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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Optimal control of universal quantum gates in a double quantum dot

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Autor(es):
Castelano, Leonardo K. [1] ; de Lima, Emanuel F. [1] ; Madureira, Justino R. [2] ; Degani, Marcos H. [3] ; Maialle, Marcelo Z. [3]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Fed Sao Carlos, Dept Fis, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Fed Uberlandia, Fac Ciencias Integradas Pontal, BR-38304402 Ituiutaba, MG - Brazil
[3] Univ Estadual Campinas, Fac Ciencias Aplicadas, BR-13484350 Limeira, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Physical Review B; v. 97, n. 23 JUN 4 2018.
Citações Web of Science: 2
Resumo

We theoretically investigate electron spin operations driven by applied electric fields in a semiconductor double quantum dot (DQD) formed in a nanowire with longitudinal potential modulated by local gating. We develop a model that describes the process of loading and unloading the DQD taking into account the overlap between the electron wave function and the leads. Such a model considers the spatial occupation and the spin Pauli blockade in a time-dependent fashion due to the highly mixed states driven by the external electric field. Moreover, we present a road map based on the quantum optimal control theory (QOCT) to find a specific electric field that performs two-qubit quantum gates on a faster timescale and with higher possible fidelity. By employing the QOCT, we demonstrate the possibility of performing within high efficiency a universal set of quantum gates [CNOT, H, and T], where CNOT is the controlled-NOT gate, H is the Hadamard gate, and T is the pi/8 gate, even in the presence of the loading/unloading process and charge noise effects. Furthermore, by varying the intensity of the applied magnetic field B, the optimized fidelity of the gates oscillates with a period inversely proportional to the gate operation time t(f) . This behavior can be useful to attain higher fidelity for fast gate operations (>1 GHz) by appropriately choosing B and t(f) to produce a maximum of the oscillation. (AU)

Processo FAPESP: 17/10190-2 - Dinâmica de spins e operações em qubits em nanoestruturas semicondutoras
Beneficiário:Marcelo Zoéga Maialle
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 12/13052-6 - Propriedades de transporte e computação quântica em nanoestruturas
Beneficiário:Leonardo Kleber Castelano
Linha de fomento: Auxílio à Pesquisa - Regular