Physics at Virginia

"Quantum information processing based on spins in semiconductor quantum dots"

Dr. Yinyu Liu , Harvard University
[Host: Utpal Chatterjee]

The field of Quantum Information is of great excitement in both fundamental physics and industry. One promising platform for quantum computing is gate defined quantum dot in semiconductors. The greatest limiting factor currently is that delicate quantum states can lose their quantum nature due to interactions with their environment. Other open challenges are to develop methods to entangle quantum bits that are separated by significant distances and can be measured quickly with high fidelity.

Silicon-based materials are promising due to the long lifetimes of electrons’ quantum states, but also challenging due to the difficulty in fabrication and valley degeneracy. I will report a singlet-triplet qubit with a qubit gate that is assisted by the valley states. This work would potentially relax the  design and fabrication requirement for scaling. Moreover, this research field has achieved strong coupling between electron spins and photons in hybrid circuit-QED architecture. Quantum optics, long distance quantum entanglement and communication via photons are promised. To address that, I will present my project on indium arsenate (InAs) double quantum dots (DQD) that are embedded in circuit-QED architecture. We demonstrated the direct evidence of photon emission from a DQD in the microwave regime and further achieved stimulated emission in a similar system. By achieving stimulated emission from one DQD in these works, we invented a semiconductor single atom maser that can be tuned in situ.  I will demonstrate that a semiconductor based quantum dot is a promising platform for quantum information as well as for fundamental physics.

Condensed Matter Seminar
Thursday, November 18, 2021
3:30 PM
Online, Room via Zoom
Note special room.

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Meeting ID: 989 9263 9357   Passcode: 575442

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