Research Labworks for MSc

Information

The Research Labwork in Physics in the 1. and 2. master semester serves the purpose of training in a specific physical issue as well as project planning in order to improve experimental skills.

One project should be completed during the semester at one afternoon per week (4 CP). The experiments can be chosen from one of the following topics: optics, solid state physics, astronomy, computational physics, and material science. Depending on the specific conditions, one project can be done by either on or more students, in the latter case, with complementary tasks.

At the end of the winter semester students submit (last week of January) and present (2nd week of February) their results in form of a scientific poster.

The Organization of the research labwork is managed by the F-Praktikum office. For choosing a project, please contact us via physik.f-praktikum@uni-jena.de. Please do not send requests individually to project supervisors.

 

Laserphysics/Optics

Nd:YLF Shortpulsed - Laser (not available) Eintrag erweitern

Flash lamp pumped Nd:YAG (also Nd:glass or Nd:YLF as used for this experiment) lasers are still the work horses used for laser material processing, i.e. cutting, drilling, welding, soldering, or forming of workpieces. Additionally, they are often used as a pump source for optical-parametric or femtosecond laser amplifiers in science or for instance as a driver for inertial confinement nuclear fusion. The latter applicationcomprises the world’s largest lasers generating up to some MJ pulse energy in only some ns in time. Because of the acceptable efficiency, low cost of ownership, and flexibility of flash lamp pumped solid state lasers for the generation of high pulse energies, they are still widely used today. This kind of lasers have the capability to generate microsecond, nanosecond and even picoseconds pulses by techniques that are universal for short pulse lasers. The underlying basics for these techniques are taught within this experiment together with pulse characterization using auto-correlation and basics of nonlinear optics as well as laser pulse amplification. Since with the rare-earth element neodymium an almost ideally four-level laser schem can be realized, it perfectly serves as a model to understand laser dynamics in more depth.    

Teaching goals and content 

  • working principle and properties of solid-state lasers (Nd:YLF)
  • spiking in free-running mode
  • dependence of output power on pump power
  • working principle of a Pockels cell
  • generation of short pulses by Q-switching
  • non-linear optics: second harmonic generation (SHG) and phase matching principle
  • generation of picosecond pulses by ‘non-linaer mirror’ mode-locking
  • measurement of pulse width by intensity auto-correlation with SHG
  • optical amplification of short pulses in flash lamp pumped rod amplifiers

Experimental techniques and equipment

 

  • flash lamp pumped Nd:YLF-laser with four laser heads
  • cavity with SHG for mode-locking
  • cavity with Pockels-cellfor q-switching
  • motorized SHG auto-correlator for ps-pulses
  • energymeter, photodiodes, oscilloscope

Supervisor:   Dr. Joachim Hein

Place:            F-Praktikum

For this experiment two students are recommended.

 

Femtosecond Laser Eintrag erweitern

Nowadays the generation of ultra-short laser pulses with a duration down to some femto seconds is state of the art. Such pulses find their application not only in the field of scientific research to investigate ultra-fast processes, to perform ultra-precise spectroscopy, or to generate extreme electrical and magnetic fields through ultra-high light intensities, but they are also applied in material processing, medicine, especially in ophthalmology. Nevertheless, the generation and metrology of ultra-short pulses require complex measurement techniques. The basics to understand the underlying effects of pulse generation, stretching and compression as well as their measurement will be taught here. Some of these effects are based on non-linear optics and frequency conversion, that requires phase matching to get reasonable efficiencies. Second harmonic generation and two-photon absorption are used for pulse characterization by auto-correlation here. The limitations of the auto-correlation for the reconstruction of the temporal behavior of the laser field will be investigated in more detail.   

Teaching goals and content 

  • Working principle and properties of solid-state lasers (Ti:sapphire)
  • Cavity stability and longitudinal cavity modes
  • Dependence of output power on pump power
  • Generation of femtosecond pulses by Kerr-lens mode-locking
  • Compensation of group velocity dispersion in optical cavities
  • Impact of spectral phase on pulse duration and temporal pulse shape
  • Measurement of band-width and duration of laser pulses
  • Application of Fourier-Transform to explain pulse stretching and compression
  • Interferometric and intensity auto-correlation and their limitations for pulse characterization
  • Measurement of group velocity dispersion (GVD) of several materials

Experimental techniques and equipment

 

  • diode-pumped, frequency-doubled 5W Nd:YV04-laser as pump source
  • homemade Ti:sapphire femtosecond laser with prism GVD compensation
  • external prism pulse compressor
  • optical spectrometer
  • second harmonic generating auto-correlator
  • photodiodes, powermeter and oscilloscope

Supervisor:   Dr. Joachim Hein

Place:            F-Praktikum

For this experiment two students are recommended.

 

High efficiency solitonic self-compression of mid-IR pulses in solids Eintrag erweitern

The quest to generate as short as possible coherent optical pulses started simultaneously with birth of laser physics. Ultrashort laser pulses have critical importance for time -resolved linear and nonlinear spectroscopy, achieving extreme peak values of electric field strength for physics of strong field light-matter interaction etc. Numerous methods were developed today that enable laser pulses with duration down to a single optical cycle.

