quantumspinliquide

Quantumspinliquide refers to a quantum spin liquid, a state of matter in condensed matter physics in which localized magnetic moments remain disordered down to the lowest temperatures due to strong quantum fluctuations and geometric frustration. There is no conventional magnetic order and spins do not freeze, despite strong interactions.

In such a state, long-range order is replaced by a highly entangled ground state with emergent gauge fields and fractionalized excitations. Depending on the system, excitations can be spinons (spin-1/2 quasiparticles), visons (vortex-like objects of the emergent gauge field), and, in some models, Majorana fermions. Theoretical descriptions include resonating valence bond ideas and lattice gauge theories with Z2 or U(1) symmetry. The Kitaev honeycomb model provides a solvable example yielding a Z2 quantum spin liquid with Majorana modes; other materials may realize U(1) spin liquids with emergent photons.

Materials candidates include frustrated magnets on kagome, triangular, and pyrochlore lattices. Notable realizations discussed in literature are ZnCu3(OH)6Cl2 (herbertsmithite), YbMgGaO4, and organic salts such as κ-(BEDT-TTF)2Cu2(CN)3.

Experimental signatures include a broad continuum of magnetic scattering without sharp magnons; absence of magnetic order at low temperature; and thermodynamic indicators such as a linear term in the specific heat or finite thermal conductivity indicating itinerant excitations. Distinguishing QSL behavior from spin glass or disorder effects remains challenging.

Researchers continue to investigate the nature and topology of quantum spin liquids and their potential applications in quantum information processing through entangled many-body states and, in some cases, topological order.

---