Q-Day: How Quantum Computing Could Be More Dangerous Than AI
AI may transform our lives, but what will the Q-Day bring? Explore the coming cryptography shift.
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So, AI is extremely dangerous — destined to one day wipe out all human jobs, take over humanity, and rule over mankind — you’ve likely heard such stories many times. In fact, this idea was popularized by movies like The Terminator. Both before and since, numerous stories and novels have envisioned robots rebelling against humans.
The word robot itself comes from the Czech word robota, which means forced labor. The term was introduced in Karel Čapek’s 1920 play R.U.R. (Rossum’s Universal Robots) in which humans create artificial workers to perform labor. These “robots” eventually rebel against their creators and begin ruling over humanity.
But the desire to conquer the world or enslave people is rooted in human biology rather than being an artificial trait. Ambition, greed, anger, pride, and the hunger for power arise from emotions that are driven by chemicals and hormones in the human brain. AI, being silicon-based machines, does not have biological systems, chemicals, or hormones, and therefore does not experience emotions or desires. At least until something like Artificial Emotion (AE) becomes a reality, humanity is safe from machines trying to dominate us out of their own desires.
It is a different matter that, like most discoveries, AI might ultimately do more harm than good to humanity and the world; but the idea of robots taking over and enslaving the human race seems far-fetched given the reality of AI today.
Today, I want to talk about something that I believe is even more dangerous than AI: Quantum Computing.
Before we understand Quantum Computing, we need to briefly understand Quantum Physics. If you’re not particularly interested in physics, feel free to skip ahead. But I promise this detour is worth it because Quantum Physics is one of the most fascinating subjects in modern science.
When Math Stops Mathing…
You see, everything we observe and experience around us falls under the realm of Classical Physics — where our simple and sober (!) Newton’s principles that we learned in school days apply, and where straightforward mathematics holds true.
However, once we move into extremely large or extremely small scales, things begin to change.
At astronomical scales — beyond our Sun, Moon, and galaxy — where gravity becomes enormous or objects move close to the speed of light — Newton’s laws start failing. That’s where Einstein’s Theory of Relativity explains the scene.
And when we venture into the realm of incredibly tiny particles like electrons and quarks, neither Newton’s nor Einstein’s theories apply; here, the rules of quantum physics take over.
You might be surprised to learn that at such a microscopic level, even our mathematics begins to break down — the proverb “math ain’t mathing” literally becomes a reality.
Despite all our progress, modern physics still lacks a single theory capable of explaining everything — from the smallest particles to the largest galaxies. Finding such a theory is one of the greatest goals of modern science and is known as the Theory of Everything.
…and the Brain Stops Braining!
Consider this: sound is a wave, but it isn’t a physical substance or object that you can lock inside a box and carry around. Yet, according to quantum physics, microscopic particles can behave both as waves and as particles.
One of the most famous demonstrations of this is the Double-Slit Experiment, where particles such as electrons produce an interference pattern like waves when not observed, yet behave like individual particles when measured.
It seems as if the electrons —
(i) know they are being observed,
(ii) have ability to change their behavior when being observed, and
(iii) have intention to change their behavior when being observed
It remains one of the most astonishing experiments ever performed in physics.
In our everyday world, an object exists in one particular state at one particular place at any given moment. In the quantum world, however, the same particle can exist in multiple states simultaneously — a phenomenon that completely defies our everyday intuition.
This bizarre idea is famously illustrated by Schrödinger’s Cat — a thought experiment in which a cat is considered both alive and dead until the box is opened and observed. Although purely hypothetical, it highlights just how counterintuitive quantum mechanics can be.
Real numbers are continuous in our mathematics, with infinitely many values between any two real numbers and endlessly extendable decimal expansions making them seem smooth. What if they cease to be continuous and instead start making sudden leaps? Something similar happens at the quantum level. This phenomenon is known as a “Quantum Jump.”
Think of it this way. When you heat a pot of water, its temperature rises smoothly from room temperature to 100°C. Now imagine a strange world where the water could not warm up continuously but instead jumped directly from one allowed temperature to another — say from 25°C to 50°C, then to 70°C, then to 90°C, and finally to 100°C.
