Researchers have created quantum superposition states (A new quantum state in semiconductor nanostructures) in semiconductor nanostructures that could be the basis for quantum computing. The trick: two optical laser pulses act like one terahertz laser pulse.
A group of German-Chinese researchers has succeeded in creating a quantum bit in a semiconductor nanostructure. Using a unique energy transition, the researchers created a state of super position in the quantum dot – a small area of semiconductor – in which the electron space at the same time has two different energies.
Such high states are essential for quantum computing. However, the excited state would require a large free electron laser capable of delivering light in the terahertz range. Additionally, this wavelength is long enough to focus light on small quantum dots.
The German-Chinese team has now achieved success with two short-wavelength optical laser cutters equipped with knives.
Feng Liu’s team from Zhejiang University in Hangzhou, together with Dr. Arne Ludwig from the Ruhr University in Bochum and other researchers from China and the UK, report their findings in the journal “Nature Nanotechnology”, published online July 24, 2023.
Lasers cause Auger radiative processes
The team used a so-called radiative Auger transition. In this process, an electron binds to a hole, releasing its energy as a photon and part of it by transferring energy to another electron. The same process can be seen in electron gaps – in other words, empty electrons. In 2021, a group of researchers succeeded for the first time in promoting radiative Auger transitions in semiconductors.
In this current project, the researchers showed that Auger’s radiative method can be very precise: they use two different laser beams with different energies from each other. With the first laser, they excited a pair of electron holes and a quantum dot to create a particle with two holes and one electron. With a second laser, they triggered a radiative Auger process to increase the space in a high-energy state system.
Two states at once
The team uses finely tuned laser pulses to create a state between the ground state of the cavity and a high energy state. So the hole is in both states at the same time. The tension that is doing is the base of the stud is buying, which does not require the state, not only in the state “0” and “1”, but also in two costs.
Hans-Gelgin creates a model of higher and highest and higher levels at the professor of professor of Andreas. In this process, the researchers increased the total number of quantum dots and ensured the high purity of the manufactured material. These methods led to the practice of the experiments of the Chinese partners in collaboration with Jun-Yong Yan and Feng Liu.
Source: Ruhr University Bochum
