Tachyonic thermal excitations and causality

Abstract

We consider an ideal Fermi gas of tachyonic thermal excitations as a continuous medium and establish when it satisfies the causality condition. At high temperature the sound speed is always subluminal $c_s<1$, but there is no stable form of tachyon matter below the critical temperature $T_c<0.23m$ that depends on the tachyon mass $m$. The pressure $P$ and energy density $E$ cannot be arbitrary small, but $P$ can exceed $E$, and $P=2.36E$ when $T\to T_c$.

11 pages, 4 figures

References in corpus (5)

• Emergent Universe and Phantom Tachyon Model
• Tachyon Matter in Loop Quantum Cosmology
• Lorentz covariant statistical mechanics and thermodynamics of the relativistic ideal gas and preferred frame
• Acoustics of tachyon Fermi gas
• Relativistic ideal Fermi gas at zero temperature and preferred frame

Cited by in corpus (5)

• Thermodynamics of exotic matter with constant w=P/E
• Careful calculation of thermodynamical functions of tachyon gas
• Specific heat and entropy of tachyon Fermi gas
• Stability of hot tachyon gas
• Thermodynamics of absolute stiff matter