2015 Impact factor 1.208
Atomic, Molecular, Optical and Plasma Physics

News / Highlights / Colloquium

EPJ D Highlight - Bringing the chaos in light sources under control

Experimental reconstruction of the phase portrait of the quantum dot light emitting diode using the embedding technique.

Study investigates how best to stabilise the output of quantum dot LEDs

Noise is an issue in optical telecommunications. And findings means of controlling noise is key to physicists investigating light-emitting diodes or lasers. Now, an Italo-Iraqi team has worked on a particular type of light source, called the quantum dot light-emitting diode (QDLED). In a study published in EPJ D, Kais Al Namee from the National Institute of Optics, in Florence, Italy and colleagues, demonstrate that modulating bias current of the QDLED could lead to countering the noise. This, in turn, leads to stabilising such light sources, making them better suited for optical telecommunications.

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EPJ D Highlight - New way of retaining quantum memories stored in light

Quantum information stored in photons can be preserved by confining light. © memorialphoto / Fotolia

Chinese scientists uncover a novel way of stopping light in a state that stores information encoded in photons, opening the door to applications in quantum information processing

A team of Chinese physicists has now developed a way to confine light. This is significant because the approach allows quantum memories stored within photons to be retained. These findings stem from a study by Nan Sun from Nanjing University of Posts & Telecommunications, China, and colleagues, which has just been published in EPJ D. The results may herald the advent of a multitude of hybrid, optoelectronic devices relying on the use of quantum information stored in photons for processing information that can be used in communication networks or quantum computing.

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EPJ D Highlight - Identifying ever-growing disturbances leading to freak waves

A schematic one-dimensional illustration of the spatiotemporal evolution of the envelope of wave-train in the absolutely unstable case.

Physicists now better understand wave systems exhibiting unusual disturbances by identifying growing localised patterns as early indicators of such disturbances

Physicists like to study unusual kinds of waves, like freak waves found in the sea. Such wave movements can be studied using models designed to describe the dynamics of disturbances. Theoretical physicists, based in France have focused on finding ways of best explaining how wave disturbance occurs under very specific initial conditions that are key to the genesis of these disturbances. They looked for solutions to this puzzle by resolving a type of equation, called the nonlinear Schrödinger equation. It is solved by applying a method designed for studying instabilities tailored to these initial conditions. Their approach makes it possible to locate exactly where and how pertinent information used to identify disturbance patterns can be extracted from localised disturbances' characteristics. The findings have been published in EPJ D by Saliya Coulibaly, from the University of Lille, and colleagues.

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EPJ D Colloquium - How many orthonormal bases are needed to distinguish all pure quantum states?

How many different measurement settings are needed in order to uniquely determine a pure quantum state, and how should such measurements be chosen? This problem goes back to a famous remark by Wolfgang Pauli in 1933, in which he raised the question whether or not the position and the momentum distributions are enough to define the wave function uniquely modulo a global phase. The original Pauli problem has a negative answer, but it has evolved into many interesting variants and has been studied from several fruitful perspectives.

In this review article the authors concentrate on a specific form of the Pauli problem, which is concerned with the minimal number of orthonormal bases in a finite dimensional Hilbert space that is needed in order to distinguish all pure quantum states.

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EPJ D Highlight - Clues to inner atomic life from subtle light-emission shifts

Hyperfine structure of the nuclear ground state (dark blue) and the isomeric 11/2 state (light blue) of 119Cd in the 5s 5p 3P2 → 5s 6s 3S1 transition

Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods

Atoms absorb and emit light of various wavelengths. Physicists have long known that there are some tiny changes, or shifts, in the light that gets absorbed or emitted, due to the properties of the atomic nucleus. Now, a team of scientists has elucidated the so-called hyperfine structure of cadmium atoms. Relying on a method called laser spectroscopy, they have measured variations in the energy transition within cadmium atom - Cd in the periodic table. They studied a chain of isotopes with an odd number of neutrons ranging from 59 in 107Cd to 75 in 123Cd. From these high-precision measurements, they were able to identify the physical cause of the shift within the nucleus. These findings by Nadja Frömmgen from the Johannes Gutenberg University Mainz, in Germany, and international colleagues have now been published in EPJ D.

