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

arXiv:quant-ph/0107084 · Physical Review Letters

Electron Entanglement via a Quantum Dot

William D. Oliver, Fumiko Yamaguchi, Y. Yamamoto

Published Jan 3, 2002• 132 citations
arXivHTMLPDF

Abstract

This Letter presents a method of electron entanglement generation. The system under consideration is a single-level quantum dot with one input and two output leads. The leads are arranged such that the dot is empty, single-electron tunneling is suppressed by energy conservation, and two-electron virtual cotunneling is allowed. Such a configuration effectively filters the singlet-state portion of a two-electron input, yielding a nonlocal spin-singlet state at the output leads. Coulomb interaction mediates the entanglement generation, and, in its absence, the singlet state vanishes. This approach is a four-wave mixing process analogous to the photon entanglement generated by a chi((3)) parametric amplifier.

DOI
10.1103/physrevlett.88.037901

Related papers

Non-empty quantum dot as a spin-entangler

Chih‐Lung Chou

We consider a three-port single-level quantum dot system with one input and two output leads. Instead of considering an empty dot, we study the situations that two input electrons co-tunnel through the quantum dot occupied by one or two dot electrons. We show that electron entanglement can be generated via the co-tunneling processes when the dot is occupied by two electrons, yielding non-local spin-singlet states at the output leads. When the dot is occupied by a single electron, we show that by carefully selecting model parameters non-local spin-triplet electrons can also be obtained at the output leads if the final dot electron has the same spin as that of the initial dot electron.

arXiv:quant-ph/0212131•Quantum Information and Computation•Jul 1, 2003•0 citations

Entanglement generation through an open quantum dot: an exact approach

Imamura, Takashi, Akinori Nishino, Naomichi Hatano

We analytically study entanglement generation through an open quantum dot system described by the two-lead Anderson model. We exactly obtain the transition rate between the non-entangled incident state in one lead and the outgoing spin-singlet state in the other lead. In the cotunneling process, only the spin-singlet state can transmit. To discuss such an entanglement property in the open quantum system, we construct the exact two-electron scattering state of the Anderson model. It is striking that the scattering state contains spin-singlet bound states induced by the Coulomb interaction. The bound state describes the scattering process in which the set of momenta is not conserved and hence it is not in the form of a Bethe eigenstate.

arXiv:0905.3445•May 21, 2009•0 citations

Entanglement generation through an open quantum dot: Exact two-electron scattering state in the Anderson model

Takashi Imamura, Akinori Nishino, Naomichi Hatano

We analytically study entanglement generation through an open quantum-dot system described by the two-lead Anderson model. We exactly obtain the transition rate between the nonentangled incident state in one lead and the outgoing spin-singlet state in the other lead. We find that only the spin-singlet state can transmit in the cotunneling process. To discuss such an entanglement property in the open quantum system, we construct the exact two-electron scattering state of the Anderson model. It is striking that the scattering state contains spin-singlet bound states induced by the Coulomb interaction. The bound state describes a scattering process in which the set of momenta is not conserved and hence, it is not in the form of a Bethe eigenstate.

Physical Review B•Dec 29, 2009•20 citations

Entangled electronic state via an interacting quantum dot

Gabriela Arias León, Otto Rendón, Horacio M. Pastawski +2 more

We study a device for entangling electrons as co-tunneling occurs through a quantum dot where on-site electron-electron interactions U are in place. The main advantage of this device is that single-particle processes are forbidden by energy conservation as proposed by Oliver et al. ( Phys. Rev. Lett. 88 (2002) 7901). Within this model we calculated the two-electron transition amplitude, in terms of the T-matrix, to all orders in the coupling to the dot, and consider a finite lead bandwidth. The model filters singlet entangled pairs with the sole requirement of Pauli principle. Feynman paths involving consecutive and doubly occupied dot interfere destructively and produce a transition amplitude minimum at a critical value of the onsite repulsion U . Singlet filtering is demonstrated as a function of a gate voltage applied to the dot with a special resonance condition when the dot levels are symmetrically placed about the input lead energy.

arXiv:cond-mat/0402603•Europhysics Letters (EPL)•May 27, 2004•4 citations

Numerical study of a quantum dot structure for entanglement generation

G. Giavaras

It has been suggested (Giavaras et al 2007 Phys. Rev. B 75 085302) that a quantum dot structure, which consists of a small open dot formed within a larger dot, can generate spin entanglement between two electrons and filter singlet–triplet states as a consequence of Coulomb interaction and the Pauli exclusion principle. In this work, we show via numerical modelling how to form the dot structure in an AlGaAs/GaAs/AlGaAs quasi-one-dimensional channel using top and back gates. We calculate the confining potential of the dot and the corresponding low-lying two-electron states and demonstrate a way of controlling the degree of entanglement and filtering by tuning the dot potential with the voltage applied to a back gate.

