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

Our group at the Technische Universität München (TUM) (https://www.denseandstrange.ph.tum.de/) studies the properties of hadronic interactions and their implications for astro-particle physics by means of accelerator experiments. The studies are connected to indirect searches for Dark Matter annihilation or decay products, such as stable Standard Model (anti-)particles in final state: p, anti-p, e+, e-, d, anti-d and others. These searches are currently being performed by several satellite- or balloon-based experiments. In particular, low-energy anti-deuterons are very promising probe for such searches, since cosmic ray-induced background is expected to be low. However, these studies suffer from the lack of our poor current knowledge of inelastic interaction cross-sections of anti-deuterons with matter, which are needed for precise calculation of primary and secondary anti-deuteron fluxes expected near the Earth.

The goal of the here advertised project is to study the inelastic interaction of (anti-)deuterons with matter using the ALICE detector at the CERN LHC. In ultra-relativistic collisions at the LHC, (anti-)deuterons are produced in large amounts, which, together with unique ALICE tracking and PID capabilities, allows one to investigate the inelastic interaction of (anti-)deuterons with the detector material. The idea of the project is to use the ALICE TPC and TOF sub-detectors for (anti-)deuteron identification and the material of the TRD sub-detector located between them as a passive absorption target. As a result, an effective anti-d + A inelastic interaction cross-section can be calculated, where A represents the properties of an averaged TRD material element.

The FRM II is presently testing and will subsequently install a source to produce ultra-cold neutrons (UCN) in the reactor. In the central section of this UCN source, helium is used for cooling. By passing through, the cooling agent helium will be irradiated by neutrons, which create radioactive tritium out of the He-3 portion. This negative side effect can be avoided respectively reduced to a permissible level if isotopically purified He-4 with no traceable He-3 content is used.

Sources for isotopically pure He-4 are scarce and availability varies with market demand. In order to ensure continuous operation of the UCN source the availability must be secured. For this reason such an isotopic purifier shall be build.

In the first phase a smaller illustrator shall be designed and made to prove feasibility and validate the concept. The above master thesis is part to this first phase.

In a second phase a scaled-up apparatus shall be manufactured for operational use.

Contact / Supervisor:

Dr. Andreas Frei, Tel. 089 289 14260, andreas.frei@tum.de

Bereits unsere eigene Existenz gibt einen Hinweis auf “neue Physik”. Die sichtbare Materie besteht aus Teilchen (nicht aus Antiteilchen), sodass während der Evolution des Universums zu einem bestimmten Zeitpunkt diese Asymmetrie zwischen Materie und Antimaterie durch einen bisher unbekannten Mechanismus hevorgerufen worden sein muss. Durch verschiedene experimentelle Daten können wir diese Asymmetrie sogar genau quantifizieren.

Die Emmy-Noether Gruppe “Baryogenese, Dunkle Materie und Neutrinos – Umfassende Analysen und präzise Methoden in der Teilchenkosmologie” unter der Leitung von Dr. Julia Harz befasst sich unter anderem mit der Fragestellung wie wir dem Mechanismus hinter der Baryonasymmetrie näher kommen können.

Im Rahmen dessen biete ich Masterarbeiten zu diesem Thema an:

(1) Eine mögliche Arbeit würde sich mit einem etabliertem, teilchentheoretischem Modell befassen, welches verschiedene offene Fragen (Dunkle Materie, Inflation, Baryogenese, Neutrinomassen etc.) addressiert. Dieses Modell soll mit einem sogenanntem globalen Fit in seinem Parameterbereich eingeschränkt werden. Das Projekt würde in internationaler Kollaboration stattfinden, während sich die Masterarbeit selbst auf den Bereich der Baryogenese fokusieren würde. Für diese Arbeit wären Programmierkenntnisse wünschenswert bzw. die Motivation solche selbständig zu erlernen.

(2) Eine zweite mögliche Arbeit würde sich mit der Möglichkeit beschäftigen, verschiedene Baryogenesemodelle mit Messungen am Large Hadron Collider zu testen. Für diese Arbeit wären fundierte, analytische Kenntnisse wünschenswert bzw. die Motivation sich mit ‘pen and paper’ in Rechnungen einzuarbeiten.

