{
  "id": 473446,
  "title": "Quantum principle allows heat to flow from cold to hot",
  "url": "https://urgent.news/2026/08/10/quantum-principle-allows-heat-to-flow-from-cold-to-hot",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-10T14:00:15.000Z",
  "source": {
    "name": "Physics World",
    "slug": "physics-world",
    "url": "https://physicsworld.com/a/quantum-principle-allows-heat-to-flow-from-cold-to-hot/"
  },
  "original_language": "en",
  "account": "Heat typically flows from hot objects to colder ones, in accordance with the second law of thermodynamics. However, a recent experiment has shown that quantum mechanics can reverse this heat flow while still adhering to the laws of thermodynamics. In an experiment involving two gas chambers at different temperatures, researchers demonstrated a phenomenon known as anomalous heat flow, where heat moves from the colder chamber to the hotter one. This was made possible by a quantum mechanism, which involved the use of an \"infinite memory\" device called a quantum demon. The quantum demon allowed cold gas particles to move into the hotter chamber, while preventing hot particles from moving to the colder chamber. Despite the apparent violation of the second law, the researchers confirmed that the erasure of the quantum demon's memory, which is necessary to maintain the anomalous heat flow, does not actually increase the total entropy of the system. The team also created a quantum engine that utilized the same mechanism to transfer heat from a cold object to a hot one while performing work. This counterintuitive result, which defies classical understanding of thermodynamics, was achieved by exploiting the principle of indefinite causal order in quantum mechanics. By manipulating the sequence of events in a quantum system, the researchers were able to create a scenario where heat flow from cold to hot is not only possible, but also consistent with the laws of thermodynamics.",
  "summary": "Heat flows from hot objects to cold objects – or does it? Although unidirectional heat flow is a natural consequence of the second law of thermodynamics, which states that entropy must either increase or stay the same, an international team has experimentally demonstrated that a quantum mechanism can reverse this flow of heat while remaining […] The post Quantum principle allows heat to flow from…",
  "key_points": [
    "Heat typically flows from hot to cold, per second law of thermodynamics",
    "Quantum mechanics allows anomalous heat flow from cold to hot",
    "Quantum demon and engine transfer heat while maintaining thermodynamic laws"
  ],
  "editors_take": "This discovery shows that quantum mechanics can be exploited to achieve anomalous heat flow, enabling the transfer of heat from cold to hot objects while still obeying the laws of thermodynamics.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}