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

Modern Physics Letters B

INTRINSIC AND EXTRINSIC DECOHERENCE FOR CHARGE QUBIT DYNAMICS IN A DOUBLE QUANTUM DOT

Li Wang, Tao Tu, Guo‐Ping Guo, Guang‐Can Guo

Published Dec 19, 2013• 0 citations
Publisher

Abstract

In this paper, we investigate different decoherence sources with a charge qubit in a semiconductor quantum dot device. We distinguish between the intrinsic qubit population leakage and extrinsic environment noise, through a crucial difference in their signatures on the dynamics of the qubit. The results demonstrated here could help to develop unified understanding of decoherence mechanism in quantum dots and allow us to design suitable protocols for control and measurement.

DOI
10.1142/s0217984914500146

Related papers

Decoherence in a crystal-phase defined double quantum dot charge qubit strongly coupled to a high-impedance resonator

Antti Ranni, Subhomoy Haldar, Harald Havir +8 more

Decoherence of a charge qubit is usually credited to charge noise in the environment. Here we show that charge noise may not be the limiting factor for the qubit coherence. To this end, we study coherence properties of a crystal-phase defined semiconductor nanowire double quantum dot (DQD) charge qubit strongly coupled to a high-impedance resonator using radio-frequency reflectometry. Response of this hybrid system is measured both at a charge noise sensitive operation point (with finite DQD detuning) and at an insensitive point (so-called sweet spot with zero detuning). A theoretical model based on the Jaynes-Cummings Hamiltonian matches the experimental results well and yields only a 10% difference in decoherence rates between the two cases, despite that the sensitivity to detuning charge noise differs by a factor of 5. Therefore, the charge noise is not limiting the coherence in this experiment with this type of semiconducting nanowire qubits. Published by the American Physical Society 2024

arXiv:2308.14887•Physical Review Research•Nov 14, 2024•10 citations

Coherent Charge Oscillation in a Semiconductor Double Quantum Dot

T. Hayashi, T. Fujisawa, Hai Du Cheong +2 more

The time evolution of a pulse-excited charge qubit in a semiconductor double quantum dot is investigated. All-electrical initialization and coherent gate control of the system are achieved, and coherent charge oscillation is observed through the transport measurements. The oscillation frequency and decoherence time T/sub 2/ are estimated by fitting the transport data with a simple model. Possible decoherence mechanisms in a charge qubit system are pointed out and discussed in detail.

IEEE Transactions on Nanotechnology•Jun 1, 2004•5 citations

Pulse Designed Coherent Dynamics of a Quantum Dot Charge Qubit

Gang Cao, Li Wang, Tao Tu +3 more

We propose an effective method to design the working parameters of a pulse-driven charge qubit implemented with double quantum dot. It is shown that intrinsic qubit population leakage to undesired states in the control and measurement process can be determined by the simulation of coherent dynamics of the qubit and minimized by choosing proper working parameters such as pulse shape. The result demonstrated here bodes well for future quantum gate operations and quantum computing applications.

Chinese Physics Letters•Mar 1, 2012•7 citations

Decoherence In Quantum Dot Charge Qubits: The Role Of Electromagnetic Fluctuations

James M. McCracken

Lateral semiconductor quantum dot structures have been proposed as an effective quantum bit (qubit) for quantum computation. A single excess electron with the freedom to move between two capacitively coupled quantum dots creates a `pseudo'-spin system with the same qubit behavior as the more natural two level system of a single electron spin. The excess electron in the double dot system is restricted to one of the two dots, thereby creating two separate and distinct states (usually referred to as |L> and |R>). The benefit of these charge qubits lie in the relative ease with which they can be manipulated and created. Experiments have been performed in this area and have shown controllable coherent oscillations and thus efficient single-qubit operations. However, the decoherence rates observed in the experiments is still quite high, making double dot charge qubits not very appealing for large-scale implementations. The following work describes the effect of the electromagnetic (EM) environment of the double quantum dot system on the decoherence of the charge state. Sources of decoherence in similar systems have been extensively investigated before and this paper follows a close theoretical framework to previous work done in the area. The effect of the EM environment can been seen in the calculations discussed below, although it is clear that the decoherence seen in experiments cannot be fully explained by the voltage fluctuations as they are investigated here. The limitations of the calculations are discussed and improvements are suggested.

Journal of International Crisis and Risk Communication Research•Jan 1, 2006•0 citations

Non-Markovian decoherence theory for a double-dot charge qubit

Matisse Wei-Yuan Tu, Wei-Min Zhang

In this paper, we develop a nonperturbation theory for describing decoherence dynamics of electron charges in a double quantum dot gated by electrodes. We extend the Feynman-Vernon influence functional theory to fermionic environments and derive an exact master equation for the reduced density matrix of electrons in the double dot for a general spectral density at arbitrary temperature and bias. We then investigate the decoherence dynamics of the double-dot charge qubit with backreaction of the reservoirs being fully taken into account. Time-dependent fluctuations and leakage effects induced from the dot-reservoir coupling are explicitly explored. The charge qubit dynamics from the Markovian to non-Markovian regime is systematically studied under various manipulating conditions. The decay behavior of charge qubit coherence and the corresponding relaxation time ${T}_{1}$ and dephasing time ${T}_{2}$ are analyzed in detail.

arXiv:0809.3490•Physical Review B•Dec 19, 2008•235 citations

Efficiency of thermal quantum information resources of two strongly coupled charge qubits in quantum dots