The CRESST (Cryogenic Rare-Event Search with Superconducting Thermometers) experiment operated at the Gran Sasso underground laboratory employs highly sensitive cryogenic detectors to the search for signals of the elusive dark matter particles, a main ingredient of the Universe whose nature is still unknown. 

The energy thresholds reached in CRESST-III are the lowest in the field, making CRESST the most sensitive experiment to light dark matter. Optimisation of the tungsten thin-film thermometers and of the techniques for data analysis promise still improvement in energy threshold, which could significantly boost the physics reach of the experiment.

Scientific topics

A student can contribute to:

- design, production and prototyping of new CRESST detectors in Munich 

- development of high purity crystals 

- development of new software tools for data analysis

- dark matter data analysis

and, if interested, can participate in the operation of the main experiment at Gran Sasso. 

Thesis can be carried out at the Max-Planck-Institute for Physics (MPP) und supervision of Dr. Federica Petricca (petricca@mpp.mpg.de) and/or at the Physics Department.

Chemische Prozesse an Oberflächen wollen verstanden werden. Wir verwenden modernste Methoden der magnetischen Resonanz, um solche Elementarprozesse zu beobachten, bei denen Spins eine Rolle spielen. Untersuchungsobjekte sind hochaktuelle oxidische Materialien für die Photokatalyse, die wir mit Hilfe von elektrisch und optisch detektierter magnetischer Resonanz studieren werden. Sie erlernen die Herstellung und Charaktersisierung dieser Materialien, das Arbeiten mit Kryostaten und Lasern, sowie die Grundlagen und Anwendungen der Elektronenspinresonanz.    

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).

Für die Entwicklung von Theraphieansätzen ist es notwendig, die Wirkung von Medikamenten auf Organe zu untersuchen. Zu diesem Ziel werden inzwischen Organoide verwendet - das sind Organ ähnliche Zellverbände, die in einer 3d Zellkultur wachsen. Trotz der immensen Erfolge, sind ganz zentrale Fragen zu der Entwicklung dieser Strukturen weitestgehend ungeklärt. Im Rahmen der Arbeit sollen die physikalsichen Eigenschaften der Umgebung auf das Organoid-Wachstum untersucht werden. Es werden Mikrorehologische und Mikroskopsiche Methoden entwickelt und verwendet um die Abhängigkeit von Mikro-Umgebung auf Organoidentwicklung zu quantifizieren. 

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

Zur Verbesserung der Effizienz des Myontriggersystems des ATLAS-Detektors am Large Hadron Collider (LHC) werden neue schnelle Triggerdetektoren (Resistive Plate Chambers) gebaut, die sehr hohe Untergrundzaehlraten aushalten und hoehere Lebensdauer und Zeitaufloesung als bisher aufweisen. Die Eigenschaften dieser Detektoren werden in vorhandenen Testaufbauten und im Teststrahl am CERN systematisch untersucht.

The matter produced in ultra-relativistic heavy-ion collisions resembles theQuark-Gluon Plasma (QGP), which is an extreme state of nuclear matterconsisting of deconfined quarks and gluons.  Such a state existed in the earlyUniverse,  just  a  few  microseconds  after  the  Big  Bang.   Its  properties  canbe experimentally accessed by measuring the azimuthal anisotropies in themomentum  distribution  of  produced  particles  in  heavy-ion  collisions—forinstance, in lead-lead collisions reconstructed with the ALICE detector atCERN’s Large Hadron Collider (LHC).Of  particular  interest  in  this  context  is  anisotropic  flow  phenomenon,which is an observable directly sensitive to the properties of QGP. In thisproject, we introduce the basics of anisotropic flow and corresponding anal-yses techniques, and we guide a student throughout all steps needed for itsfinal measurement, in the large-scale LHC datasets distributed on Grid.We start a project by briefly introducing a theoretical framework withinwhich an anisotropic flow phenomenon can be defined and quantified.  Next,we introduce sophisticated multi-particle correlation techniques, which weredeveloped recently by experimentalists particularly for anisotropic flow mea-surements.  We go in detail through the practical implementation of multi-particle correlations (students are expected at this point to perform somesimple analytic calculations, and to learn and perform programming tasksboth in ROOT and AliROOT. ROOT is the object-oriented analysis frame-work written in C++ programming language, and it is used at the moment asa default software in high-energy physics by all major collaborations world-wide, while AliROOT is the more specific analysis framework developed byALICE Collaboration, and which is based on ROOT.)We wind up the project by letting the student do an independent ani-sotropic flow analysis with his/her own newly developed code in AliROOT,utilizing multi-particle correlation techniques, over real heavy-ion collisionsrecorded at LHC, and stored on Grid.The project is open both to Bachelor and Master students.

