Fingerprints of the conformal anomaly in the thermoelectric transport in Dirac and Weyl semimetals

[EN] The conformal anomaly, a quantum anomaly related to metric deformations in conformally invariant systems, has been recently shown to give rise to a special contribution to the Nernst signal, which remains finite at zero temperature and chemical potential. In this work we provide a Kubo calculation that confirms the result of this unexpected signal in the conformal limit and extends the calculation to finite temperature and chemical potential. As a result, we predict a distinctive experimental signature of the conformal anomaly in the form of a plateau behavior in the thermoelectric coefficient as a function of the chemical potential in the extreme quantum limit.We thank A. Cortijo for invaluable help with the calculations and discussion. Useful comments from Y. Ferreiros, F. de Juan, P. Kim, K. Landsteiner, and I. Shovkovy are also acknowledged. This work has been supported by the PIC2016FR6/PICS07480, Spanish MECD Grant No. FIS2014-57432-P, European Union structural funds and the Comunidad Autónoma de Madrid NMAT2D-CM Program No. S2018/NMT-4511, and within the state assignment of the Ministry of Science and Higher Education of Russia (Grant No. 3.6261.2017/8.9)