Emergent Fine Structure Constant of Quantum Spin Ice Is Large

Quantum melting of spin ice: emergent cooperative quadrupole and chirality.

Quantum melting of spin ice is proposed for pyrochlore-lattice magnets Pr2TM2O7 (TM=Ir, Zr, and Sn). The quantum superexchange Hamiltonian having a nontrivial magnetic anisotropy is derived on the basis of atomic non-Kramers magnetic doublets. The ground states exhibit a cooperative ferroquadrupole and pseudospin chirality, forming a magnetic analog of smectic liquid crystals. Our theory accoun...

Time-Varying Fine-Structure Constant and Quantum SuperStrings

In this note we observe that Webb and co-workers’ observation of an evolving fine structure constant has since been reconfirmed. We also confirm Kuhne’s contention that this implies a cosmological constant and exhibit a cosmological mechanism for Webb’s result. We also see how this provides a mechanism to reach elementary particle scales from the Quantum Superstring scale. Kuhne[1] suggested so...

Disorder and Quantum Spin Ice

Thermodynamics of emergent magnetic charge screening in artificial spin ice

Electric charge screening is a fundamental principle governing the behaviour in a variety of systems in nature. Through reconfiguration of the local environment, the Coulomb attraction between electric charges is decreased, leading, for example, to the creation of polaron states in solids or hydration shells around proteins in water. Here, we directly visualize the real-time creation and decay ...

Giant collective spin-orbit field in a quantum well: fine structure of spin plasmons.

We employ inelastic light scattering with magnetic fields to study intersubband spin plasmons in a quantum well. We demonstrate the existence of a giant collective spin-orbit (SO) field that splits the spin-plasmon spectrum into a triplet. The effect is remarkable as each individual electron would be expected to precess in its own momentum-dependent SO field, leading to D'yakonov-Perel' dephasi...