In the visible and near-IR spectral range, most of pulse compression techniques, routinely used today for generation of few -optical-cycle pulses, are based on spectral broadening in a nonlinear medium with subsequent linear dispersion management to combine all colors in time in an ultrashort pulse. Exceptions are methods based on photonic crystal structures, suitable for microjoule level pulse energies and employing solitonic self-compression, and methods employing special regimes of filamentation in gases for pulse self-compression. The last methods can be used for millijoule level pulse energies and employ very complex nonlinear spatial-temporal dynamics, thus are not easy to implement, lack stability and have low efficiency in terms of the energy confined in the compressed pulse.

The goal of the proposed project is experimental realization and optimization of a novel pulse self -compression technique suitable for femtosecond laser pulses in the mid -IR spectral range. Most of optical materials, transparen t in the spectral range above 2 μm, have anomalous group velocity dispersion, in contrast to the visible-near-IR spectral range where the dispersion is normal. The anomalous character of the dispersion, in combination with cubic nonlinearity, enables solitonic regime of self-compression. The corresponding optical setup is very robust, essentially alignment free and can be used for pulse energies ranging from a few microjoules to several tenses of millijoules. The research work implies building the optical setup and investigation of spatial, spectral and temporal characteristics of ultrashort, intense mid-IR laser pulses undergoing self-compression in different transparent materials.

Methods

  • High power lasers
  • Setting up optical experiments with modern components
  • Logging, analyzing and interpretation of measured data, comparison to literature results

Prerequisites

  • Basic knowledge about laser and solid state physics
  • (nonlinear) optics, experimental skills, good knowledge of English

Organization

Person in charge: Prof. Dr. Christian Spielmann

Supervision: Dr. Daniil Kartashov

Place: Labs of the IOQ/QE at Max-Wien-Platz 1

Per term, two students may work on the topic

Advanced Experimental Microscopy - Super-Resolution Microscopy Eintrag erweitern

Seeing is believing. This sentence is as true as it is tricky. Most cellular components and processes, crucial for the nuanced understanding of (human) life, are not observable by conventional light microscopy since Abbe´s Law describes their maximum resolution to roughly half the wavelength of the observation light. This law is literally set in stone in Jena. However, over the past 15 years several ways of cleverly circumventing this diffraction limit were developed and implemented, achieving three-dimensional resolutions down to the nanometer range, resulting in the ever-growing field of optical super-resolution microscopy, for which the 2014 Nobel Prize in Chemistry was awarded.

The aim of this projects is to introduce, understand and apply the principles of state of the art fluorescence microscopy techniques, used e.g. in a broad range of modern biomedical and cell-biological research. Students prepare their own, fluorescently labeled, biological samples and will image them on a variety of advanced microscopes with different (resolution) capabilities. The qualitative and quantitative comparison of acquiered images will illustrate the advantages und limitations of the respective microscopy technique.

Goals and Context

  • Principles and application of advanced fluorescence microscopy techniques
  • Concept of diffraction-limited and super-resolution
  • Preparation of fluorescently labeled, biological samples
  • 3D& multi-colour imaging at the nanoscale

Methods

  • Cell culture and wet lab
  • Fluorescent labeling
  • A selection of advanced fluorescence microscopy techniques from the IAOB toolbox:
  • Confocal Laser Scanning Microscopy
  • Array Scan Microscopy
  • Stimulated Emission Depletion (STED)
  • Structured Illumination Microscopy (SIM)
  • Single-Molecule Localization Microscopy (SMLM)
  • MINFLUX Nanoscopy

Prerequisites

An open mind.

Person in charge: Christian Franke

Supervisor: Katharina Reglinski

Venue: Microscopy Labs of the IAOB in the ZAF and Abbeanum

The topic is suitable for two groups of 1 or 2 students.

 

Construction of a Michelson Interferometer for the Students Lab Eintrag erweitern

A Fourier spectrometer in the simplest realization resembles a Michelson interferometer, however, with the ability of a controlled variation of the optical path lengths, e.g., by shifting one or multiple mirrors. The latter in particular is a technical challenge, as nanometer-scale positioning is required.

The goal of the project is to build from the scratch and test a modified Michelson interferometer that can eventually be converted to a Mach-Zehnder or Sagnac interferometer. The experimental realization of the mirror movement should be done on the basis of state-of-the-art encoded Piezo motors. In particular, a test is needed to decide if an additional calibration source can be omitted by a defined and repeatable travel path.

Teaching Goals and Content 

  • Planning and building an optical setup for Fourier spectroscopy
  • Piezo motors for controlled mirror movements

Prerequisites

  • Knowledge and interests in basic optics, interference and high-resolution spectroscopy
  • Good experimental skills

Supervisor: Dr. Joachim Hein

Place:         F-Praktikum

For this experiment one or two students are recommended.

Nonlinear crystals investigation for quantum optical systems Eintrag erweitern

Quantum technologies are emerging in the last years, as they offer a surpassing performance to their classical analogues. Some applications are using entangled and correlated photons, to significantly enhance signal to noise ratio in microscopy and imaging, compute exponentially more data in quantum computers, and achieve unbreakable communication protocols by the laws of physics.

