Research Phase and Master's Thesis in the Physics programs

The recent detection of gravitational waves (GW) with the advanced LIGO/Virgo instruments in conjunction with a short gamma-ray burst (GRB) has surprised gamma-ray astronomers because of the substantially different properties of the GRB  signal as compared to canonical GRBs. This motivates an "open-mind" search for untriggered transient events in the data stream of the gamma-ray burst monitor (GBM) on the Fermi satellite. With two previous Bachelor theses we have developed a physical background model, paving the way for automated searches, and subsequent source and background fitting.
 
This thesis shall be devoted to establishing a Python program for identifying long-term (> few minutes up to a year) transients in Fermi/GBM data, localizing them on the sky, and deriving basic properties (spectrum, light curve). One pot\ential application is to determine the spectral properties of the predicted seasonal variation of the background due to axions. The project includes elements from computational and observational high-energy astrophysics, and will allow for obtaining extensive knowledge on the broad class of high-energy transients. 
 
Some background in astrophysics is advantegeous, but affinity with Python programming is a must. 
 
Contact: Jochen Greiner, jcg@mpe.mpg.de, MPE Room 1.3.13, Tel. 30000-3847

Background:
Microbeam radiation therapy (MRT) is a novel, still preclinical approach for cancer treatment that uses micrometer sized x-ray treatment fields. One of the major obstacles for a clinical application of MRT is the availability of appropriate radiation sources. Currently only large synchrotrons provide the necessary dose rates and radiation quality required for clinical treatments. In our team, we developed a system that generates microbeams for preclinical studies with a conventional x-ray tube. In order to analyze the MRT dose distribution with focus on the effect of pulse and breathing motion, we are currently seeking a motivated and curious master student.

Tasks:
- Design and fabrication of a phantom to analyze effects of motion on the physical dose distribution of microbeams
- Phantom measurement of the motion effects at our preclinical x-ray source
- Possible: Simulation of the motion effects with Monte Carlo (TOPAS)
- Ex-/In-vivo experiments at our preclinical treatment machine with an interdisciplinary team of physicists and biologists
- Possible: Development of in-vivo gating (e.g. ECG or breathing gating) including programming a user interface for our preclinical treatment machine

Profile:
- Genuine interest in medical physics
- Advantage: programming skills (e.g. Matlab, Python, or C++)
- Advantage: wet lab experience

Contact: stefan.bartzsch@tum.de

An essential step for implementation of quantum computing architectures is an efficient readout of qubits. In the field of superconducting quantum circuits, this is typically realized by dispersively coupling a superconducting qubit to a microwave resonator. Then, the frequency of the resonator depends on the state of the qubit. The former can be extracted by probing the resonator with a coherent  tone. However, efficiency of this readout approach is fundamentally limited by quantum  laws. The corresponding threshold is commonly known as the standard quantum limit and bounds quantum efficiency of the readout process by 50%. Nevertheless, recent investigations have shown that it is possible to circumvent this limit and reach quantum efficiency of the qubit readout of 100% by exploiting broadband readout signal combined with Josephson parametric amplifiers.

The goal of this Master project is to build a proof-of-principle experimental setup and perform microwave cryogenic measurements on a superconducting transmon qubit in the broadband regime in order to demonstrate violation of the standard quantum limit in the dispersive readout.

Superconducting quantum circuits form the basis of current quantum processing platforms that allow to run first algorithms. However, to make practical use of coherent quantum systems, there is considerable fundamental challenges ahead: overcoming decoherence of qubits caused by interactions with an uncontrolled environment, improving qubit control to avoid systematic errors, developing scalable multi-qubit architectures while maintaining high level of coherence, or the efficient generation of highly-entangled quantum states in quantum-classical hybrid schemes.

In this project, we plan to design and fabricate high-coherence superconducting microwave circuits (qubits and couplers) that allow for multi-qubit operations and therefore enhance the connectivity of a quantum processor. The characterization of these circuits in a cryogenic microwave measurement setup is an integral part of the project. The master project also consists of fabrication of the circuits using state-of-the-art micro- and nanofabrication techniques.

