High temperature Bose-Einstein condensation into an excited state at equilibrium

TL;DR

This paper reports on the theoretical prediction of high-temperature Bose-Einstein condensation into an excited state in strongly interacting particles, with potential realization in hydrogen layers at temperatures up to 60 K.

Contribution

It introduces a novel form of Bose-Einstein condensation into an excited state that becomes the ground state at high density, supported by mean field calculations for a graphene-like potential.

Findings

Condensation occurs at temperatures up to 60 K.

Particles hop between layers in the condensed state.

The excited state minimizes interaction energy at high density.

Abstract

We describe Bose-Einstein condensation of strongly interacting particles into a quantum state which is an excited single-particle state, but becomes the ground state as density increases because it minimizes the interaction energy compared to other states. Mean field calculations for a graphene potential just wide enough for two closely interacting layers of molecular hydrogen show condensation at temperatures up to 60 K. In the condensed state, molecules hop between layers, increasing the first peak in the pair-correlation function just past the hard core repulsion diameter.