Second order nonlinear crystals and waveguides are the essential building block of such systems. Correlated photons are created based on spontaneous parametric down-conversion (SPDC) in bulk materials, such as Potassium Titanyl Phosphate (KTP), Lithium Niobate (LN), and Beta Barium Borate (BBO). In this lab work, the performance of materials with different properties is to be investigated, according to their efficiency of creating SPDC photons, temperature tuning and spectral characterization of SPDC.

Teaching Goals and Content 

  • Laser beam alignment for single mode fiber coupling
  • Working principle of quasi phase matching in periodically poled crystals
  • Temperature tuning of periodically poled materials
  • Investigating the behavior of temperature vs. output spectrum
  • Simulation of Gaussian beams in optical components (ABCD matrix formalism)
  • The effect of using different lens focal lengths on single photon coupling

Experimental Techniques and Equipment 

  • Continuous wave pump laser at 405 nm and 775 nm
  • Polarization control and polarizing beam splitters
  • Single photon detectors
  • Spectral characterization with an optical spectrometer
  • Temperature control of the crystals
  • Two photon interference of Hong-Ou-Mandel
  • Some other equipment: Photodiodes, powermeter and oscilloscope

Supervisors:   MSc. Sakshi Sharma, MSc. Grucheska Rosario, MSc. Rana Sebak

Place:            Fraunhofer IOF institute

For this experiment two students are recommended.

Solid State Physics

Investigation of Thin Layers and Nanoparticles with X-Rays Eintrag erweitern

Learning target and topics

 Students will learn in these experiments methods on surface characterization, thin film analysis as well as x-ray diffraction analysis on nanoparticles. Therefore, grazing incidence reflectometry data as well as wide angle scattering of nanosized particle will be recorded. Surface- and interface roughness, layer thickness as well as electron density will be determined from the data analysis. For crystalline thin layers the crystal phases, particle sizes and deformation can be treated from the diffraction profile analysis (Williamson-Hall analysis). For crystalline layers a preferred orientation and an angular distribution of the crystallites can be obtained by a pole-figure measurement. The experimental data will be compared with simulation.

  •  x-ray diffraction theory (wide angle x-ray scattering)
  •  x-ray optics (grazing angle x-ray scattering)
  •  Williamson-Hall analysis
  •  Scherrer-formula
  •  crystal phase analysis
  •  kinematical and dynamical diffraction
  •  temperature vibration

Experimental equipment

For the laboratory work an x-ray diffractometer with Bragg-Brentano focusing combined to a graphite monochromator will be used. For instance polycrystalline material can be measured with this diffractometer (pole-figure measurement). A second high resolution diffractometer can be used for grazing incidence reflectometry and wide angle x-ray scattering of epitaxially grown thin films to determine particle sizes and crystalline deformation. For multilayer mirrors the layer thickness, surface- and interface roughness can be measured.

  •  x-ray diffractometry
  •  x-ray reflectometry
  •  detection of x-rays

Supervisor:      Dr. Berit Marx-Glowna

Place:              Institut für Optik und Quantenelektronik, X-ray-laboratories Max-Wien-Platz 1

The topic can be worked out by one or two students.

Investigation of Multilayer Mirrors for X-Rays Eintrag erweitern

Learning target and topics

  • Thin metal layers: deposition, characterization of the layer properties and structure
  • High vacuum technology
  • Introduction and application of various analysis methods
    • Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX)
    • Scanning Tunneling or Atomic Force Microscopy (STM, AFM)
    • AugerElectronSpectroscopy (AES)
    • X-ray diffractometry

Experimental equipment

  • Sputter coating system from Oxford Instruments
  • Thermal evaporation system (self-made)
  • Mass Spectrometer for residual gas analysis
  • Scanning Electron Microscope
  • Atomic Force Microscope
  • Scanning Tunneling Microscope
  • Auger Electron Spectrometer

Supervisor:   Dr. Thomas Siefke, Dr. Berit Marx-Glowna

Venue:           F-Praktikum, IFK and IOQ

The topic is suitable for one or two students.

 

Growth and Characterization of Carbon Nanotubes Eintrag erweitern

Hardly any other topic inspires the intellectual curiosity in the past decades such as nanotechnology. In addition to the enormous range of applications in the semiconductor, textile and automobile industry, mechanical engineering, architecture, aerospace engineering, medical and energy technology, it also provides an interesting insight into the physical and chemical processes and properties at the atomic and subatomic level. In this field the so-called carbon nanotubes are of particular importance. Since their discovery in 1991 by Sumio Ijima and his research group as well as the experimental studies of Bethune et al., different research groups largely succeeded to understand the production mechanism of these nanoscopic structures and their wide potential for applications. Beside to their high tensile strength and elasticity they have extraordinarily good conduction properties. In research they are therefore used as electronic components such as field effect transistors and electrical sensors and as probes for scanning force and scanning tunneling microscopes. In the industry they are used, among others, as conducting composites.

