Rick and Morty and the Many Worlds Interpretation of quantum physics

Posted on 9 May 2019
By Rob Lea
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Smash hit cartoon Ricky and Morty contains a multitude of nods towards current scientific ideas and principles, most still wildly theoretical. But one of the most important concepts the show explores, is the idea that there are multiple parallel dimensions — many inhabited by other versions of Rick and Morty. 

At one point in the first season after ‘Croenberging’ their own Universe, Rick and Morty escape to a parallel world — whose own Rick and Morty have met an explosive end.  The idea of multiple ‘worlds’ co existing side by side is a concept in science — one that was created to explain the weird behaviour demonstrated by quantum mechanics’ ‘double-slit experiment.’ 

It’s worth noting that many-worlds isn’t the same as the idea of extra dimensions — also put forward by some physicists. Extra dimensions are simply curled up parallels to the x, y, z spatial directions… they aren’t filled with evil, bearded versions of us… 

What phenomena displayed in an experiment could possibly require the addition of an almost infinite amount of parallel worlds to solve though? 

Particle-wave duality — everything is more complicated than you thought. 

Around the turn of the 19th Century an argument raged through the physics community regarding the nature of light. Whilst Newton had put forward a seemingly suitable description of light as a series of particles — or corpuscles, the experiments of Huygens and others had developed a very suitable wave-theory of light.

Thomas Young had a deceptively simple method to attempt to straighten out this confusion. He would pass light through a series of slits and observe the patterns he got on the other side.  If light is a wave what we should see is a series of light and dark bands.

This is because of inference. Imagine water waves meeting, where two peaks meet a greater peak is created. But where a peak and trough meet the two should cancel each other out. That’s constructive and destructive interference in a nutshell. 

That’s exactly what Young found, so light’s status as a wave was confirmed. Right? Not

The problem is that other experiments at the time were showing the light had particle-like properties. Not only that but Young’s double-slit experiment could be altered to make light act like a particle! 

The message was quite clear: sometimes light behaves like a particle, sometimes it behaves like a wave. You’ll often see this misrepresented as light is both a particle and a wave. This is incorrect. Light is neither, it’s… well, light. 

As if that wasn’t profound enough, some weirdo — actually a genius called Louis de Broglie — had the enterprising idea to replace light in the double-slit experiment with electrons.

They wanted to see if these confirmed particles could also display wave-like properties. This shouldn’t happen. The images you see on your television occur because electrons are particles. They carry charge… they shouldn’t act like waves… Surprise, surprise, they do.

Both photons — the particles of light — and electrons travel like waves but interact with matter like particles. We’ve gone further than this though, we’ve re-run this experiment with larger and larger particles — most famously with carbon-60, also known as buckyballs — these particles have also displayed this duality of nature.

But how does this get us to the Council of Ricks and evil eye-patch wearing Mortys?  Well, it’s the struggle to understand what is happening at that precise point at which a particle can no longer be modelled as a wave and instead must be considered a particle. It’s the point known as the collapse of the wave function, the most hotly contested split-second in the history of science. 

The path of multiple worlds. 

There are almost as many schools of thought on the collapse of the wave function as there are world’s to be explored in the lore of Ricky and Morty. The most popular explanation amongst physicists is the Copenhagen interpretation, but the many worlds explanation is by far the most well known outside those circles and has inspired a ton of fantastic sci-fi tales.

The many-worlds interpretation of quantum mechanics — first put forward by Hugh Everett in 1957 — proposes that the wave-function that describes our travelling particle never actually collapses. 

Instead, it grows exponentially. It quickly swallows the lab, the experimenters, their town, country, eventually the whole universe. So imagine a situation where a particle’s state could be described with a wave equation like this. 

Particle state=A*p + B*p

A is the probability that the particle (p) is in state A. B is the probability that particle is in state B. So wave function collapse would see that equation reduce to this if we find the particle in state A 

Particle state=1*p +0*p

But what if we only see the particle in state A because the wave function has expanded to include us. We are part of the equation, there is another us seeing that equation as: 

Particle state = 0*p + 1*p

This idea is often presented in fiction as for every decision one of our characters makes, parallel worlds are born, but the actual idea is far more profound than that. It means that for something as simple as the act of turning a lightbulb on would create billions of alternate worlds. 

That’s probably the reason physicists, in general, reject the many worlds hypothesis. It is pretty inelegant and requires a true infinity of Universes like ours in every way except the direction a photon took after the flick of a switch. 

There is actually a fantastic episode of Ricky and Morty that encapsulates just how quickly this situation could escalate. The season 2 opener a Rickle in Time explores the consequences of Rick and his grandchildren freezing time at the end of season 1 in order to repair the damage a house party had caused to their home. 

Unfortunately, when time is restarted every decision made by Morty and Summer causes a new world to be created. 

Quantum physicists have a different thought experiment to consider what is happening at a quantum level. Schrodinger’s cat — initially an attempt by Irwin Schrodinger to point out that something must be missing from quantum physics… I suppose in the world of Rick and Morty you’d call it…

Schrodinger’s squanch

In the Schrodinger’s cat thought experiment a cat — substituted by Rick’s unsavoury cat friend Squanchy in our case — is placed in a steel box with a ‘hellish contraption’. A tiny amount of a radioactive substance is placed in there with Squanchy — as is a small vial of deadly poison. 

If an atom of the substance decays it shatters the vial and Squanchy is killed. If it doesn’t, he lives. The decay of an atom is a quantum phenomenon, so it’s governed by a wave function and thus wave function collapse. 

Here’s the thing: if the Copenhagen Interpretation is correct the atom hasn’t decayed until it’s measured — until the box is opened. So Squanchy exists in a state of being both dead and alive. 

The many-worlds interpretation simply suggests that opening the box doesn’t force reality to ‘make a choice’ about Squanchy’s fate. Rather it just reveals to us what world we are now in. Did we land in a world with a dead Squanchy or one in which he s alive in the box…

Be warned, if it’s the latter he’s probably Squanching in there….Ew… best keep it closed. Of course, the idea of the cat being both dead and alive in the box was considered nonsense by Schrodinger and the majority of quantum physicists agree. The solution that has been offered is the interaction between the atom and the vial constitutes a measurement.  We can’t have undead cats running around. 

(Editor’s note: We at Purple Revolver Towers, Toxteth TV, would very much like to thank Rob for taking us on this scientific journey – and anticipate more science fun when the new season finally appears on our airwaves. Now put Intergalactic Cable back on your Ball Fondler!)