Simulation of Multi-Component Fermionic Quantum Matter Using Oxide Nanoelectronics

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

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.