In this project, CNTs are grown by means of the chemical vapor deposition (CVD) technique. First, the substrates needed shall be prepared by the student itself and, especially, the for the CVD process required catalyst (cobalt or iron) shall be grown structured by means of the thermal deposition method. The characterization of the substrates and CNTs shall be done by means of atomic force microscopy (AFM) and Auger electron spectroscopy (AES) as well as scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The letter is a widely-used optical analysis tool, which is perfectly suited to gain information about the quality of the CNTs as well as their structures to a certain extent. After optimizing the process parameters of the CVD, self-made CNT networks shall be tested in terms of their performance as gas sensors (FET setup). For this purpose, I-V curves are measured computer-aided in dependence of different environmental parameters (partial pressure of the gas to be detected, temperature, …).

Objectives

  • Nanotechnology / Nanostructures
  • Carbon nanotubes - structure, properties, preparation, growth, use, characterization
  • Coating processes (in particular chemical and physical gas-phase deposition)
  • Sample preparation
  • Vacuum technology
  • Learn about chemical vapor deposition (CVD) systems
  • Using the scanning electron microscope (STM) or atomic force microscope (AFM)
  • Application of Raman spectroscopy
  • Electrical characterization: I-U, sensor properties

Experimental techniques

  • CVD equipment, medium vacuum
  • Samples: single crystalline silicon with oxidic passivation and quartz with catalyst coating of both substrates
  • Vacuum coating, thermal evaporation
  • Raman spectrometer
  • Scanning electron microscope (SEM)
  • Atomic Force Microscope (AFM)
  • Auger electron spectrometer (AES)
  • Computer-aided measurements of I-V curves

 

Supervisor:      Dr. Marco Grünewald

Venue:            F-Praktikum and labs of the IFK

The topic is suitable for one or two students.  

Vacuum Coating of Thin Metal Layers Eintrag erweitern

Thin layers are layers with thicknesses in the micrometer and nanometer range. Their physical parameters such as electrical conductivity often deviates from that of the bulk material, allowing for altered, tailored properties and new functionalities. In addition, the material savings are often of great economic importance. Well known is the application in the field of protection against environmental conditions, e.g. against corrosion or oxidation. However, thin layers are most important in microelectronics, where almost all components are manufactured using thin-film technology. In optics, thin layers and layer stacks are used to influence the reflection and transmission behavior, but also the polarization. In particular, layer systems play a prominent role in X-ray optics.

In the internship, metallic layers are usually deposited and characterized by different methods. Concrete topics and goals, amongst others taken from current research projects, are proposed by the supervisor at the beginning of the internship, but can be discussed and adapted depending on the interests.

Learning goals and content

  • Deposition of thin metal layers by means of various coating methods (sputter coating, thermal evaporation)
  • Characterization of the layer properties (e.g., composition, roughness, crystalline properties) depending on substrate properties and coating parameters (e.g. chamber pressure, residual gas composition, process times, substrate heating)
  • Introduction and application of various analysis methods
    • Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX)
    • Scanning Tunneling or Atomic Force Microscopy (STM, AFM)
    • Auger Electron Spectroscopy (AES)
    • X-ray diffractometry (in cooperation with the X-ray group)

Experimental equipment

  • Sputter coating system from Oxford Instruments
  • Thermal evaporation system (self-made)
  • Mass Spectrometer for residual gas analysis
  • Quartz layerthickness monitor
  • Scanning Electron Microscope
  • Atomic Force Microscope
  • Scanning Tunneling Microscope
  • Auger Electron Spectrometer

Supervisor:   Dr. Thomas Siefke

Venue:           F-Praktikum

The topic is suitable for one or two students.

Mass Spectroscopy Eintrag erweitern

Under vacuum conditions, many physical and thermodynamic properties change, wherefore they are used in industry and research in a variety of processes and for a variety of reasons. Thus, one makes use of the reduced heat flow and conduction properties for heat isolation in order to produce particularly low or high temperatures. The industry uses vacuum for preservation or the fact that moisture can be removed from food or biological samples by freeze drying at low temperatures in vacuum by sublimation. The high energy technology uses vacuum to increase the dielectric strength. The large mean free path of atoms and molecules in vacua is fundamental to the operation of particle accelerators, electron microscopes and coating equipment, which are often already operated under ultrahigh-vacuum (UHV) conditions. An important method of modern analytics is the analysis of gas compositions by means of mass spectrometers, which is used in both structure determination and substance identification as well as quantitative analysis, especially in the trace range with detection limits down to the femtogram range (10-15 g).

In the internship, principles of vacuum generation, its measurement and characterization are introduced and investigated, which the physicist meets in almost all areas. Mass spectra are measured and interpreted under different conditions. The aim is to use the UHV chamber to characterize surfaces using desorption spectroscopy, where material (gases, etc.) is desorbed from the surface upon controlled heating and subsequent detection by means of a mass spectrometer. Important  physical quantities like binding energies can  be interferred from such data in principle.

Learning goals and content

  • Vacuum: Basics, Generation, Measurement
  • Handling of  vacuum technology
  • Special features of the ultra-high vacuum
  • Introduction of the basic principle and the technique of mass spectrometry, substance identification and interpretation of mass spectra
  • Adsorption and desorption on surfaces, physisorption, chemisorption
  • Thermal Desorption Spectroscopy (TDS)

Experimental equipment

  • Ultra high vacuum system
  • Turbomolecular pump, scroll pump
  • Ion getter pump, titanium sublimation pump
  • Vacuum measurement
  • Quadrupole mass spectrometer, residual gas analysis
  • gas inlet system, gas valves

Supervisor:   Dr. Frank Schrempel

Venue:          F-Praktikum

The topic is suitable for one or two students.

