NCTS /
## SpinChargeSeparationIn this tutorial, we will perform simuations of some particle dynamics in the Hubbard model. ## Obtaining the groundstateFirstly, we need a groundstate. Use the program hubbard-u1u1 40 hubbardlattice Now we construct an initial state for the DMRG. Choose a particle number that is close to half-filling, for example 36 particles, spin 0. mp-random -l hubbardlattice -q 36,0 -o psi and run the DMRG program until the groundstate is converged, with say mp-dmrg -w psi -H hubbardlattice:"H_t + 5*H_U" -m 50 Check that the variance and truncation error are both small before continuing. ## Inserting a particleNow we want to add one additional particle to the wavefunction, to simulate injecting a particle at the edge of the chain. To to this, we use the tool mp-apply hubbardlattice:"CHup(1)" psi excitedpsi Use ## Calculating the evolutionThe main tool for calculating time evolution is By default, Lets choose a maximum of m=200 states, and calculate a few timesteps of evolution/ mp-evolve-krylov -H hubbardlattice:"H_t + 5*H_U" -m 200 -t 0.1 -n 20 \ --normalize --verbose -w excitedpsi -o evolved This will take some time to run. You should end up with a series of wavefunctions For example, to obtain the local density at all sites from 1 to 40, of the wavefunction evolved.t0.1, try mp-localexpectation hubbardlattice evolved.t0.1 N 1 40 |

Page last modified on September 07, 2011, at 06:17 AM