NUCLEUS is an experiment aiming at the exploration of a new neutrino interaction: coherent elastic neutrino nucleus scattering (CEvNS). This detection channel offers unique possibilities to study the fundamental properties of neutrinos and adresses important questions of modern astroparticle physics. The cross-section of CEvNS is strongly enhanced compared to classic neutrino interactions (by 3-4 orders of magnitude) and therefore allows to drastically reduce the size of neutrino detectors. In Munich we have developed a prototype cryogenic detector that achieved the world-best energy threshold for nuclear recoils of about 20eV, required to exploit the full potential of CEvNS. We’ll install the detector at the CHOOZ nuclear power plant in France, one of the most intense (anti)neutrino sources on Earth. The NUCLEUS experiment is currently being built by an international collaboration lead by TUM, and is funded by the European Commission (ERC Grant), the SFB1258 and the Excellence Cluster ORIGINS. 

We offer an exciting experimental Masters thesis in the framework of the NUCLEUS experiment with a focus on the investigation of backgrounds at lowest energies (<1keV). The origin of the dominating backgrounds in this “new“ energy range are still unknown and its identification is crucial for the success for NUCLEUS and other upcoming CEvNS experiments. The work on the thesis will give insight to low-background techniques, cryogenic detectors and data analysis. The candidate will be fully integrated in the existing research group at TUM and work in cooperation with our international partners. 

Since several decades, multi-stimuli responsive hydrogels are attracting the scientific focus, based on their versatile applicability in the fields of sensoric, drug delivery or nano-switches. When changing an external stimulus such as pH, temperature, pressure or light illumination specific dynamic processes are taking place inside the hydrogel network. Thus, these polymers are an interesting foundation for new research fields such as green architecture or soft robotics. In order to apply responsive hydrogels in the aforementioned technical fields, the mechanisms behind these dynamic processes are an object of current research.

Neutron scattering is a powerful and suitable measurement technique for studying dynamic activities inside a hydrogel. Information about thickness, material composition and roughness can be obtained, even during dynamic processes.

Currently, the European Spallation Source (ESS) is being built in Lund, Sweden. It is envisioned to be the worlds most powerful neutron spallation source and will provide new possibilities in the field of neutron research. In a cooperation between Bielefeld, Darmstadt and Munich a modular sample environment for the SKADI beamline, a small angle scattering beamline at the ESS is under development.

We are currently developing the setup for grazing incidence small angle neutron scattering (GISANS) and as such development is required on the final design and layout of the measurement setup, a quick and reliable sample change system, the electronical circuit and connections to the measurement chamber, a remote-control of all elements, the read-out system.

First measurements with the constructed sample environment will be performed at neutron scattering instruments at the MLZ. Furthermore, the project offers the possibility of collaboration on national and international neutron radiation centers (ILL – Grenoble, ESS - Lund).

Quantum communication using single photons provides one route towards physically secure data transmission. However, the total length of today’s quantum key distribution systems is limited to about ~300km due to photon absorption in the “quantum channel” - typically an optical fiber. To overcome this problem, one can build so-called “quantum repeaters” in which the channel is broken down into shorter segments connected by quantum links. In our group we are working towards building a quantum repeater using optically active semiconductor-based quantum dot molecules.  We aim to make use of trapped pairs of charges – singlet-triplet (S-T) spin qubits.

In the first part of this MSc. project you fabricate a quantum photodiode structure containing coupled quantum dots. This will involve clean-room fabrication, as well as electrical characterization of the fabricated diodes. In the second part, your focus will be on optical characterization of the S-T spin qubits. The goal is to measure exceedingly long coherence times (>>1µs) for special electric fields where the energy gap of the qubit is insensitive to electric and magnetic field fluctuations.

Prior knowledge in optics, clean-room fabrication and programming are helpful – but secondary to high motivation and an open and curious mindset to tackle challenging problems. You will get experience in state-of-the-art nanofabrication, optical spectroscopy at cryogenic temperatures, as well as understanding of semiconductors in the context of quantum information and technology.

