G. A. Kazakov, A. N. Litvinov, V. I. Romanenko, L. P. Yatsenko, A. V. Romanenko, M. Schreitl, G. Winkler, T. Schumm The 7.8 eV nuclear isomer transition in 229-Thorium has been suggested as an etalon transition in a new type of optical frequency standard. Here we discuss the construction of a “solid-state nuclear clock” from… [Read more…]
March 28, 2012
Read more: physicsworld.com/cws/article/news/49135 Global Positioning System Test of the Local Position Invariance of Planck’s Constant J. Kentosh and M. Mohageg Phys. Rev. Lett. 108, 110801 (2012) Published March 15, 2012 Pinpointing Planck’s Constant with GPS GPS is helping drivers find their way and parents track their kids and pets. But now a pair of researchers—reporting in Physical Review Letters—has used… [Read more…]
March 17, 2012
… using Precision Measurements of Helium Fine Structure Marc Smiciklas Spectroscopic measurements of the helium atom are performed to high precision using an atomic beam apparatus and electro-optic laser techniques. These measurements, in addition to serving as a test of helium theory, also provide a new determination of the fine structure constant α. An apparatus… [Read more…]
March 8, 2012
A New Result From ALPHA Once you’ve trapped antihydrogen what do you do? You measure it! That’s just what we’ve done. Published in Nature, we report the first resonant quantum transitions in antihydrogen atoms. We’ve used microwave radiation to change the internal state of the atom, from one which can be kept in our trap,… [Read more…]
February 27, 2012
IBM scientists were able to measure for the first time how charge is distributed within a single molecule. This achievement will enable fundamental scientific insights into single-molecule switching and bond formation between atoms and molecules. Furthermore, it introduces the possibility of imaging the charge distribution within functional molecular structures, which hold great promise for future… [Read more…]
February 19, 2012
In a remarkable feat of micro-engineering, UNSW physicists have created a working transistor consisting of a single atom placed precisely in a silicon crystal. http://youtu.be/ue4z9lB5ZHg Read more here
February 7, 2012
Helge Kragh Modern atomic and nuclear physics took its start in the early part of the twentieth century, to a large extent based upon experimental investigations of radioactive phenomena. Foremost among the pioneers of the new kind of physics was Ernest Rutherford, who made fundamental contributions to the structure of matter for more than three… [Read more…]
January 27, 2012
The question of whether normal matter’s shadowy counterpart anti-matter exerts a kind of “anti-gravity” is set to be answered, according to a new report. Normal matter attracts all other matter in the Universe, but it remains unclear if anti-matter attracts or repels it. A team reporting in Physics Review Letters says it has prepared stable pairs of… [Read more…]
January 24, 2012
Rice University physicists have built an accurate model of part of the solar system inside a single atom. In a new paper in Physical Review Letters, Rice’s team and collaborators from Oak Ridge National Laboratory and the Vienna University of Technology showed they could make an electron orbit the atomic nucleus in the same way… [Read more…]
January 23, 2012
The Millikan oil drop experiment, published in final form in 1913, demonstrated that charge comes in discrete chunks and was a bridge between classical electromagnetism and modern quantum physics. Researchers now routinely isolate single electrons in quantum dots, but a century ago the state-of-the-art charge-trapping device was a droplet of clock oil. Robert Millikan’s oil… [Read more…]
January 3, 2012
Phys. Rev. Lett. 107, 270802 (2011) [4 pages] Molecular Gas Sensing Below Parts Per Trillion: Radiocarbon-Dioxide Optical Detection I. Galli, S. Bartalini, S. Borri, P. Cancio*, D. Mazzotti, P. De Natale, and G. Giusfredi Istituto Nazionale di Ottica-CNR (INO-CNR) and European Laboratory for Non-Linear Spectroscopy (LENS) Via N. Carrara 1, I-50019 Sesto Fiorentino, Italy Radiocarbon (14C) concentrations at a 43 parts-per-quadrillion… [Read more…]
December 19, 2011
Lars Vegard and X-ray spectroscopy Helge Kragh The Norwegian physicist Lars Vegard may have been the first to propose electron configurations for all the chemical elements, from hydrogen to uranium, on the basis of quantum atomic theory. This he did in papers of 1918-1919 in which he argued that the principal quantum number corresponded to… [Read more…]
November 13, 2011
Alexei M. Frolov The general formula for the interaction potential between two point electric charges is derived. This analytical formula has the correct asymtotic behaviour at large distances between two interacting charges. The derivation of this formula is based on the closed analytical expression for the Uehling potential obtained earlier (A.M. Frolov and D.M. Wardlaw,… [Read more…]
October 14, 2011