Electron Diffraction Eintrag erweitern

According to de Broglie matter has not only particle but also wave character. It was shown that electrons, due to their rest mass, already exhibit wavelengths of around 1 angstrom at acceleration voltages of about 150 V, which is in the range of atomic distances in solids. Crystals therefore represent natural diffraction gratings for accelerated electrons, just as they do for X-rays of similar wavelengths. However, due to the strong inelastic interaction between electrons and atoms, the inelastic mean free path of electrons in solids ranges from less than 1 to several 100 nm which is thus considerably smaller than for X-rays. This makes electron diffraction especially suited for the investigation of crystalline surfaces and thin layers.

The aim of this projects is to understand principles of electron diffraction, especially reflection high energy electron diffraction (RHEED) and low-energy electron diffraction (LEED), which are widely used characterization methods for inorganic compounds with the ability of in situ growth monitoring of thin films. Students prepare their own samples, starting from cleaning single-crystal surfaces, followed by the deposition of films via molecular beam epitaxy as well as their structural characterization by means of RHEED and LEED. All preparation and analyzing steps are performed under ultrahigh vacuum (UHV) conditions.

Goals and context

  • principles and application of electron diffraction in two dimensions (2D)
  • concept of reciprocal space
  • preparation of atomically clean single crystals and two dimensional materials
  • highly-ordered ultrathin layers by molecular beam epitaxy
  • vacuum technology (pumps, gauges, rest gas analysis etc.)

Methods

  • UHV chambers with:
    • RHEED device (electron gun, phosphor screen, camera)
    • MCP-LEED (electron gun, phosphor screen, micro channel plates, camera)
    • sputter gun and sample heater
    • vacuum pumps (roughing, turbo, ion getter, and titanium pump)
  • metal single crystals as sample substrates
  • effusion cells for deposition

Supervisor: Dr. Felix Otto    

Venue: Labs of AG Fritz (ZAF)

The topic is suitable for one or two students.

Exfoliation and PL Characterization of Transition Metal Dichalcogenides Eintrag erweitern

As and such the industry of semiconductors is beginning to get stagnant because of the overwhelming need for different materials with outstanding properties to be used in almost all areas of today´s technological backbone, graphene and its cousins transformed the world in 2010. Over the years more research has been put forward to find more materials that have similar or more extravagant properties than graphene. Transition metal dichalcogenides (TMDs), is a class of two-dimensional layered structures, that has proved over the years for its outstanding optical and electronic properties. TMDs are now extensively studied for the future usage as transistors, LEDs and almost all areas of science which will help to have more miniaturized and efficient devices in the near future.

In this series of experiments, TMDs are exfoliated and transferred onto a substrate and characterized by photoluminescence (PL) spectroscopy. The students shall try to identify the different number pf layers that have been transferred by means of the optical contrast method, which is carried out by means of a microscope and a white light setup. Upon successful identification of the layers, photoluminescence spectra of the samples are obtained by means of a laser beam which is incident on the sample. During the experiments, the students will learn the required knowledge about the PL basics and advanced knowledge about this kind of materials. The power dependance of the PL spectrum shall also be done and discussed in terms of the corresponding carrier dynamics.

Objectives

  • 2D Materials: basic theory of 2D materials, different types of 2D materials
  • TMDs: structures, optical and electronical properties (exciton and trion formation), possible relaxation mechanisms
  • Exfoliation: growth, different methods, optimization of the exfoliation methods
  • Laser: basics of laser science
  • Optical contrast method: principle of identification of layered structures
  • Photoluminescence: basic theory, relaxation mechanisms

Experimental techniques

  • Exfoliation of different TMDs
  • PL of single layer CVD-grown TMDs
  • Identification of number of layers of exfoliated samples: optical contrast method
  • Performing photoluminescence measurements: fixed power and power dependency measurements
  • Estimate of doping, trions in TMDs
  • Understanding of Excitation recombination processes: radiative and non-radiative processes

Supervisor: Paul Hermann

Venue: F-Praktikum, IFK (Room 130)

The topic can be worked on by one or two students. 

Quantitative Auger Electron Spectroscopy Eintrag erweitern

Auger electron spectroscopy (AES), which is based on the Auger effect, is one of the most important analytical method for surfaces and thin solid layers, along with X-ray excited photoelectron spectroscopy (XPS/ESCA/PES). The Auger effect, named after Pierre Auger, is a radiationless transition of an electron in the electron shell of an atom. It is an alternative process to X-ray emission when a hole is filled in a more strongly bound electron shell. The method is based on the emission of so-called Auger electrons after excitation by electrons. Usually, an electron beam in the energy range of 3 to 10 keV is used for excitation. Since an electron beam can be focused in the nm and μm range and additionally scanned over the surface, a local analysis is possible. The exit depth of the Auger electrons is limited to a few atomic layers by inelastic interaction, so that this technique is extremely surface-sensitive. All elements except H and He are in principle measurable by AES, and by using empirical sensitivity factors a quantitative determination of the chemical composition can be performed. The relative sensitivity for element detection in a material is 10-2 to 10-4. AES is often combined with noble gas ion etching (sputtering) to clean surfaces or to determine depth profiles of composition by layer-by-layer ablation.

