2,141 research outputs found
Dynamical nuclear spin polarization and the Zamboni effect in gated double quantum dots
A dynamical nuclear polarization scheme is studied in gated double dots. We
demonstrate that a small polarization () is sufficient to enhance
the singlet decay time by two orders of magnitude. This enhancement is
attributed to an equilibration process between the nuclear reservoirs in the
two dots accompanied by reduced fluctuations in the Overhauser fields, that are
mediated by the electron-nuclear spin hyperfine interaction.Comment: 4 pages, 3 figure
Toward high-fidelity coherent electron spin transport in a GaAs double quantum dot
In this paper, we investigate how to achieve high-fidelity electron spin
transport in a GaAs double quantum dot. Our study examines spin transport from
multiple perspectives. We first study how a double dot potential may
affect/accelerate spin relaxation. We calculate spin relaxation rate in a wide
range of experimental parameters and focus on the occurrence of spin hot spots.
A safe parameter regime is identified in order to avoid these spin hot spots.
We also study the non-adiabatic transitions in the Landau-Zener process of
sweeping the interdot detuning, and propose a scheme to take advantage of
possible Landau-Zener-St\"{u}kelburg interference to achieve high-fidelity spin
transport at a higher speed. Finally, we calculate the double-dot correction on
the effective -factor for the tunneling electron, and estimate the resulting
phase error between different spin states. Our results should provide a useful
guidance for future experiments on coherent electron spin transport.Comment: 10 pages, 7 figure
Spin-based quantum computation in multielectron quantum dots
In a quantum computer the hardware and software are intrinsically connected
because the quantum Hamiltonian (or more precisely its time development) is the
code that runs the computer. We demonstrate this subtle and crucial
relationship by considering the example of electron-spin-based solid state
quantum computer in semiconductor quantum dots. We show that multielectron
quantum dots with one valence electron in the outermost shell do not behave
simply as an effective single spin system unless special conditions are
satisfied. Our work compellingly demonstrates that a delicate synergy between
theory and experiment (between software and hardware) is essential for
constructing a quantum computer.Comment: 5 2-column pages in RevTe
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