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

Chinese Physics Letters

Electron States in Parallel Double Quantum Dots with a Tunable Inter-Dot Coupling

Cao Gang, Hai-Ou Li, Tao Tu, Cheng Jun Zhou, Hao Xiao-Jie, Guo Guang-Can, Guo‐Ping Guo

Published Sep 1, 2009• 10 citations
Publisher

Abstract

We study the electron states on lateral double quantum dots coupled in parallel. The charge stability diagrams are given in terms of the gate voltages of both dots. We discover that the two electron states translate from separated states to coupled states continuously by increasing the inter-dot coupling strength. Our results demonstrate that the parallel-quantum-dot tunability bodes well for future quantum computing applications.

DOI
10.1088/0256-307x/26/9/097302

Related papers

Transition between Quantum States in a Parallel-Coupled Double Quantum Dot

J. C. Chen, A. M. Chang, M. R. Melloch

Strong electron and spin correlations in a double quantum dot (DQD) can give rise to different quantum states. We observe a continuous transition from a Kondo state exhibiting a single-peak Kondo resonance to another exhibiting a double peak by increasing the interdot coupling (t) in a parallel-coupled DQD. The transition into the double-peak state provides evidence for spin entanglement between the excess electrons on each dot. Toward the transition, the peak splitting merges and becomes substantially smaller than t because of strong Coulomb effects. Our device tunability bodes well for future quantum computation applications.

arXiv:cond-mat/0305289•Physical Review Letters•Apr 27, 2004•209 citations

Charge Readout of a Vertical Quantum Dot Using a Laterally Weakly Coupled Quantum Dot as a Detector

Tetsuo Kodera, Yohei Iwai, Wilfred G. van der Wiel +3 more

We have fabricated laterally coupled four‐vertical‐quantum‐dot devices that can be used for reading out electron charge and spin information of quantum dots. In these devices, the inter‐dot coupling is tunable with a coupling gate voltage and the number of electrons in each dot is tunable with a side gate voltage. We first use two of the four dots to confirm the effect of the inter‐dot coupling strength on the stability diagram. We then use one of the two dots as a single electron transistor (SET) charge detector to detect the charge information of the other dot.

AIP conference proceedings•Jan 1, 2006•1 citation

Theory of charge stability diagrams in coupled quantum dot qubits

Nathan L. Foulk, S. Das Sarma

We predict large regions of the charge stability diagram using a multiband and multielectron configuration interaction model of a double quantum dot system. We account for many-body interactions within each quantum dot using full configuration interaction and solve for single-particle density operators. This allows charge states to be predicted more accurately than the extensively used classical capacitance model or the single-band Hubbard model. The resulting single-particle mixed states then serve as inputs into an atomic orbital picture that allows for the explicit calculation of the underlying Hubbard model parameters by performing the appropriate integrals. This numerical approach allows for arbitrary choices of electrostatic potential and gate geometry. A common assumption when calculating charge stability diagrams from the Hubbard model is that the charge stability diagrams are periodic, but we find that the tunnel couplings for valence electrons in dots with $N=3$ electrons are significantly enhanced when compared to single-electron dots. This difference is apparent in the charge stability diagram for higher occupancy Coulomb diamonds. We also quantitatively explore how the barrier gate strength and dot pitch impact this behavior. Our work should help improve the future realistic modeling of semiconductor-dot-based quantum circuits.

arXiv:2409.02301•Physical review. B./Physical review. B•Nov 25, 2024•5 citations

Voltage-tunable singlet-triplet transition in lateral quantum dots

Jordan Kyriakidis, Michel Pioro-Ladrière, M. Ciorga +2 more

Results of calculations and high source-drain transport measurements are presented, which demonstrate voltage-tunable entanglement of electron pairs in lateral quantum dots. At a fixed magnetic field, the application of a judiciously chosen gate voltage alters the ground state of an electron pair from an entagled spin singlet to a spin triplet.

arXiv:cond-mat/0111543•Physical review. B, Condensed matter•Jul 18, 2002•111 citations

Dynamics of interacting transport qubits

Christian Nietner, Gernot Schaller, Christina Pöltl +1 more

We investigate the electronic transport through two parallel double quantum dots coupled both capacitively and via a perpendicularly aligned charge qubit. The presence of the qubit leads to a modification of the coherent tunnel amplitudes of each double quantum dot. We study the influence of the qubit on the electronic steady-state currents through the system, the entanglement between the transport double quantum dots, and the back-action on the charge qubit. We use a Born-Markov secular quantum master equation for the system. The obtained currents show signatures of the qubit. The stationary qubit state may be tuned and even rendered pure by applying suitable voltages. In the Coulomb diamonds, it is also possible to stabilize pure entangled states of the transport double quantum dots.