Within the scope of the internship, an Auger spectrometer is to be qualified for the precise quantitative determination of the elemental composition of sample surfaces. For this purpose, suitable methods for the accurate measurement of the electron current and the sensitivity factors of the system are to be developed and corresponding experiments are to be carried out.

Learning goals and content

  • Principle and technique of Auger electron spectroscopy
  • Energy resolution, signal-to-noise ratio and application of methods to improve it
  • Interpretation of spectra and determination of the chemical composition of solid surfaces
  • Interaction processes of electrons in the solid state (in/elastic scattering, excitation and de-excitation processes, secondary radiation, plasmons)
  • Imaging of surface structure by sample current
  • Ultra-high vacuum techniques

Experimental equipment

  • Electron spectrometer consisting of focused scanning electron source, cylinder mirror analyzer and secondary electron multiplier
  • Measuring system for recording differential spectra
  • Ion beam sputtering for cleaning and ablation of surfaces
  • Ultra-high vacuum chamber with ion getter pump and titanium sublimation pump
  • Sample lock with turbomolecular pump and scroll pump
  • Gas inletsystem

Supervisor:   Dr. Frank Schrempel

Venue:          F-Praktikum

The topic is suitable for one or two students.

Optical Characterization of Semiconductor Nanowire-Based Lasers Eintrag erweitern

Semiconductor nanowires represent a benchmark nano-source of coherent radiation, thanks to their inherent capabilities of acting as a gain medium, an optical resonator, and a waveguide for the modes at the same time. Therefore, over the last few decades, they have been widely exploited for the development of photonic nanolasers, first, and of hybrid plasmonic nanolasers, afterwards.

The aim of this project is to introduce the student(s) to the realization and optical characterization of such nanolasers, starting from the nanowire growth inside a horizontal-tube furnace up to the μ-PL measurements for the investigation of the spontaneous (CW pumping) and lasing (pulsed pumping) regimes. The possible device schemes are:

  • Photonic devices: ZnO nanowires on a dielectric (silica) substrate
  • Planar plasmonic devices: ZnO nanowires on a bare metallic (Al) substrate
  • Modified hybrid devices: ZnO nanowires on metallic (Al) gratings.

Depending on the progress, cathodoluminescence measurements can also be integrated in the project.

Goals and context

  • Basic understanding of nanowire growth
  • Basic understanding of the possible nano-device schemes
  • Basic understanding of the different lasing characteristics

Methods

  • VLS growth in a horizontal-tube hot furnace
  • SEM imaging
  • Realization of the nanolasers via dry imprint and micro-manipulation
  • Optical characterization via μ-PL and/or CL measurements

Prerequisites

  • An open mind

Person in charge: Francesco Vitale & Carsten Ronning

Supervisor: Francesco Vitale

Language: English

Venue: Nano Group Labs in the Red House of the Institute of Solid State Physics (Helmholtzweg 3)

The topic is suitable for one or two students.

Production of very thin free-standing metal foils for EUV light Eintrag erweitern

Short wavelength radiation such as extreme ultraviolet (EUV) light has gained considerable importance in the last decades, as it allows high resolutions due to its short wavelength, can investigate optically opaque samples and allows short time scales. A promising method for generating EUV light is so-called high-harmonic generation (HHG) using laser-induced ionization. HHG radiation offers strong advantages, such as laser-like beam properties, spectral tunability, short time duration, and high coherence.

In the HHG process, an intense laser pulse (~mJ, ~30fs, >=VIS) is focused into a gas contained in a vacuum chamber. In the process, the gas is ionized. The ionized electrons begin to oscillate in the laser field and gain kinetic energy. With a small probability, the electrons can recombine with the ions and emit a high-energy photon in the beam direction.

After the generation of these high-energy photons, the EUV beam must be separated from the remaining intense laser beam if only the EUV beam is to be used. Here, thin metal foils can be used as filters or beam blockers for the long-wavelength laser radiation, since certain metals provide high transmission for EUV light while blocking the laser light. Such foils typically have a thickness of a few hundred nanometers, while the lateral dimension is in the range of millimeters to centimeters, making them extremely fragile.

The goal of this project is to understand how to fabricate these very thin, free-standing metal foils that could be used as light filters for the EUV range in the future. To do this, we need to find suitable substrates, coating parameters, and appropriate etching techniques. Students will fabricate suitable test foils and characterize them using various diagnostics. Possible methods could include SEM, AFM, optical microscope, laser/EUV transmission.

Teaching Goals and Content 

  • Design and setup of a manufacturing process for thin metal layers
  • Design and fabrication (coating and etching) of test foils
  • Characterization of foils with different methods (e.g. light microscope, AFM, SEM, transmission of intense laser radiation etc.)

Prerequisites

  • Knowledge and interests in coating and diagnostic tools as well imaging
  • Good experimental skills

Supervisors: Dr. Martin Wünsche, Dr. Thomas Siefke

Place:         Max-Wien-Platz 1

For this experiment two students are recommended.

