2024 Impact factor 0.9
Applied Physics

EPJ B Highlight - Assessing the environmental impacts of Brazil’s biofuel sector

Assessing the dependence of biofuels on other sectors

Mathematical analysis reveals that within Brazil’s agriculture and livestock industry, the biofuels sector is most heavily reliant on other sectors with high greenhouse gas emissions.

Brazil is a world leader in biofuel production, but the environmental sustainability of the sector has faced criticism due to its impacts on deforestation, water use, and biodiversity, especially in the Amazon rainforest.

Through analysis published in EPJ B, researchers led by Eder Johnson de Area Leão Pereira at the Federal Institute of Maranhão reveal new insights into the biofuel industry's dependence on high greenhouse gas (GHG) emitting sectors.

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EPJ B Highlight - Thinking about the rise of brain-inspired computing

A diagram showing the overlap of different computing regimes Credit: M. Zolfagharinejad, et al., EPJ B (2024)

A new review paper looks at the growing and interdisciplinary area of research that investigates how principles of the biological brain can be translated to computers.

The recent widespread and long-lasting chaos caused by Microsoft outages across the globe exemplifies just how integral computing has become to our lives. Yet, as computer hardware and software improve, arguably the most sophisticated and powerful computer we know of is still the human brain.

Sharing its computing power through billions of neurons interacting via trillions of synapses, the human brain doesn’t just compete with the most powerful supercomputers devised, but by consuming less energy than it takes to power the light in your fridge, your brain beats computers in the efficiency department, hands down.

It is little wonder that scientists and computer engineers are inspired by the human brain when it comes to devising new computing methods.

In a new paper published in the journal EPJ B, Mohamadreza Zolfagharinejad from the University of Twente and his coauthors discuss the rise of brain-inspired computing, its burgeoning demand, and its importance in the modern world. The review offers a comprehensive overview of the latest advances in brain-inspired computing hardware.

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EPJ B Highlight - Five ways to model text using networks

Some examples of how words connect to each other in a text, forming a network. While words such as “vertex” and “vertices” are connected for their shared form, words such as “texts”, “sentences” and “words” are connected because of their meanings. © D A Oliveira

Network theory can be used in different ways to model the relationship between words in a block of text, linking analytical patterns to coherence and to some more subjective aspects of writing quality.

The explosive growth of AI ‘chatbots’ over the last few years and their ability to generate text that simulates human writing, often very accurately, has focused attention on how text is structured.

One useful way of analysing text is to think of it as a network, and methods of network analysis that are familiar to mathematicians and computer scientists can be powerful in linguistics. Davi Alves Oliveira and Hernane Borges de Barros Pereira from the University of Bahia State, Bahia, Brazil have compared five methods of representing sentences as networks, showing that each has value for specific applications. This analysis has now been published in the journal EPJ B.

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EPJ B Topical review - Twenty-five years of random asset exchange modeling

Over the last twenty-five years, there has emerged within the subfield of econophysics a sizeable and important literature (hereinafter the “random asset exchange” literature) concerned with the application of stochastic processes to model wealth and income distributions. In a new Topical Review published in EPJ B, written by Max Greenberg (University of Massachusetts Amherst, USA) and H. Oliver Gao (Cornell University, USA), the random asset exchange literature as a whole is comprehensively exposited for the first time.

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EPJ B Highlight - A Mathematical Understanding of Project Schedules

A toy project with three interdependent activities A, B and C. The longest activity (A) sets the project duration. Copyright A. Vazquez

Complex projects are made up of many activities, the duration of which vary according to a power law; this model can be used to predict overall project duration and delay.

We have all been frustrated when a project is delayed because one sub-task cannot begin before another ends. It is less well known that the process of scheduling projects efficiently can be described in mathematical terms. Now, Alexei Vazquez, of technology company Nodes & Links and based in Cambridge, UK, has shown that the distribution of activity lengths in a project follows the mathematical relationship of power law scaling. He has published his findings in the journal EPJ B.

