# What methods exist for cooling superconducting quantum computers? [duplicate]

Existing superconducting quantum computers need to be cooled near absolute zero. For example, some of D-Wave's machines are cooled to about $20 \ \mathrm {mK}$. Their design uses a dilution refrigerator.

Are there any other cooling methods for superconducting quantum computers besides dilution refrigerators which are capable of achieving such low temperatures?

Are there any specific commercial quantum computer designs or research projects using these other cooling methods?