Electron microscopes can reveal details at the atomic scale, but getting that level of detail can require many electrons, which can damage sensitive samples. A team of researchers in Austria has developed a method that uses a quantum computer to process information carried by individual electrons, potentially allowing useful signals to be extracted from fewer electrons.
Connecting electrons to a quantum computer
In a conventional electron microscope, electrons are used to create an image of a very small object. The electrons also carry quantum information, but simply counting them does not make use of all that information.
The new approach is designed to capture more of what each electron carries. Researchers from TU Wien, the University of Vienna, JKU Linz and the University of Innsbruck propose coupling the electron beam to a quantum computer.
The key is an interaction between the electrons and ions held in place along the electron beam’s path. This interaction can create quantum entanglement between an electron and the quantum computer. Once entangled, the electron and the ion share a joint quantum state.
The quantum computer can then retain information about that electron as the next electron passes through and interacts with it.
Combining information from multiple electrons
The researchers developed quantum-computing operations that can be applied as successive electrons interact with the system. These operations are designed to combine information from several electrons in a way that produces a stronger signal while using relatively few electrons.
That matters because some samples cannot tolerate being exposed to large numbers of electrons. The researchers specifically point to biological samples such as individual proteins as an example of material that can be damaged by exposure to many electrons.
In the proposed system, the electrons would still do the basic imaging, just as they do in a conventional electron microscope. The difference is that their quantum information would also be processed by a quantum computer.
According to the researchers, information that would previously have been indistinguishable from random noise could instead become a clear signal.
The advantage comes from quantum effects
The researchers’ mathematical analysis demonstrates advantages from the proposed method. Their work is based on quantum effects that cannot be obtained through classical electron counting alone.
The approach is intended to overcome statistical limits that constrain conventional electron microscopes by making more information available from each electron.
The algorithms needed for the method were developed in collaboration with a team led by Johannes Kofler at JKU Linz.
The microscope is now being built
The work has so far demonstrated the method mathematically. The next step is to test it experimentally.
At TU Wien’s University Service Center for Transmission Electron Microscopy, an ion-based quantum computer developed by Philipp Schindler’s team at the University of Innsbruck is being integrated into an electron microscope.
The project brings together expertise in quantum information, quantum computing and electron microscopy from several Austrian universities.
The study was accepted for publication in Physical Review Letters and is currently available on the . arXiv preprint server.
