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HL: Halbleiterphysik

HL 5: Quantenpunkte und -dr
ähte: Transporteigensch. I

HL 5.3: Talk

Monday, March 11, 2002, 11:00–11:15, H17

Dissipation in quantum dot based qubit rotations and swaps — •Tobias Brandes — Dept. of Physics, UMIST, PO Box 88, Manchester M60 1QD, UK

The control of quantum superpositions in coupled electronic systems has been suggested as a possible way to realize quantum logic gates in semiconductor structures. An example are coupled quantum dots, where the interactions between electrons can be exploited to define very small effective Hilbert spaces such as that of two tunnel–splitted ground states, separated by a large energy gap from the remaining many–particle states.

In this contribution, we quantitatively investigate the role of dissipation in one–qubit adiabatic rotations and two–qubit swaps in double quantum dots. We derive the limiting cases of weak and strong decoherence and provide analytic expressions for decoherence rates.