Hawking radiation in quantum Hall system with an expanding edge: Application of anomaly method

The relationship between gravitational anomalies and Hawking radiation of black holes was revealed by Wilczek and Robinson. In this study, we apply their method to an analogue de Sitter spacetime in the quantum Hall system with an expanding edge. The chiral nature of the system eliminates the need for imposing the condition of ingoing modes near the horizon. Moreover, this system is structured so that the de Sitter space is sandwiched between two flat spaces, and although the effects of the anomaly would not appear in an ordinal de Sitter spacetime, they manifest themselves as boundary conditions between the de Sitter and the flat regions. By performing calculations under these boundary conditions, we obtain the flux of Hawking radiation in the outer flat region with the Gibbons-Hawking temperature of the de Sitter horizon. •This study applies gravitational anomaly method of calculating flux to Quantum Hall system with expanding edge.•Gibbons-Hawking temperature in analogue de Sitter spacetime is calculated.•We investigate time dependence of energy flux and find it can become negative.