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

Physical review. E

Variational quantum simulation of thermal relaxation in open qubit systems with nonadditive dissipation

Lucas Queiroz Galvão, A. C. P. Rosa, Marcelo Albano Moret, Clebson Cruz

Published Nov 20, 2025• 0 citations
Publisher

Abstract

In this paper, we present an application of the variational quantum simulation (VQS) framework to capture finite temperature open system dynamics on near-term quantum hardware. By embedding the generalized amplitude damping channel into the VQS algorithm, we model energy exchange with a thermal bath through its Lindblad representation and thereby simulate realistic dissipative effects. To explore a wide range of activation behaviors, we introduce a nonadditive relaxation time model using a generalized form of the Arrhenius law, based on the phenomenological parameter q. We compare our method on driven qubit systems subject to both static and composite time-dependent fields, comparing population evolution and trace distance errors against reference numerical solutions. Our results demonstrate that (1) VQS accurately maps the effective nonunitary generator under GAD, (2) smoother drive envelopes induced by nonaddtive parameters suppress high-frequency components and yield lower simulation errors, and (3) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the reference numerical solution's sensitivity to q increases.

DOI
10.1103/z126-zcq6

Related papers

Variational quantum simulation of a nonadditive relaxation dynamics in a qubit coupled to a finite-temperature bath

Lucas Queiroz Galvão, Clebson Cruz, Antonio Cesar do Prado Rosa Junior +1 more

In this paper, we present an application of the variational quantum simulation (VQS) framework to capture finite-temperature open-system dynamics on near-term quantum hardware. By embedding the generalized amplitude-damping channel into the VQS algorithm, we modeled the energy exchange with a thermal bath through its Lindblad representation and thereby simulated realistic dissipative effects. To explore a wide range of activation behaviors, we introduce a nonadditive relaxation-time model using a generalized form of the Arrhenius law, based on the phenomenological parameter q. We compare our method on a driven qubit subject to both static and composite time-dependent fields, comparing population evolution and trace distance errors against exact solutions. Our results demonstrate that (i) VQS accurately maps the effective nonunitary generator under generalized amplitude damping, (ii) smoother drive envelopes induced by nonaddtive parameters suppress high frequency components and yield lower simulation errors, and (iii) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the exact solution's sensitivity to q increases. Our results demonstrate that (i) VQS accurately maps the effective nonunitary generator under generalized amplitude damping, (ii) smoother drive envelopes induced by nonaddtive parameters suppress high frequency components and yield lower simulation errors, and (iii) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the exact solution's sensitivity to q increases.

arXiv:2505.12013•May 17, 2025•0 citations

Variational Quantum Simulation of Lindblad Dynamics via Quantum State Diffusion

Jianming Luo, Kaihan Lin, Xing Bao Gao

Quantum simulation of dynamics in open quantum systems is crucial but poses a significant challenge due to the non-Hermitian nature leading to nonunitary evolution and the limited quantum resources on current quantum computers. Here we introduce a variational hybrid quantum-classical algorithm designed for simulating the time evolution governed by the Lindblad master equation. Our approach involves on a stochastic unveiling of the density matrix, transforming the Lindblad equation into a wave function-based quantum state diffusion (QSD) method with the aim of reducing qubit requirements. We then apply variational quantum simulation (VQS) to efficiently capture the nonunitary evolution in QSD. We demonstrate our QSD-VQS algorithm by investigating the quantum dynamics in a two-level system subjected to an amplitude damping channel and a four-level transverse field Ising model within a dissipative environment including time-independent and periodic Hamiltonian cases. The results reveal its promising utility with upcoming hardware in the near future.

