The research on the physics of quantum dot spin optics has progressed

Professor Wu Kaifeng and his team have made progress in the research of quantum dot spin optical physics, and are the first to realize the spin-coherent manipulation
of colloidal quantum dots prepared by low-cost solution method at room temperature.
The relevant research results were released
in Nature Nanotechnology on December 20, Beijing time.

This study demonstrates the feasibility of quantum bit manipulation of colloidal quantum dots prepared by low-cost solution method at room temperature, which is of great significance
in quantum information science and ultrafast optical coherent manipulation.
"The key to the success of this work is the deep cross-integration
of physics and chemistry.
We can achieve precise chemical synthesis of colloidal quantum dots, and can also adjust its material properties on demand, and finally successfully apply the physical method of quantum state coherent manipulation to the system
.
Wu Kaifeng introduced
.

Quantum information technology is a key part
of quantum research.
The coherent manipulation of spin qubits in solid materials is one of the
important ways to realize quantum information technology.
"Qubit-based information processing is expected to be significantly faster than classical bits
.
This is one of the reasons why quantum information technology has attracted a lot of
attention.
Wu explained that qubits need to find suitable carriers and maintain long-lived quantum coherence
.

At present, traditional spin solid-state carriers mainly include epitaxial growth quantum dots and "point defect" materials
similar to diamond color centers.
Spin manipulation of epitaxial growth quantum dots generally needs to be performed
below the liquid helium temperature (-268.
9°C).
Therefore, if the spin-coherent manipulation of low-cost materials can be realized at room temperature, it will have a profound impact
on the development of quantum information technology.

Wu Kaifeng's research team has a good interdisciplinary background, and on the basis of the above physical research methods, they envisage combining chemical knowledge with its ingenuity: if quantum dots comparable to expensive "point defect" materials are found in chemical solutions at room temperature, then the problem will be solved
.

Colloidal quantum dots became the team's preferred research direction
.
The research team prepared the single-hole spin polarization state of perovskite quantum dots, and obtained hole spin
in the order of 100 picoseconds at room temperature.
After determining the carrier, the research team used the femtosecond laser ultrafast spectrum to achieve ultrafast quantum state coherent manipulation
.