Low-dimensional organic and inorganic superconductors

关于相互作用电子系统中空间维度缩小的影响，普遍存在一个共识：物质的量子力学性质被放大，集体态的范围扩大。这是电子之间相互作用的结果，电子是物质的这些基本成分，在缩减的维度中，电子可以以高度有组织和集体的方式运行。这在几类材料中得到了最好的例证，特别是所谓的非传统超导体，如有机导体、高温铜酸盐、锡酸盐等。它们之所以被称为超导体，是因为除了像汞、铝这样的简单金属在足够低的温度下没有电阻地携带电力外，超导还被发现出现在其他物质状态附近，在这些状态下，电子通过其磁矩或电荷集体排序，例如导致磁性或电荷调制结构。本五年计划致力于从理论上描述广泛类别的低维有机和无机超导体。在这些弱耦合链系统中，通过调节外压或化学成分等参数，相关超导电性可以从与其他物质状态的竞争中产生，如反铁磁性、电荷密度波，甚至是纯粹的一维Luttinger量子液体。这种相模式在许多方面是更广泛类别的非常规超导体的共同特征，本质上受量子力学定律的支配；对它的理解代表着凝聚态物理学的一大挑战。*该项目的一大类目标属于方法论层面，通过进一步扩大重整化小组工具，我们在过去几年中为这些工具开发了丰富的经验。这种方法特别适合于这些相互作用不太强的低维关联超导体。我们认为，在追求这一计划的过程中，我们可以坚定地确定，该方法可以为我们提供具有预测能力的关联低维超导体理论的主要成分。所有的方法论发展都侧重于对实验结果的解释。*

There is a consensus generalis about the impact of reducing the spatial dimension in systems of interacting electrons: quantum mechanical nature of matter is magnified and range of collective states expanded. This is a consequence of interactions between electrons, these elementary constituents of matter, which in reduced dimensions can behave in a highly organized and collective way. This is best exemplified in several classes of materials, in particular the so-called unconventional superconductors like the organic conductors, high-temperature cuprates, pnictides, . They are thus called, because besides carrying electricity without resistance like in simple metals such as mercury, aluminium, at sufficiently low temperature, superconductivity is found to emerge in the close proximity of other states of matter where electrons order collectively from their magnetic moments or their electric charges, leading for instance to magnetism or charge modulated structures.******The present five-year project is devoted to the theoretical description of the broad class of low dimensional organic and inorganic superconductors. In these weakly coupled chains systems, by tuning parameters such as external pressure or chemical constituents, correlated superconductivity can emerge from the competition with other states of matter like anti ferromagnetism, charge-density-wave or even a purely one-dimensional - Luttinger - quantum liquid. Such a pattern of phases, which in many aspects is a common feature of broader classes of unconventional superconductors, is essentially governed by law of quantum mechanics; its understanding represents a major challenge in condensed matter physics. *** One broad class of objectives of the project falls within the level of methodology, by further expanding renormalization group tools for which we have developed extensive experience in the last few years. This method is particularly suited for these low-dimensional correlated superconductors that are characterized by not too strong interactions. We think that in pursuing this program, we can firmly establish that the method can give us the main ingredients for a theory of correlated low dimensional superconductors that has predictive power. All the methodological developments serve to focus on the explanation of experimental results. *** **