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

Proceedings of the ... American Control Conference/Proceedings of the American Control Conference

Coherence preservation of Markovian open quantum systems in N-level Ξ configuration

Fei Yang, Shuang Cong, Feng Shuang

Published Jun 1, 2013• 0 citations
Publisher

Abstract

Coherence preservation of Ξ-type N-level atoms is investigated. The coherence is embodied by the coherence functions that are defined in an N-dimension Hilbert space. The objective is to design external control field that maintains the coherence functions at a constant value. For this purpose, the number of components of the field should be the same as the number of coherence functions. We demonstrate that it is possible to keep multi-coherence functions constant for an finite time by applying designed field that each component addresses a particular coherence function. In addition, the applied field has singular character that makes the field effective within an interval time, and its practical significance is discussed in this circumstance.

DOI
10.1109/acc.2013.6580145

Related papers

Coherence preservation in 3-level atom

Fei Yang, Shuang Cong

Coherence preservation of a multilevel system subject to Markovian decoherence is studied. A Lambda-type three-level atom is selected as the system model. Coherence preservation between a ground state and the excited state of such a system is defined as the control object. A control field is designed by means of constraining the constant coherence condition. For the singularities of the control field, we qualitatively analyze the breakdown time, i.e. the time of control diverging. We obtain the region in which the state stays to maintain coherence forever in the case that the three-level system is reduced to a two-level one. For other cases, we investigate how different parameters affect the breakdown time qualitatively. Numerical experiments are implemented on a three-level quantum system and the experimental results are analyzed.

Quantum Information and Computation•May 1, 2011•2 citations

State-Constrained Optimal Control for Coherence Preservation in Multi-Level Open Quantum Systems

Nahid Binandeh Dehaghani, A. Pedro Aguiar, Rafał Wiśniewski

This paper addresses the optimal control of quantum coherence in multi-level systems, modeled by the Lindblad master equation, which captures both unitary evolution and environmental dissipation. We develop an energy minimization framework to control the evolution of a qutrit (three-level) quantum system while preserving coherence between states. The control problem is formulated using Pontryagin’s Minimum Principle in the form of Gamkrelidze, incorporating state constraints to ensure coherence remains within desired bounds. Our approach accounts for Markovian decoherence, demonstrating that the Lindblad operator is non-unital, which reflects the irreversible decay processes inherent in the system. The results provide insights into effectively maintaining quantum coherence in the presence of dissipation.

IEEE Conference on Decision and Control (CDC)•Dec 9, 2025•0 citations

State-Constrained Optimal Control for Coherence Preservation in Multi-Level Open Quantum Systems

Nahid Binandeh Dehaghani, A. Pedro Aguiar, Rafał Wiśniewski

This paper addresses the optimal control of quantum coherence in multi-level systems, modeled by the Lindblad master equation, which captures both unitary evolution and environmental dissipation. We develop an energy minimization framework to control the evolution of a qutrit (three-level) quantum system while preserving coherence between states. The control problem is formulated using Pontryagin's Minimum Principle in the form of Gamkrelidze, incorporating state constraints to ensure coherence remains within desired bounds. Our approach accounts for Markovian decoherence, demonstrating that the Lindblad operator is non-unital, which reflects the irreversible decay processes inherent in the system. The results provide insights into effectively maintaining quantum coherence in the presence of dissipation.

arXiv:2411.10840•Nov 16, 2024•0 citations

Optimal Control Strategy for Coherence-preserving Based on Two-level Open Quantum Systems

Zonghai Chen

The coherence-preserving of two-level open quantum systems is recognized as a key to preserve the striking feature of the parallel character of the quantum information processing,which is crucial for implementing the quantum theory into reality. Aiming at the problem,in order to reduce this unexpected decoherence effect,the quantum master equation was mainly investigated. The orthogonal basis of geometric algebra was used to convert the quantum master equation into the state-space model; in which the useful coherent vector was attained. Then the corresponding recursive optimal control algorithm was designed to achieve both the maximal suppression of decoherence and the control energy minimizing based on a typical two-level quantum system. Afterwards,some tips of how to choose the parameters were discussed. Simulation results verify its effectiveness and superiority to coherence-preserving.

Jisuanji fangzhen•Jan 1, 2008•0 citations

Phase decoherence suppression in arbitrary n-level atom in Ξ-configuration with Bang-Bang controls

Linping Chan, Shuang Cong

In this paper, we derive the conditions of maintaining quantum coherence in arbitrary n-level atom in Ξ-configuration with Bang-Bang (BB) controls when the system exists the phase decoherence, the amplitude decoherence and the general decoherence (the amplitude damping and phase damping simultaneously), respectively. On this basis, we propose our BB decoupling scheme to suppress the phase decoherence in arbitrary n-level atom in Ξ-configuration. The corresponding decoupling operators are derived explicitly. At last we design the BB decoupling scheme to suppress phase decoherence for a six-level atom system in Ξ-configuration.

