Quantum hardware is the physical infrastructure and systems engineered to leverage quantum mechanical phenomena for computation, simulation, and information processing. As a research field, it investigates the design, fabrication, and control of quantum bits (qubits) and their interactions, exploring various physical modalities (e.g., superconducting circuits, trapped ions, photonic systems) and addressing fundamental challenges such as coherence, entanglement, scalability, and error mitigation. Its significance lies in enabling the construction of quantum computers and simulators capable of addressing problems intractable for classical computation, thereby driving transformative progress in science and technology.