It is well known that superconductivity in quasi-one-dimensional (Q1D) materials is hindered by large fluctuations of the order parameter. They reduce the critical temperature and can even destroy the superconductivity altogether. Here it is demonstrated that the situation changes dramatically when a Q1D pair condensate is coupled to a higher-dimensional stable one, as in recently discovered multiband Q1D superconductors. The fluctuations are suppressed even by vanishingly small pair-exchange coupling between different band condensates and the superconductor is well described by the mean field theory. In this case the low-dimensionality effects enhance the coherence of the system instead of suppressing it. As a result, the critical temperature of the multiband Q1D superconductor can increase by orders of magnitude when the system is tuned to the Lifshitz transition with the Fermi level close to the edge of the Q1D band.

中文翻译：

---

具有准一维带的多带材料可作为坚固的高温超导体

众所周知，准一维（Q1D）材料的超导性受到阶跃参数的大波动的阻碍。它们降低了临界温度，甚至可以完全破坏超导性。这里证明，当Q1D对冷凝物耦合到高维稳定离子时，情况会发生巨大变化，就像最近发现的多频带Q1D超导体一样。即使平均带理论中很好地描述了超导，不同带状冷凝物之间的偶对交换耦合也逐渐消失，从而抑制了波动。在这种情况下，低维效应增强了系统的相干性，而不是抑制了它。结果是，