Persistent Currents in the Heisenberg chain with a weak link

Abstract

The Heisenberg chain with a weak link is studied, as a simple example of a quantum ring with a constriction or defect. The Heisenberg chain is equivalent to a spinless electron gas under a Jordan-Wigner transformation. Using density matrix renormalization group and quantum Monte Carlo methods we calculate the spin/charge stiffness of the model, which determines the strength of the `persistent currents'. The stiffness is found to scale to zero in the weak link case, in agreement with renormalization group arguments of Eggert and Affleck, and Kane and Fisher.

14 pages, 7 figures, 2 tables, no changes to paper, author list changed on archive

References in corpus (2)

• Detecting the Kondo screening cloud around a quantum dot
• Finite Size Scaling of the Spin Stiffness of the Antiferromagnetic S=1/2 XXZ chain

Cited by in corpus (5)

• The density-matrix renormalization group
• New Trends in Density Matrix Renormalization
• Velocity of excitations in ordered, disordered and critical antiferromagnets
• Persistent current and Drude weight in mesoscopic rings
• Scaling of the spin stiffness in random spin-1/2 chains : Crossover from pure-metallic behaviour to random singlet-localized regime