By carefully controlling the position of an atomic-scale diamond defect within a volume smaller than what some viruses would fill, researchers have cleared a path toward better quantum computers and nanoscale sensors. They describe their technique in a paper published in the journal Applied Physics Letters, from AIP Publishing. (more…)
Tag Archives: spin
Teilchenphysiker der Universität Tübingen weisen erstmals den Gluonen eine wichtige Rolle beim Drehimpuls der Atombausteine zu
Protonen und Neutronen sind Bausteine aller Atomkerne und damit aller Materie. Sie setzen sich ihrerseits aus kleineren Teilchen zusammen, jeweils drei Quarks, die keine eigene innere Struktur aufweisen und durch sogenannte Gluonen aneinander gebunden werden. Das Proton besitzt außerdem einen Drehimpuls („Spin“), von dem Physiker lange annahmen, dass er in erster Linie von den Quarks verursacht wird. 1987 jedoch ergab ein Experiment an der Großforschungseinrichtung CERN, dass der Spin des Protons nur zu einem kleinen Teil durch die Spins der Quarks entsteht ‒ und die Teilchenphysik stürzte in die „Spin-Krise“. Nun haben Wissenschaftler der Universität Tübingen erstmals festgestellt, dass den Gluonen eine wichtige Rolle zukommt und sie möglicherweise den Hauptanteil des Spins tragen. (more…)
Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have once again demonstrated the incredible capabilities of metamaterials – artificial nanoconstructs whose optical properties arise from their physical structure rather than their chemical composition. Engineering a unique two-dimensional sheet of gold nanoantennas, the researchers were able to obtain the strongest signal yet of the photonic spin Hall effect, an optical phenomenon of quantum mechanics that could play a prominent role in the future of computing.
“With metamaterial, we were able to greatly enhance a naturally weak effect to the point where it was directly observable with simple detection techniques,” said Xiang Zhang, a faculty scientist with Berkeley Lab’s Materials Sciences Division who led this research. “We also demonstrated that metamaterials not only allow us to control the propagation of light but also allows control of circular polarization. This could have profound consequences for information encoding and processing.” (more…)
AUSTIN, Texas — Researchers from Amherst College and The University of Texas at Austin have described a new technique that might one day reveal in higher detail than ever before the composition and characteristics of the deep Earth.
There’s just one catch: The technique relies on a fifth force of nature (in addition to gravity, the weak and strong nuclear forces and electromagnetism) that has not yet been detected, but which some particle physicists think might exist. Physicists call this type of force a long-range spin-spin interaction. If it does exist, this exotic new force would connect matter at Earth’s surface with matter hundreds or even thousands of kilometers below, deep in Earth’s mantle. In other words, the building blocks of atoms—electrons, protons, and neutrons—separated over vast distances would “feel” each other’s presence. The way these particles interact could provide new information about the composition and characteristics of the mantle, which is poorly understood because of its inaccessibility. (more…)
MeRAM is up to 1,000 times more energy-efficient than current technologies
By using electric voltage instead of a flowing electric current, researchers from UCLA’s Henry Samueli School of Engineering and Applied Science have made major improvements to an ultra-fast, high-capacity class of computer memory known as magnetoresistive random access memory, or MRAM.
The UCLA team’s improved memory, which they call MeRAM for magnetoelectric random access memory, has great potential to be used in future memory chips for almost all electronic applications, including smart-phones, tablets, computers and microprocessors, as well as for data storage, like the solid-state disks used in computers and large data centers. (more…)
Berkeley Lab Researchers Unlock Ferromagnetic Secrets of Promising Materials
Spintronic technology, in which data is processed on the basis of electron “spin” rather than charge, promises to revolutionize the computing industry with smaller, faster and more energy efficient data storage and processing. Materials drawing a lot of attention for spintronic applications are dilute magnetic semiconductors – normal semiconductors to which a small amount of magnetic atoms is added to make them ferromagnetic. Understanding the source of ferromagnetism in dilute magnetic semiconductors has been a major road-block impeding their further development and use in spintronics. Now a significant step to removing this road-block has been taken.
A multi-institutional collaboration of researchers led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), using a new technique called HARPES, for Hard x-ray Angle-Resolved PhotoEmission Spectroscopy, has investigated the bulk electronic structure of the prototypical dilute magnetic semiconductor gallium manganese arsenide. Their findings show that the material’s ferromagnetism arises from both of the two different mechanisms that have been proposed to explain it. (more…)
*Berkeley Lab scientists helped build and operate the ALPHA antimatter trap at CERN, which has now probed the internal structure of the antihydrogen atom for the first time, taking the first step toward possible new insights into the difference between matter and antimatter*
The ALPHA collaboration at CERN in Geneva has scored another coup on the antimatter front by performing the first-ever spectroscopic measurements of the internal state of the antihydrogen atom. Their results are reported in a forthcoming issue of Nature and are now online.
Ordinary hydrogen atoms are the most plentiful in the universe, and also the simplest – so simple, in fact, that some of the most fundamental physical constants have been discovered by measuring the tiny energy shifts resulting from the magnetic and electric interactions of hydrogen’s proton nucleus with its single orbiting electron. (more…)
*Berkeley Lab Researchers Resolve Controversy Over Gallium Manganese Arsenide that Could Boost Spintronic Performance*
A long-standing controversy regarding the semiconductor gallium manganese arsenide, one of the most promising materials for spintronic technology, looks to have been resolved. Researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) in collaboration with scientist from University of Notre Dame have determined the origin of the charge-carriers responsible for the ferromagnetic properties that make gallium manganese arsenide such a hot commodity for spintronic devices. Such devices utilize electron spin rather than charge to read and write data, resulting in smaller, faster and much cheaper data storage and processing. (more…)