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New perspective in quantum mechanics and better sleep for PhD students

Besides physics, the sleep of PhD students also benefits from Vitaly Fedoseev's PhD research. He will receive his doctorate on July 7 for his work on optomechanics within quantum mechanics. And also on a setup that eliminated the need for PhD students to push a button every hour for 72 hours.

In Vitaly Fedoseev's field, you usually spend 95 percent of your time figuring out why things don't work as expected and alleviating undesirable effects of vibrations, he says. 'I spent most of my time designing, building and debugging our setup. If all the parts of the setup worked, we were measuring. Probably 5 percent of the time.'

Manipulating vibrating objects

Fedoseev was working on optomechanics, a fairly new area of research in physics. It seems promising for telecommunications and possibly quantum computing and the Internet. Within optomechanics, researchers manipulate objects that vibrate or move around a fixed point (oscillate) with light. Fedoseev: ‘Think of a mirror attached to a spring. With laser light you can measure how the mirror moves, and also influence its movement. The light between the two mirrors creates a kind of bridge through which the movement is transmitted.'

Two mirrors in Vitaly Fedoseev's optical setup, with a transparent membrane in the middle. With light hitting the center of the membrane, researchers can read the motion of the membrane and manipulate that motion as well.

The technique Fedoseev worked on, the STIRAP technique, was developed some thirty years ago to manipulate quantum states of atoms and molecules. Fedoseev first applied it in optomechanics, and successfully. Fedoseev: ‘We have shown that STIRAP transfers energy between two oscillators also in optomechanics.’

Very cold mirrors

For real applications, optomechanical STIRAP would have to take place in the quantum regime, where the mirrors are so cold that their motion is governed by the natural laws of quantum mechanics. Fedoseev took a spectacular step in that direction. 'We designed and built a very special optical system that works when you cool it down extremely.' 

A bed on the lab

When you build an optical system, align it and then cool it, the system usually gets out of alignment because materials shrink with cooling. There used to be a solution for this that cost PhD students their night's sleep. Fedoseev: ‘When I joined the research group, the setup had seven motors to keep it aligned during cooling. The process of cooling took about 72 hours and someone had to run those motors once an hour. Two PhD students put a bed on the lab to keep pushing the buttons day and night.... I then asked if we could build a better setup.’

A set up that’s ideally aligned at -273 degrees Celcius

Fedoseev got to work, together with the Fine Mechanical Department, 'with special thanks to Harmen van der Meer.' They designed and built a system that was set-up at room temperature in such a way that when cooled to -273 degrees Celsius it was almost ideally aligned.

The best moment of Fedoseev's PhD research: 'A cooldown where we saw how the optics became better and better aligned as the system cooled down. Nobody believed it was possible.' As a result, it is now possible to manipulate a quantum system efficiently and without broken nights using the STIRAP technique in an optical system. 'That will clarify whether quantum mechanics also works for macroscopic objects and not just elementary particles.' Assuming that is the case, applications in the macroscopic field are getting closer. For example, in the area of memory for quantum computers.

New job with Nobel laureate Wolfgang Ketterle

How does Fedoseev look back on his research? 'I enjoyed it very much: I like to build things with my hands. Designing and building mechanical and electronic systems, including programming microprocessors, was a great experience. Now I can say with conviction that I am a physicist.' They thought so too at MIT, the Massachusetts Institute of Technology, one of the most prestigious technical universities in the world. There, Fedoseev will work under the guidance of Nobel laureate Wolfgang Ketterle in a research group that investigates cold atoms.

Text: Rianne Lindhout

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