On the dynamics of exotic matter: towards creation of Perpetuum Mobile of third kind

TL;DR

This paper explores the theoretical dynamics of exotic fluids with negative pressure, revealing potential for perpetual energy transfer and motion, which could imply fundamental instabilities in such physical theories.

Contribution

It demonstrates that certain exotic fluids can exhibit indefinite energy growth and perpetual motion within relativistic hydrodynamics, highlighting possible instabilities.

Findings

Energy transfer from negative to positive regions leads to indefinite energy growth.

The Hwa-Bjorken solution is confined within the light cone.

Such exotic fluids may cause runaway gravitational effects.

Abstract

The one-dimensional dynamics of a classical ideal 'exotic' fluid with equation of state $p=p(\epsilon) < 0$ violating the weak energy condition is discussed. Under certain assumptions it is shown that the well-known Hwa-Bjorken exact solution of one-dimensional relativistic hydrodynamics is confined within the future/past light cone. It is also demonstrated that the total energy of such a solution is equal to zero and that there are regions within the light cone with negative $(-)$ and positive $(+)$ total energies. For certain equations of state there is a continuous energy transfer from the $(-)$-regions to the $(+)$-regions resulting in indefinite growth of energy in the $(+)$ regions with time, which may be interpreted as action of a specific 'Perpetuum Mobile' (Perpetuum Motion). It is speculated that if it is possible to construct a three-dimensional non-stationary flow of an exotic fluid having a finite negative value of energy such a situation would also occur. Such a flow may continuously transfer positive energy to gravitational waves, resulting in a runaway. It is conjectured that theories plagued by such solutions should be discarded as inherently unstable.