Modern quantum circuits allow to study strong light-matter interaction in a variety of systems. This so-called strong-coupling regime is key for many aspects of quantum information processing. This project focusses on strong coupling between a paramagnetic electron spin ensemble and a superconducting microwave resonator. Strong coupling is an established phenomenon in this system. However, many aspects regarding the dynamics of this coupled system as well as the non-linear response properties are not fully understood, yet, and we will address these aspects within this project. For this project, we will use superconducting microwave resonators based on NbTiN and spin paramagnetic spin ensembles of phosphorous donors and erbium centers in silicon.

We are looking for a highly motivated master student joining this project. Within your thesis, you will address questions regarding the dynamic response of a strongly coupled system based on a paramagnetic spin ensemble and a microwave resonator. In this context, you will fabricate and optimize microwave resonators and operate them at cryogenic temperatures. In addition, you will use complex microwave pulses, to control the coupled system and experimentally investigate its dynamical response. Within the project, you will learn how to fabricate superconducting microwave resonators in our in-house cleanroom and how to synthesize microwave pulses using arbitrary waveform generators

You will develop novel integration algorithms in high-dimensional spaces.  Possibilities include various forms of importance sampling algorithms and the further development of the Adaptive Harmonic Mean Integration algorithm using differently chosen volumes for integration.  Test problems will be chosen from physics projects to validate the algorithm.  Good programming skills and knowledge of linear algebra are a pre-requisite for the project.

This project will focus on the potential usage of advanced CT reconstruction algorithms (i.e. model-based iterative CT and CNN-based denoising) for reducing the number of projections in neuro-radiological CT applications. The project will be carried out in close collaboration with the Department of Radiology at the TUM Klinikum Rechts der Isar and an external industrial collaborator.

Character of thesis work: mainly computational physics & image processing

For more information, please contact: Clemens Schmid (clemens.schmid@tum.de), Tobias Lasser (tobias.lasser@tum.de), or Franz Pfeiffer (franz.pfeiffer@tum.de).

This project will explore the use of latest hybrid-pixel photon-counting detectors for improving the image quality in 3D (cone-beam CT) dental imaging applications. More specifically, the project aims at developing advanced dual-energy/ spectral artefact reduction algorithms and their experimental demonstration of their applicability in preclinical experiments. The project will be carried out in close collaboration with an industrial collaboration partner in the Munich area.

Character of thesis work: experimental physics (50%) & image processing (50%)

For more information, please contact: Thorsten Sellerer (thorsten.sellerer@tum.de), Franz Pfeiffer (franz.pfeiffer@tum.de)

Nanoscience can arrange minute molecular entities into nanometric patterns in an orderly manner using self-assembly protocols. For practical applications, it is desirable to support such self-assembled structures on surfaces. With this project we wish to expand the capabilities of self-assembled molecular layers by mimicking the ability of biomolecules, such as proteins, to fold into well-defined conformations.

Therefore, we will investigate the on-surface self-assembly of a series of foldamers: synthetic molecular strands that fold into helices. For controlling the surface deposition in the solid/vacuum interface, we will employ a home-developed electrospray controlled ion beam deposition (ES-CIBD). Scanning tunnelling microscopy (STM) under ultra-high vacuum conditions will be used as a convenient tool to provide real-space information about the molecular adsorption, conformation and self-assembly. The conformation and assembly will be controlled by thermal processing and choice of solid support.

Next generation organic solar cells are solar cells beyond the silicon type photovoltaic devices. Organic solar cells have reached efficiencies in the champion solar cells well above 15%. Key element of such solar cells is the highly designed active layer, which transfers light into separated charge carriers. Aim of this experimental project is the preparation and full characterization of an active layer for high performance organic photovoltaic devices to further understand the fundamental correlation between morphology and solar cell performance. In this work a novel efficiency record-setting system will be investigated regarding the influence of an additional third component, in our case, either solvent additive or polymer. The project will involve a literature review, sample preparation, photovoltaic device fabrication and photoluminescent measurements. The focus is the usage of advanced scattering techniques for the determination of structural length scales of the active layer in the solar cell.

