A beginners guide to a hidden reality: quantum mechanics and musings on a simulated reality
“What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school — and you think I’m going to explain it to you so you can understand it? No, you’re not going to be able to understand it. Why, then, am I going to bother you
with all this? Why are you going to sit here all this time, when you won’t be able to understand what I am going to say? It is my task to convince you not to turn away because you don’t understand it. You see, my physics students don’t understand it either. That is because I don’t understand it. Nobody does.”
— Richard Feynman on quantum mechanics
Physics needs to be able to predict how things (matter and energy) will behave. This is what made Einstein famous. He created the general theory of relativity that described how big things move and how gravity affects them in space and time.
Einstein’s theory works great for big things, like planets, and created all sorts of technological breakthroughs, like the global positioning system (GPS). The only problem is that the whole theory breaks down when you try to use it to understand really small things, like subatomic particles.
The best analogous example of this is temperature. Temperature only exists at a specific level. Temperature delivers a reading of heat (or lack thereof). Heat is a byproduct of how fast (or slow) molecules are moving. So if you look an individual molecule, it can’t have a temperature. Only when many molecules move together in a system can the concept of temperature be created.This is why quantum mechanics was created. There had to be a set of rules that defined how small things behave. And the fact that quantum mechanics doesn’t work on the big and general relativity doesn’t work on the small is a mystery.
Thus, this is one of the largest open questions in the scientific community: how can we create a ‘theory of everything’ that unifies quantum mechanics and the general theory of relativity.
This separation of systems that govern the large and the small has some interesting implications on things like time travel, intergalactic travel, the multiverse and simulation of consciousness. However before detailing this connection its important to get a fundamental understanding of quantum mechanics and how it differs from the way that we perceive the world in our daily lives.
The Heisenberg uncertainty principle
Systems in quantum mechanics don’t behave the way that systems we observe in our day to day lives do. The first, and best, example of this is shown in what is called the observation effect or the Heisenberg uncertainty principle (technically these are different but not by much.)
This all started with a seemingly simple question: is light a particle or is it a wave?
Scientists kept getting different theoretical answers to this question so in the 1800’s an experiment was setup to put an end to the bickering. The experiment was called, ‘Young’s double slit experiment’ and its goal was to shoot photons (small little packets of light) through a couple holes in a wall then measure if they were particles or waves.
Let’s use an analogy here to clarify what’s going on: Let’s pretend the photons are tennis balls getting shot through the two slits below. If the tennis balls are being shot straight through then only the tennis balls aimed at the two holes will make it through to the back wall. They would travel through one hole or the other. The others would bounce off of the barriers and not make it though. Logically, if light was a particle we would expect a pattern like this:
But this is not what happened. When the experiment was run, the following pattern was produced over and over and over again:
How is this possible? How are all of the tennis balls that we shoot making it through those two slits? And if they are making it through why are they evenly distributed across the entire back wall in these little groups?
The reason is that light is behaving as a wave, not a particle. So now instead of these tennis balls going straight, think of them as traveling on waves to create that pattern on the back wall:
Scientists have their answer: light behaves as a wave! Well….they still wanted to measure how wave-like the waves were i.e. how high are the peaks and how low are the troughs. So they added a tool so that they could watch the tennis balls fly through the slits in their waveform and measure it:
But something weird happened. For the first time ever, the tennis balls behaved like particles and not waves. They got the pattern they were first expecting:
And no one could figure out why. This test was rerun and rerun over again. Every time scientists measured the tennis balls by turning these detectors on they behaved like particles. Every time the scientists turned the detector off they behaved like waves. The very act of observing the tennis balls changed their properties. The superposition principle describes why this happens. It states that the tennis ball is not ever in one place. It is in every place possible at once, although some places have higher probabilities than other places, and only when the tennis ball is observed does this ‘superposition’ collapse to one observable place. In our case the wave (representing the tennis ball being everywhere at once) collapses to a particle (representing one place as we observe it).
