arXiv subjects

Filippo Troiani

Publications and source records attributed to Filippo Troiani.

43 records · Page 3Linked to original sources

arXiv2004

Competing mechanisms for singlet-triplet transition in artificial molecules

We study the magnetic field induced singlet/triplet transition for two electrons in vertically coupled quantum dots by exact diagonalization of the Coulomb interaction. We identify the different mechanisms occurring in the transition, involving either in-plane correlations or localization in opposite dots, depending on the field direction. Therefore, both spin and orbital degrees of freedom can be manipulated by field strength and direction. The phase diagram of realistic devices is determined.

cond-mat.mes-hall↗

arXiv2002

Optically induced coherence effects in `artificial atoms and molecules'

Using a master-equation approach for the description of coherent and incoherent dynamics in `artificial atoms and molecules', we present a theoretical analysis of situations where intense laser fields lead to pronounced renormalizations of carrier states. Such enhanced light-matter interactions allow for the solid-state implementation of effects hitherto only observable in atomic systems. Two prototypical examples will be presented: first, we show how two intense laser pulses can be exploited for a robust and high-fidelity population transfer of carrier states in coupled quantum dots; second, we discuss the possibility of observing self-induced transparency in a sample of inhomogenously broadened quantum dots, a phenomenon where intense laser pulses propagate without suffering significant losses.

cond-mat.mes-hall↗

arXiv2002

Electron-hole localization in coupled quantum dots

We theoretically investigate correlated electron-hole states in vertically coupled quantum dots. Employing a prototypical double-dot confinement and a configuration-interaction description for the electron-hole states, it is shown that the few-particle ground state undergoes transitions between different quantum states as a function of the interdot distance, resulting in unexpected spatial correlations among carriers and in electron-hole localization. Such transitions provide a direct manifestations of inter- and intradot correlations, which can be directly monitored in experiments.

cond-mat.mes-hall↗

arXiv2001

Quantum phases in artificial molecules

The many-body state of carriers confined in a quantum dot is controlled by the balance between their kinetic energy and their Coulomb correlation. In coupled quantum dots, both can be tuned by varying the inter-dot tunneling and interactions. Using a theoretical approach based on the diagonalization of the exact Hamiltonian, we show that transitions between different quantum phases can be induced through inter-dot coupling both for a system of few electrons (or holes) and for aggregates of electrons and holes. We discuss their manifestations in addition energy spectra (accessible through capacitance or transport experiments) and optical spectra.

cond-mat.mes-hall↗

arXiv2001

Quantum-information processing in semiconductor quantum dots

We propose an all-optical implementation of quantum-information processing in semiconductor quantum dots, where electron-hole excitations (excitons) serve as the computational degrees of freedom (qubits). The strong dot confinement leads to a strong renormalization of excitonic states, which, in analogy to NMR-based implementations of quantum-information processing, can be exploited for performing conditional and unconditional qubit operations.

cond-mat.mes-hall↗

arXiv2000

Coherent population transfer in coupled semiconductor quantum dots

We propose a solid-state implementation of stimulated Raman adiabatic passage in two coupled semiconductor quantum dots. Proper combination of two pulsed laser fields allows the coherent carrier transfer between the two nanostructures without suffering significant losses due to environment coupling. By use of a general solution scheme for the carrier states in the double-dot structure, we identify the pertinent dot and laser parameters.

cond-mat.mes-hall↗

arXiv2000

Exploiting exciton-exciton interactions in semiconductor quantum dots for quantum-information processing

We propose an all-optical implementation of quantum-information processing in semiconductor quantum dots, where electron-hole excitations (excitons) serve as the computational degrees of freedom (qubits). We show that the strong dot confinement leads to an overall enhancement of Coulomb correlations and to a strong renormalization of the excitonic states, which can be exploited for performing conditional and unconditional qubit operations.

quant-ph↗