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.

Neutronsterne sind die dichteste Objekte in unserem Universum und  keiner weiss noch was drin ist.

Es  könnte  nur Neutronen geben oder andere Hadronen,  wie  Hyperonen  ( Baryonen mit mindest  einem Strange  quark), oder man  könnte  sogar ein  Quark GLuon Plasma  dadrin finden.

Diese sehr untescheidlichen Szenarios kann man nur testen, wenn man die Wechselwirkungen zwischen den verschiedenen Konstituenten bestimmt. Wechselwirkungen zwischen  Hyperonen sind bisher nicht genau bekannt und das Themas diese Arbeit ist die Untersuchung der Korrelationen zwischen Lambda und Xi HYperonen.

Es werden Daten benutzt, die von mit dem ALICE Detektor am LHC aufgenommen worden sind und die Aufgabe besteht eine neue Analyse zu entwickeln, die uns erlauben wird verschiedene theoretische Vorhersage zu testen.

 Die Analyse wird in C++ geschrieben und es werden auch Simulationen durchgeführt werden.

Eine Vorkenntis in C++ is willkommen aber nicht notwendig. Experte im Bereiche der Analyse und Simulationen werden die direkte Betreuung der Arbeit übernehmen.

Die Kandidatin/ der kandidat werden die Möglichkeit haben, in Kontakt mit der internationalen ALICE COllaboration am CERN zu kommen.

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.

Für eine zukünftige Messung am CERN Myonstrahl M2 ist die Verwendung eines gasförmigen Wasserstoff-Volumens unter Druck vorgesehen, welches gleichzeitig als Detektorvolumens dient. Ob die gewünschte Genauigkeit im Experiment erzielt werden kann, soll über eine Untersuchung der Ereignisstruktur, insbesondere das Kleinwinkel-Streuverhalten der Myonen und die Abbremsung der Protonen im Gas, nachgewiesen werden.

Neutrinos were discovered in 1956, but only at the turn of the millennium was it experimentally proven that the three known neutrino types can convert into one another. These flavor oscillations are possible only if neutrinos have nonzero mass, which is currently the only established contradiction to the standard model (SM) of particle physics. From tritium beta  decay experiments and cosmological observations, we know that their masses are very small—less than 10^-5  of the electron mass. Neutrinos are the only fundamental spin-1/2 particles (fermions) without electric charge. As a consequence, they might be Majorana fermions, articles identical to their antiparticles. This is a key ingredient of some explanations for why matter is so much more abundant than antimatter in today’s Universe and why neutrinos are so much lighter than the other elementary particles. Majorana neutrinos would lead to nuclear decays that violate lepton number conservation and are therefore forbidden in theSMof particle physics. The so-called neutrinoless double-b (0nbb) decay simultaneously transforms two neutrons inside a nucleus into two protons with an emission of two electrons. The GERDA experiment and future LEGEND-200 experiment are located in the Italian Gran Sasso underground laboratory and are leading experiments in the world-wide competion. 

We offer the opportunity to carry out exciting experimental BSc and MSc theses with focus on liquid argon detector developments, germanium detector developments, data analysis and/or Monte Carlo simulations. You would be fully integrated in the research team and work closely together with our international partners. 

The microscopic foundations of magnetism and related phenomena are very active fields in current research. This is especially true for peculiar configurations such as highly anisotropic materials or magnetic frustration, where the onset of order is suppressed due to the competition of different types of coupling. Rare-earth tetraborides are realizations of such systems. Recently a strong magnetocaloric effect was found in TmB₄ [Orendáč et al., Sci. Rep. 8, 10933 (2018)] which indicates a strong relationship between magnetism and lattice. One can expect technical applications. It is the goal of this thesis to study the lattice excitations (phonons) in TmB₄ using inelastic light (Raman) scattering in an applied magnetic field at the onset of the different phases. The work includes a thorough introduction to spectroscopy, low-temperature, and high-field techniques. Contact: Andreas Baum, Rudi Hackl

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

Zelladhäsion ist zentral für die Funktion von Zellen, kleinste Änderungen in  den Adhäsionsbedinungen führen zu fatalen pathologischen Folgen. Im Rahmen der Arbeit sollen Modellsysteme untersucht werden, in denen die zentralen molekularen Prozesse der Adhäsion nachgebaut werden. Mit Hilfe von Super-Resolutions Mikroskopie und Mikrofluidik sollen dann die phyiskalischen Konzepte identifiziert werden.

