Quantum vortices are tiny whirlpool-like structures that occur in superfluids and superconductors at very low temperatures. They form when the fluid or material undergoes a phase transition, allowing it to flow without viscosity. These vortices are quantized, meaning they can only exist at specific energy levels, leading to unique behaviors in the system. In the context of superconductivity, quantum vortices play a crucial role in the behavior of type-II superconductors. When exposed to a magnetic field, these materials can trap magnetic flux lines in the form of vortices, which affects their electrical properties and applications in technology, such as magnetic resonance imaging (MRI) and quantum computing.