Events on Thursday, November 30th, 2023
- R. G. Herb Condensed Matter Seminar
- Coupling an Andreev spin qubit to a transmon
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Angela Kou, UIUC
- Abstract: While there are multiple platforms for implementing qubits, no single type of qubit currently excels at every task necessary to build a quantum computer. Some platforms are better-suited as quantum memories while others may be better for quantum operations. Recently, it has been suggested that building hybrid quantum systems that can harness the benefits of different platforms may be a useful model for a quantum computer. In this talk, I will discuss the advantages and challenges associated with coupling superconducting qubits to semiconducting spin qubits. These two leading platforms have complementary benefits; semiconducting spin qubits have long lifetimes but are difficult to couple over long distances while superconducting qubits can be coupled over long ranges but have shorter lifetimes. I will show our experimental work implementing an Andreev spin qubit (ASQ) and then coupling it to a superconducting transmon [1]. I will also discuss our work using a superconducting transmon to investigate mesoscopic superconducting phenomena such as the anomalous Josephson effect and the phase diagram of a superconducting quantum dot system [2,3]. [1] M. Pita-Vidal et al., Nature Physics, 19, 1110 (2023) [2] A. Bargerbos et al., PRX Quantum 3, 030311 (2022) [3] A. Bargerbos et al., PRL 131, 097001 (2023)
- Host: Maxim Vavilov
- Astronomy Colloquium
- Studying the Evolution of Radio Galaxies With the VLA Sky Survey
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Yjan Gordon, UW-Madison
- Abstract: Active Galactic Nuclei (AGN) are a key phase of galaxy of evolution, and understanding the AGN duty cycle is essential for comprehending the mechanisms that drive and regulate galaxy growth. Radio galaxies in particular are well suited to studying the evolution of AGN as the properties of the radio jets can allow for estimates of the age of the AGN. An effective way of studying large numbers of these objects is to use blind surveys of wide areas of the sky. One of the latest such projects, the Very Large Array Sky Survey (VLASS), is currently mapping >80% of the sky with the highest frequency (3GHz) and angular resolution (3'') of any near-all-sky radio survey to date. In this talk I will discuss the latest efforts with VLASS to identify radio-loud AGN at various stages of their evolution. In particular, the high resolution of VLASS is especially well suited to identifying compact radio galaxies, including young AGN that have recently been triggered. By investigating the host galaxies of young radio-loud AGN, we find that high levels of star formation are associated with the most compact radio jets, and I discuss the likely mechanisms driving this result. Finally, I consider some of the lessons learned from the early VLASS data, and directions moving forward into the era of the ngVLA and SKA.
- Host: Ke Zhang