Department of Physics &Astronomy, University College of London, London WC1E 6BT, UK.
Nat Commun. 2017 Mar 14;8:14538. doi: 10.1038/ncomms14538.
The most accepted version of the third law of thermodynamics, the unattainability principle, states that any process cannot reach absolute zero temperature in a finite number of steps and within a finite time. Here, we provide a derivation of the principle that applies to arbitrary cooling processes, even those exploiting the laws of quantum mechanics or involving an infinite-dimensional reservoir. We quantify the resources needed to cool a system to any temperature, and translate these resources into the minimal time or number of steps, by considering the notion of a thermal machine that obeys similar restrictions to universal computers. We generally find that the obtainable temperature can scale as an inverse power of the cooling time. Our results also clarify the connection between two versions of the third law (the unattainability principle and the heat theorem), and place ultimate bounds on the speed at which information can be erased.
热力学第三定律最被广泛接受的版本，即不可达原理，指出任何过程都不能在有限的步骤内和有限的时间内达到绝对零度。在这里，我们提供了一个适用于任意冷却过程的原理推导，即使是那些利用量子力学定律或涉及无限维储层的过程。我们通过考虑类似于通用计算机的热机的概念，量化了将系统冷却到任何温度所需的资源，并将这些资源转化为最小的时间或步骤数。我们通常发现可获得的温度可以按冷却时间的倒数幂缩放。我们的结果还澄清了第三定律的两个版本（不可达原理和热定理）之间的联系，并对信息可以被擦除的速度施加了最终限制。
