More on Topological Hydrodynamic Modes

TL;DR

This paper explores topologically nontrivial hydrodynamic modes via holography, demonstrating their emergence in non-inertial frames and extending the analysis to systems with additional U(1) currents, revealing complex topological phase diagrams.

Contribution

It shows that holographic models in non-inertial frames produce the same topological hydrodynamic modes and extends the topological analysis to systems with extra U(1) currents.

Findings

Holographic non-inertial frames yield topological hydrodynamic modes.

More complex topological phase diagrams are possible with additional U(1) currents.

The spectrum's topological change is linked to the non-inertial observation frame.

Abstract

Based on previous work that topologically nontrivial gapless modes in relativistic hydrodynamics could be found by weakly breaking the energy momentum conservation, in this paper, we study the holographic system which produces the same hydrodynamic modes. In the hydrodynamic system, one possibility to obtain the energy momentum non-conservation is to couple the system to external gravitational fields, i.e. to observe the system in a special non-inertial frame. Similar to what happens in the hydrodynamic system, a non-inertial frame version of holography indeed produces the same topologically nontrivial gapless hydrodynamic modes. We also generalize the study of topological modes in relativistic hydrodynamics to the case with one extra U(1) current and find that more complicated topological phase diagrams could exist when we consider more possibilities of the mass terms. We also discuss the possible underlying mechanism for this topological change in the spectrum when being observed in a non-inertial reference frame.