Phyicists Find a Charge Separation in a Molecule Consisting of Two Identical Atoms

"A dipolar molecule forms as a result of a charge separation between the negative charged electron cloud and the positive core, creating a permanent electric dipole moment. Usually this charge separation originates in different attraction of the cores of different elements onto the negative charged electrons. Due to symmetry reasons homonuclear molecules, consisting only of atoms of the same element, therefore could not possess dipole moments."

"However, the dipolar molecules that were discovered by the group of Prof. Tilman Pfau at the 5th Institute of Physics at the University of Stuttgart do consist of two atoms of the element rubidium. The necessary asymmetry arises as a result of different electronically excited states of the two alike atoms. Generally this excitation will be exchanged between the atoms and the asymmetry will be lifted. Here this exchange is suppressed by the huge size of the molecule, which is about 1000 times larger than an oxygen molecule and reaches sizes of viruses. Therefore the probability to exchange the excitation between the two atoms is so small that it would statistically only happen once in the lifetime of the universe. Consequently, these homonuclear molecules possess a dipole moment. A permanent dipole moment additionally requires an orientation of the molecular axis. Due to their size the molecules rotate so slowly that the dipole moment does not average out from the viewpoint of an observer."

Single Ions--Extremely Cool

"Quantum logic is quite a new and absolutely fascinating field of physics and might - ultimately - lead to the fabrication of a quantum computer. And it could also aid the search for the "theory of everything" - the missing link between traditional physics and quantum physics. One of the fundamental questions hereby is whether fundamental constants possibly vary. To prove this in the case of the fine-structure constant, for instance, we have to measure the spectral lines of atoms (i.e. their inner structure) more accurately than ever before. Quantum logic spectroscopy provides such a method. Physicists from the QUEST Institute at the Physikalisch-Technische Bundesanstalt (PTB) and from the Leibniz University of Hanover have come one decisive step closer to this goal: instead of complex laser arrangements, all they need is one single laser source to bring a single magnesium ion to a complete standstill. Then they use this ion to determine the properties of another ion. The new method has been published in the specialized journal Applied Physics B."

New Technique For Understanding Quantum Effects in Water

ScienceDaily (2011-10-04) -- The use of oxygen isotope substitution will lead to more accurate structural modeling of oxide materials found in everything from biological processes to electronic devices, new research suggests.

Brightest Gamma Ray on Earth--for a safer, healthier world

"Physicists have discovered that ultra-short duration laser pulses can interact with ionised gas to give off beams that are so intense they can pass through 20 cm of lead and would take 1.5 m of concrete to be completely absorbed."

"The ray could have several uses, such as in medical imaging, radiotherapy and radioisotope production for PET (positron emission tomography) scanning. The source could also be useful in monitoring the integrity of stored nuclear waste."

Squeezed laser will bring gravitational waves to the light of day

ScienceDaily (2011-09-11) -- Measuring at the limits of the laws of nature -- this is the challenge which researchers repeatedly take up in their search for gravitational waves. The interferometers they use here measure with such sensitivity that a particular quantum phenomenon of light -- shot noise -- limits the measuring accuracy. With the "squeezed light" method, scientists in Germany likewise use quantum physics in a countermove in order to remove the interfering effect. The new type of laser light improves the measuring accuracy of the gravitational wave detector GEO600 by around 50 percent and thus increases its effective sensitivity. This is the first time this technology has been used outside of a test laboratory anywhere in the world.

LHC Results Put Supersymmetry Theory 'On the Spot'

"Results from the Large Hadron Collider (LHC) have all but killed the simplest version of an enticing theory of sub-atomic physics"

"Researchers failed to find evidence of so-called "supersymmetric" particles, which many physicists had hoped would plug holes in the current theory."

"Theorists working in the field have told BBC News that they may have to come up with a completely new idea."

Rare Particle Decay Could Mean New Physics

"An incredibly rare sub-atomic particle decay might not be quite as rare as previously predicted, say Cornell researchers. This discovery, culled from a vast data set at the Collider Detector at Fermilab (CDF), is a clue for physicists trying to catch glimpses of how the universe began."

Bending Light the 'Wrong" Way

Bending light the 'wrong' way

(PhysOrg.com) -- Scientists have tried this with sophisticated meta-materials, but at the Vienna University of Technology (TU Vienna) it has now been done with simple metals; materials with a negative refractive index bend light the "wrong" way.