Researchers defy 19th Century law of Physics: Do They?

[beecee]

https://phys.org/news/2018-11-defy-19th-century-law-physics.html#jCp

Researchers defy 19th Century law of Physics in 21st century boost for energy efficiency:

November 21, 2018 by Anna Ford, University of Sussex:

Research led by a University of Sussex scientist has turned a 156-year-old law of physics on its head in a development which could lead to more efficient recharging of batteries in cars and mobile phones.

Dr. Jordi Prat-Camps, a research fellow at the University of Sussex, has for the first time demonstrated that the coupling between two magnetic elements can be made extremely asymmetrical. Working with colleagues from the Austrian Academy of Sciences and University of Innsbruck, Dr. Prat-Camps' research rips up the physics rule book by showing it is possible to make one magnet connect to another without the connection happening in the opposite direction.

Read more at: https://phys.org/news/2018-11-defy-19th-century-law-physics.html#jCp
 

 

the paper: 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.213903

Circumventing Magnetostatic Reciprocity: A Diode for Magnetic Fields:

ABSTRACT:

Lorentz reciprocity establishes a stringent relation between electromagnetic fields and their sources. For static magnetic fields, a relation between magnetic sources and fields can be drawn in analogy to the Green’s reciprocity principle for electrostatics. So far, the magnetostatic reciprocity principle remains unchallenged and the magnetostatic interaction is assumed to be symmetric (reciprocal). Here, we theoretically and experimentally show that a linear and isotropic electrically conductive material moving with constant velocity is able to circumvent the magnetostatic reciprocity principle and realize a diode for magnetic fields. This result is demonstrated by measuring an extremely asymmetric magnetic coupling between two coils that are located near a moving conductor. The possibility to generate controlled unidirectional magnetic couplings implies that the mutual inductances between magnetic elements or circuits can be made extremely asymmetric. We anticipate that this result will provide novel possibilities for applications and technologies based on magnetically coupled elements and might open fundamentally new avenues in artificial magnetic spin systems.

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Do they? What would be the full repercussions of such a discovery? Any other comments?

[Carrock]

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.213903

The article seems to be behind a paywall.

Anyone read it?

 

[Strange]

The full paper is here https://arxiv.org/abs/1802.00832

[Q-reeus]

The article title suggests something quite dramatic - failure of conservation of energy. It soon becomes evident that's not the case. Instead it boils down to a lossy coupling that laterally offsets and phase-shifts the magnetic field coupling source to load, and then back again from load to source. Because of the locally translational lateral motion of the coupling conducting ring, the lateral offsets move in the same direction in both cases, as does the relative phase-shift. Hence what gets back to the source coil is double shifted, whereas the coupling from source to load has only a single shift. Hence a net non-reciprocal mutual inductance.

There is not that much different in principle to what happens in say an induction motor as commonly used for ~ a century.

As currently realized (and I don't see room for much improvement) it is somewhat unwieldy, inherently lossy, with imo little prospect of practical use. An interesting novelty with maybe niche use.

Edited November 25, 2018 by Q-reeus
single word edit - impedence to inductance