Quantum computing

As physicists applied quantum mechanical models to computational problems and swapped digital bits for qubits, the fields of quantum mechanics and computer science began to converge. In 1980, Paul Benioff introduced the quantum Turing machine, which uses quantum theory to describe a simplified computer.^[7] When digital computers became faster, physicists faced an exponential increase in overhead when simulating quantum dynamics,^[8] prompting Yuri Manin and Richard Feynman to independently suggest that hardware based on quantum phenomena might be more efficient for computer simulation.^[9][10][11] In a 1984 paper, Charles Bennett and Gilles Brassard applied quantum theory to cryptography protocols and demonstrated that quantum key distribution could enhance information security.^[12][13]

量子電腦

讓我想起一個笑話

考數學時，有個同學都用擲銅板決定答案，很快就做完考卷。這個同學安靜一陣子，突然又開始擲銅板，老師好奇問他怎麼回事？這個同學很認真的回答：老師，我在驗算！

ChatGPT 

Imagine a traditional computer as a box with billions of tiny switches called transistors, which can be either on (1) or off (0). These switches, also known as bits, are the basic building blocks of information in a classical computer. They perform calculations by manipulating these 1s and 0s.

Now, let's jump to quantum computing. Instead of using bits, quantum computers use quantum bits, or qubits. Unlike classical bits, qubits can exist in multiple states at the same time, thanks to a phenomenon called superposition. It's like having a switch that can be both on and off simultaneously. This unique property enables quantum computers to process vast amounts of information in parallel.

Another essential feature of qubits is entanglement. When qubits are entangled, the state of one qubit is instantly related to the state of another, regardless of the distance between them. It's as if they share a mysterious connection, allowing them to communicate and work together more efficiently.

In simple terms, quantum computers use these strange properties of qubits to perform certain types of calculations incredibly faster than classical computers. They can tackle complex problems in areas like cryptography, optimization, and simulating quantum systems, which would take classical computers an impractical amount of time.

However, it's important to note that quantum computing is still in its early stages, and building stable and error-resistant qubits is a significant challenge. Scientists and engineers are working hard to overcome these obstacles, and as the technology progresses, quantum computers have the potential to revolutionize the way we approach computing and problem-solving in the future.