Seminars

Coupling Electronic Structure Theory with Machine Learning for Chemical Applications

Abstract: Our recent efforts on the development of new computational methods that couple quantum chemistry with machine learning will be discussed. First, a novel molecular fingerprinting method based on persistent homology, an applied branch of topology, that can encode the geometric and electronic structure of molecules for chemical applications will be presented. We have demonstrated its applicability on studies on non-covalent interactions between functional...

Title: Magnetic properties of NdTiO₃/SrTiO₃ interfaces and broader implications

Abstract: SrTiO₃-based thin-film heterostructures are a powerful platform for studying a wide array of electronic phases in two dimensions, at high carrier densities. I will discuss our low-temperature electronic transport studies of NdTiO₃/SrTiO₃ interfaces, which reveal an interplay between local ferromagnetic order, Kondo scattering and spin-orbit coupling. As the magnetic field angle is gradually tilted away from the sample normal,...

Quantum-Size Supported Nanoclusters as Optimal Catalysts Towards Hydrogen Evolution Reaction
 

Contact Rongchao Jin at rongchao@andrew.cmu.edu for more information.

A new experiment to study non-perturbative QED in electron-LASER and photon-LASER collisions

Abstract: The LUXE experiment (LASER Und XFEL Experiment) is a new experiment in planning at DESY Hamburg using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical LASER and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the optical LASER and high-energy secondary photons. The physics objective of LUXE are processes of Quantum Electrodynamics (QED) at the strong-field...

Abstract

Quantum information theory, a multi-disciplinary area of quantum physics, computer science, and mathematics, aims at understanding the theoretical underpinnings of quantum sciences that enables quantum computing and communications. Crucial to successful exploitation of the quantum revolutionary advances is the understanding of the non-classical phenomena of quantum entanglement. In this talk, we study the entanglement of quantum bipartite model and its applications to quantum information processing. 
 
In the first part of the talk, we discuss our...

The experimental observation of superconductivity in doped semimetals and semiconductors, where the Fermi energy is comparable to or smaller than the characteristic phonon frequencies, is not captured by the standard lore. In this talk, I present a mechanism for superconductivity in low-density three-dimensional Dirac materials that are close to a ferroelectric quantum critical point. I show that while the Coulomb repulsion between electrons is strongly screened by the lattice polarization near the critical point, the electron-phonon coupling is significantly...

Demonstrating quantum advantage using near-term, noisy intermediate-scale quantum (NISQ) processors is a topic of keen interest in quantum computing. In laser communication systems that operate in the quantum-limited weak signal regime, such as deep-space optical communications, it has been rigorously proven that there exists a fundamental gap in terms of capacity and decoding error probability between conventional receivers that detect received modulated optical pulses one at a time, and "joint detection" receivers that collectively process optical pulse sequences (codeword blocks) in the...

Quantum materials host a vast array of emergent electronic phenomena, including high-temperature superconductivity, topological properties, and nanoscale charge / spin ordering. One of the challenges is to be able to precisely and deterministically manipulate their properties. To achieve this control, we employ molecular beam epitaxy (MBE) to synthesize artificial quantum materials with atomic layer precision, combined with angle-resolved photoemission spectroscopy (ARPES) which provides direct insights into the electronic structure. In particular, I will focus on...

Title: Molecules in a Hurry to Escape Antiaromaticity

Abstract: Antiaromatic molecules, unless kinetically trapped, fused to aromatic frameworks, or stabilized by chemical modifications, often are short-lived and difficult to work with experimentally—they always find ways of escaping the state of being called “antiaromatic.” Cyclobutadiene, cyclopentadiene, pentalene, and other cyclic, π-conjugated compounds, with formal [4n] ring π-electrons, easily dimerize to get rid of antiaromaticity. Upon irradiation, benzene rather isomerize to fulvene and...

This talk will attempt to answer the question, "Why Should Engineers Care about Quantum Computation." In the talk, I will lay out key concepts and potential uses of quantum computers in quantum simulation and computation. As part of the discussion, I will emphasize the urgency of building a quantum-ready workforce, highlighting the relevance of training in engineering for building the physical quantum computing systems and understanding their potential applications. I will not assume knowledge of quantum mechanics and quantum computation, and will take a systems...