Quantum computing has been an up-and-down investment theme over the past few months. The rage kicked off when Alphabet ( GOOG 1.16%) ( GOOGL 1.13%) announced a breakthrough with its Willow quantum computing chip, and any stock associated with quantum computing rose on the news of the announcement.

Trapped-ion quantum computing leader IonQ (NYSE: IONQ) is emerging as a potential leader in the commercialization of quantum computing through its trapped-ion technology approach. Unlike traditional superconducting quantum competitors,

Rigetti (RGTI) is dropping 23%, while IonQ (IONQ) is giving back 10% and D-Wave Quantum (QBTS), which disclosed today that it may sell more shares of its stock, is plunging nearly 30%. The sector is dropping sharply again after Meta (META) CEO Mark Zuckerberg suggested that quantum computing would not be “practical” for a long time.

Quantum computing is hot right now. Shares of pure play quantum computing stocks have been soaring, and the hype train has clearly left the station. Investors should know, however, that quantum computers have never been used to solve a real-world problem faster than a traditional computer and that useful quantum computers could very well be decades away.