The smaller a device is, the higher its resonance frequency becomes. For our future quantum optomechanics experiments we will be working with mechanical resonators that operate at GHz frequencies and simultaneously couple strongly to light. Using mechanical and optical band structure calculations, you will design, make, and measure phononic and photonic cavities. The project involves nanofabrication in the cleanroom, as well as using the extreme sensitivity offered by on-chip optomechanics. We are aiming for devices made from silicon nitride, which has a lot of tensile stress in it. For micromechanical structures this material gives much better mechanical properties compared to, for example, silicon devices. An important aspect of the project is to understand if this is also true for the high frequency devices.

Hybrid materials combining nontrivial conducting and magnetic properties are of high current interest, especially in the context of potential spintronic applications. The organic charge transfer salts (BETS)₂FeX₄ with X = Cl, Br provide perfect natural structures of conducting and magnetic layers alternating on the single-molecule level. Our project is aimed at a quantitative study of the interaction between the two subsystems and of the role of the subtle structural modifications in this family. To this end, high-precision measurements of quantum oscillations in the electrical resistance and magnetization will be carried out on single crystals of these compounds under strong magnetic fields. The results will be analyzed in terms of electronic correlation and magnetic interaction effects.

Physics: Correlated electronic systems; magnetic ordering and superconductivity; magnetic quantum oscillations.

Techniques: Strong magnetic fields; magnetotransport; magnetic torque; cryogenic (liquid ⁴He and ³He) techniques.

Contact person:  Mark Kartsovnik (mark.kartsovnik@wmi.badw.de)

A common theme in developmental biology and useful feature for synthetic systems is the coupling of patterning processes (cell differentiation) with mechanical processes and cell growth and death. Understanding the interplay of these different processes is crucial to be able to explain development, as well as to manipulate pattern formation processes in  synthetic systems. In this thesis, a well-known model of tissue dynamics will be implemented and coupled to intercellular signaling dynamics in order to answer questions about the stability and robustness of the pattern creation process and the role of initial and boundary conditions. Of particular interest will be the study of feedbacks between the ‘mechanics’ and the ‘information processing’ in these systems.

Bose-Hubbard systems offer an intriguing opportunity of studying quantum driven-dissipative dynamics. Nowadays, these systems can be conveniently implemented by combining superconducting resonators with Josephson junctions. In order to successfully measure nonclassical effects in these systems, such as generation of antibunched light, one needs to accurately quantify their respective frequency range and nonlinearity strength. This goal can be achieved by cryogenic microwave measurements of a Bose-Hubbard dimer with superconducting quantum circuits and numerical modelling of the respective Hamiltonian. These two steps comprise the main body of the current master project. The successful project will potentially lead to a development of robust single-photon microwave sources and further exploration of quantum matter in the form of networks of nonlinear superconducting resonators.

Nano-mechanical strings are archetypical harmonic oscillators and can be straightforwardly integrated with other nanoscale systems. For example, the field of nano-electromechanics studies the coupling of nano-strings to microwave circuits, which resulted in the creation of mechanical quantum states and concepts for microwave to optics conversion. Here, we plan to investigate an alternative hybrid system based on ferromagnetic nanostructures integrated with nano-strings or nano-mechanical platforms. These hybrid devices enable the design and the investigation of spin-phonon coupling down to the single excitation level and are expected to allow the investigation of the Einstein-de Haas on the nanoscale, where the angular momentum change arising from magnetization reversal is transferred into a mechanical vibration of the beam. In addition, these systems are key for the investigation of strong magnon-phonon coupling.

We are looking for a motivated master student for a nano-mechanical master thesis in the context of magnon-phonon interaction. The goal of your project is to investigate the static and dynamic interplay between the mechanical and magnetic properties of a nano-mechanical system sharing an interface with a magnetic layer. In your thesis project you will fabricate freely suspended nanostructures based on silicon nitride or silicon and deposit on them ferromagnetic multi layers using state-of-the-art nano-lithography and metal deposition techniques. Further, you will probe the mechanical response of the nano-structures using optical interferometry while exciting the magnetization dynamics of the magnetic system

The field of magnonics deals with exploiting the collective spin dynamics (spin waves) of magnetically ordered materials for computational purposes. Efficient and scalable schemes for controlling spin waves in thin film ferromagnets thus have large application relevance. The magnetic torques arising due to the spin-orbit interaction allow to control spin waves by electric currents and acoustic waves at GHz frequencies. We are particularly interested in a spatially-resolved study of the interaction of spin waves with acoustic and current-induced torques in nanopatterned devices with application potential for spintronics.

