Precision Measurements at Extreme Conditions

Course with Participations of Group Members

Offers for Theses in the Group

4pi Magnetometry

Based on our expertise in precision measurements of magnetic fields, we are extending our field of research into magnetic field reconstruction, in particular by measuring the spatial distribution of magnetic fields using sensor arrays.

Spatial monitoring of magnetic fields and reconstructing their sources has an impact in several of our group's research fields, e.g., in better understanding the magnetic field generated by the human heart or in studying magnetic field disturbances in high precision experiments based on spin clocks.

We are seeking a highly motivated student who will, as a first step, design and realize a test setup with a spatial array of magnetic field sensors, develop the multi-channel readout DAQ system, and characterize the test setup.

The performance of the test setup is evaluated in the second part by reconstructing simple magnetic field sources as test cases. For this, a reconstruction algorithm has to be implemented and tested.

Students can learn to work with magnetic field sensors and DAQ systems and develop programming skills.

Please contact Philipp Rößner (philipp.roessner@tum.de) if you are interested!

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

A satellite for sodium spectroscopy in the mesosphere

We are looking for a master thesis student to build the science module for a pico-satellite at a 450 km orbit, to map the magnetic field of the earth at 92 km altitude in the mesosphere through laser spectroscopy of sodium atoms. Large telescopes use laser beams at the sodium wavelength pointing into the sky to generate a bright dot, an artificial star, in the mesosphere through fluorescence of sodium atoms. This dot is used to correct for atmospheric fluctuations to improve imaging. Our project uses this knowledge, but for a different purpose: we mount the laser on a satellite and point downwards to the earth. When the light hits the mesosphere, a bright spot is generated. If the light is modulated at the electron spin resonance frequency corresponding to the magnitude of the earth field, this is a direct measure of the magnitude of the earth’s magnetic field. The thesis work will be the test of the laser system in the lab, generating fluorescence, detecting the fluorescent light with a silicon photomultiplier and prepare components for a space exposure test at the international space station. Here you will learn atomic and particle physics techniques and applications. If you always wanted to build your own satellite and learn how satellite technology works, contact Florian Kuchler (florian.kuchler@tum.de)

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Peter Fierlinger

Building up an electrostatic particle storage ring for fundamental research

At our lab we are currently building an electrostatic particle storage ring, initially for a dark matter search (https://arxiv.org/pdf/2211.08439.pdf). During this year, we are setting up the hardware for the first stage: a 30 kV barium ion source and the whole experimental hardware of the ring with 2 m side length, here in the lab at our chair in Garching. This includes a vacuum system, electrodes for keeping particles on their trajectories and means for monitoring the particle beam. To perform a dark matter search, we polarize the Ba+ with lasers and lock the electron spin precession to the cyclotron frequency of the beam, effectively forming a crazy magnetic field sensor. Dark matter or other exotic physics would modulate the precession, and we can observe this via laser spectroscopy. If you are interested in this project, it’s a great time to join the project: all parts are coming in right now, and there is a lot of different physics to learn and work on. During the course of the thesis, the experiment should be assembled and tested with first particles in the ring. Depending on the interests, the work can be more focused on practical aspects or simulations of the details of the ring. Please contact Chiara Brandenstein (chiara.brandenstein@tum.de) if you are interested!

suitable as

• Master’s Thesis Nuclear, Particle, and Astrophysics

Supervisor: Peter Fierlinger

Dark Photon Search with an Array of Atomic Magnetometers

Atomic magnetometers use non-linear effects in laser-driven electron-spin-resonance in Alkali atoms. Such sensors can measure Femto-Tesla level magnetic fields and have a variety of applications in fundamental physics as well as in applications, for example remote sensing or medicine. In this project we will set up an array of atomic magnetometers, record the ambient magnetic field and analyze it for spurious effects. As the availability of robust and reliable sensors at this quality is rather new, a yet unexplored parameter region for new physics can be investigated in this way. We are in particular interested in ultra-light axion-like dark matter and dark photons. To be sensitive for such this type of new physics, sensors ultimately need to be placed at a remote and electromagnetically silent location. While some of the sensors are already operational, the experimental work will contain reliable operation of several sensors, as well as developing a mechanism to relate the individual channels e.g. by applying artificial reference signals. In contrast to laboratory experiments with individual sensors, here the interesting aspect is the analysis of an array of sensors placed in the ambient earth magnetic field, with correlations between sensors, directional information and new possibilities for background suppression and signal identification, e.g. using independent component analysis. We expect to find new challenges in the analysis, but also a much larger amount of information. The data will be fun to interpret, as almost everything is magnetic at the Femto-Tesla scale! Please contact Peter Fierlinger (peter.fierlinger@tum.de) or Florian Kuchler (florian.kuchler@tum.de) if you are interested.

suitable as

• Master’s Thesis Nuclear, Particle, and Astrophysics

Supervisor: Peter Fierlinger

Hyperpolarized Noble Gases and Fundamental Physics

Electric Dipole Moments (EDMs) of fundamental quantum systems would help explain the excess of matter vs. antimatter in the Universe. At our group we perform such measurements, like previously using the isotope 129-Xe, one of the most precise measurements ever performed, with an energy resolution of 10-44 Joule (https://arxiv.org/pdf/1902.02864.pdf). A new version of this experiment is currently being started. It consists of hyper-polarized 129-Xe and 3-He in the same volume and in a small but extremely well controlled magnetic field. The ratio of the magnetic resonance frequencies of both species is read out with a SQUID detector and analyzed. We are looking for a hands-on student to set up the hyperpolarization apparatus, the first part of the new experiment. It consists of a strong laser to polarize rubidium, which in turn polarizes the noble gases via spin-exchange optical pumping. It is a great opportunity to learn many techniques needed in an experimental physics lab, including useful atomic physics. If you would like to be part of the most precise experiment ever done, please contact Florian Kuchler (florian.kuchler@tum.de)!

