arXiv subjects

G. E. Murgida

Publications and source records attributed to G. E. Murgida.

4 recordsLinked to original sources

arXiv2009

Coherent control of localization, entanglement, and state superpositions in a double quantum dot with two electrons

We have recently proposed a quantum control method based on the knowledge of the energy spectrum as a function of an external control parameter [Phys. Rev. Lett. {\bf 99}, 036806 (2007)]. So far, our method has been applied to connect the ground state to target states that were in all cases energy eigenstates. In this paper we extend that method in order to obtain more general target states, working, for concreteness, with a system of two interacting electrons confined in semiconductor double quantum wells. Namely, we have shown that the same basic method can be employed to obtain localization, entanglement, and general superpositions of eigenstates of the system.

cond-mat.mes-hall↗

arXiv2008

Landau-Zener transitions in a semiconductor quantum dot

We study the transitions between neighboring energy levels in a quasi-one-dimensional semiconductor quantum dot with two interacting electrons in it, when it is subject to a linearly time-dependent electric field. We analyze the applicability of simple two-level Landau-Zener model to describe the evolution of the probability amplitudes in this realistic system. We show that the Landau-Zener model works very well when it is viewed in the adibatic basis, but it is not as robust in the diabatic basis.

cond-mat.str-el↗

arXiv2007

Quantum control using diabatic and adiabatic transitions

We exploit the concept of Landau-Zener transitions at avoided energy crossings as a quantum-control tool. In an avoided crossing the two quantum states interchange their characteristics as an external parameter is varied. Depending on the rate of change of the parameter it is possible to control the final state. We use this simple idea to travel along the energy spectrum of a realistic system: two interacting electrons confined in a quasi-one-dimensional semiconductor system.

cond-mat.mes-hall↗

arXiv2007

Coherent control of interacting electrons in quantum dots via navigation in the energy spectrum

Quantum control of the wave function of two interacting electrons confined in quasi-one-dimensional double-well semiconductor structures is demonstrated. The control strategies are based on the knowledge of the energy spectrum as a function of an external uniform electric field. When two low-lying levels have avoided crossings our system behaves dynamically to a large extent as a two-level system. This characteristic is exploited to implement coherent control strategies based on slow (adiabatic passage) and rapid (diabatic Landau-Zener transition) changes of the external field. We apply this method to reach desired target states that lie far in the spectrum from the initial state.

cond-mat.mes-hall↗