Faculty Candidate Symposium on Quantum Condensed Matter Physics and Chemistry

Abhishek Banerjee TITLE: Quantum Probes of Correlated Electrons in Flatland ABSTRACT: A central problem in modern condensed matter physics is the understanding of electronic behavior in the presence of strong electron-electron interactions. A deeper understanding of this problem has fundamental implications for high-temperature superconductivity, fault-tolerant quantum computing, and many-body quantum mechanics. However, despite extensive research, a complete understanding of the problem remains out of reach. In this talk, I will discuss how modern quantum materials such as superconductor-semiconductor hybrids, graphene, and two-dimensional semiconductors are enabling us to realize highly tunable correlated quantum systems from the ground up. At the same time, I will show how quantum technology tools such as microwave resonators, mesoscopic charge sensors, quantum point contacts, and superconducting quantum circuits can be integrated with these materials, providing access to quantum properties such as superfluid stiffness, quantum geometry, collective modes, and even individual quantum states at an unprecedented level. This combination of quantum materials and quantum technologies opens up a powerful new approach to pin down the emergent properties of correlated electrons and has direct implications in our search for materials that enable quantum computation that is intrinsically “protected” from noise and decoherence. Nikola Maksimovic TITLE: Quantum sensing of emergent phenomena in materials ABSTRACT: Interactions between particles in a many-body quantum system can lead to emergent collective phenomena. This is particularly evident in the solid state, where electrons in a solid can exhibit a wide variety of collective properties, from magnetism to superconductivity, depending on the structure and chemistry of their host material. The newest frontier in this landscape involves emergent phenomena in materials — quantum liquids, spin-charge separation, and quantum criticality in metals, among others — that challenge our existing frameworks of many-body quantum physics. Experimentally testing the evolving theories in this frontier requires advancements in both the design of the host materials, and the development of new techniques to probe their emergent physics. I will describe how synthetic techniques can be used to tune the interactions, symmetries, and dimensionality governing the electrons in a material to realize desired emergent phenomena, and how quantum sensors can be leveraged as a unique nanoscale probe of these systems. In particular, I will describe an example in which we use the coherence properties of color centers in diamond to detect signatures of a hydrodynamic spin mode in an atomically-thin magnetic insulator. The integration of materials synthesis and quantum sensing techniques has the potential to not only shed new light on existing problems like high-temperature superconductivity, but also to raise new questions about how many-body quantum systems can be used to store, process, and transmit the quantum information generated by the sensor.