Unruh Effect and Takagi's Statistics Inversion in Strained Graphene

TL;DR

This paper explores how strained graphene can simulate the Unruh effect, leading to observable phenomena like electron-hole pair production, and discusses experimental signatures and energy behaviors related to this analogue gravity system.

Contribution

It introduces a theoretical framework for realizing the Rindler Hamiltonian in strained graphene, demonstrating Unruh effect analogues and Takagi's statistics inversion in condensed matter systems.

Findings

Spontaneous electron-hole pair production due to strain-induced tunneling

Manifestation of Unruh temperature in photo-emission and STM experiments

Linear growth of electronic conductivity with frequency

Abstract

We present a theoretical study of how a spatially-varying quasiparticle velocity in honeycomb lattices, achievable using strained graphene or in engineered cold-atom optical lattices that have a spatial dependence to the local tunneling amplitude, can yield the Rindler Hamiltonian embodying an observer accelerating in Minkowski spacetime. Within this setup, a sudden switch-on of the spatially-varying tunneling (or strain) yields a spontaneous production of electron-hole pairs, an analogue version of the Unruh effect characterized by the Unruh temperature. We discuss how this thermal behavior, along with Takagi's statistics inversion, can manifest themselves in photo-emission and scanning tunneling microscopy experiments. We also calculate the average electronic conductivity and find that it grows linearly with frequency $\omega$. Finally, we find that the total system energy at zero environment temperature looks like Planck's blackbody result for photons due to the aforementioned statistics inversion, whereas for an initial thermally excited state of fermions, the total internal energy undergoes stimulated particle reduction.