The world's first programmable optical quantum memory was born, realizing effici

Recently, researchers from Paderborn University and Ulm University in Germany announced that they have successfully cooperated to develop the world's first programmable optical quantum memory. Relevant research results were published in the latest issue of Physical Review Letters.

Photo source: Paderborn University
This year, the Nobel Prize in Physics was awarded to three scientists who have made important contributions to quantum entanglement experiments, which became the focus for a while. Quantum entanglement, in fact, refers to two or more particles in an entangled state in quantum mechanics, some of which behave as a whole even if they are far apart. It is worth mentioning that entanglement systems that can contain multiple quantum particles have significant advantages in implementing quantum algorithms, which may be used for communication, data security or quantum computing in the future.

But in the past, trying to entangle more than two particles would lead to very inefficient entanglement. In some cases, if researchers want to connect two particles with other particles, they need to wait for a long time, because the interconnection that promotes this entanglement only works with limited probability. This means that once the next suitable particle arrives, photons will no longer be part of the experiment, because storing quantum bit states is a major experimental challenge.

Recently, the "integrated quantum optics" team led by Professor Christine Silberhorn of the Department of Physics of Paderburn University and the Photon Quantum System Research Institute (PhoQS) is using tiny light particles or photons as quantum systems. They worked with researchers from the Institute of Theoretical Physics of Ulm University to propose a new method.

The above research team has developed a programmable optical buffered quantum memory, which can dynamically switch between different modes (storage mode, interference mode and final release mode). The new technology works like an entangled "assembly line", in which the entangled photon pairs are generated in sequence and combined with the stored photons.

In the experimental setup, a small quantum state can be stored until another state is created, and then the two can be entangled. This allows a huge entangled quantum state to "grow" particle by particle. The research team entangled 4 and 6 particles with this method, which is more effective than any previous experiment. The success rate is 9 times and 35 times higher than that of the traditional method respectively.

Professor Christine Silberhorn explained: "Our system allows the formation of gradually increasing entangled states - which is more reliable, faster and more effective than any previous method. For us, this is a milestone. We have made amazing progress in the practical application of large entangled states in practical quantum technology."

What's more, this new method can be combined with all common photon pair sources, which means that other scientists can also use this method and benefit from it.

Source: OFweek