Quantum mechanics, which is the theory that governs the microworld of particles and atoms, definitely has the X factor.
It is unlike many other areas in physics. It is strange and counterintuitive. This makes it fascinating and dazzling.
When the Nobel prize for physics in 2022 was awarded Alain Aspect and John Clauser were awarded this award. Anton Zeilinger was also presented with the award.For research that sheds light on quantum mechanics It sparked discussion and excitement..
But debates about quantum mechanics – be they on chat forums, in the media, or in science fiction – can often get muddled thanks to a number of persistent myths and misconceptions. Here are four.
1. Cats can be alive and dead.
Erwin Schrödinger could probably never have predicted that his Think about it!, Schrödinger’s cat, would attain Status of internet memesIn the 21st Century.
It suggests that an unlucky feline stuck in a box with a kill switch triggered by a random quantum event – radioactive decay, for example – could be alive and dead at the same time, as long as we don’t open the box to check.
We’ve long known that quantum particles can be in two states – for example in two locations – at the same time. This is known as a superposition.
This was demonstrated by scientists in the double-slit experiment. In this experiment, a single quantum particle such as an electron or photon can pass through two different slits on a wall simultaneously. How did we find this?
Each particle’s state in quantum physics is also a wave. But when we send a stream of photons – one by one – through the slits, it creates a pattern of two waves interfering with each other on a screen behind the slit.
As each photon didn’t have any other photons to interfere with when it went through the slits, it means it must simultaneously have gone through both slits – interfering with itself (image below).
To make this work, however, both the states (waves in superposition) of the particle passing through each slit must be “Coherent” – having a well-defined relationship with each other.
These superposition experiments are possible with objects of increasing complexity and size.
One famous experimentAnton Zeilinger demonstrated quantum superposition using large molecules in 1999 by Zeilinger Carbon-60Also known as “buckyballs”.
What does all this mean for our cat? What does this mean for our poor cat?
A cat is not a single photon in controlled lab environments. It is far more complex and larger than that.
The trillions upon trillions atoms that make up the cat may have some coherence, but it is very short-lived.
This doesn’t mean quantum coherence cannot be achieved in biological systems. However, it won’t generally apply to large animals such as cats or humans.
2. Entanglement can be explained by simple analogies
Entanglement is a quantum property which links two different particles so that if you measure one, you automatically and instantly know the state of the other – no matter how far apart they are.
Common reasons for it Most often, these are everyday objectsOur classical macroscopic world includes dice, cards and even odd-colored socks.
Imagine that you tell a friend that you have put a blue card inside one envelope and an orange in the other. Your friend will find the orange card if they take the blue card out of your hand and open one of the envelopes.
To understand quantum mechanics, however, it is necessary to visualize the two cards in the envelopes as being in a joint superposition. This means that they are both orange/blue (specifically, orange/blue)
Unscrewing one envelope will reveal one of the randomly selected colors. The second envelope is always the opposite because it is “spookily” linked to the first.
You could make the cards appear in a different color, similar to another measurement. You could ask the question “Are you a red or green card?””.
Again, the answer would be random: red or green. Importantly, even if the cards were entangled the answer would be the opposite when the question was asked again.
Albert Einstein tried to explain it with classical intuition. He suggested that the cards could have come with a classical intuition. Set of hidden instructions for internal useThis told them what color to wear given a specific question.
He also rejected the “spooky” action of the cards between them that appears to allow them instantaneously influence each other. This would make communication faster than light speed, something Einstein banned.
Einstein’s explanation was later ruled out. Bell’s TheoremThis is a theoretical test that John Stewart Bell created and was used in experiments by the 2022 Nobel laureates. It is false to believe that one card entangled can change the state of another.
Quantum particles are just mysteriously correlated in ways we can’t describe with everyday logic or language – they don’t communicate while also containing a hidden code, as Einstein had thought.
Entanglement is a way to forget everyday objects.
3. Nature is ‘non-local’ and unreal
Bell’s theorem can often be used to show that nature doesn’t exist in a “local” sense, that is, that objects are not directly affected by their immediate environment. Another common interpretation of the statement is that quantum objects’ properties are not “real”, meaning that they exist before measurement.
But Bell’s theorem Only then can we sayQuantum physics says that nature can’t be both real and local, if we consider a few other things simultaneously.
These assumptions include the belief that measurements have one outcome and not multiple outcomes, that cause and effect flow forward in the time and that nothing is predetermined.
Nature may be local and real, despite Bell’s Theorem. If you were allowed to break other thingsWe consider common sense as the concept of time moving forward. Additional research is needed to narrow down the number of possible interpretations of quantum mechanicals.
However, most options on the table – for example, time flowing backward, or the absence of free will – are at least as absurd as giving up on the concept of local reality.
4. Nobody understands quantum mechanics
A classic quote(attributed to physicist Richard FeynmanParaphrasing is also possible in this form. Niels Bohr) surmises: “If you think you understand quantum mechanics, you don’t understand it.”
This belief is widespread. Quantum physics is said to be impossible to comprehend, even by physicists. Quantum physics, however, isn’t particularly hard for scientists from a 21st Century perspective.
It is something we are able to understand to the point that we can accurately predict quantum phenomena, simulate highly complex systems of quantum particles, and even begin to build quantum computers.
If explained in the language and concepts of quantum information, superposition or entanglement are not more complicated than high-school mathematics. Bell’s theory doesn’t require any quantum science. It can be obtained using linear algebra and probability theory in just a few lines.
The real problem lies in reconciling quantum physics and our intuitive reality. Quantum technology will continue to advance even though we may not have all the answers. We just need to be able to. Calculate and shut down.
Aspect, Clauser, & Zeilinger were Nobel winners. They refused to be silenced and kept asking why. They and others like them might one day be able to reconcile quantum weirdness and our perception of reality.
Alessandro FedrizziProfessor of Physics: Heriot-Watt UniversityAnd Mehul MalikProfessor of Physics: Heriot-Watt University
This article has been republished from The ConversationUse the Creative Commons license Learn more Original article.
