2014/12/31 by Bat-el Friedman, Richard Berkovits · 4 citations
Physics and Astronomy · #Compressibility #Condensed matter physics #Density matrix renormalization group #Electron #Hubbard model #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Renormalization #Renormalization group #Spin (aerodynamics) #Superconductivity #Thermodynamics #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.91.104203
published in Physical Review B 91(10) (American Physical Society) · Version published in PRB
openalex publication_date 2015/03/31 · arxiv created 2015/04/14 · arxiv updated 2015/04/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We discuss the compressibility in the almost staggered fermionic Harper model with repulsive interactions in the vicinity of half-filling. It has been shown by Kraus et al. [Phys. Rev. B 89, 161106(R) (2014)] that for spinless electrons and nearest neighbors electron-electron interactions the compressibility in the central band is enhanced by repulsive interactions. Here we would like to investigate the sensitivity of this conclusion to the spin degree of freedom and longer range interactions. We use the Hartree-Fock (HF) approximation, as well as the density matrix renormalization group (DMRG) calculation to evaluate the compressibility. In the almost staggered Harper model, the central energy band is essentially flat and separated from the other bands by a large gap and therefore, the HF approximation is rather accurate. In both cases the compressibility of the system is enhanced compared to the noninteracting case, although the enhancement is weaker due to the inclusion of Hubbard and longer ranged interactions. We also show that the entanglement entropy is suppressed when the compressibility of the system is enhanced.