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!
New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology
Light rays from a supernova bent by the curvature of space-time around a galaxy
21.04.2017 | Stockholm University
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy