- Published on 17 May 2016
New model for controlling hot molecules reactions, which are relevant to fusion, space exploration and planetary science
Hot molecules, which are found in extreme environments such as the edges of fusion reactors, are much more reactive than those used to understand reaction studies at ambient temperature. Detailed knowledge of their reactions is not only relevant to modelling nuclear fusion devices; it is also crucial in simulating the reaction that takes place on a spacecraft’s heat shield at the moment when it re-enters Earth’s atmosphere. Further, it can help us understand the physics and chemistry of planetary atmospheres. In a novel and comprehensive study just published in EPJ D, Masamitsu Hoshino from Sophia University, Tokyo, Japan, and colleagues reveal a method for controlling the likelihood that these reactions between electrons and hot molecules occur, by altering the degree of bending the linear molecules, modulated by reaching precisely defined temperatures.
- Published on 02 February 2016
The field of microplasmas gained recognition as a well-defined area of research and applications within the larger field of plasma science and technology about 20 years ago. Since then, the level of activity in microplasma research and applications has continuously increased.
A new review article published in EPJ D provides a snapshot of the current state of microplasma research and applications. Given the rapid proliferation of microplasma-based applications, the authors focus primarily on the status of microplasma science and on current understanding of the physical principles that govern the formation and behaviour of microplasmas. They also address microplasma applications, limiting such discussion to examples where the application is closely tied to the plasma science. The article includes some key references to recent reviews, describing some of the diverse range of current and emerging applications.
- Published on 18 January 2016
Numerical model takes us one step closer to understanding anti-hydrogen formation, to explain the prevalence of matter and antimatter in the universe
Antihydrogen is a particular kind of atom, made up of the antiparticle of an electron - a Positron - and the antiparticle of a Proton - an antiproton. Scientists hope that studying the formation of anti hydrogen will ultimately help explain why there is more matter than antimatter in the universe. In a new study published in EPJ D, Igor Bray and colleagues from Curtin University, Perth, Australia, demonstrate that the two different numerical calculation approaches they developed specifically to study collisions are in accordance. As such, their numerical approach could therefore be used to explain antihydrogen formation.
- Published on 15 December 2015
Creation of ephemeral muonium atoms could help measure proton size
A true-muonium only lives for two microseconds. These atoms are made up one positively and one negatively charged elementary particle, also known as muons. Although they have yet to be observed experimentally, a Japanese theoretical physicist has come up with new ways of creating them, in principle, via particle collisions. The first method involves colliding a negatively charged muon and a muonium atom made up of a positive muon and an electron. The second involves colliding a positively charged muon and a muonic hydrogen atom made up of a proton and a negative muon. The author found that the second option offers the most promising advances for muonium detection. These findings have been published in EPJ D by Kazuhiro Sakimoto from the Japan Aerospace Exploration Agency in Kanagawa.
- Published on 02 December 2015
High-precision and high-accuracy magnetic field measurement to support quest for missing antimatter in the universe
Every measurement is potentially prone to systematic error. The more sensitive the measurement method, the more important it is to make sure it is also accurate. This is key for example in measuring magnetic fields in state-of-the-art fundamental physics experiments. Now, an international team of physicists has developed an extremely high-precision method for the determination of magnetic fields. The resulting device, they found, has an intrinsic sensitivity that makes it ideal for fundamental physics and cosmology experiments attempting to explain the missing antimatter of the universe. The findings by Hans-Christian Koch from the University of Fribourg, Switzerland, and colleagues have just been published in EPJ D.
- Published on 17 November 2015
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.
- Published on 23 September 2015
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.
- Published on 27 July 2015
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.
- Published on 22 July 2015
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.
- Published on 29 June 2015
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.