This intuitively doesn’t make sense. To illustrate the absurdity of this finding Erwin Schrödinger came up with a thought experiment where a cat is sealed in a box with a radioactive sample that has a 50% chance of killing the cat. The box is then sealed. The cat, like our tennis balls, will take the form of all possible states. So the cat is both alive and dead. It is only when we open the box and observe the cat that the superposition of the cat is collapsed and the cat becomes alive or dead. So the very act of observing the cat causes it to live or die.
Schrödinger’s cat has now brought the superposition principle and the measurement paradox of quantum mechanics into the spotlight of public knowledge.
However, scientists still had 1 more idea for how they could disprove these theories. In the previous experiments when the tennis balls were behaving like waves we know they were actually going through both slits at the same time (superposition principle). And when the tennis balls were picking one slit or the other they were behaving like particles because they were being observed.
So scientists decided to let the tennis balls pass through the slits as waves THEN they would measure them. This would thus trick them into thinking there is no measurement, then once they’ve passed through the slits they would measure their waves. See the new setup below:
But once again, this didn’t work. The scientists weren’t able to measure the waves, and the tennis balls formed the particle pattern once again. Quantum mechanics tells us that the particles could have gone through the two slits as waves, seen that measurement was on the other side, then go back in time erasing all evidence that they were ever waves and then return as particles.
This logically doesn’t make sense to us. But remember we think of the world the way Einstein described it in space and time. Quantum mechanics and Einstein’s relativity don’t work together. So in quantum mechanics there doesn’t necessarily need to be a dimension of ‘time’ to make the physics work.
Another theory that has emerged as the leading theory among physicists is called the ‘many worlds theory’ (as a note: it is absolutely insane to me that this is a leading theory but it checks out). This theory states that waves don’t actually collapse into particles. It postulates that every time a decision point arises in quantum mechanics our reality is split into a new universe. Thus, there’s a universe where the tennis ball is a wave and a universe where the tennis ball is a particle. This line of thinking means there are infinite universes and our reality fractures infinite times a day, each with a probability attached to it. It also means that our understanding that time is a linear construct is fundamentally flawed.
One of the reasons that this is a leading theory is that almost none of the quantum mechanical formulas work when you keep a constraint on one universe. You, by definition, need to have infinite probabilistic universe in order to predict the behavior of these systems. So while fracturing universes at every quantum decision point, creating infinite realities doesn’t align with our current worldview, it’s actually a backbone of computational quantum mechanics and thus has been left in the theories.
Quantum entanglement is the theory that particles are created in pairs and those pairs are inexplicably linked. To be scientific about it:
This occurs when two quantum objects, such as photons, form at the same instant and point in space and so share the same existence. In technical terms, they are described by the same wave function.
This means that two particles could be on opposite ends of the universe and communicate with each other instantaneously. This is impossible in Einstein’s view of the world because nothing can travel faster than the speed of light; not even particle communication.
Once again: quantum mechanics tests blew everyone’s mind. The best way to understand this is to know that every particle has a series of ‘states’. An important one is called spin. You can measure particle states by spin up, spin down, spin left and spin right. You can also change the states of particles. For example you can make a spin up particle spin down.
Additionally, entangled particles can never have the same state. If Particle A & B are entangled and particle A is spin up particle B must be spin down. If particle A is changed to be spin down, particle B must be spin up.
This was the theory. But scientists wanted to test this. To do so they took two entangled particles and brought them to different laboratories. They changed the state of particle A to be spin up. Then they called the other laboratory and asked what the state of particle B was. It had changed to spin down. Then they changed particle B to be spin left and called again and Particle A had miraculously changed to spin right. How in the f*ck can these things communicate to each other? If they’re communicating faster than the speed of light then Einstein’s theory of relativity is wrong.
Again, we need to accept that quantum mechanics doesn’t represent reality in the way that we observe the world in our daily lives. So what’s actually happening here? We’re seeing the observation effect in action once again. Particle A is taking on all possible states at once, and so is particle B. Only when they are observed (measured) does their superposition collapse and the particle has a single position. At this point, since the particles are entangled the other particle knows to take the inverse state. It’s the same process that was collapsing the wave (going through both slits at once) to a particle (collapsing to a single state). Now you should be asking…how do these particles communicate to one another when their superposition collapses and they need to pick a state, and what can this communication link be used for? Look no further:
Quantum teleportation is the process of sending information from any point in the universe to any other point in the universe faster than the speed of light (maybe). This can work because of the communication pipeline that is setup when two particles become entangled. This is how the spins are communicated to the particle in the laboratory example above. Very little is known about how this connection works exactly but the basic process of quantum teleportation is as follows:
- Particle A and Particle B are entangled.