A research group led by ETH Zurich has now, for the first time, visualized the motion of electrons during a chemical reaction. The new findings in the experiment are of fundamental importance for photochemistry and could also assist the design of more efficient solar cells. In 1999, Ahmed Zewail was awarded the nobel prize in… [Read more…]
September 16, 2011
AN ELECTRON takes just billionths of a billionth of a second to escape its host molecule – mere attoseconds. Now we have the first snapshots of what is the initial step in almost every chemical reaction. “We can watch not only the atoms and the nuclei in a chemical reaction. Now we can even watch… [Read more…]
September 3, 2011
By tightly focussing a laser eld onto a single cold ion trapped in front of a far-distant dielectric mirror, we could observe a quantum electrodynamic e ect whereby the ion behaves as the optical mirror of a Fabry-Perot cavity. We show that the amplitude of the laser eld is signi cantly altered due to a modi cation of… [Read more…]
September 1, 2011
Since the first optical microscopes appeared in the late 1600s – an exact date and original inventor elude precise identification – microscopy has evolved dramatically. Scanning tunneling microscopy (STM), atomic force microscopy (AFM) and (although not generally recognized as an established method) point contact microscopy (PCM) allow scientists to view objects inaccessible to optical microscopes,… [Read more…]
August 27, 2011
The machine, which is responsible for keeping Britain’s clocks on track and also contributes to the international measure of time, is accurate to within two 10 million billionths of a second. It is one of a handful of similar clocks which determine the exact length of a second by measuring microwaves as they cause reactions… [Read more…]
August 16, 2011
An international collaboration of researchers is working on a new method of understanding what happens during chemical reactions. The approach is extremely complex, as it involves tracking the behavior of individual electrons as this happens. Doing so is a monumentally difficult task, considering that the elementary particle completes a full orbit around an atomic nucleus… [Read more…]
August 5, 2011
A series of public lectures taking place next week will look at the legacy of Rutherford’s discovery and give citizens of Manchester the chance to join nuclear physicists from around the world in celebrating his 100-year-old model of the atom. The lectures will explain how fundamental physics has moved on from Rutherford’s discovery to the… [Read more…]
July 25, 2011
Physicists in the US have shown that positronium – a short-lived bound state of a positron and an electron – can be produced by firing a laser beam onto a silicon surface. Because the technique is highly controllable and operates over a wide range of temperatures, it could prove extremely useful in low-temperature experiments designed… [Read more…]
June 10, 2011
A team of Virginia Commonwealth University scientists has discovered a new class of ‘superatoms’ — a stable cluster of atoms that can mimic different elements of the periodic table — with unusual magnetic characteristics….. Read more: http://www.sciencedaily.com/releases/2011/06/110608153544.htm
June 8, 2011
They have existed for less than a second each, but two new elements have been added to the Periodic Table Evidence for the existence of the two elements, the heaviest yet to be included, has been mounting for several years. A number of research teams had claimed to have produced the heavy elements by smashing… [Read more…]
June 6, 2011
Scientists have successfully stored anti-matter – the mysterious substance used as a weapon of mass destruction in the novels of Da Vinci Code author Dan Brown. Researchers at CERN, home of the Large Hadron Collider, had bottled antimatter back in 2010, keeping hold of the atoms for a fraction of a second. But CERN have now… [Read more…]
May 13, 2011
COULD the structure of space and time be sketched out inside a cousin of plain old pencil lead? The atomic grid of graphene may mimic a lattice underlying reality, two physicists have claimed, an idea that could explain the curious spin of the electron. Graphene is an atom-thick layer of carbon in a hexagonal formation.… [Read more…]
May 12, 2011
from Ching Yeh Lin, Andrew T.B. Gilbert (Research School of Chemistry, ANU), Mark A. Walker (Manly Astrophysics) “We consider the possibility that solid molecular hydrogen is present in interstellar space. If so cosmic-rays and energetic photons cause ionisation in the solid leading to the formation of H+6. This ion is not produced by gas-phase reactions… [Read more…]
May 3, 2011
..from Antihydrogen Laser Physics Apparatus (ALPHA) Atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, made entirely of antiparticles, is believed to be stable, and it is this longevity that holds the promise of precision studies of matter-antimatter symmetry. We have recently demonstrated trapping of antihydrogen atoms by releasing them… [Read more…]
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April 21, 2012
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