Nonequilibrium Energy Transport in Driven-Dissipative Quantum Systems

Researchers at Zhejiang Normal University, led by Junran Kong, have developed a refined methodology employing a driven quantum master equation to accurately model energy flow within driven-dissipative quantum systems. The equation’s validity has been rigorously confirmed through comparison with the established Floquet master equation, and the incorporation of the ‘driving phase’, representing the impact of external forces, demonstrably alters microscopic energy exchange processes. Their findings reveal that steady-state energy currents can be significantly increased, particularly as the system approaches resonance, suggesting potential for enhanced control over quantum transport and improved thermodynamic performance in nanoscale devices. Driven quantum master equation improves accuracy of energy current predictions in nanoscale systems Steady-state energy currents were observed to increase by up to 30% near resonance when utilising the driven quantum master equation. This represents a substantial improvement over traditional modelling techniques, which frequently introduce distortions in energy flow predictions. The enhancement unlocks the potential for precise control of energy transport in nanoscale devices, a feat previously unattainable due to limitations in accurately modelling driven-dissipative quantum systems. These systems, simultaneously experiencing energy input and dissipation, function analogously to miniature engines, demanding sophisticated theoretical treatment. The conventional approaches often struggle to capture the interplay between driving forces, dissipation, and quantum coherence, leading to inaccurate predictions of energy currents and hindering the design of efficient quantum devices. The novel equation accurately incorporates the ‘driving phase’, which accounts for the influence of external, time-dependent forces on energy exchange, within the interactions between the quantum system and its surrounding environment. This provides a more nuanced understanding of microscopic energy transfers than previously possible. The analysis was extended beyond the initial theoretical framework to encompass a nonequilibrium system comprising qubits coupled to a Kerr resonator, thereby demonstrating the equation’s broad applicability across diverse quantum architectures. Accuracy was meticulously validated by comparison with the Floquet master equation, specifically within the context of a generic nonequilibrium spin-boson model, a widely used paradigm for studying energy transfer in condensed matter systems. Detailed calculations of incoherent transition processes reveal precisely how external forces modulate transition rates between quantum states, showcasing the equation’s capacity to capture the subtle influence of the ‘driving phase’ on microscopic energy exchange. However, current calculations are predicated on the assumption of weak system-bath interactions and a specific Ohmic dissipation model, and further investigation is needed to ascertain the extent to which these simplifications might affect performance in more complex, strongly coupled environments where these assumptions may not hold. Accurate simulation of energy transfer unlocks improved quantum device design Precise control over energy flow is paramount for continued advances in quantum technologies, spanning areas from more efficient quantum computing and information processing to the development of highly sensitive quantum sensors. A comprehensive understanding of how energy dissipates and transfers within these complex systems is crucial for fully realising their potential. The driven quantum master equation offers a more accurate and versatile method for simulating energy flow, particularly in scenarios where systems are simultaneously powered by external sources and subject to energy dissipation, representing a significant refinement of existing approaches and a more subtle understanding of microscopic energy transfers. This is particularly relevant for open quantum systems, which are constantly interacting with their environment, leading to decoherence and energy loss. A more accurate and reliable method for modelling energy flow in complex quantum systems, particularly those subject to both external driving and inherent energy dissipation, is now available to researchers. By successfully modelling energy transport in diverse systems, including spin and boson models, the equation confirms its reliability and broad applicability to driven-dissipative systems; these systems behave like miniature engines, simultaneously receiving and losing energy. The ability to accurately predict energy currents opens avenues for optimising device performance, exploring novel quantum phenomena, and designing more efficient quantum technologies. The equation’s strength lies in its ability to treat the driving force and dissipation on equal footing, providing a more complete picture of the energy landscape within the quantum system. Furthermore, the driven quantum master equation allows for the investigation of non-equilibrium steady states, which are crucial for the operation of many quantum devices. The implications extend to areas such as quantum heat engines, where maximising energy conversion efficiency requires precise control over energy currents, and quantum refrigerators, where efficient heat extraction is essential. Future work will likely focus on extending the equation to handle stronger system-bath coupling and more complex dissipation models, further enhancing its predictive power and applicability to a wider range of quantum systems. 👉 More information 🗞 Nonequilibrium energy transport in driven-dissipative quantum systems 🧠 ArXiv: https://arxiv.org/abs/2603.29754