2021/09/09(Thu)
14:00 -15:00
五樓第一會議室 5F, 1st Meeting Room
視訊演講 Video Seminar [ Meeting Link / ID: 2510 626 7337 / Password: 123456 ]
Title
Controlling Macroscopic Quantum Systems with Light
Speaker
黃晟維博士 (Max Planck Institute of Multidisciplinary Sciences) Dr. Cheng-Wei Huang (Max Planck Institute of Multidisciplinary Sciences)Abstract
In this talk I will discuss two of my works in quantum materials and quantum computing. The first topic (experiment) concerns 2D charge-density-wave quantum materials. In the past decade, there have been numerous experimental evidence of the quantum hidden state of charge-density-wave systems, including a sudden drop in resistivity and an emergent mosaic STM pattern. However, there has not been any direct low-energy electron diffraction (LEED) pattern proof of the hidden state. We successfully constructed the world’s first Ultrafast-LEED and obtained the LEED image of the hidden state. Single-shot ultrafast laser was used to quench a tantalum disulfide (1T-TaS2) sample to produce a non-equilibrium quantum phase transition that leads to the hidden state. Our LEED image reveals that chiral symmetry of charge-density waves plays an importance role in hidden-state formation.
My second topic (theory) discusses how universal quantum control can be attained for particles that are without isolated energy levels. Conventional quantum computing schemes rely heavily on isolated energy levels, so they are limited to only a handful of platforms like atoms, Josephson junctions, etc.. Through destructive quantum interference in the transition amplitude, we are able to transform a generic multilevel harmonic oscillator into an effective two-level system, i.e. qubit. This could have important application in extending quantum control protocols to heavy particles such as trapped macromolecules and nanoparticles, thus pushing quantum computation to the macroscopic limit.
Abstract
Language
演講語言 (Language): in English
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