Quantum ground states of copper nitrates

Low-temperature study of matter provides a key to understanding its fundamental properties. Under conditions where thermal fluctuations do not mask fine interactions, quantum cooperative phenomena that have no analogy in classical physics come into play. Among them are superconductivity, low-temperature exotic magnetism, spin and charge density waves, and Bose-Einstein condensation, which are the most important issues for modern condensed-matter physics. Study of the quantum ground states is illustrated by the example of transition metal nitrates in which magnetically active ions form lower-dimensionality frameworks, including dimers, chains, spin ladders, and 2D planes.