We are looking for a talented and highly motivated master student who is interested in joining our spin dynamics project. During your thesis, you will use state-of-the-art nanolithography and thin film deposition tools to fabricate hybrid devices that allow for the interaction of spin waves with electrical currents and acoustic waves. You will study spin waves in these devices using optical and microwave spectroscopy methods

Nano-mechanical beams are prototype harmonic oscillators, and can be straightforwardly integrated with other nanoscale systems. For example, coupling nano-beams to coplanar microwave cavities yields so-called hybrid electro-mechanical systems with intriguing properties, e.g., electro-mechanically induced transparency. In a similar fashion, ferromagnetic nanostructures can be integrated with nano-beams. This enables the design and the investigation of spin-phonon coupling down to the single excitation level, or nanoscale Einstein-de Haas experiments, in which the angular momentum change arising from magnetization reversal is transferred into a mechanical vibration of the beam. 

We are looking for a motivated master student for a magnetic nano-beam oriented master thesis. The goal of your project is to investigate the static and dynamic interplay between the mechanical properties of double layer nano-beams and its magnetic properties. In your thesis project you will fabricate freely suspended nanostructures based on silicon nitride and ferromagnetic multi layers using state-of-the-art nano-lithography and metal deposition techniques. Further, you will probe the mechanical response of the nano-structures using optical interferometry while exciting the magnetization dynamics of the magnetic system. 

Fault Injection through Laser irradiation is an established attack method in the context of hardwarebased IT-security. Faulty data can be exploited in various ways to break the security measures of an Integrated Circuit. These techniques are referred to as “Fault Attacks”. This project will address fault injection employing a state of the art ultra-short pulse laser system. With semiconductors being inherently sensitive to light, it is feasible to induce transient currents in a chip by irradiation. The goal is to optimize the light source taking into account nonlinear optics to utilize the dominant physics in the best possible way.

The thesis is performed in cooperation with the Fraunhofer Research Institution for Applied and Integrated Security (AISEC) and comprises the following tasks:

                Development of a laser workbench including IR generation.

                Systematic studies of the laser source (focusing, wavelength, pulse duration . . . ).

                Study of the fault injection on a model system.

In optomechanics, light is used to measure and alter the dynamics of mechanical resonators. It is by far the most sensitive method to observe the tiny vibrations that nanomechanical devices perform: in one second one can determine their position with femtometer precision! Using light to measure the mechanics is not the only aspect of optomechanics. The same light can also be used to change the dynamics of the mechanical device through a process called cavity backaction. The photons exert a force on the resonator, the so-called radiation pressure. In this project we want to explore the ultimate limits to this force. The goal is to measure the force originating from a single photon! For this it is required that the photon interacts with the mechanical resonator as strongly as possible. For this we need to the design and make very low loss optical cavities, such as microring resonators. Also, the mechanical device should have a quality factor as high as possible. You will make both the optical and mechanical components from chips with highly-stressed silicon nitride using state-of-the-art nanofabrication in the cleanroom. Then the devices are placed in a vacuum chamber for their measurement. In our highly-automated setup you can very quickly characterize many of the devices on your chip. Then, with the perfect device parameters you can start to explore the more advanced measurements. Initially we can measure the devices in with pulsed light, but by using single photons we want to explore the ultimate limits to optomechanical forces.

See http://www.groups.ph.tum.de/en/qtech/openings/ for a detailed description of this project.

This project will explore the use of latest hybrid-pixel photon-counting detectors for improving the diagnostic accuracy of chest X-ray examinations. More specifically, this work will use dedicated phantoms for assessing the potential clinical benefit of photon-counting-based material decomposition algorithms for better lung cancer and tuberculosis detection. The project will be carried out in close collaboration with the Department of Radiology at the TUM Klinikum Rechts der Isar.