Material Science

Carbon Nanodots for Life Science Application (not available) Eintrag erweitern

Carbon nanodots (CND) are the newest and most fascinating members of the carbon-based materials family. Due to their nanostructure, their diameter of just a few nanometers and their unique properties, CNDs have abroad application potential as biosensors, for targeted drug release, fluorescence imaging, for the detection of biomolecules and in nanotheranostics. The aim of this project internship is to first create, develop and characterize CNDs from scratch and then investigate the interactions of the CNDs with living systems. If you are interested in new, future-oriented frontier materials and physico-chemical aspects and like to work experimentally, then join our international team.

Goals and context

  • Synthesis and creation of carbon nanodots (CNDs)
  • Characterization of CNDs
  • Structure investigation of CNDs
  • Structure-property relationships of CNDs including cell culture
  • Insight into current research and development fields in nanotechnology, materials for LIFE and smart-functional materials methods

Methods

  • Advanced literature research
  • Elaboration of CND synthesis methods
  • Analysis of CNDs, using atomic force microscopy (AFM), electron microscopy (SEM, TEM), UV-Vis, CLSM, differential-scanning-calorimetry, XRD etc.
  • Infiltration of CNDs in live cells
  • Investigation of effects of CND on live cells

Prerequisites

  • Interest in condensed matter physics, materials science and life science

Person in charge and supervisor: Prof. Dr. Klaus D. Jandt

Venue: OSIM, Löbdergraben 32

The topic is suitable for one or two students. 

Polymeric Nanoparticles (not available) Eintrag erweitern

Crystallinity-Dependent Degradation Behavior in Polymeric Nanoparticles for Drug Delivery

Since the development of new vaccines at the latest, polymer nanocontainers as carriers for durgs play an increasingly important role.

Polymeric drug delivery systems tackle cancer and infections without damaging healthy body tissue by encapsulating drugs within polymeric nanoparticles. The drug is released either at a constant rate, in order to establish and maintain a certain level of medication within the organism, or triggered at their desired operational area (eg. cancerous tissue).

To control the release characteristics, it is essential to tailor the properties of nanoparticles. An important aspect here is the degradation behavior of these particles, hence the drug release kinetics. Among other factors, the crystallinity of the nanoparticles is known to impact both the degradation and the release.

The aim of this project is to understand the principles of polymer physics and polymer nanotechnology. Special focus will be laid on the role of crystallinity of polymeric nanoparticles in their degradation behavior and advanced characterization techniques such as atomic force microscopy (AFM). Additionally, the students will learn to work with important methods to analyze nanomaterials such as quartz crystal microbalance (QCMB) and dynamic light scattering (DLS). In this project, the students will prepare their own samples, starting with nanoparticle formulation, substrate functionalization, and nanoparticle immobilization on the substrates. Subsequently, they will perform degradation experiments and characterize the nanoparticles before, during, and after degradation with the above-mentioned methods.

Goals and context

  • Formulation of polymer nanoparticles
  • Principles of structure-property relationships in polymers and polymeric nanoparticles
  • Immobilization of nanoparticles on functionalized substrates
  • Principles of biodegradation of polymers
  • Nanoparticle characterization techniques

Methods

  • Formulation of polyester nanoparticles by nanoprecipitation
  • Chemical surface modification of Si- and Au substrates
  • Immobilization of the particles on functionalized substrates
  • AFM to detect changes in particle heights and mechanical properties during degradation of the particles with proteinase K
  • DLS and QCMB to measure the degradation kinetics

Prerequisites

  • Interest in condensed matter physics and materials science

Person in charge: Prof. Dr. Klaus D. Jandt

Supervisor: MSc Karl Scheuer

Venue: OSIM, Löbdergraben 32

The topic is suitable for one or two students. 

 

Protein Nanofibers (not available) Eintrag erweitern

Frontier Materials Based on Self-Assembled Protein Nanofibers for Tissue and Organ Regeneration


Tens of thousands of people with damaged tissues or organs need help. A possible answer to the pressing need to help these people is tissue engineering, i.e., creating novel tissue using materials and cells.

Our group has developed a revolutionary new material based on self-assembled proteins: hybrid protein nanofibers (hPNFs) that seem ideal for tissue engineering applications. Due to their versatility, hPNFs may have numerous uses, for instance, as scaffolds for cell cultures, drug delivery or as biosensors. A feasible strategy to create nanofibers relies on the self-assembly mechanism of protein molecules. Several methods are reported to initiate nanofiber formation from plasma proteins at low pH, elevated temperatures, and via addition of denaturants. With latest approach it is possible to create nanofibers from two plasma proteins, so-called hybrid nanofibers.

The aim of this project is to understand the principles of the self-assembly mechanism of selected plasma proteins to mono and hybrid protein nanofibers and their degradation behavior. Special focus will be laid on the characterization of nanofibers with advanced analytical methods, including atomic force microscopy (AFM). In this project the students will prepare their own sample, starting with protein nanofibers selfassembly under various conditions, e.g., concentrations, ratios, pH, and temperatures. The obtained fibers will be characterized in terms of size and surface charge. After successful characterization, the students will perform medium-dependent stability experiments and characterize degradation kinetics of nanofibers using Dynamic Light Scattering (DLS) and Quartz Crystal Microbalance (QCM).

