Nonlinear classical Hamiltonian lattices exhibit generic solutions—discrete breathers. They
are time-periodic and (typically exponentially) localized in space. The lattices have discrete …

Abstract The Bose–Einstein condensate (BEC) is a fascinating state of matter predicted to
occur for particles obeying Bose statistics. Although the BEC has been observed with …

This article reviews experimental and theoretical work on Bose-Einstein condensation in
quantum magnets. These magnets are natural realizations of gases of interacting bosons …

We synthesize and study single crystals of a new double-perovskite Sr 2 YIrO 6. Despite two
strongly unfavorable conditions for magnetic order, namely, pentavalent Ir 5+(5 d 4) ions …

Haldane topological materials contain unique antiferromagnetic chains with symmetry-
protected energy gaps. Such materials have potential applications in spintronics and future …

The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the
macroscopic scale: the best-known examples are Bose–Einstein condensation and …

We discuss designer Hamiltonians—lattice models tailored to be free from sign problems
(“de-signed”) when simulated with quantum Monte Carlo (QMC) methods but which still host …

The microscopic origins of emergent behaviours in condensed matter systems are encoded
in their excitations. In ordinary magnetic materials, single spin-flips give rise to collective …

In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose–
Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into …

We report on magneto-optical studies of the quasi-two-dimensional van der Waals
antiferromagnet FePS3. Our measurements reveal an excitation that closely resembles the …