physicists share the prize for introducing the terrifying world of quantum mechanics

Nobel Prize in Physics 2022 was awarded trio of scientists for pioneering experiments in the field of quantum mechanics, a theory that encompasses the microscopic world of atoms and particles.

Alain Aspect of the University of Paris-Saclay in France, John Clauser of JF Clauser & Associates in the United States, and Anton Zeilinger of the University of Vienna in Austria will share the 10 million Swedish kroner (US$915,000) prize “for experiments with entangled photons, establishing the violation of inequalities Bella and the pioneer quantum computing.”

The world of quantum mechanics looks very strange indeed. In school we are taught that we can use equations in physics to predict exactly how things will behave in the future – for example, where a ball will go when we roll it down a mountain.

Quantum mechanics is different from this. Instead of predicting individual outcomes, it shows us the probability of finding subatomic particles in separate places. A particle can be in several places at once before randomly “picking” one place when we measure it.

Even the great Albert Einstein himself was perplexed by this – to the point where he became convinced that it was wrong. Instead of the results being random, he thought there must be some “hidden variables” – forces or laws that we cannot see – that predictably affect the results of our measurements.

Some physicists, however, have accepted the implications of quantum mechanics. John Bell, a physicist from Northern Ireland, made an important breakthrough in 1964 by developing a theoretical test to show that the hidden variables Einstein had in mind did not exist.

According to quantum mechanics, particles can be “entangled,” so terribly connected that when you manipulate one, you automatically and immediately manipulate the other as well. If this eeriness—particles far apart, mysteriously influencing each other instantaneously—could be explained by the particles interacting with each other through hidden variables, it would require a faster-than-light connection between them, which Einstein’s theories forbid .

Quantum entanglement is a complex concept to understand that essentially links the properties of particles regardless of how far apart they are. Imagine a light bulb which emits two photons (particles of light) traveling in opposite directions from it.

If these photons are entangled, they can share a common property, such as polarization, regardless of distance. Bell imagined experimenting with these two photons separately and comparing their results to prove that they were entangled (indeed, mysteriously related).

Klauser put Bell’s theory into practice at a time when experiments with single photons were almost unthinkable. In 1972, just eight years after Bell’s famous thought experiment, Clauser showed that light could indeed be confusing.

For now Klauser results were groundbreaking, there were several alternative, more exotic explanations for the results he got.

If light behaved differently than physicists thought, perhaps its results could be explained without confusion. These explanations are known as loopholes in the Bell test, and Aspect was the first to challenge it.

Aspect came up with an ingenious experiment to eliminate one of the most important potential loopholes in the Bell test. He showed that entangled photons in the experiment do not actually interact with each other through the latent variables to decide the outcome of the Bell test. That means they are really terribly connected.

In science, it is incredibly important to test concepts that we believe to be correct. And few played a more important role in that than Aspect. Quantum mechanics has been tested over and over again over the last century and has survived unscathed.

Quantum technology

At this point you could be forgiven for wondering why it matters how the microscopic world behaves, or that photons can be entangled. This is where Zeilinger’s vision really shines.

We once used our knowledge of classical mechanics to build machines, factories, which led to industrial revolution. Knowledge of the behavior of electronics and semiconductors led to the digital revolution.

But understanding quantum mechanics allows us to use it, to create devices that can do new things. Indeed, many believe that this will lead to the next revolution in quantum technology.

Quantum entanglement can be used in computing to process information in ways that were previously impossible. Detecting small changes in entanglement could allow sensors to detect things with greater precision than ever before. Communication with entangled light can also guarantee security, as measurements of quantum systems can detect the presence of an eavesdropper.

Zeilinger’s work paved the way for a quantum technological revolution by showing how a series of entangled systems can be connected together to build the quantum equivalent of a network.

In 2022, these applications a quantum mechanics are not science fiction. We have the first quantum computers. Companion of Micius uses obfuscation to provide secure communication around the world. And quantum sensors are used in applications from medical imaging to submarine detection.

After all, the 2022 Nobel team has recognized the importance of the practical foundations that create, manipulate and test quantum entanglement, and the revolution it is helping to usher in.

I’m glad to see these three get an award. In 2002, I started my Ph.D. at Cambridge University, which was inspired by their work. The goal of my project was to make a simple semiconductor device to generate entangled light.

This was supposed to greatly simplify the equipment needed to perform quantum experiments and allow the creation of practical devices for real-world applications. Ours work was successful and it amazes and excites me to see the leaps that have been made in this field since then.

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