Quantum spin ice

Quantum Excitations in Quantum Spin Ice.
Kate A. Ross, Lucile Savary, Bruce D. Gaulin, and Leon Balents
Phys. Rev. X 1, 021002 (2011)

Phase diagram for a material in the QSL phase of Eq. (1) at T=H=0. At a low H and T, the QSL state supports exotic excitations: ‘‘magnetic’’ (red sphere) and‘‘electric’’ (yellow sphere) monopoles, and an emergent photon
(wavy line). The field Hc marks a quantum critical point: the confinement phase transition. For H>Hc, the ground state is a simple field-polarized ferromagnet (FM), and the elementary excitations are conventional magnetic dipoles.

Spinning on Ice.
Rajiv R. P. Singh
Physics 4.77 story

a) Spin configurations on a tetrahedra that obey the “ice-rules.” (b) Proposed low-temperature phases of a quantumspin ice consist of a magnetically polarized high-field phase with usual spin-flip excitations (shown at right) and
a low-field phase consisting of “emergent” dynamical photons (shown by a wavy line) and electric and magnetic charges
(shown schematically as plus and minus charges with emanating electric fields and north (N) and south (S) poles with
emanating magnetic fields).