World Congress on Intelligent Control and Automation•Jun 1, 2011•3 citations

State transfer and coherence maintain based on DFS in open quantum systems

Shuang Cong, Jie Yang, Jianxiu Liu

To maintain state coherence in an open quantum systems, the decoherence-free subspace (DFS) is an effective method. The target state is usually needed to be in DFS. In the case the target state is not in DFS, we first design external control field I to construct a DFS included target state. Then another control field II is used to transfer the state of the system to be controlled to the expected target state. As is well known, invariant set contains all stable states of the system. Control Hamiltonian is designed to shrink invariant set and increase the transition probability from the system state to target state. In such a way, the state transfer and coherence maintain are completed. Numerical simulation is given for a four-level energy open quantum system to demonstrate the effectiveness of the control strategy proposed.

Chinese Control Conference (CCC)•Dec 24, 2012•0 citations
Coherence preservation of Ξ-type N-level atoms is investigated. The coherence is embodied by the coherence functions that are defined in an N-dimension Hilbert space. The objective is to design external control field that maintains the coherence functions at a constant value. For this purpose, the number of components of the field should be the same as the number of coherence functions. We demonstrate that it is possible to keep multi-coherence functions constant for an finite time by applying designed field that each component addresses a particular coherence function. In addition, the applied field has singular character that makes the field effective within an interval time, and its practical significance is discussed in this circumstance.
Coherence preservation of a multilevel system subject to Markovian decoherence is studied. A Lambda-type three-level atom is selected as the system model. Coherence preservation between a ground state and the excited state of such a system is defined as the control object. A control field is designed by means of constraining the constant coherence condition. For the singularities of the control field, we qualitatively analyze the breakdown time, i.e. the time of control diverging. We obtain the region in which the state stays to maintain coherence forever in the case that the three-level system is reduced to a two-level one. For other cases, we investigate how different parameters affect the breakdown time qualitatively. Numerical experiments are implemented on a three-level quantum system and the experimental results are analyzed.
This paper addresses the optimal control of quantum coherence in multi-level systems, modeled by the Lindblad master equation, which captures both unitary evolution and environmental dissipation. We develop an energy minimization framework to control the evolution of a qutrit (three-level) quantum system while preserving coherence between states. The control problem is formulated using Pontryagin’s Minimum Principle in the form of Gamkrelidze, incorporating state constraints to ensure coherence remains within desired bounds. Our approach accounts for Markovian decoherence, demonstrating that the Lindblad operator is non-unital, which reflects the irreversible decay processes inherent in the system. The results provide insights into effectively maintaining quantum coherence in the presence of dissipation.
This paper addresses the optimal control of quantum coherence in multi-level systems, modeled by the Lindblad master equation, which captures both unitary evolution and environmental dissipation. We develop an energy minimization framework to control the evolution of a qutrit (three-level) quantum system while preserving coherence between states. The control problem is formulated using Pontryagin's Minimum Principle in the form of Gamkrelidze, incorporating state constraints to ensure coherence remains within desired bounds. Our approach accounts for Markovian decoherence, demonstrating that the Lindblad operator is non-unital, which reflects the irreversible decay processes inherent in the system. The results provide insights into effectively maintaining quantum coherence in the presence of dissipation.
The coherence-preserving of two-level open quantum systems is recognized as a key to preserve the striking feature of the parallel character of the quantum information processing,which is crucial for implementing the quantum theory into reality. Aiming at the problem,in order to reduce this unexpected decoherence effect,the quantum master equation was mainly investigated. The orthogonal basis of geometric algebra was used to convert the quantum master equation into the state-space model; in which the useful coherent vector was attained. Then the corresponding recursive optimal control algorithm was designed to achieve both the maximal suppression of decoherence and the control energy minimizing based on a typical two-level quantum system. Afterwards,some tips of how to choose the parameters were discussed. Simulation results verify its effectiveness and superiority to coherence-preserving.
In this paper, we derive the conditions of maintaining quantum coherence in arbitrary n-level atom in Ξ-configuration with Bang-Bang (BB) controls when the system exists the phase decoherence, the amplitude decoherence and the general decoherence (the amplitude damping and phase damping simultaneously), respectively. On this basis, we propose our BB decoupling scheme to suppress the phase decoherence in arbitrary n-level atom in Ξ-configuration. The corresponding decoupling operators are derived explicitly. At last we design the BB decoupling scheme to suppress phase decoherence for a six-level atom system in Ξ-configuration.
To maintain state coherence in an open quantum systems, the decoherence-free subspace (DFS) is an effective method. The target state is usually needed to be in DFS. In the case the target state is not in DFS, we first design external control field I to construct a DFS included target state. Then another control field II is used to transfer the state of the system to be controlled to the expected target state. As is well known, invariant set contains all stable states of the system. Control Hamiltonian is designed to shrink invariant set and increase the transition probability from the system state to target state. In such a way, the state transfer and coherence maintain are completed. Numerical simulation is given for a four-level energy open quantum system to demonstrate the effectiveness of the control strategy proposed.