Student Seminar
Name: Mr. Atandrita Bhattacharyya
Title: Room temperature spin coherences generated from a quintet state
Date & Time: Thursday, 09th October 2025 at 4.00 p.m.
Venue: Rajarshi Bhattacharyya Memorial Lecture Hall, Chemical Sciences Building
Abstract:
Unlike classical bits, which are limited to binary states, qubits leverage quantum superposition to dramatically expand their computational capacity. However, this quantum advantage suffers from persistent interaction with the environment, which leads to decoherence. To circumvent this problem, most quantum systems must be operated at cryogenic temperatures, which is a significant technical barrier. While room-temperature alternatives like nitrogen vacancy centres in diamond exist, they suffer from poor control over defect concentration, presenting significant fabrication challenges1.
In my presentation, I will first introduce the concept of Rabi oscillations to illustrate how quantum systems can be coherently controlled and subsequently the mechanisms of dephasing that disrupt this control, necessitating the use of cryogenic conditions. Then I will briefly discuss the spin-structure of a 4-spin system. The core of my presentation will then focus on a recent study by Yanai et al.2, who have developed a novel system using a Pentacene-based Metal-Organic Framework (MOF), to optically generate EPR detected quintet spin coherences, that persist for hundreds of nanoseconds at room temperature, by exploiting a ultrafast internal conversion called singlet fission. Their innovative approach was to engineer a MOF that suppresses the molecular motions responsible for dephasing, while still permitting the crucial dynamics required to generate a correlated quintet state.
References:
1. Smyser, K. E. & Eaves, J. D. Singlet fission for quantum information and quantum computing: the parallel JDE model. Sci Rep 10, 18480 (2020).
2. Yamauchi A., Tanaka K., Fuki M., et al. Room-temperature quantum coherence of entangled multiexcitons in a metal-organic framework. Sci Adv 10, eadi3147 (2024).