Enrico Fermi Fellowship for Laura Roberts

PhD student at AEI Hannover wins generous financial support for cross-training in theoretical and experimental physics.

To the point

• Fellowship: Laura Roberts, a PhD student at the AEI in Hannover, will receive €200,000 over two years through an Enrico Fermi Fellowship.
• Theory and experiment: The fellowship is aimed at cross-training in theory and experiments. It will support Roberts’ work on preparing the first laboratory observation of a 90-year-old theoretical prediction.
• Testing new physics: Measuring the predicted effect or placing stringent limits close to it would test new physics beyond the standard model, including dark matter.

Experimentally testing a theoretical prediction from 1937 known as “vacuum magnetic birefringence” is at the heart of Laura Roberts’ PhD studies. The prediction describes how light interacts at the quantum level with a vacuum under the influence of a magnetic field. Roberts is a PhD student in the “Precision Interferometry and Fundamental Interactions” department at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute / AEI) in Hannover and currently works on site at the Deutsches Elektronen-Synchrotron (DESY) in Hamburg.

Over the next two years, Roberts’ PhD studies will be supported by an Enrico Fermi Fellowship worth €200,000. The funding is provided for salary support, a travel allowance, and research funds for the students’ supervisors.

Observing vacuum magnetic birefringence in the lab

“About 90 years after its theoretical prediction, we want to make the first lab observation of vacuum magnetic birefringence,” says Laura Roberts. “Our collaboration with colleagues at the University of Jena and at DESY will pave the way for a full-scale experiment in 2028 to measure vacuum magnetic birefringence and test new physics beyond the standard model.”

Vacuum magnetic birefringence is an extremely small effect predicted by quantum electrodynamics. This theory describes how light and matter interact at the quantum level and it predicts that the oscillation pattern, or polarization, of light traveling through a magnetic field in a vacuum should rotate slightly. This is due to the magnetic field exciting quantum fluctuations in the vacuum that interact with the light as it passes through. No direct experimental observation of this prediction has ever been made, despite many decades of efforts.

Under the supervision of Felix Karbstein at the University of Jena and Aaron D. Spector at DESY, the work of the fellowship aims to combine a detailed theoretical description of existing unique laboratory infrastructure in the context of vacuum magnetic birefringence and new hypothetical particles alongside upgrades to an ongoing pathfinder experiment.

Vacuum magnetic birefringence at ALPS II

Based on the ongoing work of their successful pathfinder experiment, the research team plans to use a very strong magnetic field, multiple beams of pure laser light, and optical resonators that reflect the light back and forth many times through the magnetic field. All of these components are installed at the Any Light Particle Search II (ALPS II) experiment, which is currently operating at DESY, and are critical for a measurement of vacuum magnetic birefringence.

Currently, ALPS II is searching for a new set of lightweight particles called axion-like-particles. These particles could explain dark matter and other phenomena beyond the standard model of particle physics.  AEI Hannover is a key contributor and collaborator on the ALPS II experiment.

After the final ALPS II science run, the commissioning of a full-scale experiment to observe and measure vacuum magnetic birefringence using the ALPS II infrastructure is expected to begin in 2028. Measuring the effect or placing stringent limits close to it would test new physics beyond the standard model.

The Enrico Fermi Fellowship

The Enrico Fermi Fellowships (EFF) are funded by the John Templeton Foundation and managed by the Center for SpaceTime and the Quantum. The fellowships offer students generous financial support to broaden their horizons through cross-training in theory and experiments. The fellowships are open to students worldwide to promote broad and diverse participation.

The EFF aims to address the growing specialization separating theoretical from experimental training, particularly in physics. Inspired by Enrico Fermi, who excelled in both fields, the fellowships target top-level graduate students interested in fundamental scientific questions who are eager to work on both theoretical and experimental aspects.

Each fellowship provides up to €105,000 per year to support students’ salaries, travel allowances, and research funds for their supervisors.