Diffusion and universal relaxation of holographic phonons

Understand

In phases where translations are spontaneously broken, new gapless degrees of freedom appear in the low energy spectrum (the phonons).

• At long wavelengths, they couple to small fluctuations of the conserved densities of the system.
• This mixing is captured by new diffusive transport coefficients, as well as qualitatively different collective modes, such as shear sound modes.
• We use Gauge/Gravity duality to model such phases and analytically compute the corresponding diffusivities in terms of data {of the dual background black hole solution}.