ニュース＆トピックス
セミナーのお知らせ: Gopal Dixit 氏 (Department of Physics, IIT Bombay, Powai Mumbai India)
以下のとおりセミナーを開催いたします。皆様のご参加をお待ちしています。
UTriplセミナー
・PSCセミナー
・IPSTセミナー
・ALICeセミナー
CIAiSセミナー
・XPSセミナー
TACMIコンソーシアムオープンセミナー
Q-STEPセミナー
日時：２０２３年３月６日（月）14:00～15:30
場所：東京大学工学部3号館4階439号室(34講義室)(事前登録制）
講演者： Gopal Dixit 氏
(Department of Physics, IIT Bombay, Powai Mumbai India)
講演題目: Graphene under Ultrafast LASER: An avenue for Quantum Technologies
Abstract
Analogues to spin, electrons in graphene endow an additional quantum attribute: valley pseudospin, which is associated with the two degenerate valleys in the energy landscape of graphene. Similar to 0 and 1, two valleys can be seen as two units of operations. Not only that, operations in between the two units, i.e., the superposition of 1 and 0, can also be realised using two valleys. Thus, these valleys have potential to encode, process, and store quantum information at room temperature — A holy grail for quantum computing.
In this talk, I will discuss how valley-selective excitation in graphene with zero bandgap can be achieved by an all-optical means. Ultrashort laser pulses are employed to obtain a desire control over valley polarisation. By tailoring the waveforms of the laser pulses to the symmetry of the graphene’s sub-lattice, first I will demonstrate that it is possible to induce and read valley polarization in graphene — a medium where light-driven valleytronics was thought to be impossible. In the later part of this talk, I will show a coherent protocol to initiate valley-selective excitation, de-excitation and switch the excitation to another valley within tens of femtoseconds. Coherent switching of electronic excitation from one valley to another on a timescale faster than the valley decoherence is quintessential for valleytronics-based emerging quantum technologies at ambient conditions.
[1] M. S. Mrudul et al., Optica 8, 422 (2021).
[2] M. S. Mrudul and G. Dixit, J. Phys. B 54, 224001 (2021). (Invited article for Emerging Leader 2021).
[3] N. Rana, M. S. Mrudul and G. Dixit, Physical Review Applied 18, 064049 (2022).
[4] N. Rana and G. Dixit (Under review).
使用言語：English/英語
紹介教員：石川 顕一
本件連絡先：
申込方法：Google forms（下記）にて参加の申し込みを行ってください。
3月3日17時までに参加登録完了のご案内をご登録頂いたアドレス宛に送付します。
会場が密にならないよう、規定人数に達した場合は申込を終了させていただきます。
https://forms.gle/Xp1A7RkxTN9BNPnA8
※本セミナーはオープンですが、記録のため参加者のお名前、ご所属、メールアドレスをいただいております。