The property you're referring to, where a qubit can exist in multiple states simultaneously, is known as superposition. In classical computing, bits represent information as either 0 or 1, but in quantum computing, qubits can be in a superposition of both 0 and 1 states.
This superposition property of qubits allows quantum computers to perform certain computations faster than classical computers in specific cases. One example is quantum parallelism. In a classical computer, if you have 'n' bits, you can represent 2^n possible states. However, you can only access one state at a time. In contrast, in a quantum computer, 'n' qubits can represent 2^n possible superposition states simultaneously. This parallelism can be harnessed to perform certain computations more efficiently.
Quantum computers can manipulate these superposition states through quantum gates, allowing for complex calculations to be performed on many possible inputs simultaneously. By leveraging interference and constructive or destructive interference between different computational paths, quantum algorithms can exploit the vast computational power offered by superposition.
One prominent example is Shor's algorithm for factoring large numbers, which is exponentially faster on a quantum computer compared to the best-known classical algorithms. This has significant implications for cryptography and the security of many encryption schemes that rely on the difficulty of factoring large numbers.
However, it's important to note that not all computations benefit from quantum computing. Quantum algorithms excel in certain areas, such as optimization, simulation of quantum systems, and solving certain mathematical problems. For other types of problems, classical computers may still be more efficient.
In summary, the ability of qubits to exist in superposition states enables quantum computers to perform certain calculations more quickly than classical computers by leveraging quantum parallelism and interference effects.