Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)

Efficient modeling of Coulomb interaction effect on exciton in crystal-phase nanowire quantum dot

Masoomeh Taherkhani, Niels Gregersen, Jesper Mørk, Dara P. S. McCutcheon, Morten Willatzen

Published Jul 1, 2016• 0 citations
Publisher

Abstract

The binding energy and oscillation strength of the ground-state exciton in type-II quantum dot (QD) is calculated by using a post Hartree-Fock method known as the configuration interaction (CI) method which is significantly more efficient than conventional methods like ab initio method. We show that the Coulomb interaction between electron and holes in these structures considerably affects the transition dipole moment which is the key parameter of optical quantum gating in STIRAP (stimulated Raman adiabatic passage) process for implementing quantum gates [1], [2].

DOI
10.1109/nusod.2016.7547003

Related papers

Type-II quantum dot nanowire structures with large oscillator strengths for optical quantum gating applications

Masoomeh Taherkhani, Niels Gregersen, Morten Willatzen +1 more

The exciton oscillator strength (OS) in type-II quantum dot (QD) nanowires is calculated by using a fast and efficient method. We propose a new structure in Double-Well QD (DWQD) nanowire that considerably increases OS of type-II QDs which is a key parameter in optical quantum gating in the stimulated Raman adiabatic passage (STIRAP) process for implementing quantum gates.

International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)•Jul 1, 2017•0 citations

Modelling of Optical Gates for Quantum Information Processing.

Masoomeh Taherkhani

A numerical tool is developed to calculate the exciton energy and oscillator strength in newly emerged type-II nanowire quantum-dots. For a singlequantum-dot, the poor overlap of the electron part and the weakly confined hole part of the exciton wavefunction leads to a small oscillator strength compared to type-I systems. To increase the oscillator strength, we propose a double-quantum-dot structure featuring a strongly localized exciton wavefunction and a corresponding four-fold relative enhancement of the oscillator strength, paving the way towards efficient optically controlled quantum gate applications in the type-II nanowire system. Next, an optical gating scheme for quantum computing based on type-II double-quantum-dots is proposed. The qubit is encoded on the electron spin and the gate operations are performed by stimulated Raman adiabatic passage (STIRAP) using the position degree of freedom in double-quantum-dots to form an auxiliary ground-state. Successful STIRAP gating processes require an efficient coupling of both qubit ground-states of the double-quantum-dot to the gating auxiliary state and we demonstrate that this can be achieved using a charged exciton state. Crucially, by using type-II quantum-dots, the hole is localized between the two spatially separated electrons in the chargedexciton complex, thereby efficiently coupling the electron states orbitals. We subsequently exploit the scheme to realize single- and two-qubit gates for quantum computation. The conditional operation is performed by using Coulomb coupling to induce a shift of the STIRAP transition frequencies leading to a conditional violation of the STIRAP two-photon resonance. We calculate the fidelity of gates and show their performance is robust against the spin and charge noises.

•Jan 1, 2018•0 citations

High-fidelity optical quantum gates based on type-II double quantum dots in a nanowire

Masoomeh Taherkhani, Morten Willatzen, Emil V. Denning +2 more

We propose an optical gating scheme for quantum computing based on crystal-phase type II double quantum dots in an InP nanowire. The qubit is encoded on the electron spin and the gate operations are performed using stimulated Raman adiabatic passage (STIRAP), using the orbital degree of freedom in double quantum dots to form an auxiliary ground state. Successful STIRAP gating processes require an efficient coupling of both qubit ground states of the double quantum dot to the gating auxiliary ground state, and we demonstrate that this can be achieved using a charged exciton state. Crucially, by using type II dots, the hole is localized between the two spatially separated electrons in the charged exciton complex, thereby efficiently coupling the electron ground-state orbitals. By taking advantage of the high-fidelity state transfer by means of STIRAP in type II double quantum dots, we propose a protocol for coherently manipulating the spin-orbital quantum state of confined electrons in a quantum dot chain of an InP nanowire. We subsequently exploit the protocol to realize single- and two-qubit gates with fidelity above 0.99.

