Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 11: Transport: Quantum Coherence and Quantum Information Systems 2 (jointly with MA and HL)

TT 11.8: Talk

Monday, March 26, 2012, 17:00–17:15, BH 243

Pauli blockade for Kramers-qubit readout in carbon nanotubes — •gábor széchenyi and andrás pályi — Institute of Physics, Eötvös University, Hungary

Carbon nanotube double quantum dots are promising candidates for a solid-state platform of quantum-information processing. In the ground state of the nanotube the physical qubit is a Kramers doublet, which involves two states with antiparallel alignment of spin and valley. To evaluate the potential in Pauli-blockade-based Kramers-qubit readout, we theoretically investigate electron transport in a situation where Pauli or spin-valley blockade is lifted by the combined effect of axial and transverse magnetic-field and short range disorder. We can identify a parameter regime where four-level (spin and valley) carbon nanotube quantum dot is reduced to an effective two-level system. We derive analytical formulas of the current as a function of applied transverse and axial magnetic field, which we compare with our numerical results.