holographic Visualization

Nowadays, holographic visualization pushes further the limits in exploring tri-dimensional digital con-tent. 3D models typically displayed through a computer screen now enter the real world as holograms. The Hologram Table allows users to visualize and manipulate huge 3D models as if they were in the space in front of them. Its use has already proved helpful for the virtual fruition and presentation of complex cultural heritage buildings and their design interventions, but it surely can do more. The work aims at exploring the possibility of expanding the capabilities of the Hologram Table interaction by developing a custom-designed experience to interact with 3D point cloud data coming from survey activity. The test case was the interesting building of the Santa Maria delle Grazie (Milan, Italy) basilica. Initial results are encouraging and show that the point model can be enriched with associated information and additional content (images and texts) available for holographic visualization

From Companion Diagnostics to Theranostics:A New Avenue for Alzheimer's Disease?

The recent literature signals a growing paradigm shift toward integrating therapeutics and diagnostics rather than developing and deploying them separately. In this gradual move toward more effective and personalized medications, companion diagnostics are an intermediate stage. The next step may be "theranostics", in which single chemical entities are developed to deliver therapy and diagnosis simultaneously. This strategy has been successfully exploited in oncology and is now emerging as a possibility for Alzheimer's disease, where its feasibility has caught the attention of researchers from industry and academia. Medicinal chemists do not yet completely understand the nuances of theranostic action and consequently have not yet developed universally validated strategies for developing theranostic clinical applications against Alzheimer's disease. However, given the emerging indications of the potentially enormous benefits that theranostics may bring to the fight against this devastating disease, further rigorous research is warranted

Chiral Polyalkylthiophenes for Organic Light Emitting Diodes

Chiral polyalkylthiophenes are noncentrosymmetric organic materials which can be used both in second harmonic-generation devices and in polarized light emitting diodes. In this work we present the synthesis and the characterization of a polyalkylthiophene with a chiral center very close to the conjugated backbone: poly(3-[(S)-2-methylbutyl]thiophene) (PMBT). Circular dichroism (CD) measurements have been carried out to ascertain the chirality of these materials. The CD spectra show intense signals both in mixed solvents and in the solid state. The strong Cotton effect can be associated to a highly ordered aggregated phase whose nature is still under investigation. We also present the photo and electroluminescence characterization of single layer light emitting diode (LED) with the following configuration: ITO (Tin Indium Oxide)/PMBT/Al