Reply to the Comment on "Negative Landau damping in bilayer graphene"

TL;DR

This paper clarifies misconceptions about negative Landau damping in graphene, demonstrating that nonlocal effects do not prevent negative damping or instabilities, and emphasizing the role of Galilean transformation in conductivity under certain conditions.

Contribution

It provides a theoretical clarification on the conductivity behavior of drift-biased graphene, addressing prior concerns and confirming the persistence of negative Landau damping.

Findings

Galilean transformation governs conductivity in drift-biased graphene with dominant electron-electron interactions.

Nonlocal effects do not prevent negative Landau damping in graphene.

Negative Landau damping and instabilities can still occur despite nonlocal effects.

Abstract

Here we address the concerns of Svintsov and Ryzhii [arXiv:1812.03764] on our article on negative Landau damping in graphene [Phys. Rev. Lett. 119, 133901 (2017)]. We prove that due to the differences between the kinetic and canonical momenta, the conductivity of drift-current biased graphene is ruled by a Galilean transformation when the electron-electron interactions predominate and force the electron gas to move with constant velocity, similar to a moving medium. Furthermore, it is shown that the nonlocal effects in graphene neither preclude a negative Landau damping nor the emergence of instabilities in graphene platforms.