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EPJ PV Highlight - Approaches for reducing metallization-induced losses in industrial TOPCon solar cells
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- Published on 24 November 2025
Approaches for reducing metallization-induced losses in industrial TOPCon solar cells
The tunnel oxide passivating contact (TOPCon) structure has been widely accepted in industrial manufacturing, making it the dominating solar cell structure in 2025. One key to further increase conversion efficiency of such solar cells is minimizing carrier recombination at metal-semiconductor interfaces.
EPJ Plus Focus Point: Best doctoral theses from the Spanish Royal Physics Society (RSEF) in 2023-24
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- Published on 24 November 2025
Guest Editors: Luis Viña, María Luisa Sarsa, Rosa María Benito Zafrilla, Diego Porras Torre, Gastón García
In this special issue of EPJ Plus three articles are included, corresponding to the authors of the PhD thesis awarded by a biannual prize established by the The Spanish Royal Physics Society (“Real Sociedad Española de Física”, RSEF). These awards, announced in the biennial meeting in San Sebastian (Spain) in July 2025, highlight the work of researchers at the beginning of their careers and aim at encouraging others to apply for a thesis award, join the RSEF, and help physics contribute to creating a more educated, tolerant, diverse and resilient society.
All articles are available here and are freely accessible until 31 December 2025. For further information, read the Editorial.
EPJ Plus Highlight - Investigating charge transport in hybrid nanowires
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- Published on 21 November 2025
Analysis reveals how electron-hole pairs are reflected and transmitted across the interfaces of a hybrid nanowire – featuring alternating sections of a normal conductor and a high-temperature superconductor.
High-temperature superconductors are quickly opening up new possibilities for nanoscale circuits, which are likely to become key building blocks of future quantum technologies. As this research advances, a deep understanding of how electrical currents flow through superconductors dominated by quantum effects is becoming increasingly important.
Through theoretical analysis detailed in EPJ Plus, Francisco Estrella and Linda Reichl at the University of Texas at Austin provide one of the most detailed descriptions to date of how electron-hole pairs behave within hybrid nanowires – made from alternating sections of normally conducting material and a high-temperature superconductor. Their results clarify how hybrid nanowires could become a reliable testbed for fundamental quantum phenomena and could help pave the way for their use in real-world quantum technologies.
EPJ Plus Focus Point Issue: Tensions in Cosmology from Early to Late Universe: Part II: New Directions in the Light of Observations from the Most Modern Astronomical Facilities
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- Published on 29 October 2025
Guest Editors: Salvatore Capozziello, E. Di Valentino, Vahe G. Gurzadyan
The papers included in this Focus Point collection are devoted to the studies on the cosmological tensions and challenges stimulated by the latest observational data. The first results of the LARES-2 laser ranging satellite on the high precision testing of the frame-dragging effect predicted by General Relativity are presented. The data on the S-stars monitoring in the Galactic center obtained by GRAVITY collaboration were analysed within the Physics-informed neural network (PINN) approach. The results enabled to probe the role of the cosmological constant, of the dark matter, the star cluster in the core of the Galaxy obtaining an upper limit for the star density. The topics include the conversion of high-frequency relic gravitational waves into photons in cosmological magnetic field, cosmological gravitational waves stochastic background generation through the spontaneous breaking of a global baryon number symmetry, observational predictions of the Starobinsky inflation model and other studies.
All articles are available here and are freely accessible until 31 December 2025. For further information, read the Editorial.
EPJ E Highlight - Modelling reversibility transitions in soft athermal materials
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- Published on 21 October 2025
By accounting for long-range interactions between suspended particles, a new model provides a more accurate description of how soft athermal materials transition between reversible and irreversible states.
When soft athermal materials like foams, emulsions, or particle suspensions are gently shaken or sheared back and forth, they can learn to move in perfect rhythm: after each cycle, every particle returns to its original place. But if the driving becomes too strong, that tidy choreography breaks down, and particles wander irreversibly. This reversible–irreversible transition marks the boundary between an ordered and a chaotic state in driven soft matter. So far, however, researchers have struggled to recreate these properties through theoretical models – making it more difficult for them to understand how soft athermal materials behave in real-world applications.
Through new research published in EPJ E, a team led by CNRS researchers Romain Mari and Eric Bertin at Grenoble-Alpes University introduces a new and improved model, which reproduces the reversible–irreversible transition far more accurately. Their approach offers fresh insights into the deeply complex behaviours of soft athermal materials, and could help researchers to develop their application across a diverse range of real-world scenarios.
