High-momentum oscillating tails of strongly interacting one-dimensional gases in a box

We study the equilibrium momentum distribution of strongly interacting one-dimensional mixtures of particles at zero temperature in a box potential. We find that the magnitude of the 1/k4 tail of the momentum distribution is not only due to short-distance correlations, but also to the presence of the rigid walls, breaking the Tan relation relating this quantity to the adiabatic derivative of the energy with respect to the inverse of the interaction strength. The additional contribution is a finite-size effect that includes a k-independent and an oscillating part. This latter, surprisingly, encodes information on long-range spin correlations.

Automated summary

We investigate the equilibrium momentum distribution of strongly interacting one-dimensional mixtures of particles at zero temperature confined in a box potential. We find that the magnitude of the tail of the momentum distribution, characterized by 1/k4, is influenced not only by short-distance correlations but also by the presence of rigid walls. This additional contribution, which includes a k-independent term and an oscillating part, breaks the Tan relation and surprisingly encodes information on long-range spin correlations.