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How entanglement creates thermodynamics

Giuseppe Frisella
5 min readSep 7, 2023

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There is a very deep relationship between quantum entanglement and entropy.

Entropy, despite being an emergent property, is much more fundamental than it first appears.

In order to understand why a law can be both emergent and fundamental, one must pinpoint the origin of thermodynamic entropy.

And, as is often the case, this means resorting to quantum mechanics. There exists an analogous to classical thermodynamic entropy called Von Neumann entropy.

Before explaining Von Neumann entropy, it is necessary to clarify what is meant by entropy and what links entropy and information.

The common thermodynamic entropy can be thought of as the amount of free energy available to do work. Another equivalent way is to think that if all the particles of a gas inside a box are packed in one corner, the system has a lower entropy compared to the state in which they fill the whole box. That is because the volume of space where the particles can be found increases, and so does our ignorance and the information that we need to specify their positions.

Entropy is, in a sense, missing information, not accessible information.

The link between thermodynamic entropy and information is also formally described by a further type of entropy, the…

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Giuseppe Frisella
Giuseppe Frisella

Written by Giuseppe Frisella

I'm a curious person and I'm on Medium mainly to read and share thoughts and knowledge. I love science, especially physics and evolutionary biology.

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