Physical review. B./Physical review. B•Apr 10, 2019•11 citations

Rabi oscillations in a semiconductor quantum dot: Influence of local fields

Gregory Ya. Slepyan, A. Magyarov, С. А. Максименко +2 more

The influence of electron-hole dipole-dipole interactions (local fields) on the excitonic Rabi oscillations in an isolated quantum dot (QD) has been theoretically investigated. An analysis for the QD interaction with monochromatic field and ultrashort Gaussian pulse has been performed. On the basis of optical Bloch equations the Rabi oscillation dynamics has been investigated. As a result, the bifurcation and essentially anharmonic regimes in the Rabi oscillations in a QD exposed to the monochromatic field have been predicted. The strong dependence of the period of Rabi oscillations on the QD depolarization has been revealed. For the Gaussian pulse it has been shown that the final state of inversion as a function of the pulse peak strength demonstrates step-like transitions.

Physical Review B•Jul 29, 2004•53 citations

Quantum Computing with QD Excitons

Hidehiko Kamada

This paper discusses the potential application of elementary excitation in semiconductor quantum dots to quantum computation. We propose a scalable hardware design and all-optical implementation of logical gates that exploit the discrete nature of electron and hole states and their well-concentrated oscillator strength for ultrafast gate operations. We also propose a multiple-bit design based on the nearest neighbor dipole-dipole coupling. Rabi population oscillation of an excitonic two-level system in an isolated single In xGa1-xAs quantum dot is manifested by quantum wave function interferometry in the time domain, demonstrating a long lived coherence of zero-dimensional excitonic states and revealing the coherent population flopping under strong optical field. Phase-sensitive coherent gate operations on a single-dot exciton qubit are demonstrated.

•Jan 1, 2003•2 citations

Decoherence and quantum entangled exciton states in semiconductor quantum dot molecule