Fahad Aljuaydi, Fadwa Benabdallah, Abdel‐Baset A. Mohamed +1 more

Investigating quantum characteristics in a solid-state system is a crucial focus for advanced exploration. Within this scenario, double quantum dots emerge as a flexible and promising framework with the capability of bringing about significant progress in the fields of quantum computation and nanotechnology. The study presented in this work conducts a comprehensive examination of the capabilities embedded in two charge qubits residing within quantum dots, particularly focusing on their ability to generate essential quantum information resources within a thermal environment. The investigation delves into the assessment of local quantum Fisher information at the individual qubit level, local quantum uncertainty, and the quantification of entanglement through negativity. Through this meticulous exploration of quantum characteristics, the study aims to provide valuable insights into the complex interplay of thermal dynamics and quantum correlations inherent in the charge qubits within the semiconductor framework. A noteworthy revelation from our study is the discernible dependence of non-classical resources on intrinsic parameters, such as Coulomb interaction parameters, as well as extrinsic factors, including temperature. This highlights the nuanced influence of both intrinsic and extrinsic variables on the quantum properties, opening avenues for a more profound comprehension of the complex interactions that mold the quantum landscape in solid-state systems.

Modern Physics Letters A•Apr 14, 2025•1 citation
In this paper, we investigate different decoherence sources with a charge qubit in a semiconductor quantum dot device. We distinguish between the intrinsic qubit population leakage and extrinsic environment noise, through a crucial difference in their signatures on the dynamics of the qubit. The results demonstrated here could help to develop unified understanding of decoherence mechanism in quantum dots and allow us to design suitable protocols for control and measurement.
Decoherence of a charge qubit is usually credited to charge noise in the environment. Here we show that charge noise may not be the limiting factor for the qubit coherence. To this end, we study coherence properties of a crystal-phase defined semiconductor nanowire double quantum dot (DQD) charge qubit strongly coupled to a high-impedance resonator using radio-frequency reflectometry. Response of this hybrid system is measured both at a charge noise sensitive operation point (with finite DQD detuning) and at an insensitive point (so-called sweet spot with zero detuning). A theoretical model based on the Jaynes-Cummings Hamiltonian matches the experimental results well and yields only a 10% difference in decoherence rates between the two cases, despite that the sensitivity to detuning charge noise differs by a factor of 5. Therefore, the charge noise is not limiting the coherence in this experiment with this type of semiconducting nanowire qubits. Published by the American Physical Society 2024
Lateral semiconductor quantum dot structures have been proposed as an effective quantum bit (qubit) for quantum computation. A single excess electron with the freedom to move between two capacitively coupled quantum dots creates a `pseudo'-spin system with the same qubit behavior as the more natural two level system of a single electron spin. The excess electron in the double dot system is restricted to one of the two dots, thereby creating two separate and distinct states (usually referred to as |L> and |R>). The benefit of these charge qubits lie in the relative ease with which they can be manipulated and created. Experiments have been performed in this area and have shown controllable coherent oscillations and thus efficient single-qubit operations. However, the decoherence rates observed in the experiments is still quite high, making double dot charge qubits not very appealing for large-scale implementations. The following work describes the effect of the electromagnetic (EM) environment of the double quantum dot system on the decoherence of the charge state. Sources of decoherence in similar systems have been extensively investigated before and this paper follows a close theoretical framework to previous work done in the area. The effect of the EM environment can been seen in the calculations discussed below, although it is clear that the decoherence seen in experiments cannot be fully explained by the voltage fluctuations as they are investigated here. The limitations of the calculations are discussed and improvements are suggested.
In this paper, we develop a nonperturbation theory for describing decoherence dynamics of electron charges in a double quantum dot gated by electrodes. We extend the Feynman-Vernon influence functional theory to fermionic environments and derive an exact master equation for the reduced density matrix of electrons in the double dot for a general spectral density at arbitrary temperature and bias. We then investigate the decoherence dynamics of the double-dot charge qubit with backreaction of the reservoirs being fully taken into account. Time-dependent fluctuations and leakage effects induced from the dot-reservoir coupling are explicitly explored. The charge qubit dynamics from the Markovian to non-Markovian regime is systematically studied under various manipulating conditions. The decay behavior of charge qubit coherence and the corresponding relaxation time T1{T}_{1}T1​ and dephasing time T2{T}_{2}T2​ are analyzed in detail.
Investigating quantum characteristics in a solid-state system is a crucial focus for advanced exploration. Within this scenario, double quantum dots emerge as a flexible and promising framework with the capability of bringing about significant progress in the fields of quantum computation and nanotechnology. The study presented in this work conducts a comprehensive examination of the capabilities embedded in two charge qubits residing within quantum dots, particularly focusing on their ability to generate essential quantum information resources within a thermal environment. The investigation delves into the assessment of local quantum Fisher information at the individual qubit level, local quantum uncertainty, and the quantification of entanglement through negativity. Through this meticulous exploration of quantum characteristics, the study aims to provide valuable insights into the complex interplay of thermal dynamics and quantum correlations inherent in the charge qubits within the semiconductor framework. A noteworthy revelation from our study is the discernible dependence of non-classical resources on intrinsic parameters, such as Coulomb interaction parameters, as well as extrinsic factors, including temperature. This highlights the nuanced influence of both intrinsic and extrinsic variables on the quantum properties, opening avenues for a more profound comprehension of the complex interactions that mold the quantum landscape in solid-state systems.