Quantum computers use qubits that exist in superposition, representing both 0 and 1 simultaneously—a feat impossible for classical bits.

The power of quantum computing stems from two core principles of quantum mechanics: superposition and entanglement. Superposition allows a qubit to exist in multiple states simultaneously, unlike a classical bit which is strictly binary. This means that while N classical bits can represent only one of 2^N possible states at any given time, N qubits can represent all 2^N states at once.In October 2019, researchers at Google published a landmark paper in Nature announcing that their 53-qubit Sycamore processor had achieved "quantum supremacy"—the point where a quantum device performs a calculation that no classical computer can complete in a reasonable timeframe. The task involved sampling the output of a pseudo-random quantum circuit, and the Sycamore processor completed it in just 3 minutes and 20 seconds. Google estimated that IBM's Summit, the world's most powerful supercomputer at the time, would need 10,000 years to produce the same result. Although IBM later contested this timeframe, the experiment demonstrated the extraordinary potential of quantum systems for parallel processing.Beyond raw speed, quantum entanglement allows qubits to be linked so that the state of one instantly influences another, regardless of physical distance. This interconnectedness enables quantum computers to scale their processing power exponentially as more qubits are added. Today, researchers are harnessing these machines to simulate molecular structures for drug discovery and to explore approaches to advanced encryption security.