And this is important because at low temperatures, gapless quantum systems can undergo phase transitions, while gapped systems cannot.

这很重要， 因为在低温下，无间隙量子系统可以发生相变，而间隙系统则不能。

But figuring out if a system is gapped or gapless has long been known to be a very difficult problem.

但长期以来人们都知道，确定一个系统是否有间隙或无间隙是一个非常困难的问题。

Stuxnet, which infected Iranian systems that were " air gapped" (that is, physically disconnected from the internet), mechanically damaged machinery, yet remained undetected for months.

Stuxnet 病毒感染了伊朗的“气隙”系统（即物理上与互联网断开连接）、机械损坏的机器， 但数月仍未被发现。