That’s not how water actually behaves, but it gives an intuition for what happens in the quantum world, where certain physical quantities — most notably the energy of electrons in atoms — can change only in discrete steps rather than continuously.
Entanglement
Quantum computing involves a fascinating concept called “entanglement.” If one were to choose the strangest and most baffling concept in the world of quantum physics, this would likely be it.
To understand it, we first need to understand the “qubit.” You’ve probably heard of a bit. Every modern computer stores information using bits, where each bit is either a 0 or a 1. Quantum computers, however, use qubits instead of bits.
Thanks to the principles of Quantum Physics, a qubit doesn’t have to be just 0 or just 1. It can exist in a combination of both states simultaneously — a property known as superposition. (Just like in Schrödinger’s famous thought experiment discussed earlier, where the cat is considered to be in a superposition of being alive and dead until the box is opened and observed.)
Things become even stranger when two or more qubits become entangled.
The Mysterious Bond Between Qubits
Imagine two qubits, A and B. If they aren’t entangled, they behave independently. But if they become entangled, a bond forms between them, making it nearly impossible to understand them in isolation.
Suppose you measure qubit A and find that it is 0. Instantly, you also know that qubit B is 1. If A turns out to be 1, B will be 0.
The most astonishing part is that this entanglement persists even if the two qubits are separated by enormous distances — whether the qubits are right next to each other or at opposite ends of the universe.
At first glance, it might seem as though they are sending messages to each other faster than the speed of light. But according to our current understanding of physics, no information is actually traveling between them in that way. And this is one of the most mysterious and mind-bending aspects of quantum physics.
The (mis)assumption
Now let’s return to the main topic. Let me explain why not just I, but many scientists worldwide, consider quantum computing to be a greater threat than AI.
The reason is simple: Cryptography. From banking systems and government agencies to NASA and the smartphone in your pocket, nearly every secure digital system relies on cryptography.
You’ve probably heard terms like encryption and end-to-end encryption (E2EE). They are all applications of cryptography.
Whenever encryption is mentioned, you’ll usually see a lock icon. However, encryption doesn’t simply lock data in a way that can be broken to retrieve the original information intact.
Instead, it scrambles the information so thoroughly that, without the correct password (the cryptographic key), even a supercomputer would take centuries — or, if the encryption algorithm is sufficiently strong, even longer than the age of the universe — to restore it to its original form.
For decades, modern cybersecurity has relied on exactly this assumption. The assumption has been that brute-forcing modern encryption is computationally impossible.
Quantum Computing threatens that assumption.
The Q-Day
For certain classes of problems, a quantum computer could solve calculations in minutes, seconds, or even less that would require classical supercomputers thousands or even millions of years. This poses a potential threat to the entire landscape of modern cryptography.
This isn’t merely science fiction.
In 2019, Google announced that its quantum processor, Sycamore, had completed a specialized calculation in about 200 seconds that, according to Google’s estimate at the time, would have taken the world’s fastest supercomputer thousands of years to perform. This milestone became known as Quantum Supremacy.
This realization made the world aware that if quantum computing continues to advance at this pace, we might reach a point scientists call “Q-Day” — the day quantum computers become capable of breaking even the strongest encryption methods we use today.
That is why governments, security agencies, universities, and technology companies are already working on Post-Quantum Cryptography — new encryption methods designed to remain secure even in the age of quantum computers.
What is Next?
While AI has the potential to transform our lives, quantum computing could shake the very foundations of global digital security. If practical large-scale quantum computers become a reality, they won’t just change computing — they could force us to redesign much of the world’s digital infrastructure from the ground up.
Consequently, the coming years promise to be among the most fascinating and pivotal in the world of technology.
And if the concept of quantum computing has already left you astounded, get ready for the next technological frontier — Photon Computing. Some researchers believe that it could overcome several limitations of Quantum Computing itself.
But what exactly is Photon Computing?