Semiconductor Science and Technology•Jun 24, 2008•2 citations

Spin-Entangled Currents Created by a Triple Quantum Dot

Daniel S. Saraga, Daniel Loss

We propose a simple setup of three coupled quantum dots in the Coulomb blockade regime as a source for spatially separated currents of spin-entangled electrons. The entanglement originates from the singlet ground state of a quantum dot with an even number of electrons. To preserve the entanglement of the electron pair during its extraction to the drain leads, the electrons are transported through secondary dots. This prevents one-electron transport by energy mismatch, while joint transport is resonantly enhanced by conservation of the total two-electron energy.

arXiv:cond-mat/0205553•Physical Review Letters•Apr 24, 2003•190 citations
This Letter presents a method of electron entanglement generation. The system under consideration is a single-level quantum dot with one input and two output leads. The leads are arranged such that the dot is empty, single-electron tunneling is suppressed by energy conservation, and two-electron virtual cotunneling is allowed. Such a configuration effectively filters the singlet-state portion of a two-electron input, yielding a nonlocal spin-singlet state at the output leads. Coulomb interaction mediates the entanglement generation, and, in its absence, the singlet state vanishes. This approach is a four-wave mixing process analogous to the photon entanglement generated by a chi((3)) parametric amplifier.
We consider a three-port single-level quantum dot system with one input and two output leads. Instead of considering an empty dot, we study the situations that two input electrons co-tunnel through the quantum dot occupied by one or two dot electrons. We show that electron entanglement can be generated via the co-tunneling processes when the dot is occupied by two electrons, yielding non-local spin-singlet states at the output leads. When the dot is occupied by a single electron, we show that by carefully selecting model parameters non-local spin-triplet electrons can also be obtained at the output leads if the final dot electron has the same spin as that of the initial dot electron.
We analytically study entanglement generation through an open quantum dot system described by the two-lead Anderson model. We exactly obtain the transition rate between the non-entangled incident state in one lead and the outgoing spin-singlet state in the other lead. In the cotunneling process, only the spin-singlet state can transmit. To discuss such an entanglement property in the open quantum system, we construct the exact two-electron scattering state of the Anderson model. It is striking that the scattering state contains spin-singlet bound states induced by the Coulomb interaction. The bound state describes the scattering process in which the set of momenta is not conserved and hence it is not in the form of a Bethe eigenstate.
We analytically study entanglement generation through an open quantum-dot system described by the two-lead Anderson model. We exactly obtain the transition rate between the nonentangled incident state in one lead and the outgoing spin-singlet state in the other lead. We find that only the spin-singlet state can transmit in the cotunneling process. To discuss such an entanglement property in the open quantum system, we construct the exact two-electron scattering state of the Anderson model. It is striking that the scattering state contains spin-singlet bound states induced by the Coulomb interaction. The bound state describes a scattering process in which the set of momenta is not conserved and hence, it is not in the form of a Bethe eigenstate.
We study a device for entangling electrons as co-tunneling occurs through a quantum dot where on-site electron-electron interactions U are in place. The main advantage of this device is that single-particle processes are forbidden by energy conservation as proposed by Oliver et al. ( Phys. Rev. Lett. 88 (2002) 7901). Within this model we calculated the two-electron transition amplitude, in terms of the T-matrix, to all orders in the coupling to the dot, and consider a finite lead bandwidth. The model filters singlet entangled pairs with the sole requirement of Pauli principle. Feynman paths involving consecutive and doubly occupied dot interfere destructively and produce a transition amplitude minimum at a critical value of the onsite repulsion U . Singlet filtering is demonstrated as a function of a gate voltage applied to the dot with a special resonance condition when the dot levels are symmetrically placed about the input lead energy.
It has been suggested (Giavaras et al 2007 Phys. Rev. B 75 085302) that a quantum dot structure, which consists of a small open dot formed within a larger dot, can generate spin entanglement between two electrons and filter singlet–triplet states as a consequence of Coulomb interaction and the Pauli exclusion principle. In this work, we show via numerical modelling how to form the dot structure in an AlGaAs/GaAs/AlGaAs quasi-one-dimensional channel using top and back gates. We calculate the confining potential of the dot and the corresponding low-lying two-electron states and demonstrate a way of controlling the degree of entanglement and filtering by tuning the dot potential with the voltage applied to a back gate.
We propose a simple setup of three coupled quantum dots in the Coulomb blockade regime as a source for spatially separated currents of spin-entangled electrons. The entanglement originates from the singlet ground state of a quantum dot with an even number of electrons. To preserve the entanglement of the electron pair during its extraction to the drain leads, the electrons are transported through secondary dots. This prevents one-electron transport by energy mismatch, while joint transport is resonantly enhanced by conservation of the total two-electron energy.