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Dephasing of intraband transitions in InAs/GaAs quantum dots

R. Ferreira

Jan 1, 20080 citations

InAs/GaAs single-electron quantum dot qubit

Shu‐Shen Li, Jian‐Bai Xia, Jinlong Liu +4 more

The time evolution of the quantum mechanical state of an electron is calculated in the framework of the effective-mass envelope function theory for an InAs/GaAs quantum dot. The results indicate that the superposition state electron density oscillates in the quantum dot, with a period on the order of femtoseconds. The interaction energy Eij between two electrons located in different quantum dots is calculated for one electron in the ith pure quantum state and another in the jth pure quantum state. We find that E11〉E12〉E22, and Eij decreases as the distance between the two quantum dots increases. We present a parameter-phase diagram which defines the parameter region for the use of an InAs/GaAs quantum dot as a two-level quantum system in quantum computation. A static electric field is found to efficiently prolong the decoherence time. Our results should be useful for designing the solid-state implementation of quantum computing.The time evolution of the quantum mechanical state of an electron is calculated in the framework of the effective-mass envelope function theory for an InAs/GaAs quantum dot. The results indicate that the superposition state electron density oscillates in the quantum dot, with a period on the order of femtoseconds. The interaction energy Eij between two electrons located in different quantum dots is calculated for one electron in the ith pure quantum state and another in the jth pure quantum state. We find that E11〉E12〉E22, and Eij decreases as the distance between the two quantum dots increases. We present a parameter-phase diagram which defines the parameter region for the use of an InAs/GaAs quantum dot as a two-level quantum system in quantum computation. A static electric field is found to efficiently prolong the decoherence time. Our results should be useful for designing the solid-state implementation of quantum computing.

Journal of Applied PhysicsDec 15, 2001144 citations

Reducing pure dephasing of quantum bits by collective encoding in quantum dot arrays

Anna Grodecka, Paweł Machnikowski, Lucjan Jacak

We show that phonon-induced pure dephasing of an excitonic (charge) quantum bit in a quantum dot (QD) may be reduced by collective encoding of logical qubits in QD arrays. We define the logical qubit on an array of 2, 4 and 8 QDs, connecting the logical |0⟩ state with the presence of excitons in the appropriately chosen half of dots and the logical |1⟩ state with the other half of the dots occupied. We give quantitative estimates of the resulting total error of a single qubit operation for an InAs/GaAs system.We show that phonon-induced pure dephasing of an excitonic (charge) quantum bit in a quantum dot (QD) may be reduced by collective encoding of logical qubits in QD arrays. We define the logical qubit on an array of 2, 4 and 8 QDs, connecting the logical |0⟩ state with the presence of excitons in the appropriately chosen half of dots and the logical |1⟩ state with the other half of the dots occupied. We give quantitative estimates of the resulting total error of a single qubit operation for an InAs/GaAs system.

Journal of Physics Conference SeriesFeb 28, 20060 citations

The Decoherence of Single Electron Quantum Dot Qubit

Yi-Fu Yu, Wei-Ping Li, Ji-Wen Yin +1 more

International Journal of Theoretical PhysicsMay 23, 20117 citations

The Decoherence of GaAs Quantum Dot Qubit Due to Electron–Phonon Interactions

Shi‐Hua Chen

Journal of Low Temperature PhysicsApr 30, 20130 citations

Dephasing in InAs/GaAs quantum dots

Paola Borri, W. Langbein, Jesper Mørk +4 more

The room-temperature dephasing in InAs/GaAs self-assembled quantum dots is measured using two independent methods: spectal-hole burning and four-wave mixing. Dephasing times weakly dependent on the excitation density are found, with a low density value of $290\ifmmode\pm\else\textpm\fi{}80 \mathrm{fs}$ from spectal-hole burning and of $260\ifmmode\pm\else\textpm\fi{}20 \mathrm{fs}$ from four-wave mixing.

Physical review. B, Condensed matterSep 15, 1999133 citations

Dephasing rate in an InAs/GaAs single-electron quantum dot qubit

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