We show that in superfluids with fermionic imbalance and uniform ground state, there are stable solitons. These solutions are formed of radial density modulations resulting in nodal rings. We demonstrate that these solitons exhibit nontrivial soliton-soliton and soliton-vortex interactions and can form complicated bound states in the form of “soliton sacks.” In a phase-modulating (Fulde-Ferrell) background, we find different solitonic states, in the form of stable vortex-antivortex pairs.

中文翻译：

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费米子不平衡系统中的环形孤子和孤子麻袋

我们表明在具有铁离子不平衡和均匀基态的超流体中，存在稳定的孤子。这些解决方案由径向密度调制形成节点环。我们证明了这些孤子表现出非平凡的孤子-孤子和孤子-涡旋相互作用，并且可以以“孤子袋”的形式形成复杂的束缚态。在调相（Fulde-Ferrell）背景下，我们以稳定的涡旋-反涡旋对的形式发现了不同的孤子状态。