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EPJ B Highlight - Coalescence-fragmentation cycles based on Human conflict

Lewis Richardson’s models of insurgency warfare applies to general group dynamics. Credit: NOAA Presentation/Public Domain

Inspired by insurgency warfare dynamics, a model predicts patterns of how groups gel and shatter

In 1960, Lewis Fry Richardson famously observed that the severity of a wartime event is described by a simple power law distribution that scales according to the size of the conflict. Statisticians since have since proposed various modifications, but they continue to agree that casualty count in a violent conflict tends to scale with the size of the insurgent group that caused the conflict. In a study published in EPJ B, Brennen Fagan, of the University of York, UK, and his colleagues analyze models of how complex systems coalesce and fragment based on these warfare dynamics. Their work evaluates the robustness of these models and elucidates the relationship between microscopic dynamics and observed phenomena.

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EPJ B Highlight - Exploring exotic behaviours in population-imbalanced fermionic systems

Forming exotic phases of matter

New studies show that oscillations in the quantum states of composite particles in trapped systems can be adjusted using an external magnetic field.

Over the past 20 years, many physicists have studied ultra-cold fermionic systems contained in magnetic or optical traps. When an external magnetic field is applied to a two-species fermionic system, the particles can pair together to form composite ‘bosonic molecules’ with a full-integer spin. These molecules undergo “Bose-Einstein Condensation” when cooled, where all the particles accumulate in the lowest-energy quantum state. The precision of these experiments has now been improved by trapping the particles inside optical lattices: periodic patterns formed by counter-propagating laser beams.

Through new research published in EPJ B, Avinaba Mukherjee and Raka Dasgupta at the University of Calcutta, India, have theoretically predicted a distinctive trend in the oscillations of Bose-Einstein condensates formed from these fermions – which can be adjusted using an external magnetic field. They specifically addressed systems where the two species have unequal population (creating leftover unpaired fermions): leading to exotic new phases. Their result could help physicists to detect such novel phases of matter in imbalanced fermionic systems and could open up new opportunities for quantum technologies.

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EPJ B Highlight - Harvesting vibrational energy from coloured noise

Schematic diagram of a tri-stable energy harvesting system with linked electronics and energy store. Credit: T. Zhang, Y. Jin

Two engineers from Beijing Institute of Technology in China have shown how to optimise the output of a device that can convert ambient vibrational energy into useful electric power.

The energy demands of today’s ubiquitous small electronic devices – including sensors, data transmitters, medical implants and ‘wearable’ consumer products such as Fitbits – can no longer be met by chemical batteries alone. This gap can be filled by energy harvesters, which turn ordinary, ambient vibrational energy into electrical energy. The most efficient types of harvester are tri-stable energy harvesters, which can convert even low-frequency random vibrations into alternating current (AC) and thence into direct current (DC). Tingting Zhang and Yanfei Jin from Beijing Institute of Technology in China have now investigated how the properties of these systems can be altered to optimise the power output; their findings are published in EPJ B.

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EPJ B Highlight - Investigating the role of random walks in particle diffusion

Distribution curve with sharp central peak

Theoretical analysis reveals new insights into unusual patterns displayed by diffusing particles in recent experiments.

Several recent experiments identify unusual patterns in particle diffusion, hinting at some underlying complexity in the process which physicists have yet to discover. Through new analysis published in EPJ B, Adrian Pacheco-Pozo and Igor Sokolov at Humboldt University of Berlin show how this behaviour emerges through strong correlations between the positions of diffusing particles travelling along similar trajectories. Their results could help researchers to create better models of the diffusion process – ultimately drawing deeper insights into how fluids behave.

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EPJ B: Prof. Dr. Reinhold Egger new Editor-in-Chief for the Condensed Matter section as of 1 January 2024

(c) Heinrich-Heine-Universität Düsseldorf

The publishers of The European Physical Journal B are pleased to announce the appointment of Prof. Dr. Reinhold Egger as new Editor-in-Chief for the Condensed Matter section of the journal as of January 1st, 2024.

Reinhold Egger has been a full professor of theoretical physics at Heinrich-Heine-Universität Düsseldorf since 2001. He has worked in many different areas of condensed matter physics, including nonequilibrium quantum transport, topological quantum matter, superconductivity and low-dimensional quantum field theory. He has been part of the board of EPJB since 2011 and he is recipient of the Gerhard-Hess-Preis of the DFG and of the Physics Prize of the Akademie der Wissenschaften zu Göttingen.

The publishers take the opportunity to thank wholeheartedly Dr. Eduardo Hernandez, for his dedicated work and leadership during his term as Editor-in-Chief of EPJB.

Editors-in-Chief
V. Mauchamp et P. Moreau
ISSN (Print Edition): 1286-0042
ISSN (Electronic Edition): 1286-0050

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