The international collaboration is comprised of researchers from the University of Colorado, USA and the Niels Bohr Institute at the University of Copenhagen and the results have just been published in the prestigious scientific journal, Science.
An atomic clock consists of gas atoms captured in a magnetic field where they are held stationary with precise laser light and are cooled down to near absolute zero, minus 273 degrees Celsius. In this state the researchers can use the quantum properties of the atoms and get them to function as a clock movement with a pendulum."An atom consists of a nucleus and some electrons that spin in clearly defined orbits around the nucleus. By using the focused laser light one can make the electron swing back and forth in a clearly defined way between these orbits, and it is that which forms the pendulum in the atomic clock", explains nuclear physicist at the Niels Bohr Institute at the University of Copenhagen, Jan W. Thomsen, who has worked with the new experiments together with researchers at the University of Colorado in Boulder, USA.
"The problem was that the atoms did not behave as they should according to the theory of quantum physics", tells Jan W. Thomsen and explains, that atoms have two fundamental states – they either rotate a complete revolution around themselves and are then called bosons or they rotate half-integers (½ or 1½) around themselves and are then called fermions. These two types behave completely differently. The bosons clump tightly together, while the fermions are repelled by each other and it is impossible to get them near to each other.
Journey into the quantum world
For atomic clocks one uses fermions because they do not interact – according to the theory of physics of quantum mechanics. Yet they did, as it turned out. And what was the reason? The researchers wanted to find out what was really happening and they started a colossal series of time consuming experiments that have given a whole new insight into how cold atoms behave.
"It was an fascinating journey into the world of quantum mechanics. We found out that not all fermions were the same. At the very low temperatures the fermions begin to 'see' each other and interact and then the atomic clock begins to go awry", explains Jan W. Thomsen. The experiments showed that the fermion's quantum properties were being affected by the exposure to light itself and this lead to the loss of precision in the atomic clock. By tuning the light frequency in a certain way one could control the fermions and avoid the loss of precision.
The result is that an atomic clock is now three times more precise than before and that the clock now loses only one second per 300 million years as opposed to one second per 150 million years. Even though it is only small fraction of a second, it has great potential in the application in areas having to do with the determination of great distances, for example, measuring the distance to distant galaxies in space. If one looks back towards the Earth one could measure the tiny movements in the continental drift and that can perhaps give geophysicists a new tool to work with to predict earthquakes.
The question is whether they are now satisfied with the atomic clock's precision? "Not completely", answers Jan W. Thomsen, "we dream of getting an atomic clock with perfect precision". So the research in the world of quantum mechanics continues towards a new goal.
Jan W. Thomsen, PhD. nuclear physicist, Niels Bohr Institute, University of Copenhagen, +45 3532-0463, +45 3532-0462, firstname.lastname@example.org
Gertie Skaarup | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences