What are decoherence and disentanglement, and how do they affect the stability and usefulness of entangled states in practical applications?

Decoherence is the process by which a quantum system loses its quantum properties due to interactions with its environment, leading to the breakdown of superposition and entanglement. Disentanglement refers to the loss of entanglement between particles. Both phenomena affect the stability and usefulness of entangled states by introducing errors and noise, thus challenging the maintenance of entanglement in practical applications such as quantum computing and communication.