2. A third particle, particle C is brought in to be teleport-ed.
3. Particle A downloads all of the information from particle C then sends it via entanglement to particle B. Now something strange happens. Particle B becomes an exact copy of particle C, then particle C is deleted.
This brings up two interesting philosophical questions:
- Since the particle information is being sent and a copy is being made — is this really teleportation?
- If we scale this up to work on humans would it be moral i.e. making an exact copy of someone and deleting the original?
Tim Urban from Wait But Why already tackled these questions with supreme elegance so there’s not much I can add. Check out the debate here.
This sounds like a philosophical thought experiment, however Chinese researchers have already successfully put this into practice. The MIT technology review explains:
“…[a] Chinese team created entangled pairs of photons on the ground at a rate of about 4,000 per second. They then beamed one of these photons to the satellite, which passed overhead every day at midnight. They kept the other photon on the ground.
Finally, they measured the photons on the ground and in orbit to confirm that entanglement was taking place, and that they were able to teleport photons in this way. Over 32 days, they sent millions of photons and found positive results in 911 cases. “We report the first quantum teleportation of independent single-photon qubits from a ground observatory to a low Earth orbit satellite — through an up-link channel — with a distance up to 1400 km,” says the Chinese team.”This is the first time that any object has been teleported from Earth to orbit, and it smashes the record for the longest distance for entanglement.
Again, we know that this works on the small (photons) and not the large (humans) but that doesn’t mean there aren’t applications for this technology that humans can use in the short term. One of the most exciting applications of quantum entanglement and teleportation is quantum computing.
This can be complicated to explain, so here’s Justin Treaudeau taking a shot at it:
Traditional computing, or boring computing, is based off of a classical bit. The circuit board opens the flow of electricity — 1, or it closes the circuit breaking the flow of electricity — 0. This binary system is how all computers work today. Advances in computing come from Moore’s law which observed that transistors were shrinking at a rate that twice as many could fit into a computing chip every year. Eventually this led to exponential growth as it doubled computing power every two years. However we are now running up against the physical limits of how many transistors can be fit into chips within computers. In 2016 the MIT Technology Review released a paper called, ‘Moore’s Law is Dead. Now What?’ which theorized there is less than a generation left of growth.
Quantum computers render Moore’s Law irrelevant. Because quantum particles can occupy multiple states at once (superposition), the quantum version of bits (quibits) can be both 1 and 0 at the same time. This relieves the constraint that classical computing power runs up against. When you have 1 classical bit you have 2 potential outcomes. A quantum bit has 3 possible outcomes. When you pair quantum bits together (via entanglement) the computing power grows exponentially compared to classical compute.
One of the reasons for this exponential growth is because of entanglement. The best way to think about it is by comparing quantum states to classical states. In a classical system you need to tell each bit what to do. You go along telling every bit to be a 0 or a 1. But from what we learned in entanglement theory, every entangled quantum particle has the inverse state of its partner. This means in quantum computing we only need to tell half the qbits what to do, and from that we can calculate exactly what the other half will do. This is partly why quantum computers can process data so much faster.
This type of exponential growth is hard to comprehend. But that’s part of the reason that the numbers in the chart above are such a big deal. Think of it this way: everything that humans have accomplished since the dawn of man is represented by the computing power from the orange line. Google, Facebook, iPhones, solar power, NASA, the NSA and streaming services. All of that is possible from the orange line.
You ever hear someone say: we can’t imagine the technology of the future….That’s because of the blue line. Take everything we’ve accomplished with the computing power of the orange line, now think what we can do with the blue line. It’s inconceivable. It’s physically unimaginable.
Philosophy and science tend to meet when fact based projections are difficult to comprehend. It happens when discussing the universe, infinity and consciousness. Quantum computing is no different. It allows us to ask: what would a civilization do with that type of computing power?
