21 July 2022

Annabelle Bohrdt and Benjamin Merkel win the MCQST PhD Awards 2021

The MCQST PhD Award honors the best PhD theses in quantum science and technology selected from the MCQST community. The prize highlights and recognizes excellence in research at an early career stage, and aims to encourage awardees to pursue a future career in science. MCQST considers outstanding theses in the field of quantum science and technology (grade: summa cum laude) from the disciplines of physics, mathematics, computer science, electrical engineering, material science, and chemistry from both, LMU and TUM.

From the submitted theses, the jury selected and awarded two outstanding works in 2021:

• "Probing Strongly Correlated Many-Body Systems with Quantum Simulation" by Annabelle Bohrdt (TU Munich)
• "Enhancing the Emission and Coherence of Erbium Dopants" by Benjamin Merkel (MPI of Quantum Optics & TU Munich)

The award ceremony took place during the Munich Conference on Quantum Science and Technology 2022 in Sonthofen on Wednesday, July 6th. Alongside the recognition of their excellent scientific work and contribution to the MCQST scientific community, the award consist of €1500 each, generously donated by TOPTICA Photonics AG.

Annabelle Bohrdt

Probing strongly correlated many-body systems with quantum simulation

TU Munich

In the past two decades, quantum simulation experiments have been established as a valuable tool in the exploration of strongly correlated quantum many-body systems, which are generically extremely hard to simulate classically. During my PhD, I have contributed to this field by developing:

• new measurement schemes for quantum simulators, for example to measure out-of-time ordered correlation functions or the spectral function;
• a detailed theoretical description of a single hole in a quantum antiferromagnet, which we have tested thoroughly in numerics and experiments;
• conceptually new analysis tools, for example pattern recognition algorithms and machine learning techniques, to extract all possible information from experimental data from quantum projective measurements.

Benjamin Merkel

Enhancing the Emission and Coherence of Erbium Dopants

MPI of Quantum Optics & TU Munich

Connecting quantum devices over long distances via photonic links is much sought-after since it would enable both quantum secure communication and distributed quantum computation. Among potential candidates for network nodes, Erbium doped crystals stand out because they provide an optical transition at a telecom wavelength and long coherence times at liquid-helium temperature, while offering the technical simplicity of a solid-state system. In my doctoral research, I investigated how the optical and spin properties of Erbium dopants could be enhanced further. In one part, I gained coherent control over an ensemble of Erbium spins and increased their coherence by dynamical decoupling of dipolar interactions – supported by a thorough theoretical analysis. In a second part, I increased the photon emission rate and extraction efficiency by embedding the crystal in an actively stabilized optical resonator.

Combining the results from both parts of my research brings us closer to a practical realization of large-scale quantum network.

“As a PhD student I started with an empty lab and had the pleasure to fill it year after year with more exciting experiments and top-notch technology, while at the same time I could gain increasing knowledge of fascinating physics: it was a great experience to work at an excellent institute associated with MCQST and I highly appreciate that my doctoral research has been honored with this year’s PhD Award.”

Congratulations to Annabelle and Benjamin and all the best for their future!