255 research outputs found

    A Quantum Breakdown Model: from Many-body Localization to Chaos with Scars

    Full text link
    We propose a quantum model of fermions simulating the electrical breakdown process of dielectrics. The model consists of MM sites with NN fermion modes per site, and has a conserved charge QQ. It has an on-site chemical potential μ\mu with disorder WW, and an interaction of strength JJ restricting each fermion to excite two more fermions when moving forward by one site. We show the N=3N=3 model with disorder W=0W=0 show a Hilbert space fragmentation and is exactly solvable except for very few Krylov subspaces. The analytical solution shows that the N=3N=3 model exhibits many-body localization (MBL) as M→∞M\rightarrow\infty, which is stable against W>0W>0 as our exact diagonalization (ED) shows. At N>3N>3, our ED suggests a MBL to quantum chaos crossover at small WW as M/NM/N decreases across 11, and persistent MBL at large WW. At W=0W=0, an exactly solvable many-body scar flat band exists in many charge QQ sectors, which has a nonzero measure in the thermodynamic limit. We further calculate the time evolution of a fermion added to the particle vacuum, which shows a breakdown (dielectric) phase when μ/J<1/2\mu/J<1/2 (μ/J>1/2\mu/J>1/2) if W≪JW\ll J, and no breakdown if W≫JW\gg J.Comment: 21+8 pages, 17+5 figure
    • …
    corecore