Character of thesis work: experimental physics (50%) & image processing (50%)

For more information, please contact: Thorsten Sellerer (thorsten.sellerer@tum.de), Franz Pfeiffer (franz.pfeiffer@tum.de)

Quantum microwaves emitted by superconducting circuits can be used for distributed quantum computation or improved quantum illumination/radar. You will join the Quantum Flagship activities on the latter, working towards the demonstration of a quantum advantage in a laboratory setting.

Keywords: Quantum microwaves, quantum communication, quantum illumination, quantum radar

Quantum optics is an extremely powerful approach towards quantum communication, quantum sensing, and quantum computing. In particular, quantum information stored in photons has very low decoherence and can be transmitted over large distances through optical fibers. To date, most experiments in quantum optics use optical tables full with mirrors and beam splitters that all have to be carefully aligned and stabilized. This may be good enough for initial demonstrations, but in order to bring quantum science into the realm of quantum technology, a more scalable approach is required.

With our expertise in making photonic chips using advanced nanofabrication, we are making putting these exciting quantum optics experiments on chips. Here, light is routed via optical waveguides. Furthermore, by bending a waveguide, one gets the equivalent of a free-space mirror; a beam splitter cube becomes a directional coupler and so on. By combining these elements, we can make the building block for e.g. an optical quantum computer. With that, the possibilities are almost unlimited.

For such large-scale optical quantum circuits we also want to incorporate single-photon sources, superconducting single-photon detectors, and optomechanical phase shifters. This all happens on a single chip. Making and characterizing the components is the first step and from there on, you are making more and more complex quantum chips. You will be doing the nanofabrication in the cleanroom, and then use our optical measurement setups to see how each device is performing. Depending on your preference, it may also be possible to add a modelling component to the project.

See http://www.groups.ph.tum.de/en/qtech/openings/ for a detailed description of this project.

Nanostructuring of thin films has been utilized as a method for light trapping and enhancing the optical path-length of photons within the absorbing material. Structured surfaces utilize geometries to enforce such routes, which are commonly attained by energy, cost-extensive techniques such as lithography, plasmon resonance. Hybrid perovskites are solution processable materials that exhibit efficiencies competitive with the state-of-the-art silicon solar cells, at significantly lower costs. The precursors exhibit colloidal nature, which makes it possible to tune thin film morphologies by controlling the chemical nature of these precursors by harnessing self-assembly behaviour in drying colloidal dispersions.

Mixed hybrid perovskite thin films will be prepared from colloidal solutions. The solution will be characterized by SAXS, DLS, UV-Vis. Interaction of the solution with substrates will be studied by means of contact angle measurements. Thin films prepared from colloidal dispersions will be characterized by XRD, SEM, AFM, UV-Vis. Solar cells will be prepared and characterized for their photovoltaic response.

Whereas macroscopic sensors made of stimuli-responsive hydrogels are well established, in the nanoworld such sensors still face many challenges. Potential fields of application of such sensors extend from engineering to bioengineering and medicine, e.g. as nanosensors for the control of concentration of glucose for diabetes patients or as switchable surface in the frame of tissue engineering. In this experimental project smart hydrogels, made of stimuli-responsive hydrogels will be investigated. Hydrogel films with thicknesses of a few tens to some hundreds of nanometers and spontaneously deswell or swell due to external stimuli, like temperature or the concentrations of ions. The changes in thickness and in molecular interactions in swelling or collapsing hydrogels will be probed during the switching process by different lab-based techniques. A comprehensive understanding of the switching process can be achieved by complementary neutron scattering experiments at large scale facilities. The project will involve a literature review, preparation of hydrogels, as well as experimental investigations and interpretations of the repeated switching of the stimuli-responsive hydrogels.

Magnon transport in magnetic insulators has similarities and differences compared to the familiar transport properties of their charge counterparts. For example, diffusive transport is a shared feature, while the obvious difference is that charges are a conserved quantity and magnons are excitations decaying with a characteristic lifetime. The aim of this thesis is to obtain a better understanding how to control the magnon transport in magnetic insulators (e.g. yttrium iron garnet). In particular, we plan to focus on heat driven magnon transport properties as well as the control of the magnon conductance by electrical means. Interesting transport observables in this context will be magnon resistivity as well as the investigation of magnon correlation length.

