Quantum fluid refers to a state of matter that exhibits unique properties due to quantum mechanics. Unlike classical fluids, quantum fluids can flow without viscosity, allowing them to move without losing energy. This behavior is observed in systems like superfluid helium, where the fluid can flow through tiny openings without resistance. In addition to superfluidity, quantum fluids can also display phenomena such as quantum vortices, which are swirling patterns that occur at very low temperatures. These properties make quantum fluids a subject of interest in both fundamental physics and potential applications in quantum computing and low-temperature physics.