Electronic hydrodynamics

Our reseearch activities on electronic hydrodynamics are pursued as part of the EU-supported network Hydrotronics, coordinated at KIT.

The fluid flow of liquids is governed by the laws of hydrodynamics. Our research activities are concerned with the question under what circumstances the flow of electrons in solids is governed by hydrodynamic behavior. We proposed in 2008/2009 that ultrapure graphene at the neutrality point should be an excellent example for hydrodynamic transport of an electron fluid. By now a number of exciting experimental observations have been made that demonstrate hydrodynamic flow of electrons in graphene and a number of other materials of high purity.

Our theory for quantum transport in the hydrodynamic regime leads to exotic behavior such as Lévy flights in phase space and non-local transport phenomena, including modified boundary conditions of the electron flow. We also analyzed anisotropic Dirac and Weyl systems, where the much discussed bound for the ratio of the viscosity to entropy density is violated and utilized the duality of quantum field theory and gravity theories to analyze a modified bound.

Return to the research group - strongly correlated electrons.

Selected Publications:

• Non-local hydrodynamic transport and collective excitations in Dirac fluids, E. I. Kiselev and J. Schmalian, Phys. Rev. B 102, 245434 (2020). https://arxiv.org/abs/2007.00365
• Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points, G. A. Inkof, J. M.C. Küppers, J. M. Link, B. Goutéraux, and J. Schmalian, Journal of High Energy Physics 11, 088 (2020). https://arxiv.org/abs/1907.05744
• Transport properties of strongly coupled electron–phonon liquids, A. Levchenko and J. Schmalian, Annals of Physics 419, 168218 (2020). https://arxiv.org/abs/2005.09694
• Lévy Flights and Hydrodynamic Superdiffusion on the Dirac Cone of Graphene, E. I. Kiselev and J. Schmalian, Physical Review Letters 123, 195302 (2019). https://arxiv.org/abs/1906.07123
• Boundary conditions of viscous electron flow, E. I. Kiselev and J. Schmalian, Physical Review B 99, 035430 (2019). https://arxiv.org/abs/1903.08037
• Elastic response of the electron fluid in intrinsic graphene: The collisionless regime, J. M. Link, D. E. Sheehy, B. N. Narozhny, and J. Schmalian, Physical Review B 98, 195103 (2018). Editors’ suggestion https://arxiv.org/abs/1808.04658
• Hierarchy of information scrambling, thermalization, and hydrodynamic flow in graphene, M. J. Klug, M. S. Scheurer, and J. Schmalian, Physical Review B 98, 045102 (2018). https://arxiv.org/abs/1712.08813
• Out-of-bounds hydrodynamics in anisotropic Dirac fluids, J. M. Link, B. N. Narozhny, E. I. Kiselev, and J. Schmalian, Physical Review Letters 120, 196801 (2018). https://arxiv.org/abs/1708.02759
• Hydrodynamic Approach to Electronic Transport in Graphene, B. N. Narozhny, I. V. Gornyi, A. D. Mirlin, and J Schmalian, Annalen der Physik 11, 1700043 (2017). https://arxiv.org/abs/1704.03494
• Universal collisionless transport of graphene, J. M. Link, P. P. Orth, D. E. Sheehy, and J. Schmalian, Physical Review B 93, 235447 (2016). https://arxiv.org/abs/1511.05984
• Emergent non-Fermi liquid at the quantum critical point of a topological phase transition in two dimensions, H. Isobe, B.-J. Yang, A. Chubukov, J. Schmalian, and N. Nagaosa, Physical Review Letters 116, 076803 (2016). https://arxiv.org/abs/1508.03781
• Graphene: A nearly perfect fluid, M. Müller, J. Schmalian, and L. Fritz, Physical Review Letters 103, 025301 (2009). Editors’ suggestion, selected for a Viepoint in Physics, featured as Research Highlights in Nature Nanotechnology (17 July 2009), featured in ScienceNews (June 2009) https://arxiv.org/abs/0903.4178
• Quantum critical transport in clean graphene, L. Fritz., J. Schmalian, M. Mueller, S. Sachdev, Physical Review B 78, 085416 (2008). https://arxiv.org/abs/0802.4289
• Quantum critical scaling in graphene, D. E. Sheehy and J. Schmalian, Physical Review Letters 99 226803 (2007). https://arxiv.org/abs/0707.2945