255 research outputs found
A Quantum Breakdown Model: from Many-body Localization to Chaos with Scars
We propose a quantum model of fermions simulating the electrical breakdown
process of dielectrics. The model consists of sites with fermion modes
per site, and has a conserved charge . It has an on-site chemical potential
with disorder , and an interaction of strength restricting each
fermion to excite two more fermions when moving forward by one site. We show
the model with disorder show a Hilbert space fragmentation and is
exactly solvable except for very few Krylov subspaces. The analytical solution
shows that the model exhibits many-body localization (MBL) as
, which is stable against as our exact
diagonalization (ED) shows. At , our ED suggests a MBL to quantum chaos
crossover at small as decreases across , and persistent MBL at
large . At , an exactly solvable many-body scar flat band exists in
many charge 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
() if , and no breakdown if .Comment: 21+8 pages, 17+5 figure
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