The quantum break-though is getting closer, and it's exciting. Here's a quick overview on how quantum computers process information, how they differ from classical computers, what superposition means and why quantum computers need a cold af environment to operate in.

How long away are large-scale quantum computers?
Quantum technology is not just a cute little invention that will aid humans live their cute little lives more efficiently, but it could earthquake-shake the way we utilize technology from detecting cancer cells before they even start to grow to addressing questions about the origins of the universe that humans alone have simply not been able to answer. Quantum technology is a huge leap to the unknown for humanity, and it’s important to understand why these computers are not like your regular MacBook.
Large-scale quantum computers are still years away. Some say five, some say 10, Jensen Huang from Nvidia said maybe over 20 years away. Nonetheless, the technology is advancing at an incredibly quick pace. The race on who gets to build the world’s first large-scale quantum computer is ongoing in different parts of the world like in the US and China, in all sorts of labs like those of IBM’s and Google’s. No one can yet predict when the massive technological break-through will happen or who will be the first one succeed, but what we can predict is how quantum computers will change the way the world works now.

Classical and quantum computers process information differently
Classical computers, the ones that us dry-eyed humans spend hours staring at every day, process information in bits that are either 1 or 0 at a time. Bits are the very foundation of computers as humans know them now. For example, a simple word like "hi" could be turned into a code where the letter "h" could be represented as 0110100 and "i" as 01101001. By combining these bits, the computer processes and displays the letters on the screen. Bits can be either on or off, true or false, yes or no… one at a time.
Quantum computers do something that - in theory -should be impossible: They process information as qubits, state of which can be both 1 and 0 at the same time (More technically, in a state that combines the two). In quantum mechanics, a particle can exist in different states simultaneously, called a superposition. By being in multiple states at once, quantum computers can process a vast number of possibilities at the same time, unlike classical computers that need to complete one task before moving onto the next one.
Discovering a maze with superposition
Superposition is often described as solving a maze: Instead of discovering each possible path one by one (1 or 0), superposition allows to discover all possible paths in parallel (1 and 0) - which is incredibly lot quicker than discovering each path separately. However, superposition doesn’t immediately know which path of the maze is correct. To find a way out, quantum computers use another principle, interference, which focuses on the most likely outcome.

Quantum computers often need an extra-ultra-cool, cold af environment
Quantum computers are not replacing your MacBook, at least taken how they operate now. Not only will it be years until large-scale quantum computers are actually useful, they now are extremely sensitive to outside conditions, like temperature and noise. Most of them need an extra-ultra-cool environment, like Google’s latest quantum chip Willow, that operates almost at absolute zero (-273°C). The state of superposition is delicate, and the coldness minimizes factors that might intervene with its calculations, like electromagnetic waves or heat from the outside.

Not to replace, but to complement
Don’t worry, the 1s and 0s that you are basically reading now from this screen are still just as meaningful as they were before. Quantum computing should be used to benefit humanity, like inventing cures to diseases or finding solutions to help prevent climate change. However, the infrastructure of quantum computers the energy-needs of the cooling systems are so expensive and high, that only a few organizations and governments have access to them today. The goal is not to replace classical computing, but to complement it. Your MacBook can stay!
-S
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