Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 37: Quantum Coherence, Quantum Information Systems 1
TT 37.14: Talk
Wednesday, March 13, 2013, 13:00–13:15, H19
Singlet-triplet qubits embodied by multi-electron quantum dots — •Sebastian Mehl1,2 and David P. DiVincenzo1,2 — 1Peter Grünberg Institut (PGI 2), Forschungszentrum Jülich, D-52428 Jülich — 2Institute for Quantum Information, RWTH Aachen, D-52056 Aachen
Singlet-triplet qubits (STQs) have attracted attention as one possible realization scheme of a logical qubit in a spin based quantum computer [1]. Commonly, the singlet and spinless triplet level of two single occupied quantum dots are defining the qubit states in these system. We describe an alternative approach to implement STQs using multi-electron quantum dots [2]. Instead of employing singly occupied quantum dots, we fill both quantum dots with three electrons. The qubit states have identical charge configurations for specific external parameters, which protects a STQ from dephasing phenomena affecting only the charge sector. Such qubits are perfectly immune gate voltages fluctuations produced by charge noise [3]. We specify the protection criteria and relate them to available materials and fabrication techniques. Furthermore, we describe full single qubit control of the three electron STQ, while pulsing via electric bias between two regimes immune to charge noise. We discuss limitations and experimental difficulties in realizing our proposed manipulation scheme.
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L.P. Kouwenhoven et al., Rep. Prog. Phys. 64, 701 (2001)
X. Hu and S. Das Sarma, PRL 96, 100501 (2006)