However, ultra-cold atoms do not do this, a phenomenon known as ‘many-body localisation’. Normally, many regular interacting atoms will swirl around and mix in a system, losing all memory of their previous state. Though many of the major experiments are still ongoing, he says the project has already had an intriguing result, by providing confirmation of behaviour that had previously only been predicted by theory.
Once the atoms are cool enough, the researchers place them in a special grid of lasers that hold them in place in an ordered way, like eggs in a carton, or in a random landscape. When the sides of the trap are fully lowered, around 1 % of the original atoms - the very coldest - are left at the bottom. The process of ultra-cooling atoms is usually done in two main ways, laser cooling, which uses lasers to slow down an atom, and evaporative cooling, which traps atoms in an electromagnetic ‘jar’ which helps atoms to shed their energy. ‘Questions, for example, of whether when one does an experiment at increasingly long time, (do) the quantum effects decay or survive in this system?’ he said. Altman believes they can answer questions about how atoms behave at the border of everyday and quantum physics. Since ultra-cold atoms can be controlled and monitored better, Prof. The group focuses on theoretical aspects of ultra-cold atoms which can be tested in UQUAM’s experimental centres in Germany and France. Altman heads a theoretical research group at the Weizmann Institute of Science, Israel. ‘Everything evolves in time slowly and you can really watch the evolution in real time, you can measure things in a more detailed way than you can measure with any other system,’ he said. ‘Ultra-cold atoms give you a big advantage in that they give you amazing control over interactions and the measurements you make on the system,’ said Professor Ehud Altman, one of four principal investigators in the project. The UQUAM project, funded by the EU’s European Research Council (ERC), cools atoms to near this temperature in order to see how they behave and how we may control these near-still atoms. ‘Nothing mixes, nothing moves, so you cannot even define the temperature.’ Professor Ehud Altman, Weizmann Institute of Science, Israel The heat in a scalding cup of coffee is actually caused by the atoms that make up the drink moving, spinning, or shaking at a faster rate than the comparatively slower atoms in a cold coffee.Ītoms will move less as the environment becomes colder, coming to a complete standstill at absolute zero (0° Kelvin, or -273.25° Celsius). Understanding more about quantum behaviour has applications as diverse as high speed computing and better solar cells.Īt the atomic level, heat is nothing more than the extent by which atoms move. Now, scientists are developing ways of watching these tiny particles in slow motion, opening a new window into this mysterious world. The smallest known particles, such as photons and electrons, follow their own rules of behaviour described as quantum physics. The closer you look at something, the more strangely it behaves.
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