The Journal of Physical Chemistry Letters•Mar 22, 2024•21 citations

Energy relaxation via quantum thermalization: A superconducting qubit coupled to an interacting many-body two-level system

Xue-Yi Guo

Two-level systems (TLS) are widely recognized as a dominant source of energy relaxation in superconducting qubits, limiting coherence times and device performance. While TLS-induced dissipation is often modeled as independent channels, interacting TLS can form finite many-body environments whose dynamical role in qubit relaxation remains insufficiently understood. Building on the information-erasure-based framework for irreversible thermalization developed in our previous work, we present a microscopic model and numerical simulations of a superconducting qubit coupled to a finite interacting many-body TLS environment as a concrete physical realization of this mechanism. We show that effective irreversible energy relaxation can emerge from intrinsic many-body dynamics without invoking external baths or phenomenological dissipation. The introduction of information erasure drives a transition from coherent oscillatory energy exchange to nonoscillatory exponential relaxation of the qubit. The relaxation times exhibit the scaling $T_1, T_2 \propto J_{q,τ}^{-2}$ with respect to the qubit-TLS coupling strength, consistent with Fermi's golden rule and Lindblad-type descriptions. Importantly, both exponential decay and its scaling behavior arise directly from microscopic many-body dynamics. These results provide quantitative insight into TLS-induced decoherence mechanisms and establish a microscopic link between information erasure, many-body thermalization, and irreversible relaxation in superconducting quantum systems.

quant-pharXiv:2603.13322•APS Open Science•Mar 5, 2026•0 citations

Variational quantum simulation of dynamical quantum phase transition in Markovian open quantum systems

Yukai Guo, Jinjian Yu, Xing Bao Gao

We investigate dynamical quantum phase transitions (DQPTs) in Markovian open quantum systems using a variational quantum simulation (VQS) algorithm based on quantum state diffusion (QSD). This approach reformulates the Lindblad master equation as an ensemble of pure-state trajectories, enabling efficient simulation of dissipative quantum dynamics with effectively reduced quantum resources. Focusing on the one-dimensional transverse-field Ising model (TFIM), we simulate quench dynamics under both local and global Lindblad dissipation. The QSD-VQS algorithm accurately captures the nonanalytic cusps in the Loschmidt rate function, and reveals their modulation by dissipation strength and system size. Notably, DQPTs are gradually suppressed under strong local dissipation, while they persist under strong global dissipation due to collective environmental effects. Benchmarking against exact Lindblad solutions confirms the high accuracy and scalability of our method.

Chinese Journal of Chemical Physics•Aug 1, 2025•0 citations

Control of open quantum systems: Manipulation of a qubit coupled to a thermal bath by an external driving field

Haoran Sun, Michael Galperin

Fast and reliable manipulation with qubits is fundamental for any quantum technology. The implementation of these manipulations in physical systems is the focus of studies involving optimal control theory. Realistic physical devices are open quantum systems. So far, studies in optimal control theory have primarily utilized the Redfield/Lindblad quantum master equation to simulate the dynamics of such systems. However, this Markov description is not always sufficient. Here, we present a study of qubit control utilizing the nonequilibrium Green's function method. We compare the traditional master equation with more general Green's function results and demonstrate that even in the parameter regime suitable for the application of the Redfield/Lindblad approach, the two methods yield drastically different results when addressing evolution involving mixed states. In particular, we find that, in addition to predicting different optimal driving profiles, a more accurate description of system evolution enables the system to reach the desired final state much more quickly. We argue that the primary reason for this is the significance of the non-Markov description of driven system dynamics due to the effect of time-dependent driving on dissipation.

arXiv:2412.12624•Dec 17, 2024•0 citations

Assessment of weak-coupling approximations on a driven two-level system under dissipation

