Quantum Simulation of an FFLO Superconductor

超导性的发现是20世纪世纪物理学的分水岭，引发了凝聚态物理学的新领域，并使新技术成为可能。 超导性的本质是某些材料在冷却到临界温度Tc以下时成为完美的电导体。 Tc通常低于空气液化的温度。 超导电性背后的机制还不完全清楚，我们也不知道Tc的上限。 我们知道，带电粒子是由各种有效相互作用相互弱结合的电子对。 其中一个被提出的配对机制是“FFLO超导体”，以四个提议者的首字母命名，其中这些对可以在强磁场的存在下存活。 尽管有许多研究，FFLO超导体仍然难以捉摸。 然而，它的存在将使物理学家更深入地了解超导性的内部运作，并将开启新的应用，如超高速电子计算机和磁共振成像（MRI）。 PI将使用量子模拟来实现FFLO超导体的模型，其中超冷原子代替电子，电子在由驻波光制成的周期性晶格中移动。 这种类型的量子模拟忠实地实现了FFLO超导体的模型，并将使PI和学生能够测试理论预测。 预计有几名学生将在PI的这个项目中获得博士学位，其中一些人可能会在创新的初创公司就业，贡献他们的专业知识来开发量子计算的新技术。超导和磁性是电子材料中常见的物质相，它们不共存。 如果库珀对获得有限的质心动量，而不是像超导的标准理论中那样形成零动量对，则FFLO超导体可以适应共存的磁场。 人们认为，FFLO是最有利于在低维，无论是在准一维或二维。 到目前为止，还没有直接的证据表明有限动量库珀对。 PI将通过模拟受到磁场的实际电子材料来解决具有有限动量配对的FFLO状态是否是物质的合法相，其中自旋不平衡的原子费米气体被限制在使用2D光学晶格形成的一维波导的二维阵列中。 晶格势足够弱，使得相邻波导中的原子通过隧道耦合相互作用。 该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The discovery of superconductivity was a watershed moment in 20th century physics, sparking the new field of condensed matter physics, as well as enabling new technologies. The essence of superconductivity is that some materials become perfect conductors of electricity when cooled below a critical temperature Tc. Tc is typically below the temperature where air liquifies. The mechanisms that underlie superconductivity are not fully known, nor do we know the upper limit of Tc. We do know that the charge-carrying particles are pairs of electrons that are weakly bound to each other by various effective interactions. One of the proposed pairing mechanisms is the “FFLO superconductor,” named after the initials of the four proposers, in which the pairs may survive the presence of a strong magnetic field. Despite many searches, the FFLO superconductor remains elusive. Its existence, however, would give physicists more insight into the inner workings of superconductivity and it would unlock new applications, such as ultra-fast electronic computers and magnetic resonance imaging (MRI). The PI will use quantum simulation to realize a model of the FFLO superconductor, for which ultra-cold atoms stand-in for the electrons, which move in a periodic crystal lattice made from standing waves of light. This type of quantum simulation faithfully realizes a model of the FFLO superconductor and will enable the PI and students to test the theoretical predictions. Several students are expected to earn PhD degrees working on this project with the PI, and likely some of these will gain employment at innovative start-up companies contributing their expertise to develop new technologies for quantum computation.Superconductivity and magnetism are phases of matter commonly found in electronic materials that do not coexist. The FFLO superconductor may adapt to a co-existing magnetic field if the Cooper pairs acquire a finite center-of-mass momentum rather than forming zero momentum pairs as in the standard theory of superconductivity. It is believed that FFLO is most favored in low-dimensions, either in quasi-1D or 2D. As of yet, there is no direct evidence for finite momentum Cooper pairs. The PI will resolve whether the FFLO state, with finite-momentum pairing, is a legitimate phase of matter by simulating the actual electronic materials subjected to a magnetic field, with a spin-imbalanced atomic Fermi gas confined to a two-dimensional array of one-dimensional waveguides formed using a 2D optical lattice. The lattice potential is weak enough that atoms in adjacent waveguides interact via tunnel coupling. The resulting domain walls, the definitive signature of the FFLO state, will be directly imaged.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.