Collapse and revival of entanglement of two-qubit in superconducting   quantum dot lattice with magnetic flux and inhomogeneous gate voltage
  We study the entanglement of a two-qubit system in a superconducting quantum dot (SQD) lattice in the presence of magnetic flux and gate voltage inhomogeneity. We observe a universal feature for the half-integer magnetic flux quantum which completely washes out the entanglement of the system both at zero and finite temperature. We observe that the ground state is always in a maximally entangled Bell state when there is no inhomogeneity in gate voltage in the superconducting quantum dot lattice. We find an important constraint in magnetic flux for ground state entanglement. We also observe few behavior of entanglement at finite temperature is in contrast with the zero temperature behavior. 
Sujit Sarkar
cond-mat.supr-con