EPJ B Highlight - Examining heat transfer in granular materials
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- Published on 22 February 2023
Heat transfer through granular materials in a humid atmosphere occurs mainly through the air in the case of larger particles, and via water capillary bridges for smaller particles.
Granular materials contain large numbers of small, discrete particles, which collectively behave like uniform media. Their thermal conductivity is crucial to understanding their overall behaviour – but so far, researchers haven’t considered how this value is affected by the surface roughness of their constituent particles. Through new analysis published in EPJ B, Bo Persson at the Peter Grünberg Institute, part of the Jülich Research Centre in Germany, has discovered that when this roughness is considered, thermal conductivity in granular materials is heavily influenced by particle sizes. These findings could help physicists to better describe a wide array of granular materials: from sand and snow, to piles of rice, coffee beans, and fertilizer.
EPJ B Highlight - Finely-tuned quantum dots enhance nonlinear optics
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- Published on 10 February 2023
Quantum dots with finely-tuned spherical defects could display advanced ‘nonlinear’ optical properties, new calculations have suggested. Adjusting the sizes of these defects could enable researchers to tightly control the brightness and frequency of the light they produce when illuminated.
Quantum dots are semiconductor particles measuring just a few nanometres across, which are now widely studied for their intriguing electrical and optical properties. Through new research published in EPJ B, Kobra Hasanirokh at Azarbaijan Shahid Madani University in Iran, together with Luay Hashem Abbud at Al-Mustaqbal University College, Iraq, show how quantum dots containing spherical defects can significantly enhance their nonlinear optical properties. By fine-tuning these defects, researchers could tightly control the frequency and brightness of the light emitted by quantum dots.
In Memory of Prof Amit Dutta
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- Published on 27 January 2023
It is with great sadness that we learn of the sudden passing of Professor Amit Dutta (Indian Institute of Technology, Kanpur, India), member of the Editorial Board of EPJB. An elected Fellow of the Indian Academy of Sciences, Bengaluru, Prof Dutta was a member of the Physics Department at IIT Kanpur since 2003, having obtained his PhD from Jadavpur University in 2000. He was a post-doctoral fellow at the Max-Plank-Institut fur Physik Komplexer Systeme, Dresden and the Institut fur Theoretishe Physik, Universitat Wurzburg, and his research interests were in the fields of quantum phase transitions, non-equilibrium dynamics of quantum many body systems and quantum information.
EPJ B Topical Issue on Recent developments in the functional renormalization group approach to correlated electron systems
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- Published on 13 January 2023
Guest editors: Carsten Honerkamp, Dante Kennes, Volker Meden, Michael Scherer and Ronny Thomale.
This Topical Issue of EPJ B brings together a collection of articles on the recent progress of the application of the functional renormalization group to correlated electron systems.
In condensed-matter physics strong correlations between electrons in materials and devices are responsible for the formation of many intriguing emergent phenomena, including various types of magnetism, (unconventional) superconductivity, Kondo-like effects or interaction-induced topological phases. Theoretical progress in the understanding of correlated electron systems requires the dedicated development of modern and powerful quantum many-body methods. One rather versatile method is the functional renormalization group, which has recently witnessed major methodological advances and extensions. This includes aspects of the renormalization group formulation, increased computer power and enhanced interlinks to ab initio quantum material methods, extensions to novel strongly correlated electronic models, and electronic systems out of equilibrium.
EPJ B Highlight - Assessing the effect of hydraulic fracturing on microearthquakes
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- Published on 15 August 2022
New research examines mining sites with hydraulic fracturing comparing it to those without to determine the practice’s effect on seismic hazards.
The analysis of low-intensity human-caused microearthquakes, including their magnitude and frequency, has become an important factor in mining. This is a consideration not only for the safety of mining staff, but also for extraction rates and mine stability that can have major impacts on business performance. Increasingly, the practice of hydraulic fracturing is used to precondition mines and diminish the magnitude of induced tremors as well as reduce the number of rock fragments extracted.
