Physics team discovers Mpemba quantum effect with many ‘interesting’ implications

Initially led out of pure curiosity, the researchers made a discovery that bridges the gap between Aristotle’s observations two millennia ago and modern understanding, while opening the door to a whole host of “cool” implications – and ” cooling”.

The Mpemba effect is best known as a puzzling phenomenon, in which hot water freezes more quickly than cold water. Observations of this counterintuitive effect date back to Aristotle who, more than 2,000 years ago, noted that the Greeks of Pontus exploited this effect in their fishing practices.

The Mpemba effect has also piqued the curiosity of other great minds throughout history, such as René Descartes and Francis Bacon. It continues to be the subject of numerous news articles and regularly appears as a curious subject in various contexts, such as in the cooking competition MasterChef, where contestants tried to capitalize on the effect to deliver frozen delights faster than This only seems possible in dessert challenges.

And now we can say that this strange effect is much more pervasive than expected since the Trinity QuSys team, led by Professor John Goold of the School of Physics, has just published a research paper in the journal Physical Examination Letters. The paper describes their breakthrough in understanding the effect in the very different and extremely complex world of quantum physics.

Professor Goold said: “The Mpemba effect takes its name from Erasto Mpemba who, as a schoolboy in 1963, made ice cream in his home economics class in Tanzania. Mpemba didn’t wait for his hot ice cream mixture to cool. before putting it straight in the fridge and was, unsurprisingly, perplexed to find that it froze before all of his classmates’ colder samples.

“He pointed this out to his teacher, who ridiculed him for not knowing his physics background. Newton’s law of cooling, for example, tells us that the rate at which an object cools is proportional to the temperature difference between the object and its surroundings. However, Mpemba convinced a visiting professor, Denis Osoborne from the University of Dar es Salaam, to test what he had seen and the two men published a paper. which actually proved this strange effect.

Although the Mpemba effect is not yet fully understood (its presence is hotly debated on the macroscopic scale), it is much more apparent on the microscopic scale, where physicists use the theory of quantum mechanics to describe nature. .

The Mpemba quantum effect has recently become a hot topic, but a myriad of questions remained unanswered; for example, what is the relationship between the quantum effect and the original effect? And can we construct a thermodynamic framework to better understand the phenomenon?

The QuSys research group’s breakthrough answers some of the key questions.

Professor Goold said: “We are experts in the interface between non-equilibrium thermodynamics and quantum theory and, as such, have the appropriate toolbox to address these questions. Our work essentially provides a recipe for generating the Mpemba effect in quantum systems. where a physical transformation that effectively “warms up” the quantum system can be carried out. This transformation of the quantum system then paradoxically allows it to relax or “cool” exponentially more quickly by exploiting unique characteristics of quantum dynamics.

Using the toolbox of non-equilibrium quantum thermodynamics, the team was able to bridge the gap between Aristotle’s observations from two millennia ago and our modern understanding of quantum mechanics.

And this now opens the door to many questions related to research and applications.

Professor Goold added: “Although we initially undertook this project out of intellectual curiosity, it forced us to ask several fundamental questions about the relationship between the laws of thermodynamics that describe cooling and quantum mechanics, which describes reality at the fundamental level. We are currently developing a geometric approach to the problem, which will hopefully allow us to understand different types of Mpemba effect within the same mathematical framework.

“What you actually have in this really ‘cool’ Mpemba effect is a way to accelerate cooling, and cooling quantum systems is absolutely vital for applications in quantum technologies. With that in mind, I’m sure As some of the tools we use develop to study this fundamental effect will be critically important for understanding things like heat flow and how to minimize dissipation in future technologies.