Researchers from Nagoya University in Japan and the Slovak Academy of Sciences discovered that quantum theory doesn’t forbid violations of the second law of thermodynamics. However, quantum processes can still comply with the law.
This finding shows that quantum theory and thermodynamics work well together, even though they are separate fields. This could lead to new advancements in quantum technologies like quantum computing and tiny engines.
In simpler terms, the second law of thermodynamics means that things naturally tend to become more disordered over time. Imagine trying to keep your room clean—no matter how hard you try, it always seems to get messy again on its own! Likewise, in a cyclic engine (like a car engine), you can’t produce work by just using heat from one temperature source.
This rule is fundamental in physics but can sometimes be tricky to fully grasp.
The paradox of “Maxwell’s Demon,” proposed by James Clerk Maxwell in 1867, illustrates this debate. The demon sorts fast and slow molecules in a gas, seemingly creating a temperature difference and defying the second law.
Physicists have tried to resolve this paradox by treating the demon as a physical system subject to thermodynamic laws, requiring energy to erase its memory and offsetting the violation.
The researchers created a mathematical model for a “demonic engine,” where the demon measures a system, extracts work from it by coupling to a thermal environment, and erases its memory. They found that under certain conditions, the work extracted can exceed the work expended, seemingly violating the second law.
They found that we can design quantum processes to follow the second law, showing a balance between quantum mechanics and thermodynamics. Their discovery shows that the second law does not limit quantum measurements, allowing us to implement any quantum process without violating thermodynamic rules.
This research enhances our understanding of the limits of quantum systems. It offers a foundation for developing new quantum technologies while adhering to thermodynamic principles.
Journal Reference:
- Minagawa, S., Mohammady, M.H., Sakai, K. et al. The universal validity of the second law of information thermodynamics. npj Quantum Inf 11, 18 (2025). DOI: 10.1038/s41534-024-00922-w
Source: Tech Explorist
