What Makes Quantum Computing Special?
Read this: 1111 1111 0110 0110 0000 0000
It’s hard to understand the meaning of those numbers, right? Well, this is actually how modern computers work. They use bits, essentially a combination of 0s and 1s, to render information. In fact, the string of bits above is how a computer reads the colour orange. So if a computer renders the colour orange using as many as 24 bits, what does a more complicated binary code look like?
What if I told you that there was a new emerging technology; a supercomputer that doesn’t use bits, but another unit that, through the mysteries of quantum physics, is exponentially faster than using millions of bits to render information? What if I told you that this supercomputer is so powerful, that it could break modern encryption?
Welcome to quantum computing.
So, what’s the difference between qubits and bits?
First things first, let’s clarify the difference between bits and and qubits — the fundamental unit of quantum computing. Bits, as mentioned before, are how modern computers read information. They can be in two states: 0s or 1s.
Qubits, on the other hand, can be photons, atoms, electrons, molecules or perhaps something else to render information into a computer. It also has two states, usually spin up and spin down, where spin up is considered as 0 and spin down is considered as 1 (this just makes qubits easier to measure). Interestingly enough, qubits can be in both states at the same time…because of superposition.
What is superposition?
Superposition is a term used to describe the movement of particles when it has “no real world equivalent” or in essence, these particles defy physics because they can be in two states at once (hence quantum physics). Imagine a qubit as a sphere where spin up (0) is at the north, and spin down (1) is at the south. The red line represents the qubit’s state; as you can see, its both spin up and spin down, though it is more towards the spin up state.
Since the qubit’s current state is more towards spin up, we can measure it as spin up. This is because qubits lie on a magnetic field — when they are at their lowest energy, they are spin down (this is equivalent to the opposite direction of the magnetic field). By applying more energy, the qubit becomes spin up (the same direction of the magnetic field). In the picture above, if we give the qubit more energy, it will be fully spin up and exit superposition.
Thus, as a normal computer will have to read the strings of 0s and 1s one at a time, a quantum computer is immensely faster as qubits can be in both states at once, or in superposition. Furthermore, since we can control the state of qubits, we can make quantum computers complete specialized tasks that normal computers cannot. However, when we measure the state of a qubit…well, entanglement occurs.
What is entanglement?
Entanglement signifies that the quantum states of two or more objects have reference to each other, even if those two particles are significantly far apart. For example, if you try and measure the direction of the spin for a qubit and it is spin up, a separate qubit will be spin down; thus, no matter what, their spins will be opposite. This is called the conservation of angular momentum; the choice of measurement in one location appears to be affecting the state of the particles in the other location.
Einstein called this entanglement “spooky action at a distance” because it seemed like information was being performed between particles faster than the speed of light.
Entanglement gives qubits more computational power for it doubles the amount of parallel operation that can be done. This is why only 300 entangled qubits in superposition could map out all the information in the universe starting from the Big Bang.
So…what else can quantum computers do?
Quantum computers will be able to process special algorithms such as prime factoring. Prime factorization can take modern computers months or years to even process, while a quantum computer is much faster. Because of quantum superposition, an algorithm can search both the 0 and the 1 at the same instant.
Why is this impressive? Prime factorization is used to secure public key encryption systems. For instance, you have “public key” that consists of two relatively large prime numbers to encrypt a message and a “secret key” that consists of those two primes used to decrypt the message. As long as you have the “secret key”, only you can know these prime factors and can decrypt the messages….However, with quantum computers, they can prime factor at a rapid speed, enabling them to decrypt the message.
Credit cards’ numbers are encrypted to be the product of two prime numbers in which normal computer won’t be able to decode, but a quantum computer would be able to.
But there’s no need to worry!
Quantum computers are indeed very powerful, but it may still take a few years to be able to achieve a universal quantum computer. This is because of quantum decoherence. Qubits are extremely fragile and their ability to stay in superposition or entanglement is low because of interactions with the environment. Decoherence leads to errors in quantum information since there must be interactions between a qubit and its environment in order to read its processed data. Therefore, quantum decoherence must be solved before being able to make a universal quantum computer.
The race to build the world’s first quantum computer is still ongoing. This supercomputer is most likely still over a decade away from complete development, though we have already seen incremental steps from IBM, Microsoft, Google, Intel and other big companies. With the intriguing wonders of quantum computers on the way, we can only imagine what new advancements they could bring into our society.
Hi! I’m Jenny, a sixteen-year old innovator hoping to solve the world’s biggest problems. If you liked this article, stay tuned for more😎
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