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Observing the emergence of a quantum phase transition shell by shell

The upper part represents the experiment with a laser that shines on the 2D trap with atoms. In the lower part you can see how the atoms act when they pair, while the water represents their properties as superfluids. Illustration: Jonas Ahlstedt.
The upper part represents the experiment with a laser that shines on the 2D trap with atoms. In the lower part you can see how the atoms act when they pair, while the water represents their properties as superfluids. Illustration: Jonas Ahlstedt.

By studying cold atoms, researchers have in a unique way been able to observe a precursor to a quantum phase transition, and thereby study physical processes that can be compared to the Higgs mechanism. The discovery can, among other things, provide more knowledge about quantum mechanical processes that are similar to the processes in which matter changes its state from gas, liquid, or solid form into another state. The result can also provide more knowledge about superfluids and superconductors.

Stephanie Reimann, professor of Mathematical Physics and a Principal Investigator at NanoLund, has together with former post doc Johannes Bjerlin at LTH, and colleagues in Heidelberg in Germany and Aarhus in Denmark, recently succeeded in conducting a study, built around a unique experiment in Germany, where this analogy to the Higgs mechanism can now be confirmed in a system with only a few atoms.

“We started working on the theoretical basis for how quantum phase transitions occur in systems with a few particles five years ago, but now our colleagues in Germany have succeeded in conducting an experiment that confirms that theory with unusually high precision”, says Johannes Bjerlin.

Link to a press-release about the precursor to a quantum phase transition on LU:s swedish website

Link to full the article "Observing the emergence of a quantum phase transition shell by shell" on Nature's website