This is because the process generally only works well for one polarisation. Additional elements in the experimental setup are therefore used to split, redirect, and rotate the light’s polarisation. The result is a setup with hundreds of optical components such as beam splitters, mirrors, and lentes – chaotic to the untrained eye, but in fact perfectly coordinated. “Then everything passes through there, gets nicely converted, and both parts come out again with the same wavelength,” Maya summarizes casually. However, she notes that a great deal of effort is required to ensure the conversion to the telecom wavelength works well and with acceptable efficiency. Currently, the efficiency stands at 50 percent, which would already be worthwhile over a distance of three to four kilometers, as Maya emphasizes.

Maya has been working on her frequency conversion setups for about two years. This makes her all the more proud that they now work and are being put to use: “We’re using this in lots of cool experiments now, and I’m really happy that I’m now one of the experts in this field.” Even a major quantum computing company from the U.S. recently asked her for her technical assistance. “It’s nice to see that you’re making an impact,” says the physicist.

Further Challenges

However, simply tuning the emitted photons to the correct wavelength is far from enough to connect two quantum storage devices that are far apart. Another challenge in their experiment is synchronization, as Maya explains: “We have two highly complex laboratories with a huge number of signals. They all have to happen at exactly the right time.” And this has to happen over a very long period of time, because the rate at which the experiment occurs is very low. “We have one successful event every five minutes,” says the doctoral student, “which means that to get enough statistical data, you have to measure for a long, long, long time.” The labs therefore have to remain stable for a long time, even without anyone present. “We usually take the measurements overnight, turn it on once, and hope that everything works.” The better Maya and her colleagues understood the experiment and potential sources of interference, the better the success rate they found the next morning.

For example, they discovered that the elevator in the building causes changes in the magnetic field, which can affect an atom that must maintain its state for a long time. Temperature changes in the ground in which the fiber optic cable is laid can also influence the quantum state. “That’s not a problem in itself, because you can compensate for it,” explains Maya, “but you have to do it regularly.” Every eight minutes, a test light is therefore sent through the fiber to check whether it is stable. “If not, we compensate for it automatically, and then we can continue measuring,” says the doctoral student.

Quantum Repeaters/QMunicate

To ensure that the quantum signal isn’t lost over long distances, Maya is also working on so-called quantum repeaters. Even after being converted to the telecom wavelength, part of the signal is still absorbed by the optical fiber. “You can’t just build a classical repeater that measures, amplifies, and transmits the signal,” Maya explains, “that doesn’t work in quantum physics.” Instead, she says, you need clever protocols with nodes at intervals along the total route, each of which is entangled with the others. This can be continued indefinitely, “like a chain.”

The development and deployment of such quantum repeaters is one of the focus areas of the startup QMunicate, which Maya is currently heavily involved in founding. She developed the idea for the startup together with a colleague from the quantum dynamics group. Together, they participated in IdeaLab, a two-day workshop organized by TUM Venture Labs Quantum/Semicon, which is part of Munich Quantum Valley, and learned what it takes to “turn a cool research idea into a business.” “That’s how we got started,” Maya says, “and then we’ve been thinking a lot and refining it over the past two years.” Things really took off last fall, with continued support from an UnternehmerTUM program: “We participated in XPLORE, which is a three-month program where you learn a lot about business and product-market fit and all those technical terms that physicists aren’t familiar with,” she says with a laugh. Afterward, they took part in a six-month incubation program run by the Max Planck Society, which is set to conclude this month. All that remains now is the formal founding of their company.

“At the heart of QMunicate are once again the optical resonators that our group has been working on for 25 years. These can be used to connect quantum computers with one another,” Maya elaborates on her startup’s concept. “We want to solve the problem of quantum computer scalability by creating a good interface between atoms and photons, thereby enabling the connection of multiple quantum processing units (QPUs).” The quantum repeaters mentioned earlier are also set to play an important role, as are so-called networking QPUs, “essentially QPUs with an internet connection,” which are intended to be connected to one another and to large servers. “So it’s about building the infrastructure, the hardware for a quantum internet,” Maya sums it up.

Maya likes her new role as CEO of the startup more than she would have thought. “I’m still very glad I studied physics and not business administration,” she says; but she really enjoys learning all of this in the context of her own company. “Ask me again in six months, once we’ve secured our first round of investment,” she says with a laugh, “that’s always very stressful.”

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As she completes her Ph.D. and is in the midst of the exciting startup phase, Maya is currently at a turning point in her career. For young researchers who may be deciding on their next step after finishing their master's degree, she has clear advice: “Only pursue a Ph.D. if you're truly passionate about the subject, and definitely not just for the title!” It’s too hard and mentally challenging for that: “It only makes sense if you enjoy it.” She also recommends taking enough time to find a good research group and an exciting topic, ideally changing your topic again after your master’s thesis—“because you can simply learn and gain so much more that way.” Her Ph.D. also had its typical ups and downs: “I was frustrated both in the lab and while writing papers. And I was happy in the lab and happy while writing papers.” And now, well, now it’s almost done.

Published 29 May 2026; Interview 11 May 2026