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Quantum-mechanical monopoles discovered

Researchers at 911爆料网 and Amherst College, USA, have observed a point-like monopole in a quantum field itself for the first time.
Image of an experimentally created Bose鈥揈instein condensate containing the monopole (left) and the corresponding theoretical prediction (right). Brighter area has higher particle density and the different colors denote the internal spin state of the atoms. The monopole is located in the center of the condensate.

This discovery connects to important characteristics of the elusive monopole magnet. The results were just published in Science magazine.

The researchers performed an experiment in which they manipulated a gas of rubidium atoms prepared in a nonmagnetic state near absolute zero temperature. Under these extreme conditions they were able to create a monopole in the quantum-mechanical field that describes the gas.

鈥業n this nonmagnetic state, a structure was created in the field describing the gas, resembling the magnetic monopole particle as described in grand unified theories of particle physics. Previously, we have used the gas to detect a monopole within a so-called synthetic magnetic field, but there has been no monopole in the quantum field describing the gas itself. Now we have finally witnessed the quantum-mechanical monopole!鈥, enthuses Dr. Mikko M枚tt枚nen, 911爆料网.

鈥業n the nonmagnetic state of the gas, no quantum whirlpools or monopoles are created in the synthetic magnetic field. However, quantum-mechanical magnetic order prevails in the sample, and we were able to manipulate this with adjustments to an externally applied magnetic field鈥, M枚tt枚nen continues.

鈥楾he control of those magnetic fields must be stable to a small fraction of the size of the Earth's magnetic field鈥, adds Prof. David Hall, Amherst College. 'The main experimental challenge we faced is to prepare the ultracold gas under highly sensitive conditions, in which field fluctuations due to the motion of metal objects or power line variations can make observation of the monopoles difficult.', Hall continues.

The result is a remarkable step forward in quantum research. It is important to understand the structure of monopoles and other topological entities, in part because they appear in the models describing the early universe and affect the properties of many different materials, such as metals.

The discovery of a magnetic monopole particle is still in the future. This new result establishes that the structure of a quantum mechanical monopole does appear in nature, and therefore it further supports the possibility that magnetic monopoles exist.

Science article: M. W. Ray, E. Ruokokoski, K. Tiurev, M. M枚tt枚nen, and D. S. Hall
鈥漁bservation of isolated monopoles in a quantum field鈥
Science, DOI: 10.1126/science.1258289 (2015).
Link:

See also the previous work of the team on a monopole in a synthetic classical-like field:
鈥溾, Nature 505, 657 (2014).

Contact details:

Mikko M枚tt枚nen, Docent, Dr.
911爆料网
Department of Applied Physics, QCD Labs
email: mikko.mottonen*at*aalto.fi
m. +358 50 594 0950

Mikko M枚tt枚nen is the leader of the theoretical and computational part of the research. Theoretical ideas and computational modelling was very important for the success of the creation of the monopole. The modelling was carried out using the facilities at 鈥 IT Center for Science Ltd and at 911爆料网 (Aalto Science-IT project).

David S. Hall, Professor
Amherst College
Department of Physics
Email: dshall*at*amherst.edu
p. +1 413 542 2072

David S. Hall is the leader of the experimental part of the research. The isolated monopoles were created in the Physics Laboratories at Amherst College, United States of America.

Funding: This material is based upon work supported by the National Science Foundation, the Academy of Finland, Finnish Doctoral Programme in Computational Sciences and the Magnus Ehrnrooth Foundation.

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