Dynamic universality class of the QCD critical point

We show that the dynamic universality class of the QCD critical point is that of model H and discuss the dynamic critical exponents. We show that the baryon diffusion rate vanishes at the critical point. The dynamic critical index $z$ is close to 3.Comment: 12 pages. To be published in PRD. Appendix about isospin density added, introduction expande

Effective Lagrangian and Topological Interactions in Supersolids

We construct a low-energy effective Lagrangian describing zero-temperature supersolids. Galilean invariance imposes strict constraints on the form of the effective Lagrangian. We identify a topological term in the Lagrangian that couples superfluid and crystalline modes. For small superfluid fractions this interaction term is dominant in problems involving defects. As an illustration, we compute the differential cross section of scatterings of low-energy transverse elastic phonons by a superfluid vortex. The result is model-independent.Comment: 10 pages, 1 figure; one reference adde

Short-distance and short-time structure of a unitary Fermi gas

We consider the operator product expansions for unitarity fermions. We compute the dynamic structure factor S(q,w) at large frequency and wavenumber away from the one-particle peak. The overall normalization of S(q,w) is determined by Tan's contact parameter, and the dependence on q and w is obtained in closed analytic form. We also find energy deposited into the system by small, rapid variations of the inverse scattering length.Comment: 11 pages, 8 figure

Domain walls of high-density QCD

We show that in very dense quark matter there must exist metastable domain walls where the axial U(1) phase of the color-superconducting condensate changes by 2pi. The decay rate of the domain walls is exponentially suppressed and we compute it semiclassically. We give an estimate of the critical chemical potential above which our analysis is under theoretical control.Comment: 4 pages; Eq. (16) corrected, 2 new references added, published versio

Pi0 -> Gamma Gamma in Dense QCD

QCD superconductors in the color-flavor-locked (CFL) phase support light excitations (generalized pions) in the form of particle-particle or hole-hole excitations. We analyze the generalized process $\tilde\pi^0\to\tilde{\gamma}\tilde{\gamma}$ in the weak coupling limit and show that it is related to the recently suggested Wess-Zumino-Witten (WZW) term. In dense QCD, the radiative decay of the generalized pion is constrained by geometry and vanishes at large density.Comment: 7 pages, 1 figur