Wallace S. Teixeira, F. L. Semião, Jani Tuorila +1 more

Abstract The standard weak-coupling approximations associated to open quantum systems have been extensively used in the description of a two-level quantum system, qubit, subjected to relatively weak dissipation compared with the qubit frequency. However, recent progress in the experimental implementations of controlled quantum systems with increased levels of on-demand engineered dissipation has motivated precision studies in parameter regimes that question the validity of the approximations, especially in the presence of time-dependent drive fields. In this paper, we address the precision of weak-coupling approximations by studying a driven qubit through the numerically exact and non-perturbative method known as the stochastic Liouville–von Neumann equation with dissipation. By considering weak drive fields and a cold Ohmic environment with a high cutoff frequency, we use the Markovian Lindblad master equation as a point of comparison for the SLED method and study the influence of the bath-induced energy shift on the qubit dynamics. We also propose a metric that may be used in experiments to map the regime of validity of the Lindblad equation in predicting the steady state of the driven qubit. In addition, we study signatures of the well-known Mollow triplet and observe its meltdown owing to dissipation in an experimentally feasible parameter regime of circuit electrodynamics. Besides shedding light on the practical limitations of the Lindblad equation, we expect our results to inspire future experimental research on engineered open quantum systems, the accurate modeling of which may benefit from non-perturbative methods.

