What are qubits and how are they different from classical bits?

Qubits, short for quantum bits, are the fundamental units of information in quantum computing. They are the quantum analog of classical bits, but differ in several key aspects.

Firstly, while classical bits can only exist in one of two states, either 0 or 1, qubits can exist in a superposition of both states simultaneously. This means that a qubit can be in a state that is a combination of 0 and 1, represented as |0⟩ and |1⟩, respectively. The superposition allows qubits to hold and process multiple pieces of information simultaneously, providing a significant advantage over classical bits.

Secondly, qubits can also exhibit a phenomenon called entanglement. Entanglement is a correlation between two or more qubits, where the state of one qubit is dependent on the state of another, regardless of the distance between them. This property enables qubits to be interconnected in a way that classical bits cannot, allowing for the creation of complex quantum algorithms and computations.

Lastly, qubits are highly susceptible to noise and decoherence, which refers to the loss of quantum information due to interactions with the environment. Unlike classical bits, which are robust and stable, qubits require careful error correction techniques to maintain their fragile quantum states.

In summary, qubits are the building blocks of quantum computing and differ from classical bits in their ability to exist in superposition, exhibit entanglement, and their vulnerability to noise and decoherence. These unique properties make qubits a powerful resource for performing complex computations and solving problems that are beyond the capabilities of classical computers.