1212.6779 (Alejandro M. Lobos et al.)

Phase coherence in one-dimensional superconductivity by power-law
hopping    [PDF]

Alejandro M. Lobos, Masaki Tezuka, Antonio M. García-García

A central result in one-dimensional (1D) superconductivity is that even at zero temperature quantum fluctuations destroy phase coherence. Here we put forward a mechanism which can restore phase coherence: power-law hopping. We study a 1D attractive-U Hubbard model with power-law hopping by Abelian bosonization and density-matrix renormalization group (DMRG) techniques. The parameter that controls the hopping decay acts as the effective, non-integer spatial dimensionality $d_{eff}$. We show analytically that for any $d_{eff}$ > 1 at zero temperature, power-law hopping suppresses fluctuations and induces phase coherence, namely, long-range superconducting order. A detailed DMRG analysis fully supports these findings. These results are also of direct relevance to quantum magnetism as our model can be mapped onto a spin-chain with power-law decaying couplings, which can be studied experimentally by cold ion-trap techniques.

View original: http://arxiv.org/abs/1212.6779