We are looking for a master student interested in magnon transport experiments. In order to answer questions regarding magnon transport in magnetic insulators, your thesis will contain aspects of the fabrication of nano-scale devices using electron beam lithography as well as ultra-sensitive low-noise electronic measurements in a cryogenic environment

More than half of the stars forms in multiple systems. The dynamical interactions between the multiple stars can have a profound influence on the formation and evolution of stars and planets. This, however, is not well understood, especially at the early stages of star formation, due to the difficulty of observing young stars obscured by its surrounding natal cloud. Recent high-resolution ALMA (the Atacama Large Millimeter/submillimeter Array) observations have spatially resolved the emission from complex organic molecules around a very young protostellar binary system [1], also constraining the stellar masses and orbital parameters. The emission from these molecules coincides with features seen in the dust around the binary accretion disks, possibly corresponding to spirals or tightly wound structures. These features are difficult to explain if the emission arises solely due to heating from the forming protostars, the most common scenario used to explain the appearance of warm complex organic molecule emission around protostars. We propose to investigate the role of shocks created by the binary interactions in the production and distribution of molecular tracers at scales from a few up to 100 astronomical units. Gravitational forces from the binary stars can create shocks in the disk surrounding them. Detailed numerical simulations will be needed to investigate the temperature and density structure created by the interaction. This study will shed light on how the binary interactions can influence the chemical inventory in multiple systems at planet formation scales. During this master project, the student will carry out 3D hydrodynamical simulations with the orbital and gas properties observed in the protostellar binary [2]. Detailed thermo-dynamics will be built to investigate the origin of the high temperature and density tracers seen in the gas phase towards this embedded binary system. The student will analyze the spirals or other types of shocks features formed in the simulations, and how it depends on the numerical and physical parameters.

Prerequisites: Basic knowledge in programming (C/C++ and Python will be used).

Contact: Dr. Munan Gong <munan@mpe.mpg.de>, Dr. Maria Jose Maureira <maureira@mpe.mpg.de>, Prof. Dr. Paola Caselli <caselli@mpe.mpg.de>

[1] Maureira et el. 2020, "Orbital and Mass Constraints of the Young Binary System IRAS 16293-2422 A". The Astrophysical Journal 897.

[2] Moody et al. 2019, "Hydrodynamic Torques in Circumbinary Accretion Disks", The Astrophysical Journal 875.

Synchronization is a universal phenomenon that is knows since they days of Huygens. When two or more oscillators with slightly different frequencies are coupled, they will start to move in phase. We can create small mechanical devices using advanced nanofabrication techniques here on campus. By sending light of the right wavelength, they start to oscillate, and when increasing the power the optomechanical coupling synchronizes them. The goal of this project is to synchronize devices made from silicon nitride, which is a special material with a lot of stress in it, and to increase the number of synchronized oscillators. The larger the system becomes, the richer the nonlinear dynamics will become. You will first make the devices in the cleanroom, measure them, and analyze the data.

See http://www.groups.ph.tum.de/en/qtech/openings/ for a detailed description of this project.

Titanium dioxide is a semiconductor widely used in solar cells. To harness the energy of the solar spectrum, it is sensitised with dyes which are bound by single or dual tethers. Most commonly these anchors are carboxylate groups, however catecholates and hydroxamates are also reported as convenient and robust alternatives.

With this project we aim to provide a comparative study on the microscopic events that lead the different tethers to guide the adsorption of molecular dyes on model titania surfaces. Scanning tunnelling microscopy under ultra-high vacuum conditions and at a temperature range of 250 to 350 K will be used as a convenient tool to provide real-space information about the adsorption and diffusion of single and dual anchors on single crystal surfaces of titanium dioxide.

The broken inversion symmetry at the interface of thin film ferromagnets and normal metals with strong spin-orbit coupling can give rise to chiral magnetic order. These chiral magnetic materials show exotic magnetic properties such as a skyrmion lattice phase and have strong application potential for future spintronic devices. For these applications, a detailed understanding of the magnetization dynamics in these materials is required. The goal of this master thesis is to fabricate such thin film multilayer structures using sputter deposition techniques and analyze their dynamic magnetic properties using broadband ferromagnetic resonance spectroscopy.

