The Limited Times

Now you can see non-English news...

Why quantum entanglement revolutionizes our understanding of nature

2022-10-17T08:48:52.801Z


The Nobel Prize for Physics to Alain Aspect, John F. Clauser and Anton Zeilinger confirms that, beyond theoretical reasoning, nature really behaves in a strange way


The Royal Swedish Academy of Sciences last week awarded the Nobel Prize in Physics to Alain Aspect, John F. Clauser and Anton Zeilinger for their pioneering work on quantum entanglement, key in the development of new quantum technologies.

His contributions experimentally demonstrated different aspects related to entanglement, such as the existence of violations of Bell's inequalities or quantum teleportation.

Entanglement is one of the most fundamental and surprising properties of quantum mechanics.

It allows two separate particles, even miles apart, to be connected in a way that classical physics cannot explain.

Thus, the measurement of a physical property —such as the polarization of a photon— in one of them will determine what is observable in the other, without the existence of physical signals between the two.

This anti-intuitive phenomenon led Albert Einstein, Boris Podolski and Nathan Rosen to question, in 1935, the validity of quantum mechanics as a physical model to describe nature.

More information

Alberto Casas' fundamental guide to understanding the Nobel Prize in Physics: "We are alive thanks to the uncertainty principle"

30 years later, John Bell formalized the intuition of Einstein and his co-authors, showing that from their work the incompatibility of the theory of quantum mechanics with a classical model of nature, called the local model of hidden variables, was extracted.

Bell's formalization, fundamental from a conceptual point of view, is surprisingly simple from a mathematical point of view: he proposed a scenario where two people, Alice and Bob, separated in space and each in possession of a particle, perform measurements on these.

Alice has several measuring devices and each of these measurements can get different results.

She does the same with Bob.

After making these measurements a sufficiently large number of times, it will be possible to determine, experimentally,

In this context, Bell showed that, if the local hidden variables model is assumed to explain this experiment, the prior probabilities must satisfy certain mathematical inequalities, since called Bell's inequalities.

Furthermore, Bell proved that, in accordance with the postulates of quantum mechanics, in the above scenario Alice and Bob could perform certain measurements on particles that are entangled whose associated probabilities do not satisfy the stated inequalities.

It is concluded, therefore, that it is not possible to explain certain experimental probabilities that quantum mechanics predicts by means of a local model of hidden variables.

Anton Zeilinger, Alain Aspect, and John F. Clauser.

It is at this point that the winners of the 2022 Nobel Prize in Physics made their contributions. Between 1969 and 1972 John F. Clauser deepened Bell's ideas, simplifying the proposed scenario to adapt it to the experimental capabilities of that time.

So, he carried out the first experiment that confirmed the existence of measurements whose associated probabilities did not verify Bell's inequalities and therefore were not explainable by a classical model of nature.

Thus, it was confirmed that, beyond theoretical reasoning, nature really behaves in a strange way.

However, Clauser's experiment did not indicate how to deal with certain problems arising from the appearance of errors in the measurements of these experiments.

A decade later, Alain Aspect came up with the solution, in what for many years was considered the experiment that really demonstrated the existence of violations of Bell inequalities.

These ideas open the doors to new technologies in computing and cryptography.

One of the most surprising phenomena and, in fact, very present in many of the applications of these new technologies, is the ability to transmit all the information from one physical particle to another —both being intertwined—, sending only a few bits of information classic.

This means that quantum information can be sent without a quantum channel being involved in the process.

This phenomenon is called quantum teleportation and the third Nobel laureate, Anton Zeilinger, was the first to prove its existence, in 2012, through an experiment that transferred information between two particles separated by a distance of 143 kilometers.

Although from a mathematical point of view, Bell's work and the different experimental implementations that have been carried out do not present great complexity, the intuition and depth of his ideas have been key in the technological revolution that quantum information theory entails.

In addition, the great interest in potential quantum applications in areas as relevant as computing or cryptography has led to a much deeper study of Bell's inequalities and possible generalizations of it.

Today these problems are connected to fields such as complexity theory, in computer science, or von Neumann algebras, in the field of mathematical analysis.

Carlos Palazuelos

is a professor at the Complutense University of Madrid and a member of the

ICMAT

Coffee and Theorems

is a section dedicated to mathematics and the environment in which it is created, coordinated by the Institute of Mathematical Sciences (ICMAT), in which researchers and members of the center describe the latest advances in this discipline, share meeting points between mathematics and other social and cultural expressions and remember those who marked their development and knew how to transform coffee into theorems.

The name evokes the definition of the Hungarian mathematician Alfred Rényi: “A mathematician is a machine that transforms coffee into theorems”.

Edition and coordination:

Ágata A. Timón G Longoria (ICMAT)

.

You can follow MATERIA on

Facebook

,

Twitter

and

Instagram

, or sign up here to receive

our weekly newsletter

.

Source: elparis

All news articles on 2022-10-17

You may like

Trends 24h

News/Politics 2024-03-28T06:04:53.137Z

Latest

© Communities 2019 - Privacy

The information on this site is from external sources that are not under our control.
The inclusion of any links does not necessarily imply a recommendation or endorse the views expressed within them.