Simulation of Multi-Component Fermionic Quantum Matter Using Oxide Nanoelectronics

该项目旨在构建一种新型量子模拟器，即模拟量子计算机，其中电子之间的可调谐相互作用将用于模拟致密核物质并探测其量子特性。中子和质子是原子核的组成部分，它们是由被称为夸克的基本粒子的束缚态组成的。中子由一个“上”夸克和两个“下”夸克组成，而质子由两个“上”夸克和一个“下”夸克组成。当大型恒星燃烧殆尽时，它们往往会以超新星的形式爆炸。它们残骸的命运取决于原始恒星的大小。大恒星的残骸倾向于坍缩成高密度的中子星，超大恒星被认为会坍缩成密度更大的“夸克”星，超大恒星会坍缩成黑洞。为了给人一种尺度感，中子星的半径通常只有10公里，但质量是10-30个太阳。假设中子星是由处于超流体状态的中子汤组成的；中子的量子简并压力平衡了阻止中子星进一步坍缩的巨大引力。对于非常大的恒星，引力将中子粉碎成它们的组成夸克，而正是夸克的量子简并压力阻止了夸克恒星的坍缩。然而，致密核物质的性质，比如在中子星和夸克星中发现的，在很大程度上是未知的。这个项目将试图通过用固态系统模拟致密核物质来揭开其中的一些谜团。理解多组分费米子系统是一个涉及核物理、中子星物理以及更传统的凝聚态系统的交叉领域。在过去，研究小组已经证明了两种复合氧化物LaAlO3和SrTiO3之间的界面具有许多有趣的性质：(a)界面上的电子密度可以通过STM光刻法重新配置，(b)电子-电子相互作用可以通过控制电子密度来调节，(c)可以形成两个和三个电子的束缚态。下一步，研究人员将结合这些特性，为多费米子束缚态构建一个可重构的量子模拟器。精通这类问题将是开发更通用的“通用”量子模拟器的一个里程碑，它可以广泛地有助于理解量子物质的本质和开发新型量子材料。该项目由物理部量子信息科学项目和材料研究部凝聚态物理项目联合支持。该奖项反映了美国国家科学基金会的法定使命，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 project is aimed at the construction of a new kind of quantum simulator, an analogue quantum computer, in which tunable interactions between electrons will be used to simulate dense nuclear matter and probe its quantum properties. Neutrons and protons, the building blocks of atomic nuclei, consist of bound states of elementary particles called quarks. The neutron is made up of an "up" quark and two "down" quarks, while the proton of two "up" quarks and a "down" quark. When large stars burn out, they tend to explode in supernovae. The fate of their remains depends on the size of the original stars. Remains of large stars tend to collapse into super-dense objects called neutron stars, very large stars are believed to collapse into even denser objects called "quark" stars, and the super-large stars collapse into black holes. To give a sense of scale, neutron stars typically have a radius on the order of only 10 kilometers but a mass of 10-30 suns. It is hypothesized that neutron stars consist of a soup of neutrons in a superfluid state; the quantum degeneracy pressure of the neutrons balances the huge gravitational forces preventing neutron stars from collapsing further. For very large stars, the gravitational forces smash the neutrons into their constituent quarks, and it is the quantum degeneracy pressure of quarks that prevents quark stars from collapsing. However, the properties of dense nuclear matter, like that found in neutron and quark stars, are largely unknown. This project will attempt to uncover some of these mysteries by simulating dense nuclear matter with a solid-state system. Understanding multi-component fermionic systems is a cross-cutting area of inquiry with implications in nuclear physics, physics of neutron stars, as well as more conventional condensed matter systems. In the past, the research team has demonstrated that the interface between two complex oxides LaAlO3 and SrTiO3 has a number of interesting properties: (a) the electron density at the interface is reconfigurable by STM lithography, (b) electron-electron interactions can be tuned by controlling the electron density, and (c) it is possible to form bound states of two and three electrons. In the next step, the researchers will combine these properties in order to build a reconfigurable quantum simulator for multi-fermion bound states. Proficiency in this class of problems would be a milestone in the development of a more general "universal" quantum simulator that can broadly contribute to understanding of the nature of quantum matter and developing novel quantum materials. The project is jointly supported by the Quantum Information Science Program in the Physics Division and by the Condensed Matter Physics Program in the Division of Materials Research.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.