NEPOMUC provides the world’s most intense positron beam. The positron is a applied as unique probe for material defect studies, surface investigation and fundamental research in quantum physics. Steering and optimization of the positron beam requires the employment of diagnostic devices capable of determining the position and size of the beam along the transfer line. Ideally such devices should be fast, precise, reliable and inexpensive enough for an abundance of them to be installed along the transfer line.

A possible approach to synthesizing such devices is that of employing Faraday-cups-like charge collectors to partially shield the beam path and to measure the collected positron current as a function of the Faraday cup position. Your job as an applicant will be that of building, with the support of the NEPOMUC team and the physics department mechanical workshop, a working prototype of such device and characterize its performance.

The work will involve the following tasks:

1. Optimizing a proposed design for the device, selecting the proper size and type of electronic and mechanical components according to available technology.
2. Producing the CAD drawing necessary for the manufacture of the device.
3. Supervising the manufacture of the prototype.
4. Characterizing the performance of the device, either with a test beam or directly at NEPOMUC.
5. (Optional) Writing the firmware necessary to run a control board for the device.

As the required task is by its nature extremely interdisciplinary, you are not required to be able to follow through the entire design and construction process by yourself and will, instead, be provided with guidance and tutoring. This is also in accord with the particular importance that we, as an institution, attach to the training aspect during the internship. This said a certain level of autonomy is expected from you.

Das sogenannte Standardmodell der Teilchenphysik beschreibt die sichtbare Welt um uns herum mit äußerster Genauigkeit. Allerdings kann es bisher nur ca. 5% unseres Universums erklären. Weitere 25% bestehen aus sogenannter “Dunkler Materie”. Diese wird nicht nur durch unterschiedliche experimentelle Beobachtungen bekräftigt, sondern ihre Dichte durch die kosmische Hintergrundstrahlung sogar genau quantifiziert.

Die Emmy-Noether Gruppe “Baryogenese, Dunkle Materie und Neutrinos – Umfassende Analysen und präzise Methoden in der Teilchenkosmologie” unter der Leitung von Dr. Julia Harz befasst sich sowohl mit der Fragestellung welche teilchenphysikalischen Modelle Dunkle Materie erklären könnten und wie diese getestet werden können als auch mit der Verbesserung der Präzision der theoretischen Rechnungen zur Dunklen Materie Dichte, eine Observable, die dann mit den experimentellen Ergebnissen verglichen werden kann.

Eine mögliche Masterarbeit würde sich mit der Fragestellung beschäftigen, wie sogenannte nichtperturbative Effekte Einfluss auf die theoretisch vorhergesagte Restdichte haben. Dies kann je nach Interesse im Rahmen verschiedener Aspekte geschehen, wie z.B. durch die Studie eines spezifischen Modells oder auch durch die Entwicklung eines Computerprogramms.

Hybrid solar cells combine an inorganic and an organic component into a photovoltaic cell. They combine the advantages of inorganic materials (e.g. metal oxides: TiO2 or GeO) such as high charge carrier mobility and very high stability with those of organic materials (e.g. conducting polymers: PTB7) such as cost-effectiveness and flexibility. In comparison with standard silicon solar cells, the hybrid solar cells can be easily manufactured and can allow for alternative processing techniques as for example spray-coating and printing. In contrast to dye sensitized solar cells (DSSCs), hybrid solar cell devices contain no dye as active components and consequently problems such as photo-bleaching are mitigated. Moreover, all materials in the hybrid solar cells are solid and thus no sealing to protect against leakage of aggressive solvents such as in DSSCs is required. Regarding application, the hybrid solar cells are more environmentally friendly. Compared to organic solar cells, which are composed purely out of organic components, hybrid solar cells are expected to have higher lifetime stability. In particular, a degradation of the morphology, which is one pathway in organic solar cell degradation, cannot happen in the hybrid solar cells. The inorganic component acts as a corset to the morphology and prevents structural changes. Despite all these advantages of hybrid solar cells, so far most research on alternative solar cells beyond the silicon solar cells, has been focused on DSSCs and organic solar cells. hybrid solar cells have gained much less attention and therefore have a high undiscovered potential, which will be investigated in the present thesis based on novel pathways.

