Nonlocal quantum field theory without acausality and nonunitarity at quantum level: is SUSY the key?

The realization of a nonlocal quantum field theory without losing unitarity, gauge invariance and causality is investigated. It is commonly retained that such a formulation is possible at tree level, but at quantum level acausality reappears at one loop. We suggest the the problem of acausality is, in a broad sense, similar to the one about anomalies in quantum field theory. By virtue of this analogy, we suggest that acausal diagrams resulting from the fermionic sector and the bosonic one might cancel each other, with a suitable content of fields and suitable symmetries. As a simple example, we show how supersymmetry can alleviate this problem in a simple and elegant way, i.e., by leading to exact cancellations of harmful diagrams, to all orders of perturbation theory, in the case of a nonlocal Wess-Zumino model. On the other hand, the same is true for a super Yang-Mills model, but in this case, other important acausal diagrams are also originating from supersymmetric D-terms. As a consequence, we conjecture that, for a generic gauge theory, an infinite number of superfields are needed in order to obtain a complete cancellation between all diagrams. This framework is naturally occurring in string theory, where infinite Kaluza-Klein towers of higher-spin fields are generally predicted.Comment: Supergraphs reformulation in non-local case are added, with a formal derivation of these. More explicit calculations, in main interesting one-loop processes, are explicitly shown. More comments and references. Main results and Conclusions remain the sam

Industrial symbiosis: anaerobic digestion of waste products as mitigation strategy

La simbiosi industriale è una strategia aziendale con la quale è possibile aumentare la sostenibilità dei processi produttivi. La partnership tra un’azienda vinicola e una società energetica ha consentito un’innovazione di processo che consente il riutilizzo dei rifiuti alimentari dalla produzione del vino. L’azienda vinicola produce 5.200.000 tonnellate di uva. Con un biodigestore è possibile reinserire nel ciclo produttivo circa 220.000 tonnellate di rifiuti alimentari, composti da: rifiuti vegetali, trucioli di legno e rifiuti da potatura. Il riutilizzo degli scarti di produzione genera 105.000 MWh di calore e 81.000 MWh di energia elettrica, con un risparmio di 35.000 tonnellate di CO2 . I risultati ottenuti possono essere ottenuti dalle aziende alimentari che richiedono un elevato fabbisogno energetico e che producono notevoli quantità di rifiuti organici.Industrial symbiosis is a business strategy through which it is possible increase the sustainability of production processes. The partnership between a winery and an energy company has enabled the implementation of a production innovation that allows the upgrading by food waste from wine production. The winery produces 5,200,000 tons of grapes. Through the creation of a biodigester it is possible to re-enter in the production cycle about 220,000 tons of food waste, consisting of: vegetable waste, wood chips and waste from pruning. The reuse of production waste can generate 105,000 MWh of heat and 81,000 MWh of electrical energy, allowing savings of 35,000 tons of CO2 . The results obtained could be reached by food manufacturers that require a high energy needs and that produce significant amounts of organic waste

Sustainability of technological innovation investiments. Photovoltaic panels case study

as photovoltaic panels. In the case study analysed are shown the benefits obtained from the investments of the central Italy after installing photovoltaic systems. The total expenditure for the electricity purchase is € 52.326, while the total benefit of the investment is € 18.789, equal in percentage to a 53% energy saving over a period of 20 years. The company expeniture in the absence of a photovoltaic system is equal to € 109.03, while in the presence of a plant, considering also all costs incurred for € 93.090, with a percentage of profit on the investment made equal to almost 15% in 20 years

