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arXiv · 2606.30277

Existence and absence of Bose-Einstein condensation in the interacting random Kac-Luttinger model

C. Boccato·J. Kerner·M. Pechmann·W. Spitzer
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Abstract

In this paper, we study interacting bosons at zero temperature in a random and higher-dimensional continuum model introduced by Kac and Luttinger. For weak interactions we prove that there is condensation in the lowest eigenstate of the one-particle Hamiltonian (type-I BEC). For strong interactions, however, we show that condensation in a localized state cannot occur. We also prove generalized condensation, where a family of eigenstates of the one-particle Hamiltonian is macroscopically occupied as a whole. Combining these results yields a scenario where there is generalized condensation into a family of eigenstates of the one-particle Hamiltonian, but none of them is macroscopically occupied itself (type-III BEC). This proves a transition in the type of condensation. To the best of our knowledge, this is the first rigorous result in this direction for a random continuum model in higher dimensions.

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C. Boccato, J. Kerner, M. Pechmann, W. Spitzer. 2026-06-29. Existence and absence of Bose-Einstein condensation in the interacting random Kac-Luttinger model. https://arxiv.org/abs/2606.30277

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