HomeNewsPhysicsMystery object attributable to spontaneous symmetry breaking revealed

Mystery object attributable to spontaneous symmetry breaking revealed


Figure 1: Composite defect in a 23Na superfluid confined in a pancake-shaped two-dimensional “electromagnetic container”. The blacker colour signifies a area of excessive fluid density. The core of the topological defect corresponds to the white area within the heart of the image. Credit: Phys. Rev. Lett. 122, 095301 (2019)

Hiromitsu Takeuchi, a lecturer on the Graduate School of Science, Osaka City University, and a researcher on the Nambu Yoichiro Institute of Theoretical and Experimental Physics (NITEP), has theoretically recognized the character of a mysterious topological defect produced by the not too long ago found non-equilibrium time evolution of spontaneous symmetry breaking (SSB). Since the SSB realized on this system is just like the SSB that has been identified to happen in isotropic superconductors and superfluid 4He, it was anticipated to provide topological defects with vortex-like properties within the fluid, referred to as quantum vortices. However, the topological defect noticed on this experiment has a construction that bore little resemblance to the beforehand talked about SSB, and its bodily properties have been shrouded in thriller. In this analysis, the concept of making use of the Joukowski rework, which is used to calculate the elevate of airplane wings, to quantum vortices was launched for the primary time, and the evaluation revealed that probably the most steady state of this mysterious topological defect is a brand new topological defect referred to as a quantum elliptic vortex. The outcomes of this analysis have been revealed on-line in Physical Review Letters, thought of to be one of the vital prestigious journals within the area of physics.


A time- and space-dependent operate referred to as a “field” is usually used to explain the properties of bodily programs through which SSB happens. If the movement of the sphere may be calculated, the habits of the system may be predicted. However, the calculation is mostly troublesome as a result of the levels of freedom of the sphere are infinite.

One efficient strategy to describe the advanced movement of a area is to symbolize the levels of freedom of an object floating in it, referred to as a topological defect. The area across the “core” of a topological defect has a sure construction. Therefore, by describing the middle of the core because the movement of a mass level, the movement of the sphere may be roughly predicted.

This state of affairs is much like how the long run change in wind route may be predicted to some extent by trying on the path of the attention of a storm. In supplies the place SSB usually happens, resembling superconductors and superfluids, this “wind” corresponds to present with out resistance and stream with out friction, respectively. Since the construction of the sphere across the core may be predicted in response to the symmetry breaking, it has been thought that the habits of topological defects, and therefore the habits of the sphere, may be understood if the symmetry breaking is known on a worldwide scale.

Mystery object caused by spontaneous symmetry breaking revealed
Figure 2: Flow (numerical calculation) round an odd rotationally symmetric quantum vortex (left) and a quantum elliptic vortex (proper). The arrows point out the route of the stream; the whiter the colour, the stronger the stream. The define of the core is printed by dashed strains. The background colour represents the phase θ of the macroscopic wave operate (advanced operate) similar to the superfluid area. Credit: Osaka City University

A phenomenon that refutes this concept was not too long ago noticed by Professor Shin’s experimental group at Seoul National University [Phys. Rev. Lett. 122, 095301 (2019)]. Since the symmetry breaking on this experimental system is much like that in well-known odd superconductors and superfluids, the form of the core of the topological defect, referred to as a quantum vortex, is anticipated to be spherical like the attention of a storm in a two-dimensional cross part.

However, the precise cross-sectional construction of the phase defect noticed was utterly totally different. Figure 1 reveals an experimental {photograph} of the construction similar to the cross part of a topological defect attributable to a sudden phase transition. At the time, this topological defect was thought of to be a compound of two identified topological defects (composite defect) and was interpreted as a transient state that happens briefly throughout the phase transition course of close to the essential level.

In this research, to make clear the bodily properties of the composite defect noticed within the experiment, Hiromitsu Takeuchi launched the concept of making use of the Joukowski rework, which is used to calculate the elevate of an airplane wing, to the quantum vortex. Based on this concept, the topological defect noticed within the experiment is finally stabilized as a brand new topological defect referred to as a quantum elliptic vortex. Ordinary quantum vortices have a rotationally symmetric stream of their cross-section, like an eye fixed of a storm (Fig. 2, left). However, the cross part of the newly proposed quantum elliptic vortex spontaneously breaks the rotational symmetry and types a stream alongside the ellipse. It was beforehand thought that the exterior form of a topological defect was decided primarily based on the way in which the worldwide SSB of the bodily system happens, however this consequence clearly overturns that notion.

It is theoretically identified that such an odd construction happens close to the essential level of the phase transition, and that the native SSB contained in the core of the topological is deeply concerned in its stability.

Although SSB has been studied for a very long time, there is no such thing as a common understanding of how the native SSB contained in the core happens and the way it impacts the of topological defects. Topological defects seem not solely in particular supplies resembling superconductors, but additionally in quite a lot of bodily programs starting from comparatively acquainted supplies resembling crystals and liquid crystals to cutting-edge science and expertise resembling spintronics, and they’re thought of to play vital roles in a rotating neutron star and the phase transition dynamics within the early universe. There is hope that new developments in SSBs, resembling Takeuchi’s discovery, can be caused by enhancements in experimental strategies and corresponding advances in concept, and that they may have a ripple impact on the complete area of physics.


A new direction of topological research is ready for take off


More info:
Hiromitsu Takeuchi, Quantum Elliptic Vortex in a Nematic-Spin Bose-Einstein Condensate, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.126.195302

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Osaka City University

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Mystery object attributable to spontaneous symmetry breaking revealed (2021, June 10)
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