Microsoft on Wednesday unveiled a new chip that it said showed quantum computing is ¡°years, not decades¡± away, joining Google and IBM in predicting that a fundamental change in computing technology is much closer than recently believed.

Quantum computing holds the promise of carrying out calculations that would take today¡¯s systems millions of years and could unlock discoveries in medicine, chemistry and many other fields where near-infinite seas of possible combinations of molecules confound classical computers.

Quantum computers also hold the danger of upending today¡¯s cybersecurity systems, where most encryption relies on the assumption that it would take too long to brute-force access.