A new paper published in EPJ B assesses the impact of hydraulic fracturing on seismic hazards like microearthquakes, an important issue for the safety of workers and the continuation of mining operations. The paper is authored by Erick de la Barra, Pedro Vega-Jorquera and Héctor Torres from the University of La Serena, Chile, alongside Sérgio Luiz E. F. da Silva from Politecnico di Torino, Department of Applied Science and Technology, Turin, Italy.
EPJ B Highlight - Bringing consistency to methods of 2D material analysis
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- Published on 12 July 2022
New research introduces a more cohesive approach to the functional renormalization group — a key tool in the analysis of 2D materials
In materials science, the term “2D materials” refers to crystalline solids that consist of a single layer of atoms, with arguably the most famous example being graphene — a material made of a single layer of carbon atoms. These materials are promising for a wide range of applications including in sophisticated electronics and quantum computing thanks to their unique quantum properties.
One of the most promising methods of investigating these materials, and specifically their temperature instabilities, and for investigating quantum many-body phenomena is the functional renormalisation group (FRG). Yet, despite significant efforts, no systematic and comprehensive cohesion exists for different momentum space FRG implementations.
A new paper published in EPJ B and authored by Jacob Beyer, Institute for Theoretical Solid State Physics, RWTH Aachen University, Germany, alongside Jonas B. Hauck, and Lennart Klebl of the university’s Institute for Theory of Statistical Physics lays out a potential groundwork for achieving consistency across FRG methods.
EPJ B Highlight - Studying the pseudogap in superconducting cuprate materials
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- Published on 06 May 2022
Despite being vital to the study of superconductivity in cuprate materials the physical origins of the pseudogap remain a mystery.
Over three decades since the discovery of high-temperature superconductivity in ceramic cuprate materials, investigating the electronic states in cuprate materials to advance the understanding of the superconducting phase and related phenomena has become of incredible importance.
In a new paper published in the EPJ B, Ernesto Raposo from the Federal University of Pernambuco, Brazil, and his co-authors, look at one of the essential physical properties of cuprate superconducting compounds, the pseudogap, which describes a state where the Fermi surface of a material possesses a partial energy gap.
EPJ B Highlight - Thin quantum wires work better with less insulating coatings
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- Published on 19 April 2022
New theoretical analysis considers cases where the electrons are allowed to exist beyond the boundaries of semiconducting quantum wires – with important implications for their performance.
Thin, semiconducting wires have attracted much recent attention in physics – both in experiments and theoretical analysis. Named ‘quantum wires,’ these structures are often coated in insulating materials, and several previous studies have now explored how the mismatch between the insulating properties of both materials can influence their performance. Through new analysis published in EPJ B, Nguyen Nhu Dat and Nguyen Thi Thuc Hien at Duy Tan University, Vietnam, show that thinner wires with less insulating coatings can improve the mobility of the electrons they carry.
EPJ B Highlight - Simulating realistic lane changes in two-lane traffic
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- Published on 19 April 2022
A new approach to simulating traffic considers how drivers will change lanes at different rates depending on the density of traffic surrounding them
Many urban areas worldwide are now rapidly expanding, often with major negative impacts on traffic congestion. To address this issue, researchers have constructed models aiming to simulate the flow of traffic – but so far, they haven’t widely considered the impacts of drivers changing lanes. In a new study published in EPJ B, Nikita Madaan and Sapna Sharma at the Thapar Institute of Engineering and Technology, India, show how the lane-changing behaviours observed in real drivers can be incorporated into simulations of two-lane roads.
EPJ B Highlight - Ranking nanodevice functionality methods
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- Published on 08 April 2022
Examining the charge transfer influence of three charge control methods and producing a hierarchy promises important practical applications in nanodevices.
As the demand for nanodevices grows so too does the need to improve the functionality of such devices, which is vulnerable to changes in the charge distribution, energy levels or conformation. Hence the desire to assess the three current charge control methods: gating by electro-chemicals, doping by pendant groups and doping by annealed motifs.
A new paper published in EPJ B authored by Zainelabideen Yousif Mijbil, from the College of Science, Al-Qasim Green University, Al-Qasim Town, Babylon Province, Iraq, aims to prioritize and rank nano-device functionality methods according to their potential impact as well as justifying the reason for such an influence-based hierarchy.
