Study of entanglement properties and its dynamics in solids using density matrix spectroscopy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01016
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Osaka Metropolitan University (2022-2023); Osaka Prefecture University (2021)
• Principal Investigator: Oohata Goro 大阪公立大学, 大学院理学研究科, 准教授 (10464653)
• Co-Investigator(Kenkyū-buntansha): 溝口 幸司 大阪公立大学, 大学院理学研究科, 教授 (10202342)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 量子もつれ / 密度行列 / 励起子分子 / 量子コヒーレンス / 非線形分光

Outline of Final Research Achievements

We have investigated entanglement properties and dynamics of excitons and biexcitons in semiconductors using Density Matrix Spectroscopy (DMS) technique, achieving the following results:
(1) The dynamics of spin entanglement inherent in biexcitons and the polarization-spin entanglement between photons and excitons were successfully measured for the first time.
(2) We have newly developed frequency-domain DMS. Using this technique, the "frequency entanglement" inherent in biexcitons was successfully measured for the first time. Furthermore, the density matrix and its time evolution of the superposition state of two excitons (heavy hole exciton/light hole exciton) in GaAs multiple quantum wells were measured and the quantum coherence and its relaxation behavior were quantitatively discussed.

Free Research Field

光物性，量子光学

Academic Significance and Societal Importance of the Research Achievements

量子情報技術で特に重要な量子力学特有の性質である，量子もつれや量子コヒーレンスは物質科学を始め様々な分野においても大変重要であるが，分光測定としてこれを明らかにする術がこれまで確立されてこなかった．今回，我々が独自に開発した密度行列分光法により，半導体中の励起子や励起子分子についてこれら量子もつれの物性やダイナミクスの測定が初めて可能となった．この手法は様々な物性測定に適用可能であり，今後の多方面の展開が期待できる．