A quantum computer is a computational device that harnesses the principles of quantum mechanics to process information. Unlike classical computers, which employ binary bits to represent and manipulate data, quantum computers employ quantum bits, or qubits. Qubits, owing to the phenomenon of superposition, can simultaneously exist in multiple states, enabling parallel computation. Furthermore, qubits can become entangled, resulting in interdependence between their states, facilitating highly correlated operations.

Quantum computers exhibit the potential for significant speed-ups in solving certain computational problems, particularly those characterized by massive data sets or complex algorithms. This advantage stems from their ability to exploit quantum parallelism and entanglement, which allows for the simultaneous exploration of numerous computational pathways.

However, the realization of practical quantum computing faces formidable challenges, including qubit coherence and stability, error mitigation, and the development of scalable hardware architectures. Despite ongoing advancements, quantum computers remain primarily experimental and are yet to attain widespread commercial viability.