We are looking for a highly motivated master student to carry out these experiments on interfacial effects in metallic multilayers. In this thesis you will work on the fabrication of these multilayer structures using UHV sputter deposition systems and subsequently determine their magnetic properties using broadband ferromagnetic resonance spectroscopy and SQUID magnetometry

Disorder has a drastic influence on transport properties. In the presence of a random potential, a system of electrons can become insulating; a phenomenon known as many-body localization (MBL) that has been envisioned by the Nobel laureate Phil Anderson. However, even beyond the vanishing transport such systems have very intriguing properties. For example, many-body localization describes an exotic state of matter, in which fundamental concepts of statistical mechanics break down. In this project we will explore these exciting aspects of many-body localization.

Im Rahmen des MADMAX Projektes zur Suche nach dunkler Materie Axionen werden verschiedene
Testaufbauten bei Raumtemperatur und in flüssigem Helium (4 K)
zur Kalibrierung und zur Untersuchung der genauen Signalantwort des
experimentellen Aufbaus betrieben. Es werden Reflektionsdaten Daten
genommen und ausgewertet.

In the frame work of the MADMAX projects several test stands at room tamperature and in liquid helium
for the investigation of the detailled system response and for calibration of the setup are being operated. Reflectivity data will be atken and analyzed.

PEN ist ein industriell hergestelltes Plastikmaterial, das das Interesse als Szintillator für Experimente der Teilchenphysik auf sich gezogen hat. PEN szintilliert im blauen Regime, ideal für viele Photosensoren. Zusätzlich hat PEN exzellente mechanische Eigenschaften. Ausserdem konnte eine sehr extrem niedrige Belastung surch natürliche Radiositope nachgewiesen werden. Dies macht PEN als strukturelles, szintillierendes Material für Experimente zur Suche nach extrem seltenen Ereignissen interessant. In diesem Zusammenhang wurden PEN Platten für das LEGEND200 Experiment zur Suche nach neutrinolosem Doppelbetazerfall hergestellt. Im Rahmen dieser Arbeit sollen die optischen Eigenschaften diser Platten vermessen werden. Es sollen verschiedene PEN Samples mit einem existierenden Messaufbau auf Emissions- und Absorbtionsspektrum, sowie Lichtausbeute und Attenuierungslänge untersucht werden.

PEN is an industrial plastic that  has drawn the interest as a new type of plastic scintillator material. PEN scintillates in the blue regime, which is ideal for most photosensor devices. In addition, PEN has excellent mechanical properties and very good radiopurity has been achieved, which makes it an ideal candidate as an active structural scintillator material in low-background physics experiments. In this context, PEN plates have been produced for use in the LEGEND200 experiment for the search of neutrinoless double beta decay. The goal of this thesis will be the measurement of the main optical properties of PEN. The emission and absorption spectrum, attenuation length, and light output will be measured for several PEN samples using existing setups.

The combination of quantum mechanical calculations and machine-learning techniques has led to massive advances in the high-throughput computational screening of materials and molecules. Here, it is frequently stated that training data obtained from quantum mechanical simulations (e.g. using density functional theory) is 'noise-free', because the calculations can be numerically converged to very high precision. However, this assumes that the self-consistent algorithm used to calculate the Kohn-Sham determinant always converges to the correct ground-state solution, which is by no means guaranteed. The goal of this project is to quantify the noise introduced into DFT data by different choices of intital guess and convergence acceleration. To this end, the true ground-state solutions for a representative set of molecules will be determined using wavefunction stability analysis. This benchmark will allow the development of an effective 'black-box' method for obtaining well-converged training data. Furthermore, the effect of noise on quantum mechanical machine-learning applications will be studied.

The candidate should be interested learning the fundamentals of density functional theory and supervised machine learning. The project will require the development of automated workflows for high-throughput electronic structure calculations and data analysis. Experience with a scripting language (e.g. Python) and UNIX operating systems is advantageous but not mandatory.

Questions about the project can be directed to johannes.margraf@ch.tum.de.