If you think about it, a slice of pizza is basically a computer that simulates a slice of pizza down the quark level.

Honestly, the random number generation on quantum computers is practically useless. Speeds will not get anywhere near as close to a pseudorandom number generator, and there are very simple ones you can implement that are blazing fast, far faster than any quantum computer will spit out, and produce numbers that are widely considered in the industry to be cryptographically secure. You can use AES for example as a PRNG and most modern CPUs like x86 processor have hardware-level AES implementation. This is why modern computers allow you to encrypt your drive, because you can have like a file that is a terabyte big that is encrypted but your CPU can decrypt it as fast as it takes for the window to pop up after you double-click it.

While PRNG does require an entropy pool, the entropy pool does not need to be large, you can spit out terabytes of cryptographically secure pseudorandom numbers on a fraction of a kilobyte of entropy data, and again, most modern CPUs actually include instructions to grab this entropy data, such as Intel’s CPUs have an RDSEED instruction which let you grab thermal noise from the CPU. In order to avoid someone discovering a potential exploit, most modern OSes will mix into this pool other sources as well, like fluctuations in fan voltage.

Indeed, used to with Linux, you had a separate way to read random numbers directly from the entropy pool and another way to read pseudorandom numbers, those being /dev/random and /dev/urandom. If you read from the entropy pool, if it ran out, the program would freeze until it could collect more, so some old Linux programs you would see the program freeze until you did things like move your mouse around.

But you don’t see this anymore because generating enormous amounts of cryptographysically secure random nubmers is so easy with modern algorithms that modern Linux just collects a little bit of entropy at boot and it uses that to generate all pseudorandom numbers after, and just got rid of needing to read it directly, both /dev/random and /dev/urandom now just internally in the OS have the same behavior. Any time your PC needs a random number it just pulls from the pseudorandom number generator that was configured at boot, and you have just from the short window of collecting entropy data at boot the ability to generate sufficient pseudorandom numbers basically forever, and these are the numbers used for any cryptographic application you may choose to run.

The point of all this is to just say random number generation is genuinely a solved problem, people don’t get just how easy it is to basically produce practically infinite cryptographically secure pseudorandom numbers. While on paper quantum computers are “more secure” because their random numbers would be truly random, in practice you literally would never notice a difference. If you gave two PhD mathematicians or statisticians the same message, one encrypted using a quantum random number generator and one encrypted with a PRNG like AES or ChaCha20, and asked them to decipher them, they would not be able to decipher either. In fact, I doubt they would even be able to identify which one was even encoded using the quantum random number generator. A string of random numbers looks just as “random” to any random number test suite whether or not it came from a QRNG or a high-quality PRNG (usually called CSPRNG).

I do think at least on paper quantum computers could be a big deal if the engineering challenge can ever be overcome, but quantum cryptography such as “the quantum internet” are largely a scam. All the cryptographic aspects of quantum computers are practically the same, if not worse, than traditional cryptography, with only theoretical benefits that are technically there on paper but nobody would ever notice in practice.

no that’s dialectics 😏

A lot of people who present quantum mechanics to a laymen audience seem to intentionally present it to be as confusing as possible because they like the “mystery” behind it. Yet, it is also easy to present it in a trivially simple and boring way that is easy to understand.

Here, I will tell you a simple framework that is just 3 rules and if you keep them in mind then literally everything in quantum mechanics makes sense and follows quite simply.

1. Quantum mechanics is a probabilistic theory where, unlike classical probability theory, the probabilities of events can be complex-valued. For example, it is meaningful in quantum mechanics for an event to have something like a -70.7i% chance of occurring.
2. The physical interpretation of complex-valued probabilities is that the further the probability is from zero, the more likely it is. For example, an event with a -70.7i% probability of occurring is more likely than one with a 50% probability of occurring because it is further from zero. (You can convert quantum probabilities to classical just by computing their square magnitudes, which is known as the Born rule.)
3. If two events or more become statistically correlated with one another (this is known as “entanglement”) the rules of quantum mechanics disallows you from assigning quantum probabilities to the individual systems taken separately. You can only assign the quantum probabilities to the two events or more taken together. (The only way to recover the individual probabilities is to do something called a partial trace to compute the reduced density matrix.)

If you keep those three principles in mind, then everything in quantum mechanics follows directly, every “paradox” is resolved, there is no confusion about anything.

For example, why is it that people say quantum mechanics is fundamentally random? Well, because if the universe is deterministic, then all outcomes have either a 0% or 100% probability, and all other probabilities are simply due to ignorance (what is called “epistemic”). Notice how 0% and 100% have no negative or imaginary terms. They thus could not give rise to quantum effects.

These quantum effects are interference effects. You see, if probabilities are only between 0% and 100% then they can only be cumulative. However, if they can be negative, then the probabilities of events can cancel each other out and you get no outcome at all. This is called destructive interference and is unique to quantum mechanics. Interference effects like this could not be observed in a deterministic universe because, in reality, no event could have a negative chance of occurring (because, again, in a deterministic universe, the only possible probabilities are 0% or 100%).

If we look at the double-slit experiment, people then ask why does the interference pattern seem to go away when you measure which path the photon took. Well, if you keep this in mind, it’s simple. There’s two reasons actually and it depends upon perspective.

If you are the person conducting the experiment, when you measure the photon, it’s impossible to measure half a photon. It’s either there or it’s not, so 0% or 100%. You thus force it into a definite state, which again, these are deterministic probabilities (no negative or imaginary terms), and thus it loses its ability to interfere with itself.

Now, let’s say you have an outside observer who doesn’t see your measurement results. For him, it’s still probabilistic since he has no idea which path it took. Yet, the whole point of a measuring device is to become statistically correlated with what you are measuring. So if we go to rule #3, the measuring device should be entangled with the particle, and so we cannot apply the quantum probabilities to the particle itself, but only to both the particle and measuring device taken together.

Hence, for the outside observer’s perspective, only the particle and measuring device collectively could exhibit quantum interference. Yet, only the particle passes through the two slits on its own, without the measuring device. Thus, they too would predict it would not interfere with itself.

Just keep these three rules in mind and you basically “get” quantum mechanics. All the other fluff you hear is people attempting to make it sound more mystical than it actually is, such as by interpreting the probability distribution as a literal physical entity, or even going more bonkers and calling it a grand multiverse, and then debating over the nature of this entity they entirely made up.

It’s literally just statistics with some slightly different rules.