Physics

Researchers at Pacific Northwest National Laboratory are uniting theory, computation and experiment to discover exactly how heavy elements, such as uranium and technetium, interact in their environment.

As part of that effort, scientists have combined sensitive experimental measurements with fi rst principle electronic structure calculations to measure, and to really understand, the structural and bonding parameters of uranyl, the most common oxidation state of uranium in systems containing water.

The insights were achieved by PNNL scientist Bert de Jong and associates Gary Groenewold of Idaho National Laboratory and Michael Van Stipdonk of Wichita State University, employing the supercomputing resources of the William R.

Some materials change their electrical resistance in the presence of an external electromagnetic field. This concept is fundamental to data storage. Understanding large resistance changes, known as colossal magnetoresistance, could lead to new devices with increased data density and reduced power requirements.

"This is an extremely important piece of work with broad potential application in developing the next generation of electronic and data-storage devices," said Brookhaven physicist Yimei Zhu.

The Brookhaven scientists were studying crystalline perovskite manganites that had been doped with extra charge carriers - electrons or "holes" (the absence of electrons) - using various state-of-the-art electron microscopy techniques.

Could extraterrestrial life be made of corkscrew-shaped particles of interstellar dust? Intriguing new evidence of life-like structures that form from inorganic substances in space are revealed today in the New Journal of Physics. The findings hint at the possibility that life beyond earth may not necessarily use carbon-based molecules as its building blocks. They also point to a possible new explanation for the origin of life on earth.

Life on earth is organic.

For the past few months, members of the department of physics at Florida State University have begun using a groundbreaking new research facility to conduct experiments that may help provide answers to just such questions.

RESOLUT -- short for "REsonator SOLenoid with Upscale Transmission" -- is the name of the facility, which is located within the John D. Fox Superconducting Accelerator Laboratory on the FSU campus.

Most continental rocks on Earth align their magnetic moments with the current magnetic field – they are said to have ‘induced’ magnetism. “I consider induced rocks to have ‘Alzheimers’. These are the rocks that forgot where they were born and how to get home,” explains Suzanne McEnroe from the Geological Survey of Norway at a European Science Foundation (ESF), EuroMinScI conference near Nice, France this year.

However, not all of Earth’s continental rocks have an induced magnetization. Some rocks stubbornly refuse to swing with the latest magnetic field, and instead keep hold of the direction they were born with. These rocks are said to have a remanent magnetization.

When most people look at a window they see solid panes of glass but to physicists it isn't so simple. Window glass has always been a puzzle but an Emory University research team led by physicist Eric Weeks has found another clue.

Weeks has devoted his career to probing the mysteries of "squishy" substances that cannot be pinned down as a solid or liquid. Referred to as "soft condensed materials," they include everyday substances such as toothpaste, peanut butter, shaving cream, plastic and glass.

Scientists fully understand the process of water turning to ice.

A nuclear physicist from Florida State University collaborated with other scientists from the United States, Japan and England in an experiment that illustrated how the “normal” rules of physics don’t apply for some unstable elements.

Kirby W. Kemper, the Robert O. Lawton Distinguished Professor of Physics and vice president for Research at FSU, took part in an experiment at the National Superconducting Cyclotron Laboratory, a national user facility located at Michigan State University in East Lansing, Mich. In the experiment, Kemper and his colleagues found that the structure of atomic nuclei of one radioactive isotope in particular -- magnesium-36, or Mg-36 -- is odd and unexpected.

“Ten years ago, complicated experiments like this one were a dream,” Kemper said.

Most people think of Sir Isaac Newton as the father of gravity but he also created one of the earliest observations of interference in his “dusty mirror” experiment.

In a darkened room, he used a prism and a small hole in a screen to form a quasi-monochromatic beam from sunlight, which he shone onto a back-quick silvered mirror. The mirror was angled to return the beam back through the hole and on the screen. Newton observed dark and light rings of light, which he found “strange and surprising.”

It was 100 years later when the British scientist Thomas Young determined the rings were caused by interference at the screen between two paths of light scattering from dust particles on the mirror's front surface.

Like navigating spacecraft through the solar system by means of gravity and small propulsive bursts, researchers can guide atoms, molecules and chemical reactions by utilizing the forces that bind nuclei and electrons into molecules (analogous to gravity) and by using light for propulsion. But, knowing the minimal amount of light required, and how that amount changes with the complexity of the molecule, has been a problem.

Now, by creating a quantum mechanical analog of Ulam’s conjecture, researchers at the University of Illinois and the University of California have expanded the flexibility and controllability of quantum mechanical systems.

The dream of theoretical physics is to unite behind a common theory that explains everything, but that goal has remained highly elusive.

String theory emerged 40 years ago as one of the most promising candidates for such a theory, and has since slipped in and out of favor as new innovations have occurred. Now Europe is fortunate to have one of the world’s leading experts in string theory working on an ambitious project that could make significant progress towards a unified theory, and at least help resolve two mysteries.

One is how the universe emerged in the beginning as a random fluctuation of a vacuum state, and the other is a common explanation for all sub-atomic particles.