Seminar

A Pitt-CMU Colloquium

Abstract: This largely historical colloquium is devoted to the evolution of experimental particle physics at colliders from the early 80s to the present, and beyond that to what is expected at the HL-LHC. I will cover my own experience from UA2 (1982-1990) to ATLAS (1984-2022) in some detail, from the discovery of the W/Z bosons at the CERN SppbarS to that of the Higgs boson at the LHC, but I will also use the measurement of the mass of the W boson as a common thread between these two experiments and those at LEP and the TeVatron.

A Pitt/CMU Colloquium

Abstract: For over half a century, high-energy particle accelerators have been a major enabling technology for particle and nuclear physics research as well as sources of X-rays for photon science research in material science, chemistry and biology. We will briefly review recent advances of the accelerator community to increase the energy and improve the performance of accelerators, reduce their cost, and make them more power efficient.

Numerous ideas and proposals of future accelerators were discussed in the course of the “...

Abstract: Quantum computing has been attracting public attention recently. This interest is driven by the advancements in hardware, software, and algorithms required for its successful usage and the promise that it entails the potential acceleration of computational tasks compared to classical computing. This perspective talk presents a short review of quantum computing, how this computational approach solves problems, and three fields that quantum computing can potentially impact the most while relevant to chemical engineering: computational chemistry, optimization, and...

A Pitt Physics seminar

Abstract: The discovery of graphene inaugurated research on the novel relativistic and topological electronic properties of 2D honeycomb quantum materials. One wonders whether other elemental graphene analogues beyond the group 4a elements exist. Motivated by revolutionary exploration of the synthesis and electronic characterization in Xenes, we address whether metallic elements can also embody similar molecular and electronic structures. We find that alkaline earth Ca monolayer (calcene) on Cu(111) indeed forms a new 2D honeycomb...

A CMU-Pitt Colloquium

Abstract: Electrons inside matter can behave as complex particles that do not exist in the Standard Model. These seemingly impossible effects are examples of emergent phenomena—that is, unexpected collective behavior—of electrons in quantum materials. The discovery and characterization of new emergent phenomena in quantum materials not only expand the boundary of our knowledge, but also provide unique opportunities for future quantum technologies. However, these effects often manifest in subtle ways, and thus detecting them requires...

A CMU-Pitt Colloquium

Abstract: Quantum materials host exotic states of matter with unique macroscopic phenomena, ranging from various correlated electron states to topological orders. The ability to manipulate and probe their emergent behavior with nanoscale precision is at the forefront of condensed matter research and underlies the future progress of new electronic and photonic technologies. Polaritonic platforms utilizing hybrid light-matter excitations with extreme light confinement enable a unique form of experimental inquiry into the...

A CMU-Pitt Colloquium

Abstract: With the advancements in quantum materials research, the emergent quantum many-body phenomena, such as competing orders, topological order and fractionalization, can be realized in much more controllable ways. 

However, resolving them experimentally can be challenging. In this talk, I will tell two stories of understanding the emergent phenomena in quantum materials, with setups both in and out of equilibrium. First, I will discuss our theory of the charge orders in recently extensively studied Vanadium based kagomé...

A CMU-PITT Colloquium

Abstract: Quantum materials provide an exciting platform to realize emergent phenomena and topological properties in condensed matter systems. Our ability to synthesize these materials with atomic precision enables us to rationally design quantum structures with tailored properties. In this talk, I will provide examples of such an approach using thin film synthesis by molecular-beam epitaxy that allows access to tuning parameters, such as, interfacial engineering and dimensional confinement, and the creation of artificial...

A CMU-PITT Colloquium

Abstract: The emergence of the two-dimensional (2D) transition metal dichalcogenides (TMDCs) ushers in a new era of light-matter interaction, offering exciting opportunities in quantum information science (QIS). In monolayer TMDCs, the reduced screening enhances the Coulomb interaction and gives rise to strongly bound excitons with the binding energy of hundreds of meV. In addition, the excitons in TMDCs possess a new quantum degree of freedom, valley-spin, which is promising for quantum information processing and can be accessed...

A CMU-PITT Colloquium 

Abstract: Moire heterostructure is an exciting class of highly-tunable platforms hosting various types of strongly-correlated physics. In this talk, I will present two different emergent quantum phenomena arising in this platform: (i) Correlated insulator and correlated semimetal in twisted graphene layers, and (ii) fractional Chern insulators and emergent quantum electrodynamics in Moire materials under magnetic field.

The first part of the talk covers the rich physics of twisted graphene layers originated from multi-flavored...