a computer that does certain types of complicated calculations much faster than a traditional computer, using qubits (= units of computer information that have quantum characteristics ) instead of bits (= units of computer information that must be either 0 or 1)

A quantum computer would need hundreds or thousands of qubits to do meaningful work.

A quantum computer could easily factor large integers, allowing them to break most cryptographic systems. 量子计算机可以轻松地分解大整数，使它们能够破解大多数加密系统。