Overlapping reality with quantum superposition

The film depicts the quantum concept of superposition. This is through Evelyn being one person in multiple, parallel universes.

The plot suggests each action in a parallel universe exists simultaneously. That is until something collapses the superposition and determines the actual outcome.

Helping to unpack the idea of superposition is our Quantum Science Leader, Dr James Quach.

“Physicists tend not to use parallel universes to explain superposition, but instead reference the idea of something being both up and down, heads and tails, or a cat being both alive and dead,” James said.

“In computing, a classical ‘bit’ can only be in one of two possible states at any given time: on or off.

“In contrast, a quantum bit (qubit) can be on or off but also be in a superposition of these two states, meaning it is both on and off at the same time,” he said.

Not an easy concept to get your head around. But in this case, understanding the impact of the concept is probably more important for us mere mortals, than the how.

Quantum computers promise incredible power compared to classical computers. They’re on the verge of revolutionising various scientific fields such as cryptography, materials science and drug discovery.

Superposition is also key to new technologies involving quantum sensors and communication systems. These technologies take advantage of the sensitivity of quantum systems to measure and transmit information with unprecedented accuracy and security.

The impact of superposition on the future is difficult to predict. But it will almost certainly have significant implications for science and technology. It may even change our core understanding of how the world works.

Untangling quantum entanglement

The other quantum concept referenced throughout Everything Everywhere All at Once is entanglement.

Superposition is the idea of being in several states/universes at the same time. Entanglement, on the other hand, is the interconnectedness of the different versions of Evelyn. She discovers that she’s entangled with herself in other universes. She is connected to her other selves even though she’s in different locations.

This entanglement allows Evelyn to communicate with her other selves in different universes and share memories and emotions with them. Which means they can work together to prevent a parallel universe version of her daughter Joy (Stephanie Hsu) from destroying the entire multiverse.

The film’s exploration of quantum entanglement is an interesting and creative interpretation of the concept. But what does this actually mean for us in real life?

“The idea of entanglement suggests two or more particles become linked in such a way that their physical properties are interdependent, even when they are physically separated,” James said.

“It has numerous potential applications, which will drive the growth of many emerging fields, including quantum computing, quantum communication, and quantum cryptography.

“Quantum entanglement is beginning to help computers work faster, makes communication channels more secure and is measuring things more precisely,” he said.

And there’s also the way that quantum entanglement challenges our fundamental understanding of the nature of reality. As well as the relationship between the observer and the observed in the quantum world. As such, it has the potential to upend our understanding of the universe and the laws that govern it. No biggie, right?

But best leave that for another day. Everything Everywhere All at Once may have helped us better contend with the mind-boggling ideas behind quantum physics. Or not.