Experiments cast doubts on the existence of quantum spin liquidsTherefore, helium gas, for example, can become liquid at -270 degrees, but never solid under atmospheric pressure: There is no helium ice. For this problem, quantum mechanics suggests the solution that the orientation and bond of two spins are not rigid, but the spins fluctuate. Quantum mechanics can, however, break this rule. One problem is that it is extremely challenging to measure electron spins down to such extremely low temperatures, especially along different crystal directions and in variable magnetic fields. However, it could also be that such a disordered, dynamic state simply does not exist in nature. All previous experiments have been able to probe quantum spin liquids only more or less indirectly, and their interpretation is based on certain assumptions and models. Using on-chip microwave lines, one can directly observe the properties of the spins down to a few hundredths of a degree above absolute zero.
Article from EurekAlert.