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

Magnetic Field Sensing Drone

We are looking for a student to assemble and commission a drone with 5 kg payload, to be used for areal magnetic field sensing. The sensors to be used are two self-oscillating Rubidium magnetometers or optionally fluxgate magnetometers, hanging on drone on a 10 m long cable. By recording GPS data together with magnetic field signals, the sensors can be used as differential probes to provide information about local magnetic field distortions underground. Applications can be (industrial) geology, archeology, finding dud shots or mines. All hardware is here, you can start immediately! Please contact Peter Fierlinger (peter.fierlinger@tum.de) if you are interested!

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

Magnetic fields of fetal hearts

Measuring magnetic fields of fetal hearts inside a pregnant woman is a novel opportunity to develop novel diagnostic methods. Listening to the magnetic fields generated by the muscles of the heart of the fetus is fully passive and non-invasive with a variety of potential future applications. In a collaboration with the Deutsches Herzzentrum München we do perform measurements with pregnant women and currently develop a diagnostic method. As a thesis project, we are interested to investigate in depth the structure of the magnetic signals, which are detected by an array of magnetic field sensors. There is much more information compared to electric signals, in particular directional information and a possibility to reconstruct the signal by developing a model, deduced from a large number of measurements at different positions. The work will include simulations using finite element methods, statistical methods for signal processing, work with humans to acquire magnetic heart data, as well as cutting edge atomic sensing technology. We are looking for a student who is interested to work at this interdisciplinary connection of medicine and physics to explore new terrain in future medical diagnostics. Please contact Lena Wunderl (lena.wunderl@tum.de) or Philipp Rößner (philipp.roessner@tum.de) if you are interested!

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

Optical Atomic Magnetometer

Our group is actively developing optical atomic magnetometers, a type of sensors using light-atom interactions to detect magnetic fields.This approach, sitting on the junction of laser-optics, quantum-optics and atom-physics, offer a wide range of possibilities for undergraduate and graduate students, from theoretical approaches to practical experiments.

Possible thesis projects are: the Characterization of a non-magnetic Optical Atomic Magnetometer Array at the panEDM Experiment (at ILL), the Development of a non-magnetic Free Space Cesium Magnetometer, the Development of an Optical Earth Field Cesium Magnetometer, the Characterisation and Improvement of Cesium Vapor Cells and Upgrading and Characterisation of a Magnetically Shielded Test Chamber for Magnetometers.

Students can learn a variety of skills, such as handling laser optics and different measurement systems, designing sensors, or developing operating and analysis software.

If you are interested or want to learn more on this topic - feel free to contact philipp.roessner@tum.de!

suitable as

• Master’s Thesis Nuclear, Particle, and Astrophysics

Supervisor: Peter Fierlinger

Optical Atomic Magnetometer

Our group is actively developing optical atomic magnetometers, a type of sensors using light-atom interactions to detect magnetic fields.This approach, sitting on the junction of laser-optics, quantum-optics and atom-physics, offer a wide range of possibilities for undergraduate and graduate students, from theoretical approaches to practical experiments.

Possible thesis projects are: the Characterization of a non-magnetic Optical Atomic Magnetometer Array at the panEDM Experiment (at ILL), the Development of a non-magnetic Free Space Cesium Magnetometer, the Development of an Optical Earth Field Cesium Magnetometer, the Characterisation and Improvement of Cesium Vapor Cells and Upgrading and Characterisation of a Magnetically Shielded Test Chamber for Magnetometers.

Students can learn a variety of skills, such as handling laser optics and different measurement systems, designing sensors, or developing operating and analysis software.

If you are interested or want to learn more on this topic - feel free to contact philipp.roessner@tum.de!

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

Precision magnetic field measurements with Atomic Magnetometry

Atomic magnetometers use non-linear effects in laser-driven electron-spin-resonance in Alkali atoms. We develop and work with such sensors, ranging from fundamental particle physics (dark matter searches and time-reversal-symmetry breaking electric dipole moment searches) to applications (novel medical diagnostic methods). Here we look for a motivated student to set up a atomic magnetometer for operation at a remote site on a mountain without human generated noise to search for ultra-light axion dark matter or dark photons. Such phenomena would appear as tiny magnetic signals at the Femto-tesla level and cannot be found in the lab, as they would be shielded by the same electromagnetic shielding, which is needed against human generated noise. The project consists of setting up, testing and characterizing an already operational sensor in the lab and make it run and take data autonomously with batteries. Once it works reliably, it is placed at a silent, remote location on a mountain and records data. Afterwards, the data is analyzed for signs of data matter. Depending on the quality of the data, this relatively new approach can lead to a publication. Please contact Peter Fierlinger (peter.fierlinger@tum.de) or Florian Kuchler (florian.kuchler@tum.de) if you are interested.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Peter Fierlinger

Current and Finished Theses in the Group