Breaking Barriers: Quantum Physics Ushers in a New Era of Energy Harvesting

article image copyrights & info: Efficient heat-energy conversion from a non-thermal Tomonaga-Luttinger liquid
Yamazaki et al. (2025) | Communications Physics
image source: isct.ac.jp (Link)

Breaking Barriers: Quantum Physics Ushers in a New Era of Energy Harvesting

Efficient heat-energy conversion from a non-thermal Tomonaga-Luttinger liquid
Yamazaki et al. (2025) | Communications Physics
image source: isct.ac.jp

Every modern device—from smartphones to supercomputers—produces waste heat. Traditionally, much of that heat simply dissipates unused, representing an enormous reservoir of lost energy. For decades, scientists have tried to recapture this energy using thermoelectric and heat-to-electricity converters, yet they have run into a stubborn obstacle: the fundamental limits of thermodynamics, especially the well-known Carnot efficiency.

But recent breakthroughs from Japanese researchers suggest that these long-standing limits may no longer be unbreakable. By tapping into unusual quantum states that don’t behave like ordinary thermal systems, they have demonstrated a new way to convert waste heat into electricity with efficiencies that surpass classical theoretical boundaries.

This emerging field—energy harvesting using quantum physics—could transform how we power future electronics, reduce energy waste, and open new pathways in quantum computing.

The Challenge of Traditional Energy Harvesting

Energy harvesters collect power from environmental sources such as vibrations, light, or heat. Waste heat in particular is abundant: it pours out of computers, smartphones, factory machinery, and massive power-generation systems. Converting even a fraction of that heat into usable energy could dramatically improve global energy efficiency.

However, conventional heat-to-electricity systems have a built-in limitation.
These systems rely on thermal equilibrium—a state where heat spreads evenly across particles. Under these conditions, the maximum possible efficiency is bounded by the Carnot limit, while the Curzon–Ahlborn efficiency describes the upper efficiency at maximum power output. Both restrict how much electricity can practically be harvested from waste heat.

For years, these limits were considered fundamental and unbreakable.

A Quantum-Based Solution That Breaks Thermodynamic Limits

A research team led by Professor Toshimasa Fujisawa (Institute of Science Tokyo) in collaboration with Senior Distinguished Researcher Koji Muraki (NTT Basic Research Laboratories) has found a way around these restrictions. Both sources emphasize that the breakthrough hinges on using quantum states that avoid thermalization, meaning they don’t behave like normal heat-equilibrated systems.

The Role of the Tomonaga-Luttinger Liquid

At the center of their innovation is the non-thermal Tomonaga-Luttinger (TL) liquid, a special one-dimensional quantum electron system.
Unlike conventional materials, a TL liquid does not distribute heat evenly among its particles. When energy enters the system, it retains a high-energy, non-thermal state instead of settling into equilibrium.

Both provided sources agree that this quantum behavior is the key to surpassing classical limits.

From Theory to Experiment: Demonstrating Quantum Heat Conversion

To test the idea, the team designed an experiment using:

A quantum point contact transistor to inject waste heat
A non-thermal TL liquid to transport this heat
A quantum-dot heat engine to transform that transported heat into electricity

The non-thermal heat travelled several micrometers before reaching the quantum-dot engine, where it produced:

A significantly higher electrical voltage
Higher conversion efficiency
Performance superior to systems using conventional quasi-thermalized heat

Both source texts highlight this same outcome.

Professor Fujisawa notes that the results strongly support the use of TL liquids as new non-thermal resources for future energy-harvesting architectures.

A New Theoretical Framework

To explain how these unusual electron states behave, the team developed a model based on a binary Fermi distribution.
According to the research:

This model accurately describes the non-thermal energy states in the TL system
The technique surpasses both the Carnot efficiency and the Curzon-Ahlborn efficiency

Both sources affirm this groundbreaking claim, and neither provides conflicting perspectives.

Implications for Future Technology

The implications are far-reaching:

Low-power electronics could become vastly more efficient
Quantum computers—notorious for producing substantial waste heat—could recycle their own excess energy
Sustainable technology could advance through quantum-enhanced energy reuse
Industrial systems could reclaim previously inaccessible waste heat

As Fujisawa notes, this research suggests that even the complex heat produced inside quantum devices can be converted into usable power, potentially fueling the next generation of high-performance, energy-conscious technologies.

Conclusion: A Quantum Leap Toward a Sustainable Future

Quantum physics is rewriting the rules of energy conversion. By escaping the constraints of thermal equilibrium, researchers have shown that it is possible to harness waste heat with efficiencies once thought to be unattainable. This breakthrough not only challenges the foundations of classical thermodynamics but also opens a gateway to cleaner, smarter, and more sustainable technologies.

The discovery is more than a technical achievement—it is a glimpse of a future where every device, from handheld gadgets to quantum processors, becomes part of a self-sustaining energy ecosystem. As quantum research continues to evolve, so too does our capacity to transform invisible waste into meaningful power.

The next era of energy harvesting may be defined not by engineering alone, but by the strange and powerful laws of the quantum world.

Sources