Für eine bestehende Helium Kälteanlage soll ein Simulationsmodell in Matlab® programmiert und getestet werden. Das Simulationsmodell soll zur Regleroptimierung und zur Ausbildung von Anlagenbedienern genutzt werden. Es ist eine Gruppenarbeit von bis zu 2 Studierenden möglich.

Das Thema wird in bewertbare einzelne Arbeitspakete aufgeteilt sein. Neben der Einarbeitung in das Thema der Kern und Teilchenphysik werden Fähigkeiten zur Team-Arbeit in Forschergruppen und Projektmanagement Fähigkeiten für Naturwissenschaftler weiterentwickelt. Die Projektlastenhefte werden gemeinsam erarbeitet

Kontakt: Rainer Stoepler 089/ 28914272 oder 0162 2944773

rstoepler@tum.de

Organic photovoltaic (OPV) technology has seen a rapid evolution over the last decade. The unique selling points of OPVs, such as excellent light harvesting capability, freedom of form, color and transparency, environmental friendliness, easy scalability and lower manufacturing costs based on roll-to-roll printing methods, position this technology for the mobile power market, and this most properly reflects the state of the art in commercialization. An important milestone towards OPV commercialization has been surpassed by reaching a power conversion efficiency (PCE) of up to 17%. The main limitation in OPVs is due to the intrinsic narrow absorption window (~100-200 nm) of polymers compared to inorganic semiconductors such as Si, which makes it challenging to fully cover the solar spectrum with a single junction device. To overcome the absorption limitation, ternary blend organic solar cells represent one of the dominant strategies that has been explored in the last decade. The outstanding advantage of ternary blends consists of maintaining the simplicity of the processing conditions used for single active layer devices. Interestingly, the open circuit voltage (Voc) is tunable depending on the loading concentration of the ternary compound in both ternary systems compromised of i) two donors and one accepter as well as ii) one donor – two accepters blends.

The origin of the composition-tunability of Voc and the optimal electronic correlations between the components remains as an open question in OPV field. Obviously, it is very challenging to develop a complete model for Voc in ternary systems mainly due to the fact that this model should take all the electronic interactions between the components into account and consider their role in the photogeneration. Moreover, the model should be compositional dependent and accounts for the different microstructures and transport mechanisms operating simultaneously in the system. To this end, a semi-empirical method is required to link the electrical characteristics of ternaries to their morphological properties and draw a comprehensive picture from the morphology models reported in literature as the origin of Voc changes in ternary systems.

This project will focus on solving the aforementioned key challenge by employing a semi-emprical method based on kinetic Monte Carlo (kMC). An existing lattice kinetic Monte Carlo model, previously applied to the modeling of binary polymer:fullerrene solar cells, will be extended to treat ternary blends. This will allow us to correlate nano-morphological features with measured optical properties and obtained Voc, a crucial capability for the design of optimized, high performance ternary solar cells. 

Materials for high energy density, solid-state batteries have been tremendously explored in the last decade. In particular, lithium-ion technology has attracted major interest. Among the many different types of batteries, the so-called polymer-based thin film batteries are very attractive as they can be incorporated into thin film devices. An inherent important part of such thin film lithium ion batteries is the membrane and solid-state polymer electrolyte membranes have attracted high attention in this respect. Lithium ions’ incorporation into solid-state polymer electrolyte membranes had shown a significant effect on both, the structure and properties, of the membranes in either the bulk or film format. The morphological reorganization and the thermodynamic properties of the solid-state polymer electrolyte membrane upon adding lithium salts and small molecules are the subjects of the experimental investigation. The polymer membranes will be prepared with printing. The structure and crystallinity of the lithium-doped membranes at different temperatures will be investigated with small/wide-angle X-ray scattering (SAXS/WAXS). The effects of morphology on the ionic conductivity of these ion-conducting membranes will be investigated using impedance spectroscopy. Aim of the present study is to increase conductivity with the help of small molecule additives, which can further improve the membrane morphology beyond the possibilities of the standard approach. Such high conductivity will be very beneficial for further downsizing of polymer-based thin film batteries.

