The concept of "quantum liquid" is not a well-defined term in physics. However, if we consider certain states of matter that exhibit quantum mechanical properties, such as superfluids or Bose-Einstein condensates (BECs), it is important to understand that their behavior is fundamentally different from that of everyday matter.
Superfluids and BECs are characterized by phenomena such as quantum coherence and macroscopic wave functions. These states arise at extremely low temperatures, typically close to absolute zero. At such temperatures, the quantum nature of matter becomes more apparent, and particles behave collectively rather than as distinct entities.
Given this context, it is difficult to speak about "touching" or interacting with quantum liquids in the same way we interact with everyday matter. In a superfluid or a BEC, particles can flow without friction and exhibit other quantum properties, but these states do not possess the same kind of individual particle behavior that we are accustomed to in our macroscopic world.
So, while we cannot touch or interact with quantum liquids in the same manner as we do with ordinary matter, scientists can study and manipulate these quantum systems using specialized experimental techniques and sophisticated apparatus.