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EPJ D Colloquium - Recent advances in the application of the Schwinger multichannel method with pseudopotentials to electron-molecule collisions

Model based on the molecular orbital theory

A new Colloquium paper published in EPJ D describes recent advances in the use of the Schwinger multichannel method and considers potential future applications of the technique. Based on the Schwinger variational principle for the scattering amplitude, the Schwinger multichannel method was designed to account for exchange, polarization and electronically multichannel coupling effects in the low-energy region of electron scattering from molecules with arbitrary geometry.

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EPJ D Highlight - Organic nanoparticles, more lethal to tumours

Man Receiving Radiation Therapy for Cancer Treatment. © Mediteraneo / Fotolia

Carbon-based nanoparticles could be used to sensitize cancerous tumours to proton radiotherapy and induce more focused destruction of cancer cells, a new study shows

Radiotherapy used in cancer treatment is a promising treatment method, albeit rather indiscriminate. Indeed, it affects neighbouring healthy tissues and tumours alike. Researchers have thus been exploring the possibilities of using various radio-sensitizers; these nanoscale entities focus the destructive effects of radiotherapy more specifically on tumour cells. In a study published in EPJ D, physicists have now shown that the production of low-energy electrons by radio-sensitizers made of carbon nanostructures hinges on a key physical mechanism referred to as plasmons—collective excitations of so-called valence electrons; a phenomenon already documented in rare metal sensitizers. This reseach was conducted by Alexey Verkhovtsev, affiliated with the MBN Research Center in Frankfurt, Germany and A.F. Ioffe Physical-Technical Institute in St Petersburg, Russia and an international team.

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EPJ D Highlight - Novel plasma diagnostics method

Sketch of the momentum fluxes across the sheath edge.

Physicists have now devised an elegant plasma pressure diagnostic method by studying forces akin to the pressure change at the inner walls of energy saving light bulb when the light is switched on

Could the mundane action of switching on an energy saving light bulb still hold secrets? It does, at least for physicists. These bulbs are interesting because they contain low-temperature plasma—a gas containing charges from ions and electrons. Now, a German team has developed a method that could be used for measuring the increase in the plasma force on the inner side of such a light bulb when the light is switched on. These findings from Thomas Trottenberg and colleagues from Christian-Albrechts University in Kiel, Germany, have just been published in EPJ D. They have implications for plasma diagnostics concerning plasma-wall interactions used in surface modification and the production of thin film solar cells and microchips.

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EPJ D Highlight - The new frontier in plasma medicine

Likelihood that negatively charged oxygen ions will demonstrate scattering in water vapour based on experimental results.

Data on the transport of electrical charges in water vapour provide the key ingredients to new plasma models applicable to medicine

Applications of plasmas in medicine are a new frontier in therapeutic treatment. For example, they can help in stimulating tissue regeneration in the contexts of wound healing and dermatology. Before these and further applications can be developed, it is essential to understand the processes at work in plasmas - a unique kind of gas-like state of matter containing charged particles. Now a study published in EPJ D by a team led by Zoran Petrović from the University of Belgrade, Serbia, provides previously unavailable data on oxygen ion transport and the likelihood of such ions interacting with water molecules. These could contribute to new models of plasmas in liquids which account for how discharges are created in water vapour.

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EPJ D Highlight - Novel high-power microwave generator

Axial profile of the axisymmetric semi-circular structure to be used as a slow wave structure in backward wave oscillators.

A new study explores the viability of a novel structure to be used as a component of a high-power microwave source, designed to transfer energy to targets via ultra-high-frequency radio waves

High-power microwaves are frequently used in civil applications, such as radar and communication systems, heating and current drive of plasmas in fusion devices, and acceleration in high-energy linear colliders. They can also be used for military purpose in directed-energy weapons or missile guidance systems. In a new study published in EPJ D, scientists from Bangladesh demonstrate that their proposed novel method, which is capable of producing such microwaves, offers a viable alternative to traditional approaches. The solution was developed by Md. Ghulam Saber and colleagues from the Islamic University of Technology in Gazipur, Bangladesh.

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Editors-in-Chief
V. Buzek, H. Kersten and A.V. Solov'yov
Thank you very much for the super-efficient handling of my manuscript.

Xin Zhang

ISSN (Print Edition): 1434-6060
ISSN (Electronic Edition): 1434-6079

© EDP Sciences, Società Italiana di Fisica and Springer-Verlag

Conference announcements

POSMOL 2017

Magnetic Island, Queensland, Australia, 22-24 July 2017