EPJ B Highlight - Simulating better performance in piezoelectric energy harvesters
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- Published on 21 October 2025
Analysis explains how nonlinear piezoelectric devices are far better than their linear counterparts at harvesting energy from noisy vibrations across a broad range of frequencies
Over the past few decades, the capabilities of piezoelectric energy harvesters have steadily improved, paving the way for micro- and nano-electronic devices which can be powered directly from the energy of ambient, noisy vibrations in their surrounding environments. So far, however, these devices have only been able to harvest from vibrations within a narrow frequency range, severely limiting their performance in real-world scenarios.
Through new analysis published in EPJ B, Martín Giuliano and Alejandro Sánchez at the National University of Mar del Plata, Argentina, show how this performance could be improved by integrating nonlinear dynamics into piezoelectric energy harvesters – allowing them to capture the inherently broad spectrum of frequencies associated with noisy vibrations. The duo’s findings could help guide the development of next-generation energy harvesters, making them far more autonomous than existing designs.
EPJ Plus Highlight - An interferometric approach to multi-parameter measurement
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- Published on 21 October 2025
Novel interferometer setup enables multiple parameters of an optical network to be measured simultaneously, with a precision limited only by the laws of quantum mechanics
Quantum mechanics has vastly improved our ability to make precise measurements. By harnessing effects such as entanglement, squeezing and interference, researchers have surpassed the noise limits imposed on classical techniques – allowing for higher-resolution measurements of quantities including energy, time, and polarization. Over the past decade, it has become especially important for researchers to measure multiple physical parameters of a quantum system simultaneously. However, previous approaches have faced numerous challenges – including the constraints they impose on the values of unknown parameters.
Through new research published in EPJ Plus, an international team from the University of Bari, Italy, and the University of Portsmouth, UK, presents an interferometry-based quantum sensing scheme capable of simultaneously estimating multiple parameters of an optical network, with a sensitivity limited only by the fundamental laws of quantum mechanics. Their approach could help to improve the precision and scope of quantum measurements across applications ranging from biological imaging to gravitational wave detection.
EPJ Plus Highlight - Probing quantum weirdness using particle colliders
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- Published on 21 October 2025
An international collaboration of researchers presents a roadmap of future experiments at colliders like the LHC, investigating the nature of quantum correlations, such as entanglement and Bell nonlocality at ultra-high energies
So far, many of the most mind-bending properties of quantum mechanics have only been studied extensively in low-energy laboratory setups. Recently, however, researchers have begun to consider how these experiments could be carried out at higher energies – achievable through particle accelerators like the Large Hadron Collider (LHC). Offering energies some 12 orders of magnitude higher than lab setups, these instruments provide a novel environment where quantum phenomena can be probed experimentally.
Through a new paper published in EPJ Plus, an international collaboration of researchers presents a roadmap for these studies: identifying the challenges that need to be overcome, and setting out realistic goals for future research, which may be carried out in different scenarios at future generations of colliders. The team’s analysis could help guide efforts to deepen our understanding of the enigmatic nature of quantum mechanics.
EPJ B Highlight - Calculating the impact of domain walls on systems’ free energies
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- Published on 17 October 2025
Mathematical approach improves calculations of how phase boundaries affect a material’s properties
The behaviours of many materials are strongly influenced by abrupt boundaries between different phases, called domain walls. In particular, the patterns in which domain walls arrange themselves are closely connected to a material’s free energy: a temperature-dependent quantity representing the balance between a system’s tendency toward low energy and high entropy.
Through new analysis published in EPJ B, a collaboration of European researchers have developed and applied a method that accounts for all possible arrangements of domain walls within a model system. By providing a robust approach for calculating its free energy, including finite-size effects, their method could help improve models of a wide array of structures where domain walls play a key role.
EPJ D Highlight - Towards better neutral beam measurements for fusion reactors
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- Published on 17 October 2025
New experiments show how a force probe can accurately track neutral particle beams, helping to improve fusion plasma stability
Neutral beam injection (NBI) is a valuable method for heating plasma inside a nuclear fusion reactor, and could be key to the success of upcoming projects including ITER. For the technique to work, however, the energy imparted by particle beams must be measured as accurately as possible. While ion beams can be tracked directly by their electric currents, chargeless neutral particles require more elaborate approaches – such as calorimetric profiling, spectroscopy, ionization-based methods.
In a new study published in EPJ D, researchers led by Thomas Trottenberg at Christian-Albrechts-University of Kiel, Germany, present a method to measure neutral beams using a device called a ‘force probe’, which directly measures the momentum transferred to a target. With initial measurements closely matching theoretical predictions, the demonstration could be an important step toward realizing nuclear fusion’s potential.
