When ice is warmed, the water molecules forming its structure vibrate more and more vigorously until finally the forces between them are no longer strong enough to hold them together – the ice melts and turns into liquid water. Quantum physics predicts that similar phenomena can be observed if the quantum mechanical fluctuations of the particles in a material can be altered. Such changes of state triggered by purely quantum effects – known as quantum phase transitions – play a role in many astonishing phenomena in solid-state systems, including high-temperature superconductivity. Researchers from Switzerland, Britain, France and China have now specifically altered the magnetic structure of the material TlCuCl3 by exposing it to a varying external pressure at different temperatures. By performing neutron-scattering measurements, they could observe what happens during a quantum phase transition, and compare the “quantum melting” of the magnetic structure with the classical “thermal melting” phase transition.
from Phys.org: Physics News http://ift.tt/1ijKzIW