You are here

Effective field theory for fluids with kinematic constraints

Andrew Lucas, CU Boulder
Tuesday, January 10, 2023 - 3:00pm
PAT C-421

In recent years, we have discovered a zoo of new dynamical universality classes that arise in kinematically constrained systems.  In this talk, I will introduce a prototypical (but particularly fascinating) example: the hydrodynamics of a theory with momentum conservation, along with a U(1) charge and dipole conservation law.   Without dipole conservation, such a theory is described by the Navier-Stokes equations; with dipole conservation, it exhibits qualitatively distinct features.   While hard to realize in a lab, I will present a classical microscopic Hamiltonian system in this universality class, simulations of which have revealed the breakdown of hydrodynamics due to strong thermal fluctuations below 4+1 dimensions.   I will discuss our efforts to build a systematic effective field theory for this system. This EFT reveals that the “sound mode” of the dipole-conserving fluid is a Goldstone boson, transforming nonlinearly under dipole shift.  This mode remains part of the EFT even when, in low dimensions, a Mermin-Wagner Theorem would forbid spontaneous symmetry breaking.   Moreover, our EFT allows us to couple this “fracton phase of matter” to background fields, including curved spacetime.  In the flat space limit, we reproduce the coupling to “mixed rank tensor gauge fields” from previous literature.

Event Type: