Local Quantum Coherence Persists with Intersource Interactions at Nonzero Temperature

The emergence of coherence, a fundamental quantum property, usually requires precise external control, but can also arise spontaneously through interactions with a system’s surroundings. Yehor Hudenko from Charles University, Michal Kolář and Radim Filip from Palacký University, along with Artem Ryabov from Charles University, investigate how interactions within these surroundings affect this spontaneous coherence. Their work demonstrates that coherence not only survives in a complex, interacting environment, but can actually become stronger at higher temperatures than previously thought. This research reveals key principles governing autonomously generated coherence and offers potential pathways for observing this delicate quantum state under realistic, non-ideal conditions, opening new avenues for exploring quantum phenomena in complex systems.

Quantum Coherence and Thermodynamic Processes

This body of work explores the intersection of quantum mechanics and thermodynamics, with implications for emerging quantum technologies. The research focuses on understanding how quantum coherence influences thermodynamic processes like heat transfer and energy conversion, spanning topics including the design of quantum heat engines, refrigerators, and systems far from equilibrium. A central theme is controlling entropy production, a key challenge in building efficient quantum devices. Researchers are actively exploring physical platforms for realizing these quantum technologies, with superconducting circuits and diamond nitrogen-vacancy (NV) centers receiving significant attention.

This research extends to the development of highly sensitive quantum sensors and architectures for future quantum computers, drawing upon advanced mathematical tools and theoretical frameworks to analyze and optimize these systems. A key trend is the emphasis on practical applications, striving to build and improve quantum devices for energy conversion, sensing, and computation. The consistent focus on quantum coherence highlights its crucial role as a resource for enhancing device performance, painting a picture of a vibrant and rapidly evolving field at the forefront of quantum science and technology.

Thermal Equilibration Drives Autonomous Quantum Coherence

Scientists have discovered a new mechanism for generating quantum coherence without relying on continuous external driving. Their research demonstrates that coherence can arise spontaneously through interactions between a quantum system and its environment. The team investigated a system comprising a central quantum system and a chain of interacting quantum systems acting as the environment, revealing that the entire system can reach thermal equilibrium while simultaneously generating coherence. Researchers developed a mathematical model to describe the interactions between the target and source systems, calculating the system’s behavior at a given temperature to determine how coherence emerges. They quantified this coherence, allowing them to analyze its dependence on system parameters and revealing that coherence can increase with temperature, reaching a maximum at a finite value. This counterintuitive behavior stems from energy-level crossings within the combined system, offering a pathway for observing autonomous coherence generation under realistic thermal conditions.

Environmental Interactions Sustain and Enhance Quantum Coherence

This research demonstrates that quantum coherence, a fragile quantum property, can be sustained and even enhanced through interactions with the surrounding environment. Scientists have shown that coherence doesn’t simply disappear at non-zero temperatures, but can be actively maintained by the environment itself, provided the environmental components interact with each other. The team analyzed a model comprising a central quantum system coupled to a chain of interacting quantum systems, all held in thermal equilibrium. Experiments revealed that the degree of quantum coherence is significantly influenced by the interactions within the environment, exhibiting a non-monotonic temperature dependence where coherence increases with temperature up to a maximum value before decreasing. This unique behavior offers improved prospects for observing autonomous coherence generation under realistic thermal conditions, with the strength of the inter-source interaction and the system’s ground-state energy level crossing directly impacting the temperature dependence of the coherence. This breakthrough delivers a new understanding of how to generate and sustain quantum coherence in complex systems, potentially paving the way for more robust quantum technologies.

Autonomous Coherence From Environmental Interactions

This research demonstrates that quantum coherence can emerge spontaneously, not just from external driving, but from interactions with the surrounding environment, even at finite temperatures. Scientists have shown that interactions between the environmental components can actually enhance coherence compared to scenarios where they do not interact. The team investigated a model comprising a central quantum system coupled to interacting source systems. The results reveal a unique temperature dependence, including instances where coherence increases with temperature, reaching a maximum at a finite value. This behavior arises from energy-level crossings within the combined system, offering strategies for optimizing coherence through careful control of system parameters. While the model focuses on nearest-neighbor interactions, the findings suggest general properties of autonomously generated coherence and provide viable routes for its observation in condensed-matter systems, providing a crucial step towards understanding and harnessing autonomous coherence for new quantum technologies operating in realistic thermal environments.