That question has largely given rise to simulation theory, or the theory that reality itself only exists within advanced computer simulations. If it becomes technically possible via quantum computing to create a simulation, it’s impossible to prove that it hasn’t already happened (that also means its not falsifiable, which is why some scientists won’t look into this field.). There are two technical issues with the simulation theory:
- There isn’t enough computing power to simulate the universe.
- Assuming the computing power exists, there’s not enough energy on Earth to power a computer large enough to run these simulations. One of the hidden problems in quantum computing is that you need exponentially more energy to power these supercomputers than you do with standard computing.
Since quantum computing largely solves #1, we can explore how it’s theoretically possible to solve #2. The idea of power sources this large are typically looked at in the context of a Kardashev scale which defines 3 types of civilizations:
- A Type I civilization can use and store all of the energy which reaches its planet from its parent star.
- A Type II civilization can harness the total energy of its planet’s parent star
- A Type III civilization can control energy on the scale of its entire host galaxy
We’ll use this scale to show a theoretical possibility to achieving a Type II civilization that could use its planet star to power quantum computers powerful enough to simulate infinite realities.
At this point it is time to make a very important distinction. When you look at science, including quantum mechanics it tells you about the world. It tells you what it is. It ends there. Quantum mechanics is a system that describes reality. But when you interpret the system and start looking into how things ought to be, or what they should be it becomes a philosophical or moral conversation. As science continues to be used in pop culture these two things begin to mold together; but as a consumer it’s important to decouple the ideas so you know when something is science vs. an argument for how something ought to be. One is science and one is not. On the other hand when we use science to tell us what could be — we enter the realm of science based fiction. All three have their place, just know where you are when.
To clearly state the obvious: if we were to simulate all of reality, for all time, for everyone we would need a really big and really powerful computer. (Joke: think about the size of the mouse!).
The human brain runs at 10 to the power of 17 operations or 100 million, billion operations per second. But if we’re simulating humanity, you don’t want a computer that can do this for just 1 second or for just 1 human. You want to do this for all humans across all time. So to do this it would take a million, trillion ,trillion, trillion operations per second. Even if you used all of the energy available on earth, your power source wouldn’t be sufficient to handle the computing power necessary to sustain the simulation.
Now, if we are dealing with a type II civilization and we could harness the totality of the radiation energy emitted from the sun, we could simulate many thousands of earth’s. The leading theory on the best way to harness the sun’s energy is to create a Matrioska Brain. This gets its name from the Matrioska doll which encases dolls within dolls.
It’s actually a very apt analogy, since the general premise would be to surround the sun in increasing larger cases. Radiation would penetrate each case at a decremental rate, until 100% of the energy is absorbed
This would not only be the power source, it would also be the super computer. This power source, which would last until the star burned out, would then be able to handle the computational power that could conceivably simulate the universe. From here humans would then upload their consciousness to the supercomputer and live out their biological days within the simulation.
One of the reasons we can’t explore if this exists anywhere in the universe today is because If this were to be done, it would also render the star completely invisible since 100% of its energy (light) is being absorbed. So if these structures existed in the universe we wouldn’t be able to see them from Earth.
It may be that past civilizations have explored the universe far and wide and found nothing. An argument for the simulation theory is that this civilization stopped exploring outward and have chosen to isolate themselves within the simulation.
The founding principle of classical physics is that a real, objective world exists, a world the scientist can understand in limitless detail. Quantum theory takes away this certainty, asserting that scientists cannot hope to discover the “real” world in infinite detail, not because there is any limit to their intellectual ingenuity or technical expertise, nor even because there are laws of physics preventing the attainment of perfect knowledge. The basis of quantum theory is more revolutionary yet: it asserts that perfect objective knowledge of the world cannot be had because there is no objective world.
— David Lindley
Sources: MIT Technology Review: https://www.technologyreview.com/s/601441/moores-law-is-dead-now-what/
Sam Harris Podcast #124 In search of reality
Wait But why: https://waitbutwhy.com/2014/12/what-makes-you-you.html
London City Girl: https://www.youtube.com/channel/UCnS0yS5dq_x0bXkXhGjEo3g