by Staff Writers
Munich, Germany (SPX) Aug 01, 2012
Phase transitions between different states of matter can be associated with a specific type of excitation called the "Higgs excitation". This phenomenon has now been ob-served in a two-dimensional quantum gas at temperatures near absolute zero. In physics spontaneous symmetry breaking is a fundamental feature of transitions between different states of matter.
An example of this phenomenon is the abrupt alignment of spin orientation in a ferromagnetic substance when the material is cooled below the so-called Curie temperature.
Phase transitions introduce a new degree of order into the system, which may in turn provoke a specific type of excitation that causes the ensemble of particles to behave in a coordinated fashion. If their collective motion conforms to rules akin to those of the theory of relativity, a so-called Higgs excitation may arise.
Tracking transient excitations
The problem is that, as in particle physics, they are difficult to detect ex-perimentally because they rapidly decay.
Higgs excitations are expected to have particularly short lifetimes in low-dimensional atomic systems. Indeed, some physicists have doubted whether they could be observed in such systems at all.
An unpredictable phenomenon
For the experiments, they used an ultracold two-dimensional gas made up of rubidium atoms. This system is in the vicinity of a phase transition, in a state that behaves in accordance with relativistic field theories.
"We are excited to study phenomena close to absolute zero temperature that usually occur at the highest energies", says Bloch. Furthermore, the observations allow the researchers to characterize a phenomenon that is, as yet, not fully understood theoretically. This makes the new data still more valuable. (Nature, 2012) MPQ/god
Publication: Manuel Endres, Takeshi Fukuhara, David Pekker, Marc Cheneau, Peter Schaub, Christian Grob, Eugene Demler, Stefan Kuhr, and Immanuel Bloch The 'Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Tran-sition Nature, 26. July, 2012.
Understanding Time and Space
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Munich, Germany (SPX) Jul 31, 2012
Phase transitions between different states of matter can be associated with a specific type of excitation called the "Higgs excitation". This phenomenon has now been ob-served in a two-dimensional quantum gas at temperatures near absolute zero. In physics spontaneous symmetry breaking is a fundamental feature of transitions between different states of matter. An example of this phenomenon ... read more
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