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

2D materials were shown in 2015 to host randomly occurring single-photon emitting sites. Due to unique properties, such as ultimate proximity of the light sources to the surface that result in high photon extraction efficiencies, nuclear spin-free isotopes, valley pseudospin and potential for scalability, 2D materials are extremely promising as building blocks for solid-state photon-based quantum information. They have the potential to overcome the limitations of the current systems as highly sensitive, easily integrable quantum light sources and qubits of the future [1]. However, in current 2D quantum emitters the photon emission energy is random [2]. This prevents photon indistinguishability, a non-negotiable requirement for both fundamental studies and applications. Moreover, the current fabrication process is incompatible with silicon photonics and on-chip integration. To unleash the full impact of 2D materials on quantum science and technology, we are currently attempting a novel fabrication strategy. In the first part of the project, you will realize quantum dots of 2D semiconductors top-down, with dimensions below those achievable through conventional lithography systems, using a combination of etching masks made of colloidal quantum dots and by Helium Ion Beam Lithography followed by Reactive Ion Etching. Such quantum dots will be deterministic, scalable and will overcome the critical limitations of the current solid-state quantum emitters in 2D materials. You will study the optical properties of such quantum emitters at cryogenic temperatures and in the presence of magnetic fields. Further, you will have the option of integrating such quantum emitters and their arrays with optical cavities and waveguides, realizing spin-qubits registers made of arrays of independently charged quantum-dots and studying the effect of interactions among separate quantum emitters placed at a subwavelength distance. No current solid-state quantum dot system satisfies the requirements to do so. 

Some experience in the areas of optics, electronics, programming or cleanroom fabrication will be beneficial, but secondary to your personal motivation and commitment to this fascinating project. You will gain skills and knowledge and probably become an expert in various scientific research tasks, including but not limited to nanoscale cleanroom fabrication and state-of-the-art electro-optical measurements at cryogenic temperatures.

You should: be a highly motivated student with a curious and open mind looking to solve big problems. This is a challenging but potentially ground-breaking project in the framework of quantum science and technology. You will work in close collaboration with a small team of Ph.D. students and a postdoc, therefore teamwork is crucial. You must enjoy working with others, have a knack for a good laugh and you shouldn’t take yourself too seriously, these skills will help with the regular frustrations arising when doing research. 

You will get: experience on state-of-the-art (or beyond) nanofabrication and on performing optical spectroscopy in state-of-the-art laboratories, a sound understanding of the physics of 2D materials and solid-state quantum optical systems, and if everything goes well a nice (or even amazing) paper in a top journal. Maybe most importantly, you will also have a lot of fun along the way.

Finally, we like and promote a diverse working environment, as such we particularly welcome applications from female students, foreigners, and members of minority groups. 

For inquiries feel free to write to Dr. Matteo Barbone: Matteo.Barbone@wsi.tum.de - or Marko Petric (marko.petric@wsi.tum.de) 

[1] Igor Aharonovich, Dirk Englund, and Milos Toth, Nat. Photon. 10 (10), 631 (2016)

[2] C. Palacios-Berraquero, et al., Nat. Commun. 8, 15093 (2017)

In nature, quarks and gluons cannot exist as free particles. They are always confined into hadrons. Unfortunately, the equations of the strong interaction that governs the behavior of quarks and gluons cannot be directly solved at energy scales where hadrons form. Hence theoretical predictions of hadron properties such as their masses and decay modes are very difficult. This is in particular true for hadrons that are made of the three lightest quarks: „up“, „down“, and „strange“. Also on the experimental side much confusion exists on what concerns masses, decay widths, and the assignment of quantum numbers of some observed hadrons, let alone the interpretation of their internal structure.

Our group participates in the COMPASS experiment at CERN, where we study the production of mesons (hadrons with integer spin) in the scattering of a 190 GeV pion beam off a stationary proton target. The produced highly excited mesons have extremely short life times of the order of 10^-24 seconds and can hence be measured only via their decay products. Our group employs and develops mathematically involved statistical analysis tools in order to identify the produced mesons with high sensitivity and to measure their properties with high precision. We have recently found a new meson with surprising properties and also did groundbreaking work on precision measurements of the properties of the pion. This science is directly connected to the understanding of the strong force at large distances and low energies and the search for new forms of matter and therefore addresses one of the last open questions of the Standard Model.