The variable X-ray emission of PSR B0943+10

The old pulsar PSR B0943+10 (P=1.1 s, characteristic age tau=5 Myr) is the best example of mode-switching radio pulsar. Its radio emission alternates between a highly organized state with regular drifting subpulses (B mode) and a chaotic emission pattern (Q mode). We present the results of XMM-Newton observations showing that the X-ray properties of PSR B0943+10 depend on its radio state (Hermsen et al. 2013). During the radio fainter state (Q mode) the X-ray flux is more than a factor two larger than during the B-mode and X-ray pulsations with about 50% pulsed fraction are detected. The X-ray emission of PSR B0943+10 in the B-mode is well described by thermal emission with blackbody temperature kT=0.26 keV coming from a small hot spot with luminosity of 7x10^28 erg/s, in good agreement with the prediction of the partially screened gap model, which also explains the properties of the radio emission in this mode. We derived an upper limit of 46% on the X-ray pulsed fraction in the B-mode, consistent with the geometry and viewing angle of PSR B0943+10 inferred from the radio data. The higher flux observed during the Q-mode is consistent with the appearance of an additional component with a power-law spectrum with photon index 2.2. We interpret it as pulsed non-thermal X-rays produced in the star magnetosphere. A small change in the beaming pattern or in the efficiency of acceleration of the particles responsible for the non-thermal emission can explain the reduced flux of this component during the radio B-mode.Comment: Accepted for publication in MNRA

X-ray emission from hot subdwarfs with compact companions

We review the X-ray observations of hot subdwarf stars. While no X-ray emission has been detected yet from binaries containing B-type subdwarfs, interesting results have been obtained in the case of the two luminous O-type subdwarfs HD 49798 and BD +37 442. Both of them are members of binary systems in which the X-ray luminosity is powered by accretion onto a compact object: a rapidly spinning (13.2 s) and massive (1.28 M_sun) white dwarf in the case of HD 49798 and most likely a neutron star, spinning at 19.2 s, in the case of BD +37 442. Their study can shed light on the poorly known processes taking place during common envelope evolutionary phases and on the properties of wind mass loss from hot subdwarfs.Comment: To be published in the proceedings of the 40th Liege International Astrophysical Colloquium "Ageing low mass stars: from red giants to white dwarfs

L’eco-efficienza dei contenitori di vetro sottile

La valutazione economica della produzione sostenibile dei contenitori di vetro dimostra che l’assottigliamento dei contenitori e il loro riciclo comporta vantaggi ambientali immediatamente quantificabili.Economic assessment of the sustainable production of glass containers shows that making the containers thinner and recycling them carries immediately quantifiable environmental advantages

Search for X-ray emission from subdwarf B stars with compact companion candidates

Stellar evolutionary models predict that most of the early type subdwarf stars in close binary systems have white dwarf companions. More massive companions, such as neutron stars or black holes, are also expected in some cases. The presence of compact stars in these systems can be revealed by the detection of X-rays powered by accretion of the subdwarf's stellar wind or by surface thermal emission. Using the Swift satellite, we carried out a systematic search for X-ray emission from a sample of twelve subdwarf B stars which, based on optical studies, have been suggested to have degenerate companions. None of our targets was detected, but the derived upper limits provide one of the few observational constraints on the stellar winds of early type subdwarfs. If the presence of neutron star companions is confirmed, our results constrain the mass loss rates of some of these subdwarf B stars to values <10^{-13}-10^{-12} Msun/yr.Comment: Accepted for publication in Astronomy and Astrophysic

The effect of X-ray dust-scattering on a bright burst from the magnetar 1E 1547.0-5408

A bright burst, followed by an X-ray tail lasting ~10 ks, was detected during an XMM-Newton observation of the magnetar 1E 1547.0-5408 carried out on 2009 February 3. The burst, also observed by SWIFT/BAT, had a spectrum well fit by the sum of two blackbodies with temperatures of ~4 keV and 10 keV and a fluence in the 0.3-150 keV energy range of ~1e-5 erg/cm2. The X-ray tail had a fluence of ~4e-8 erg/cm2. Thanks to the knowledge of the distances and relative optical depths of three dust clouds between us and 1E 1547.0-5408, we show that most of the X-rays in the tail can be explained by dust scattering of the burst emission, except for the first ~20-30 s. We point out that other X-ray tails observed after strong magnetar bursts may contain a non-negligible contribution due to dust scattering.Comment: 8 pages, 2 tables and 10 figures; accepted to publication in MNRA