7 papers
Spin Coherent-State Path Integrals and the Instanton Calculus
Anupam Garg, Evgueny Kochetov, Kee-Su Park +1
We use an instanton approximation to the continuous-time spin coherent-state path integral to obtain the tunnel splitting of classically degenerate ground states. We show that prov…
Spin tunnelling in Molecular Magnets
Anupam Garg
We study spin tunneling in magnetic molecules, with special reference to Fe8. The article aims to give a pedagogical discussion of what is meant by the tunneling of a spin, and how…
Diabolical Points in Molecular Magnets with a Four-Fold Easy Axis
Chang-Soo Park, Anupam Garg
We study the points of degeneracy (diabolical points) in magnetic molecules such as Mn_{12}-acetate that have an easy axis of four-fold symmetry. This is done for general magnetic…
Topological Quenching of Spin Tunneling in Mn_12-acetate Molecules
Chang-Soo Park, Anupam Garg
We investigate the topological quenching of spin tunneling in Mn_12-acetate molecules with an applied magnetic field along the hard axis. The model Hamiltonian describing this syst…
Discrete phase integral method for five-term recursion relations
Anupam Garg
A formalism is developed to study certain five-term recursion relations by discrete phase integral (or Wentzel-Kramers-Brillouin) methods. Such recursion relations arise naturally…
Coherent Magnetic Moment Reversal in Small Particles with Nuclear Spins
Anupam Garg
A discrete WKB method is developed for calculating tunnel splittings in spin problems. The method is then applied to the issue of how nuclear spins affect the macroscopic quantum c…