This science project, involves the use of several state-of-the-art technologies:

• Building of analysis models in close collaboration with theorists
• Handling of very large data sets (several Petabytes)
• Elaborate data fitting with more than 1000 parameters
• Use of large computing clusters (200 cores at E18 + 2000 cores at LRZ/Excellence cluster)
• Software development to exploit new CPU/GPU technologies

In addition, we operate and maintain a large-scale scientific apparatus, which involves tasks like:

• Calibration of particle detectors
• Adaptation of large simulation codes

We offer thesis topics at various levels of difficulty, which cover a wide range of subjects in strong-interaction physics, statistics, and/or computer science. They include for example

• Data handling and event selection
• Simulation of high-energy scattering processes and detector response
• Estimation of model parameters from high-dimensional data
• Model building and model selection
• Parallelization of analysis software

You have the opportunity to perform your own science analysis, e.g. searching for new particles and determining their properties. The analysis work can start at different levels within the analysis chain: from the selection of a reaction process itself in order to study the feasibility of a full-fletched analysis up to the final fitting process leading to scientific publications. The topic can be chosen according to personal preference and interest. Thesis projects usually involve travels to CERN.

Experience in programming (C++, Python) is helpful, but not required.

Contact: Boris Grube , room PH1 3574, Tel. 089 289 12588

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.

In vielen wichtigen elektrochemischen Prozessen (wie zB der Reduktion von CO₂) vermutet man Prozesse, bei denen zwei Radikale beteiligt sind. Interessanterweise wurden diese chemischen Elementarprozesse noch nicht beobachtet. In dieser Arbeit soll eine elektrochemische Zelle in ein klassisches Spinresonanz-Spektrometer integriert werden und dann die Signatur solcher Biradikale im Stromtransport beobachtet werden. Sie werden in dieser Masterarbeit hochempfindliche Methoden der magnetischen Resonanz sowie die wichtigsten Askepte der Elektrochemie kennenlernen und an einem Thema an der vordersten Front der Physik und Chemie des Klimawandels forschen.   

Iron-based pnictides and chalcogenides are model systems for complex materials having several electron bands, derived from Fe 3d orbitals, crossing the Fermi energy. These multiband systems are characterized by the proximity of various intertwined phases including unconventional superconductivity and magnetism. The magnetic state displays remarkable anisotropic properties which require mono-domain samples for successful studies. Mono-domain samples can be obtained by suppressing one of the two equivalent domain orientations, i.e. by de-twinning the crystals. Here, EuFe₂As₂ is unique since the twins may be removed in moderate magnetic fields. The samples stay single-domain even after switching off the field. This facilitates a “clean” experiment without the superposition of various fields. This study contributes to answer the question as to the driving force behind magnetism, structural distortions, and superconductivity in the iron-based compounds.

It is planned to study spin excitations and phonons in EuFe₂As₂ close to the various phase transition lines and to compare the spectroscopy results with theoretical predictions. The samples are prepared in the group of Philipp Gegenwart, University of Augsburg. For the related theory work there is a long-standing collaboration with groups in Frankfurt/Main (Roser Valentí) and Washington, D.C., USA (Igor Mazin).

The work includes a thorough introduction to spectroscopy, low-temperature, and high-field techniques. Contact: Andreas Baum, Rudi Hackl

Optomechanics provides extremely sensitive methods to measure the displacement of mechanical resonators. However, the forces are much smaller in optomechanics compared to those in nanoelectromechanical systems (NEMS). The goal of the project is to make, and measure opto-electromechanical devices which have strong electrostatic interactions. This includes the electrostatic spring effect where the resonance frequency depends strongly on the applied voltage. The next step is trying to measure the potential by measuring the ringdown of different mechanical modes. The devices will be made using advanced nanofabrication techniques such as electron beam lithography and reactive ion etching.

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

Viele Erweiterungen des Standardmodells sagen neue schwere Resonanzen voraus, die in Bosonpaare, ZZ, WW, WZ, HZ, HW zerfallen. Mit Hilfe simulierter Daten werden die Selektionskriterien fuer diese Zerfaelle optimiert und die Nachweissignifikanzen bestimmt. Die Ergebnisse werden auf die neuesten Daten des ATLAS-Experiments bei der bisher hoechsten Proton-Proton-Kollisions- Energie von 13 TeV bestimmt.

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.

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.