We develop a nonperturbative numerical method to study tunneling of a single electron through an Aharonov-Bohm ring where several strongly interacting electrons are bound. Inelastic processes and spin-flip scattering are taken into account. The method is applied to study microscopic mechanisms of dephasing in a nontrivial model. We show that the electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing: the transmission probability at flux $\ensuremath{\Phi}=\ensuremath{\pi}$ is high even at small interaction strength. In addition to inelastic scattering, we identify two energy-conserving mechanisms of dephasing: symmetry-changing and spin-flip scattering. The many-electron state on the ring determines which of these mechanisms will be at play: transmitted current can occur either in elastic or inelastic channels, with or without changing the spin of the scattering electron.We develop a nonperturbative numerical method to study tunneling of a single electron through an Aharonov-Bohm ring where several strongly interacting electrons are bound. Inelastic processes and spin-flip scattering are taken into account. The method is applied to study microscopic mechanisms of dephasing in a nontrivial model. We show that the electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing: the transmission probability at flux $\ensuremath{\Phi}=\ensuremath{\pi}$ is high even at small interaction strength. In addition to inelastic scattering, we identify two energy-conserving mechanisms of dephasing: symmetry-changing and spin-flip scattering. The many-electron state on the ring determines which of these mechanisms will be at play: transmitted current can occur either in elastic or inelastic channels, with or without changing the spin of the scattering electron.

arXiv:cond-mat/0305335Physical review. B, Condensed matterAug 13, 200310 citations

Modulation of dephasing due to a spin-boson environment

Elisabetta Paladino, Maura Sassetti, G. Falci

arXiv:cond-mat/0412615Chemical PhysicsDec 4, 200312 citations

New mechanism for spin relaxation during light scattering

V. A. Voǐtenko

Jan 1, 19951 citation

Non-Markovian hole spin kinetics in p -type GaAs quantum wells

Pei Zhang, M. W. Wu

Based on fully microscopic kinetic spin Bloch equation approach, we show the non-Markovian effect in spin dephasing of heavy holes in $p$ -type GaAs quantum wells. The non-Markovian effect manifests itself in spin dephasing when the mean spin precession time is shorter than the momentum relaxation time. The spin dephasing becomes slower when the non-Markovian effect is important. Moreover, quantum spin beats due to the memory effect of the non-Markovian hole--longitudinal-optical phonon scattering are predicted.Based on fully microscopic kinetic spin Bloch equation approach, we show the non-Markovian effect in spin dephasing of heavy holes in $p$-type GaAs quantum wells. The non-Markovian effect manifests itself in spin dephasing when the mean spin precession time is shorter than the momentum relaxation time. The spin dephasing becomes slower when the non-Markovian effect is important. Moreover, quantum spin beats due to the memory effect of the non-Markovian hole--longitudinal-optical phonon scattering are predicted.

arXiv:0708.4086Physical Review BNov 27, 200710 citations

Electron spin dephasing by hyperfine-mediated interactions in a nuclear spin bath

Łukasz Cywiński, Wayne M. Witzel, S. Das Sarma

Bulletin of the American Physical SocietyAug 29, 20081 citation

Transverse Spin Dynamics in the Anisotropic Heisenberg Model Realized with Ultracold Atoms

Niklas Jepsen, Wen Wei Ho, Jesse Amato-Grill +3 more

In Heisenberg models with exchange anisotropy, transverse spin components are not conserved and can decay not only by transport, but also by dephasing.Here, we utilize ultracold atoms to simulate the dynamics of 1D Heisenberg spin chains and observe fast, local spin decay controlled by the anisotropy.However, even for isotropic interactions, we observe dephasing due to a new effect: an effective magnetic field created by superexchange.If spatially uniform, it leads only to uniform spin precession and is, therefore, typically ignored.However, we show through experimental studies and extensive numerical simulations how this superexchange-generated field is relevant and leads to additional dephasing mechanisms over the exchange anisotropy: There is dephasing due to (i) inhomogeneity of the effective field from variations of lattice depth between chains; (ii) a twofold reduction of the field at the edges of finite chains; and (iii) fluctuations of the effective field due to the presence of mobile holes in the system.The latter is a new coupling mechanism between holes and magnons.All these dephasing mechanisms have not been observed before with ultracold atoms and illustrate basic properties of the underlying Hubbard model.In Heisenberg models with exchange anisotropy, transverse spin components are not conserved and can decay not only by transport, but also by dephasing.Here, we utilize ultracold atoms to simulate the dynamics of 1D Heisenberg spin chains and observe fast, local spin decay controlled by the anisotropy.However, even for isotropic interactions, we observe dephasing due to a new effect: an effective magnetic field created by superexchange.If spatially uniform, it leads only to uniform spin precession and is, therefore, typically ignored.However, we show through experimental studies and extensive numerical simulations how this superexchange-generated field is relevant and leads to additional dephasing mechanisms over the exchange anisotropy: There is dephasing due to (i) inhomogeneity of the effective field from variations of lattice depth between chains; (ii) a twofold reduction of the field at the edges of finite chains; and (iii) fluctuations of the effective field due to the presence of mobile holes in the system.The latter is a new coupling mechanism between holes and magnons.All these dephasing mechanisms have not been observed before with ultracold atoms and illustrate basic properties of the underlying Hubbard model.

arXiv:2103.07866Physical Review XDec 17, 202165 citations

Based on fully microscopic kinetic spin Bloch equation approach, we show the non-Markovian effect in spin dephasing of heavy holes in

p

-type GaAs quantum wells. The non-Markovian effect manifests itself in spin dephasing when the mean spin precession time is shorter than the momentum relaxation time. The spin dephasing becomes slower when the non-Markovian effect is important. Moreover, quantum spin beats due to the memory effect of the non-Markovian hole--longitudinal-optical phonon scattering are predicted.