Universal behaviors of speed of sound from holography

摘要

We investigate the speed of sound in (d + 1)-dimensional quantum field theory by studying its dual (d+ 2)-dimensional gravity theory from gauge/gravity correspondence. Instead of the well-known conformal limit c_s~2→ 1/d at high temperature, we reveal two more universal quantities in various limits: c_s~2→ (d ? 1)/16π at low temperature and c_s~2→ (d ? 1)/16πd at large chemical potential.