Physics

An international team of scientists, including several at The Johns Hopkins University, has detected a hidden magnetic “quantum order” that extends over chains of nearly 100 atoms in a material that is otherwise magnetically disordered.

The findings, which are published online today (July 26) in the journal Science, may have implications for the design of devices and materials for quantum information processing, including large-scale quantum computers capable of tackling problems exponentially faster than can conventional computers.

The team’s results are important because they demonstrate that the magnetic moments (the measure of the strength of a magnetic source) of a large number of atoms can band together to form quantum states much like those of a very large molecule.

Physicists at the Commerce Department’s National Institute of Standards and Technology (NIST) have induced thousands of atoms trapped by laser beams to swap “spins” with partners simultaneously.

The repeated exchanges, like a quantum version of swinging your partner in a square dance but lasting a total of just 10 milliseconds, might someday carry out logic operations in quantum computers, which theoretically could quickly solve certain problems that today's best supercomputers could not solve in years.

The atomic dance advances prospects for the use of neutral atoms as quantum bits (qubits) for storing and processing data in quantum computers.

There are many objects in nature, such as flowers, that are “pre-programmed” to develop into delicate, beautiful and intrically shaped forms. But can this pre-determined process be duplicated by man starting with plain, flat surfaces?

Yes, say Dr. Eran Sharon and his co-workers, Yael Klein and Efi Efrati, at the Hebrew University of Jerusalem Racah Institute of Physics, who have succeded for the first time anywhere in programming polymer sheets to bend and wrinkle by themselves into prescribed structures. Their work was described in the journal Science.

They made flat discs of a soft gel that, when warmed gently, curved into domes, saddles and even sombrero shapes.

New fundamental particles aren’t found only at Fermilab and at other particle accelerators. They also can be found hiding in plain pieces of ceramic, scientists at the University of Illinois report.

The newly formulated particle is a boson and has a charge of 2e, but does not consist of two electrons, the scientists say. The particle arises from the strong, repulsive interactions between electrons, and provides another piece of the high-temperature superconductivity puzzle.

Twenty-one years ago, superconductivity at high temperatures was discovered in copper-oxide ceramics (cuprates).

Each time you press "save" on your computer you force atoms on magnets to align their polarity with the intruding magnetic field. Helping physicists understand why it happens and why it isn't a physics-induced train wreck more often is the goal of Joshua Deutsch and Andreas Berger and they say their research could advanced materials research.

Correcting even a single typo in an e-mail means changing dozens of bits of information. For each bit, a magnetic head grazes a tiny patch of your disk drive, forcing its polarity, or "spin," to align up or down--the magnetic equivalent of a one or a zero.

It may seem odd to think about using metallic structures for transmitting light because light quickly attenuates on passing through a metal, but light waves travelling only a few centimeters don't lose their energy and that discover could change the face of nanotechnology.

The discovery, known as acoustic plasmon, are surface plasmons formed by the group excitation of electrons but it is produced by the interaction between light and metal surfaces.

The advantage of acoustic plasmons over the long-known surface plasmons is that they are created with a different amount of energy.

A research team headed by Yadong Yin at the University of California, Riverside has created a liquid that changes its color “on demand” and can take on any color of the rainbow.

Nanoscopic particles made of tiny magnetic crystals coated with a plastic shell self-assemble in solution to form photonic crystals—semiconductors for light. When a magnetic field is applied, the optical properties of the crystals change, allowing their color to be very precisely adjusted through variation of the strength of the field.

The crystals involved are not “conventional” lattices of ions or molecules like the ones for salt. They are colloidal crystals, periodic structures that form from uniform solid particles that are finely dispersed in a liquid.

Very precise time keeps the Internet and e-mail functioning, ensures television broadcasts arrive at our TVs and is integral to a network of global navigation satellites (such as the Global Positioning System) used for precision mapping and surveying, environmental monitoring and personal location-based services. But time can only be useful if it is the same for everyone. And that requires a single source against which we can all check our clocks.

CERN Director General Robert Aymar announced that the Large Hadron Collider (LHC) will start up in May 2008 despite the fact that a low-energy run originally scheduled for this year has been dropped due to delays, coupled with the failure in March of a pressure test in one of the machine’s components.

In that instance, a magnet assembly known as the inner triplet, provided to CERN as part of the contribution of the US to the LHC project, failed a pressure test. A repair has been identified and is currently being implemented.

The LHC is a scientific instrument of unprecedented complexity, and at 27 kilometers in circumference, is the world’s largest superconducting installation.

A new type of stainless steel alloy developed at Oak Ridge National Laboratory could allow for significantly increased operating temperatures and corresponding increases in efficiency in future energy production systems.

The new alloys offer superior oxidation resistance compared to conventional stainless steels, without significant increased cost or decreased creep resistance (sagging at high temperature). What sets this proprietary material apart from other stainless steels is its ability to form protective aluminum oxide scales instead of chromium oxide scales.

The combination of creep and oxidation resistance offered by these alloys previously was available only with nickel-base alloys, which are about five times more costly than the new stainless steels.