Tachyons: these particles faster than light become a reality

Particles faster than light, known as tachyons, have long been considered a theoretical curiosity incompatible with special relativity. A new study might well change this perception.


Physicists from the universities of Warsaw and Oxford have demonstrated that the prejudices against tachyons were unfounded. In fact, these hypothetical particles offer us a better understanding of the causal structure of relativity.

The idea of movements beyond the speed of light (superluminal) is one of the most controversial topics in physics. Tachyons, derived from the Greek tachýs meaning fast, were perceived as entities incompatible with the theory of special relativity.

The main objections to the existence of tachyons included the supposed instability of their ground state, which would have resulted in the formation of "avalanches" of superluminal particles. Moreover, it was thought that the number of observed particles depended on the observer, which is incompatible with classical physics where the number of particles should remain constant. Finally, the possibility that these particles possessed negative energies constituted a major obstacle to their acceptance within the framework of quantum theory.

A group of researchers, including notably Jerzy Paczos and Kacper Dębski, discovered that these problems arose from incomplete boundary conditions in previous theories. Incorporating the final state of the system, in addition to its initial state, resolved these difficulties, making the theory of tachyons coherent.

Andrzej Dragan, one of the authors, explains that this new approach allows considering the influence of the future on the present, a concept already existing but rarely applied in quantum physics. This has allowed them to extend the state space and integrate tachyons.

The researchers also predict the emergence of a new type of quantum entanglement intertwining past and future, a consequence of the extended boundary conditions. This raises the question of the potential observation of tachyons in the future.

According to the authors' hypothesis, tachyons play a crucial role in the process of spontaneous symmetry breaking, related to the formation of matter. Excitations of the Higgs field could thus have traveled at superluminal speeds before the symmetry breaking.