78 research outputs found
Is blockchain able to enhance environmental sustainability? A systematic review and research agenda from the perspective of Sustainable Development Goals (SDGs)
Blockchain is a disruptive technology that is revolutionizing information technology and represents a change of cultural paradigm for the way in which information is shared. Companies are rushing to understand how they can use blockchain distributed ledger technology to innovate processes, products and transactions. In a globalized world where environmental sustainability is a critical success factor, what is the role of the blockchain? By using a systematic review approach and the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) protocol, this study attempts to identify whether and how blockchain technology is considered able to affect environmental sustainability. Findings from 195 studies from 2015 to 2020 were analysed after the search protocol was applied. The results indicate that blockchain technology could contribute to environmentally sustainable development goals (SDGs) from different points of view, such as supporting the realization of a sustainable supply chain, improving energy efficiency and promoting the creation of secure and reliable smart cities. Furthermore, the investigation highlights the sectors where to focus research investments, providing a way to reward sustainable behaviour and increasing environmental sustainability. On the other hand, blockchain has no negligible negative effects on the environment that need to be considered before adoption
Spin Content of the Quantum Soliton
The classical soliton solution, quantized by means of suitable translational
and rotational collective coordinates, is embedded into the one-particle
irreductible representation of the Poincare group corresponding to a definite
spin. It is shown, that within the conventional quasiclassical expansion such
embedding leads to a set of nontrivial consistency conditions imposed on the
classical solution. The validity of these relations is considered for a number
of soliton models in 2+1- and 3+1-dimensions.Comment: 10 pages, Standard LaTe
Real Time Analysis of Thermal Activation via Sphaleron Transitions
We study the process of thermal activation mediated by sphaleron transitions
by analyzing the real-time dynamics of the decay out of equilibrium in a
dimensional field theory with a metastable state. The situation considered is
that of a rapid supercooling in which the system is trapped in a metastable
state at a temperature larger than the mass of the quanta, but smaller than the
energy to create a critical droplet. The initial density matrix is evolved in
time and the nucleation rate (probability current at the saddle point) is
computed. The nucleation rate is {\it time dependent}, vanishing at early
times, reaching a maximum at a time with the mass of quanta
in the metastable state, and decreasing at long times as a consequence of
unitarity. An estimate for the average number of particles of ``true vacuum''
produced as a function of time during the nucleation process is obtained.Comment: 26 pages 6 figures (available upon request), PITT-93-06, LATE
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