Gapped momentum states

Understand

Important properties of a particle, wave or a statistical system depend on the form of a dispersion relation (DR).

• Two commonly-discussed dispersion relations are the gapless phonon-like DR and the DR with the energy or frequency gap.
• More recently, the third and intriguing type of DR has been emerging in different areas of physics: the DR with the gap in momentum, or $k$-space.
• It has been increasingly appreciated that gapped momentum states (GMS) have important implications for dynamical and thermodynamic properties of the system.