Researchers from several countries have found a strange thermal effect. It lets quantum systems take in heat from cold places. They used this to build a quantum heat engine. This engine can create mechanical work and cooling at the same time.
Normally, heat moves from hot areas to cold ones. This is how things like power plants and refrigerators work. But quantum systems can act differently.
Indefinite Causal Order
Quantum systems often do things that classical physics can't explain. One idea is "Indefinite Causal Order" (ICO). This means two events can happen in a mix of different orders.
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Start Your News DetoxZhong-Xiao Man, a quantum mechanics researcher, explained this. He noted that even if two channels are at the same temperature, a quantum system might not reach that temperature. This is very different from classical physics.
The researchers wondered what would happen if a quantum system and a channel started at different temperatures. They also considered what would happen with two cold places. Their theory suggested the quantum system could pull heat from colder areas.
They then built a new quantum Otto engine. It proved their predictions. Man said that in the quantum world, two heat processes can happen in a mix of different orders. This creates an unusual heat flow. It lets the engine get energy from a colder place, which isn't possible in classical physics.
What This Means for the Future
The researchers turned a theory into a real device. This shows that these effects are not just signs of indefinite causal order. They can also happen with a clear causal structure.
This discovery could help create new quantum technologies. These technologies could control heat and energy in different ways. The quantum heat engine they built is just a first step. It could lead to many new devices, like quantum processors and sensors.
Rosario Lo Franco, a researcher involved in the work, mentioned future research. He said they want to look beyond perfect thermodynamic cycles. They plan to study more realistic setups where operations happen in a set amount of time.
Franco added that speed is important for practical devices. It affects both how well they work and how much power they produce. He wants to understand how these limits affect their engine.
The findings were published in Physical Review Letters.
Deep Dive & References
Unusual quantum effect used to build a heat engine that produces work and cooling - Physical Review Letters, 2024