A. Hichri, S. Jaziri, R. Ferreira

Recently a pair of vertically aligned quantum dots has been suggested as optically driven quantum gate. The later is built when two different particles, an electron and a hole, are created optically. The two particles form entangled states. We study theoretically the dynamics of a single heavy hole exciton confined in a small vertically coupled quantum dot. We use harmonic potentials to model the confining of electrons and holes and calculate the exciton's energy spectrum using the Hund-Mulliken approach, and including the Coulomb interaction. The entanglement may be controlled by the application of external electric field. At certain times of dynamical evolution one can generate a maximally entangled coherent exciton state by initially preparing the quantum dots in a superposition of coherent state. In ideal situations, entangled quantum states would not decohere during processing and transmission of quantum information. However, a real quantum system is inevitably influenced by its environment. Since, we study the decoherence effect caused by the interaction of the confined carriers with the acoustic phonon effects. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics•Feb 1, 2004•2 citations
The binding energy and oscillation strength of the ground-state exciton in type-II quantum dot (QD) is calculated by using a post Hartree-Fock method known as the configuration interaction (CI) method which is significantly more efficient than conventional methods like ab initio method. We show that the Coulomb interaction between electron and holes in these structures considerably affects the transition dipole moment which is the key parameter of optical quantum gating in STIRAP (stimulated Raman adiabatic passage) process for implementing quantum gates [1], [2].
A numerical tool is developed to calculate the exciton energy and oscillator strength in newly emerged type-II nanowire quantum-dots. For a singlequantum-dot, the poor overlap of the electron part and the weakly confined hole part of the exciton wavefunction leads to a small oscillator strength compared to type-I systems. To increase the oscillator strength, we propose a double-quantum-dot structure featuring a strongly localized exciton wavefunction and a corresponding four-fold relative enhancement of the oscillator strength, paving the way towards efficient optically controlled quantum gate applications in the type-II nanowire system. Next, an optical gating scheme for quantum computing based on type-II double-quantum-dots is proposed. The qubit is encoded on the electron spin and the gate operations are performed by stimulated Raman adiabatic passage (STIRAP) using the position degree of freedom in double-quantum-dots to form an auxiliary ground-state. Successful STIRAP gating processes require an efficient coupling of both qubit ground-states of the double-quantum-dot to the gating auxiliary state and we demonstrate that this can be achieved using a charged exciton state. Crucially, by using type-II quantum-dots, the hole is localized between the two spatially separated electrons in the chargedexciton complex, thereby efficiently coupling the electron states orbitals. We subsequently exploit the scheme to realize single- and two-qubit gates for quantum computation. The conditional operation is performed by using Coulomb coupling to induce a shift of the STIRAP transition frequencies leading to a conditional violation of the STIRAP two-photon resonance. We calculate the fidelity of gates and show their performance is robust against the spin and charge noises.
We propose an optical gating scheme for quantum computing based on crystal-phase type II double quantum dots in an InP nanowire. The qubit is encoded on the electron spin and the gate operations are performed using stimulated Raman adiabatic passage (STIRAP), using the orbital degree of freedom in double quantum dots to form an auxiliary ground state. Successful STIRAP gating processes require an efficient coupling of both qubit ground states of the double quantum dot to the gating auxiliary ground state, and we demonstrate that this can be achieved using a charged exciton state. Crucially, by using type II dots, the hole is localized between the two spatially separated electrons in the charged exciton complex, thereby efficiently coupling the electron ground-state orbitals. By taking advantage of the high-fidelity state transfer by means of STIRAP in type II double quantum dots, we propose a protocol for coherently manipulating the spin-orbital quantum state of confined electrons in a quantum dot chain of an InP nanowire. We subsequently exploit the protocol to realize single- and two-qubit gates with fidelity above 0.99.
The influence of electron-hole dipole-dipole interactions (local fields) on the excitonic Rabi oscillations in an isolated quantum dot (QD) has been theoretically investigated. An analysis for the QD interaction with monochromatic field and ultrashort Gaussian pulse has been performed. On the basis of optical Bloch equations the Rabi oscillation dynamics has been investigated. As a result, the bifurcation and essentially anharmonic regimes in the Rabi oscillations in a QD exposed to the monochromatic field have been predicted. The strong dependence of the period of Rabi oscillations on the QD depolarization has been revealed. For the Gaussian pulse it has been shown that the final state of inversion as a function of the pulse peak strength demonstrates step-like transitions.
This paper discusses the potential application of elementary excitation in semiconductor quantum dots to quantum computation. We propose a scalable hardware design and all-optical implementation of logical gates that exploit the discrete nature of electron and hole states and their well-concentrated oscillator strength for ultrafast gate operations. We also propose a multiple-bit design based on the nearest neighbor dipole-dipole coupling. Rabi population oscillation of an excitonic two-level system in an isolated single In xGa1-xAs quantum dot is manifested by quantum wave function interferometry in the time domain, demonstrating a long lived coherence of zero-dimensional excitonic states and revealing the coherent population flopping under strong optical field. Phase-sensitive coherent gate operations on a single-dot exciton qubit are demonstrated.
Recently a pair of vertically aligned quantum dots has been suggested as optically driven quantum gate. The later is built when two different particles, an electron and a hole, are created optically. The two particles form entangled states. We study theoretically the dynamics of a single heavy hole exciton confined in a small vertically coupled quantum dot. We use harmonic potentials to model the confining of electrons and holes and calculate the exciton's energy spectrum using the Hund-Mulliken approach, and including the Coulomb interaction. The entanglement may be controlled by the application of external electric field. At certain times of dynamical evolution one can generate a maximally entangled coherent exciton state by initially preparing the quantum dots in a superposition of coherent state. In ideal situations, entangled quantum states would not decohere during processing and transmission of quantum information. However, a real quantum system is inevitably influenced by its environment. Since, we study the decoherence effect caused by the interaction of the confined carriers with the acoustic phonon effects. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)