July 13, 2024


Science It Works

Science fiction becomes reality

By Opinion Time of article published May 16, 2021

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By: Louis Fourie

QUANTAM mechanics has many mysteries, of which the most well-known is probably the fact that the outcome of a quantum experiment can change, depending on whether we measure the property of the particles.

This “observer effect” seems to undermine the basic supposition behind all science, namely that there is an objective world, regardless of the actions of us as human beings. If the way the world behaves depends on how – or if – we observe it, what does “objective reality” really mean? Is objectivity merely an illusion?

One of the most interesting experiments is the “double-slit experiment”. If a beam of light is projected at a screen with two vertical slits close to one another, some of the light will pass through the slits and interfere with each other. If the peaks overlap, they reinforce each other, but when a peak and trough overlap, they cancel each other out. This wave interference, or diffraction, creates alternating light and dark stripes.

Similarly, quantum particles can be sent through the slits one by one. Theoretically, there should be no interference along its route but, strangely, the pattern of the particle reveals interference bands, called single particle interference. It seems that the same particle passes through both slits and interferes with itself. The combination of “both paths at once” is known as a state of superposition.

Nature knows when we intend to look. But, strangely, if a detector is used to determine if the particle goes through one of the slits, the interference vanishes. Merely by observing the path of a particle, without disturbing its movement, we change the outcome. This means that the observer forces the quantum particle to assume a specific position and thus produce the results of the measurement.

It gets even more peculiar. If a particle’s behaviour depends on whether we look, the outcome should be different if it is measured after it has passed through the slits. By then the particle ought to have decided which path it will take or if it will take both.

Strangely, it was discovered during experiments that the delaying of the measurement makes no difference. If the particle’s path is measured before its arrival at a detector is registered, all interference is lost. It seems that nature is not just aware that we are looking, but even if we are intending to look.

Physicists do not agree on the interpretation of the slit and delay experiments, but it seems certain that consciousness and quantum mechanics are somehow connected.

Quantum computation depends on superposed states carrying out multiple computations simultaneously and in parallel, according to quantum linear superposition. It can reach beyond classical computing when using quantum algorithms, which can exploit the phenomenon of quantum parallelism.

Quantum computers are, therefore, able to “demonstrate the resolution of a problem that, with techniques on a supercomputer, would take longer than the age of the universe.”

In a world where processing power is often a limiting factor, breaking the quantum barrier is expected to lead to significant benefits for businesses and society.

It seems that, at a quantum level, science fiction appears to become reality, and particles can easily travel backward or forwards in time and teleport (quantum tunnelling) between two positions. Quantum computing is, therefore, playing an important role in research, monitoring and business.

According to Geordie Rose, the chief technology officer at D-Wave, the Canadian manufacturer of Quantum computers “by 2028 intelligent machines will exist that can do anything humans can do. Quantum computers will have played a critical role in the creation of this new type of intelligence”.

Louis CH Fourie is a technology strategist.

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