Thermodynamics of the Topological Kondo Model

Abstract

Using the thermodynamic Bethe ansatz, we investigate the topological Kondo model, which describes a set of one-dimensional external wires, pertinently coupled to a central region hosting a set of Majorana bound states. After a short review of the Bethe ansatz solution, we study the system at finite temperature and derive its free energy for arbitrary (even and odd) number of external wires. We then analyse the ground state energy as a function of the number of external wires and of their couplings to the Majorana bound states. Then, we compute, both for small and large temperatures, the entropy of the Majorana degrees of freedom localized within the central region and connected to the external wires. Our exact computation of the impurity entropy provides evidence of the importance of fermion parity symmetry in the realization of the topological Kondo model. Finally, we also obtain the low-temperature behaviour of the specific heat of the Majorana bound states, which provides a signature of the non-Fermi-liquid nature of the strongly coupled fixed point.

42 pages, 4 figures. v2: Comments about the role of the fermion parity added, appendix expanded

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Cited by in corpus (11)

• Violation of the Wiedemann-Franz law in the Topological Kondo model
• Multi-particle scattering and breakdown of the Wiedemann-Franz law at a junction of N interacting quantum wires
• Topological Kondo Device for distinguishing Quasi-Majorana and Majorana signatures
• Tunable Kondo screening length at a Y-junction of three inhomogenous spin chains
• $6\pi$ Josephson effect in Majorana box devices
• Junction of three off-critical quantum Ising chains and two-channel Kondo effect in a superconductor
• Multichannel topological Kondo effect
• Topological Kondo effect with spinful Majorana fermions
• The topological Kondo model out of equilibrium
• Relevance of Anisotropy in the Kondo Effect: Lessons From the Symplectic Case
• Spin and thermal current scaling at a $Y$-junction of XX spin chains