Indecisive quanta

In ytterbium nickel phosphide there is a quantum critical point between the ferromagnetic and non-magnetic states that was previously not thought possible.

What do the melting points of ice and high-temperature superconductivity have in common? Nothing. Yet there is a peculiar connection. This major unsolved enigma in physics and other quantum mechanical phenomena have to do with what are known as phase transitions, which also includes the melting of ice. However, these are "quantum phase transitions", which are closely intertwined with other quantum mechanical phenomena. They exist entirely at the lower end of the temperature scale, near absolute zero. Physicists from the Max Planck Institute for Chemical Physics of Solids in Dresden have now created an exotic material: At extremely low temperatures, it does not know whether it should pass through a phase transition into a magnetic state or not. It sits at a quantum critical point. Such strange states of matter give clues to help understand exotic phenomena, like high-temperature superconductivity, where a material loses its electrical resistance even at relatively high temperatures.