Linking quantum entanglement to cold coffee

Just think about how your coffee reaches room temperature over time.


According to theoretical physicists from Trinity College Dublin, there is a deep association between quantum entanglement and thermalization, the process of physical bodies reaching thermal equilibrium through mutual interaction.

The best example of thermalisation includes- the coffee mug and the coffee, cools down, and reaches to room temperature over time. Quantum entanglement, on the other hand, is a different story.

But, scientists, in a recent study, have shown both are inextricably linked to each other.

In Quantum entanglement, particles interact with each other at some point in time to become correlated in a way that is not possible classically. Measurements on one particle affect the outcomes of measurements of the other— even if they are light-years apart. Einstein called this effect ‘spooky action at a distance’.

Professor John Goold from Trinity said, “It turns out that entanglement is not just spooky but ubiquitous and in fact, what is even more amazing is that we live in an age where technology is starting to exploit this feature to perform feats which were thought to be impossible several years go. These quantum technologies are being developed rapidly in the private sector with companies such as Google and IBM leading the race.”

How quantum entanglement linked to cold coffee?

Professor Goold elaborates: “When you prepare a cup of coffee and leave it for a while, it will cool down until it reaches the temperature of its surroundings. This is thermalisation. In physics, we say that the process is irreversible—as we know, our once-warm coffee won’t cool down and then magically warm back up.”

“How irreversibility and thermal behavior emerges in physical systems is something which fascinates me as a scientist as it applies on scales as small as atoms, to cups of coffee, and even to the evolution of the universe itself. In physics, statistical mechanics is the theory that aims at understanding this process from a microscopic perspective. For quantum systems, the emergence of thermalisation is notoriously tricky and is a central focus of this current research.”

“In statistical mechanics, there are various ways, known as ensembles, in which you can describe how a system thermalizes, all of which are believed to be equivalent when you have a large system (roughly on scales of 10^23 atoms).”

“However, what we show in our work is that not only is entanglement present in the process, but its structure is very different depending on which way you choose to describe your system. So, it gives us a way to test foundational questions in statistical mechanics. The idea is general and can be applied to a range of systems as small as a few atoms and as large as blackholes.”

The study is published in the journal Physical Review Letters.

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