arXiv:1204.2978•Physical Review B•Jun 15, 2012•7 citations

Automated tuning of inter-dot tunnel coupling in double quantum dots

Cornelis Jacobus van Diepen, Pieter T. Eendebak, Bruno T. Buijtendorp +5 more

Semiconductor quantum dot arrays defined electrostatically in a 2D electron gas provide a scalable platform for quantum information processing and quantum simulations. For the operation of quantum dot arrays, appropriate voltages need to be applied to the gate electrodes that define the quantum dot potential landscape. Tuning the gate voltages has proven to be a time-consuming task, because of initial electrostatic disorder and capacitive cross-talk effects. Here, we report on the automated tuning of the inter-dot tunnel coupling in gate-defined semiconductor double quantum dots. The automation of the tuning of the inter-dot tunnel coupling is the next step forward in scalable and efficient control of larger quantum dot arrays. This work greatly reduces the effort of tuning semiconductor quantum dots for quantum information processing and quantum simulation.

arXiv:1803.10352•Applied Physics Letters•Jul 16, 2018•70 citations
We study the electron states on lateral double quantum dots coupled in parallel. The charge stability diagrams are given in terms of the gate voltages of both dots. We discover that the two electron states translate from separated states to coupled states continuously by increasing the inter-dot coupling strength. Our results demonstrate that the parallel-quantum-dot tunability bodes well for future quantum computing applications.
Strong electron and spin correlations in a double quantum dot (DQD) can give rise to different quantum states. We observe a continuous transition from a Kondo state exhibiting a single-peak Kondo resonance to another exhibiting a double peak by increasing the interdot coupling (t) in a parallel-coupled DQD. The transition into the double-peak state provides evidence for spin entanglement between the excess electrons on each dot. Toward the transition, the peak splitting merges and becomes substantially smaller than t because of strong Coulomb effects. Our device tunability bodes well for future quantum computation applications.
We have fabricated laterally coupled four‐vertical‐quantum‐dot devices that can be used for reading out electron charge and spin information of quantum dots. In these devices, the inter‐dot coupling is tunable with a coupling gate voltage and the number of electrons in each dot is tunable with a side gate voltage. We first use two of the four dots to confirm the effect of the inter‐dot coupling strength on the stability diagram. We then use one of the two dots as a single electron transistor (SET) charge detector to detect the charge information of the other dot.
We predict large regions of the charge stability diagram using a multiband and multielectron configuration interaction model of a double quantum dot system. We account for many-body interactions within each quantum dot using full configuration interaction and solve for single-particle density operators. This allows charge states to be predicted more accurately than the extensively used classical capacitance model or the single-band Hubbard model. The resulting single-particle mixed states then serve as inputs into an atomic orbital picture that allows for the explicit calculation of the underlying Hubbard model parameters by performing the appropriate integrals. This numerical approach allows for arbitrary choices of electrostatic potential and gate geometry. A common assumption when calculating charge stability diagrams from the Hubbard model is that the charge stability diagrams are periodic, but we find that the tunnel couplings for valence electrons in dots with N=3N=3N=3 electrons are significantly enhanced when compared to single-electron dots. This difference is apparent in the charge stability diagram for higher occupancy Coulomb diamonds. We also quantitatively explore how the barrier gate strength and dot pitch impact this behavior. Our work should help improve the future realistic modeling of semiconductor-dot-based quantum circuits.
We investigate the electronic transport through two parallel double quantum dots coupled both capacitively and via a perpendicularly aligned charge qubit. The presence of the qubit leads to a modification of the coherent tunnel amplitudes of each double quantum dot. We study the influence of the qubit on the electronic steady-state currents through the system, the entanglement between the transport double quantum dots, and the back-action on the charge qubit. We use a Born-Markov secular quantum master equation for the system. The obtained currents show signatures of the qubit. The stationary qubit state may be tuned and even rendered pure by applying suitable voltages. In the Coulomb diamonds, it is also possible to stabilize pure entangled states of the transport double quantum dots.
Semiconductor quantum dot arrays defined electrostatically in a 2D electron gas provide a scalable platform for quantum information processing and quantum simulations. For the operation of quantum dot arrays, appropriate voltages need to be applied to the gate electrodes that define the quantum dot potential landscape. Tuning the gate voltages has proven to be a time-consuming task, because of initial electrostatic disorder and capacitive cross-talk effects. Here, we report on the automated tuning of the inter-dot tunnel coupling in gate-defined semiconductor double quantum dots. The automation of the tuning of the inter-dot tunnel coupling is the next step forward in scalable and efficient control of larger quantum dot arrays. This work greatly reduces the effort of tuning semiconductor quantum dots for quantum information processing and quantum simulation.