arXiv:2011.06106•New Journal of Physics•Dec 16, 2021•9 citations
In this paper, we present an application of the variational quantum simulation (VQS) framework to capture finite temperature open system dynamics on near-term quantum hardware. By embedding the generalized amplitude damping channel into the VQS algorithm, we model energy exchange with a thermal bath through its Lindblad representation and thereby simulate realistic dissipative effects. To explore a wide range of activation behaviors, we introduce a nonadditive relaxation time model using a generalized form of the Arrhenius law, based on the phenomenological parameter q. We compare our method on driven qubit systems subject to both static and composite time-dependent fields, comparing population evolution and trace distance errors against reference numerical solutions. Our results demonstrate that (1) VQS accurately maps the effective nonunitary generator under GAD, (2) smoother drive envelopes induced by nonaddtive parameters suppress high-frequency components and yield lower simulation errors, and (3) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the reference numerical solution's sensitivity to q increases.
In this paper, we present an application of the variational quantum simulation (VQS) framework to capture finite-temperature open-system dynamics on near-term quantum hardware. By embedding the generalized amplitude-damping channel into the VQS algorithm, we modeled the energy exchange with a thermal bath through its Lindblad representation and thereby simulated realistic dissipative effects. To explore a wide range of activation behaviors, we introduce a nonadditive relaxation-time model using a generalized form of the Arrhenius law, based on the phenomenological parameter q. We compare our method on a driven qubit subject to both static and composite time-dependent fields, comparing population evolution and trace distance errors against exact solutions. Our results demonstrate that (i) VQS accurately maps the effective nonunitary generator under generalized amplitude damping, (ii) smoother drive envelopes induced by nonaddtive parameters suppress high frequency components and yield lower simulation errors, and (iii) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the exact solution's sensitivity to q increases. Our results demonstrate that (i) VQS accurately maps the effective nonunitary generator under generalized amplitude damping, (ii) smoother drive envelopes induced by nonaddtive parameters suppress high frequency components and yield lower simulation errors, and (iii) the variational manifold exhibits dynamical selectivity, maintaining mapping fidelity even as the exact solution's sensitivity to q increases.
Quantum simulation of dynamics in open quantum systems is crucial but poses a significant challenge due to the non-Hermitian nature leading to nonunitary evolution and the limited quantum resources on current quantum computers. Here we introduce a variational hybrid quantum-classical algorithm designed for simulating the time evolution governed by the Lindblad master equation. Our approach involves on a stochastic unveiling of the density matrix, transforming the Lindblad equation into a wave function-based quantum state diffusion (QSD) method with the aim of reducing qubit requirements. We then apply variational quantum simulation (VQS) to efficiently capture the nonunitary evolution in QSD. We demonstrate our QSD-VQS algorithm by investigating the quantum dynamics in a two-level system subjected to an amplitude damping channel and a four-level transverse field Ising model within a dissipative environment including time-independent and periodic Hamiltonian cases. The results reveal its promising utility with upcoming hardware in the near future.
Two-level systems (TLS) are widely recognized as a dominant source of energy relaxation in superconducting qubits, limiting coherence times and device performance. While TLS-induced dissipation is often modeled as independent channels, interacting TLS can form finite many-body environments whose dynamical role in qubit relaxation remains insufficiently understood. Building on the information-erasure-based framework for irreversible thermalization developed in our previous work, we present a microscopic model and numerical simulations of a superconducting qubit coupled to a finite interacting many-body TLS environment as a concrete physical realization of this mechanism. We show that effective irreversible energy relaxation can emerge from intrinsic many-body dynamics without invoking external baths or phenomenological dissipation. The introduction of information erasure drives a transition from coherent oscillatory energy exchange to nonoscillatory exponential relaxation of the qubit. The relaxation times exhibit the scaling T1,T2∝Jq,τ−2T_1, T_2 \propto J_{q,τ}^{-2}T1​,T2​∝Jq,τ−2​ with respect to the qubit-TLS coupling strength, consistent with Fermi's golden rule and Lindblad-type descriptions. Importantly, both exponential decay and its scaling behavior arise directly from microscopic many-body dynamics. These results provide quantitative insight into TLS-induced decoherence mechanisms and establish a microscopic link between information erasure, many-body thermalization, and irreversible relaxation in superconducting quantum systems.
We investigate dynamical quantum phase transitions (DQPTs) in Markovian open quantum systems using a variational quantum simulation (VQS) algorithm based on quantum state diffusion (QSD). This approach reformulates the Lindblad master equation as an ensemble of pure-state trajectories, enabling efficient simulation of dissipative quantum dynamics with effectively reduced quantum resources. Focusing on the one-dimensional transverse-field Ising model (TFIM), we simulate quench dynamics under both local and global Lindblad dissipation. The QSD-VQS algorithm accurately captures the nonanalytic cusps in the Loschmidt rate function, and reveals their modulation by dissipation strength and system size. Notably, DQPTs are gradually suppressed under strong local dissipation, while they persist under strong global dissipation due to collective environmental effects. Benchmarking against exact Lindblad solutions confirms the high accuracy and scalability of our method.
Fast and reliable manipulation with qubits is fundamental for any quantum technology. The implementation of these manipulations in physical systems is the focus of studies involving optimal control theory. Realistic physical devices are open quantum systems. So far, studies in optimal control theory have primarily utilized the Redfield/Lindblad quantum master equation to simulate the dynamics of such systems. However, this Markov description is not always sufficient. Here, we present a study of qubit control utilizing the nonequilibrium Green's function method. We compare the traditional master equation with more general Green's function results and demonstrate that even in the parameter regime suitable for the application of the Redfield/Lindblad approach, the two methods yield drastically different results when addressing evolution involving mixed states. In particular, we find that, in addition to predicting different optimal driving profiles, a more accurate description of system evolution enables the system to reach the desired final state much more quickly. We argue that the primary reason for this is the significance of the non-Markov description of driven system dynamics due to the effect of time-dependent driving on dissipation.
Abstract The standard weak-coupling approximations associated to open quantum systems have been extensively used in the description of a two-level quantum system, qubit, subjected to relatively weak dissipation compared with the qubit frequency. However, recent progress in the experimental implementations of controlled quantum systems with increased levels of on-demand engineered dissipation has motivated precision studies in parameter regimes that question the validity of the approximations, especially in the presence of time-dependent drive fields. In this paper, we address the precision of weak-coupling approximations by studying a driven qubit through the numerically exact and non-perturbative method known as the stochastic Liouville–von Neumann equation with dissipation. By considering weak drive fields and a cold Ohmic environment with a high cutoff frequency, we use the Markovian Lindblad master equation as a point of comparison for the SLED method and study the influence of the bath-induced energy shift on the qubit dynamics. We also propose a metric that may be used in experiments to map the regime of validity of the Lindblad equation in predicting the steady state of the driven qubit. In addition, we study signatures of the well-known Mollow triplet and observe its meltdown owing to dissipation in an experimentally feasible parameter regime of circuit electrodynamics. Besides shedding light on the practical limitations of the Lindblad equation, we expect our results to inspire future experimental research on engineered open quantum systems, the accurate modeling of which may benefit from non-perturbative methods.