TGD based description of contactless friction in magnetic systems

Science daily has a highly interesting article with the title "Friction without contact discovered as magnetic forces break a 300-year-old law" (see this"). I am grateful to Gary Ehlenberger for sending the link. There is an article by Hongri Gu, Anton L ders, Clemens Bechinger with title "Non-monotonic magnetic friction from collective rotor dynamics" published in Nature Materials, 2026; DOI: 10.1038/s41563-026-02538-1 (see this).

Researchers at the University of Konstanz have identified a completely new type of sliding friction. The figure of the popular article (see this") illustrates the phenomenon.

There are two parallel magnetic layers composed of permanent dipole magnets with magnetization parallel to the layer. The magnets in the upper layer are free to rotate, while those in the lower layer are fixed. For the general sliding motion the dipole magnets of the upper layer experience a torque forcing them to rotate. As a consequence, the upper magnets periodically reorient, dissipating energy and giving rise to contactless friction. What is new and unexpected is that by decreasing the distance between the layers, which controls the effective load, the friction does not increase monotonically, in contrast to the prediction of Amontons law.

1. Amontons' law was originally linked to mechanical friction describing how much force presses two surfaces together. Indeed heavier objects are harder to move along surfaces than lighter ones. The explanation for the mechanical friction is that surfaces deform slightly under pressure, creating more microscopic contact points that increase resistance. The generalization of Amonton's law for magnets characterizes contactless friction: the distance of magnets gives rise to the effective weight, which increases as the distance is reduced. This explains why magnets with opposite dipole directions stick together.
2. For a pair of magnetic layers, the observed new kind of resistance to motion arises from the collective behavior of magnetic elements: which is rather complex when the individual magnets can rotate. Friction does not always increase steadily with the load (now the distance between the layers) but can reach a clear peak when magnetic ordering inside the system becomes frustrated.
3. Frustration occurs in spin glasses (see this) consisting of dipoles which can have different orientations and makes them extremely complex systems with a large number of free energy minima. Frustration, appearing already for 3 magnetic dipoles, means that the interaction energy for a single pair can be minimized but this is not possible for all pairs. Two people can agree, but in a group of 3 people, the third person tends to remain the third wheel. As a consequence, there are several free energy minima, which are degenerate in energy and the system does not know which of them to choose.

The contactless friction has a nice description based on the TGD view of space-time and classical fields.

1. In TGD, the classical fields are associated with what I refer to as field body as a space-time surface associated with the space-time surface of H= M⁴×CP₂ defining what might be called the physical body. The field body carries geometrized classical fields having a complex topology involving for instance magnetic monopole flux tubes and sheets (see for instance this and this).
2. The physical contact would be present also now but between the field bodies and produce small "field body friction". Monopole flux tubes associated with two dipole magnets minimize interaction energy when the flux tubes have opposite direction: in the contact the magnetic fields of flux tubes would cancel and flux tubes would fuse. Frustration can occur since flux tube can be parallel only with single flux tube unless all are parallel (for the role of spin glasses in TGD see this). Only the minimization of the interaction energy when the flux tubes have opposite direction and fuse to a single flux tube.
3. This explains why two dipole magnets tend to stick to each other: their separation creates magnetic field energy as separate flux tubes with opposite direction of flux are created. When the flux tube directions vary, spin glass phase emerges and the motion forces the and friction occurs so that there are several minima of free energy. Energy and external force is needed to move the layers with respect to each other.

See the article TGD and condensed matter or the chapter chapter with the same title.

For a summary of earlier postings see Latest progress in TGD.

For the lists of articles (most of them published in journals founded by Huping Hu) and books about TGD see this.