Goals and context

  • Principles of self-assembly mechanism of proteins
  • Protein concentration measurement and solution dilution
  • Formulation of mono and hybrid protein nanofibers
  • Nanomaterial characterization techniques
  • Detection of nanofibers degradation

Methods

  • Synthesis and characterization of PNFs and hPNFs
  • UV-vis to define proteins’ concentrations
  • Drop-casting to immobilize nanofibers on PS substrates
  • AFM to detect and characterize nanofiber dimensions
  • DLS for structural and physical characterization of protein nanofibers
  • QCM to detect nanofibers degradation kinetics

Prerequisites

  • Interest in soft matter physics and materials science

Person in charge: Prof. Dr. Klaus D. Jandt

Supervisor: MSc Elbay Malikmammadov

Venue: OSIM, Löbdergraben 32

The topic is suitable for one or two students. 

 

Isostatic Pressing of Titanium Oxide Powder (not available) Eintrag erweitern

Isostatic Pressing of Titanium Oxide Powders – Microstructure Evolution and Analysis

Surface science contributes to the improvement of materials and devices’ usability where the interface plays a crucial role. The surface properties utilization of titanium oxide (TiO2) is used in many fields of industry, e.g., the photocatalytic degradation of binder in paints or biocompatibility of the bone implants. Powder pressing is one of the most commonly used methods in modern condensed matter materials engineering and is widely used to obtain TiO2 polycrystals. The final microstructure of the polycrystal depends on initial powder properties, such as grain size or shape, but also can be engineered by choosing the right process parameters (e.g. time or treatment temperature).

The aim of the project is to understand the microstructure evolution of the polycrystalline samples after each of the production steps, i.e., pressing, sintering, and thermal etching. Special focus will be laid on the role of starting powder properties on sample microstructure evolution and advanced characterization methods, such as atomic force microscopy (AFM) and scanning force microscopy (SEM). In this project, students will prepare their own samples and carry out comprehensive sample characterization, from density and porosity determinations, through surface roughness measurements with AFM (before and after the thermal etching), to SEM-based microstructural-crystallographic characterization, namely electron backscatter diffraction (EBSD).

Goals and context

  • Principles and application of isostatic presses
  • Concept of powder compaction and polycrystal formation
  • Rutile pellets preparation
  • Surface reconstructions during thermal treatment
  • Grain orientation characterization
  • Comparison of different polycrystals obtained in the same process (influence of powder characteristics and thermal treatments).

Methods

  • Isostatic powder pressing
  • Geometrical and Archimedes methods to determine density and porosity
  • Powder thermal processing
  • AFM to characterize topography and surface roughness
  • EBSD to determine the crystallographic orientation
  • Optical microscopy for surface structure observation

Prerequisites

  • Interest in condensed matter physics, surface science and materials science

Person in charge: Prof. Dr. Klaus D. Jandt

Supervisor: MSc Maja Struczynska

Venue: OSIM, Löbdergraben 32

The topic is suitable for one or two students. 

 

Soft Materials for Soft Robotic Actuators (not available) Eintrag erweitern

Innovative Soft Materials for Soft Robotic Actuators

Inspired by natural muscle tissue, the central challenge of soft robotics is to find and develop independently driven materials for actuators that have a high expansion density.

These completely new and fascinating materials are not only interesting for basic research, but also offer numerous application possibilities in innovative technologies (nanorobotics) and industry.

The aim of this work is to develop from scratch organic materials for which light and/or temperature changes play key roles as an external movement stimulus and shape memory effects. If you are interested in new, future-oriented frontier materials and physico-chemical aspects and like to work experimentally, then join our international team.

Goals and context

  • Creation of new soft matter actuator materials (SMAM)
  • Characterization and analysis of these materials
  • Structure elucidation of SMAM
  • Structure-property relationships of SMAM
  • Insight into current research and development fields in nanotechnology and smart-functional materials methods

Methods

  • Advanced literature research
  • Elaboration of SMAM synthesis methods
  • Analysis of SMAM, using atomic force microscopy (AFM), electron microscopy (SEM, TEM), UV-Vis, CLSM, differential-scanning-calorimetry, XRD etc.
  • Determination of the mechanical and switch properties of SMAM
  • Building of novel small soft robots

Prerequisites

  • Interest in condensed matter physics, materials science and soft matter physics

Person in charge and supervisor: Prof. Dr. Klaus D. Jandt

Venue: OSIM, Löbdergraben 32

The topic is suitable for one or two students. 

 

Computational Physics and Theory

N-Body-Simulation of Planet Dynamics (not available) Eintrag erweitern

Goals and context:

In this project, mutual gravitational perturbations in systems containing stars, planets, and minor bodies are studied. Depending on the scenario and configuration, these perturbations can lead to different types of short and long-term phenomena: resonances and chaotic behavior as well as secular effects. Possible examples for specific scenarios include: capture in and release from orbital resonances; long-term stability of planetary systems; Lyapunov exponent and chaotic motion; influence of small perturbers on chaotic systems; secular perihelion drift in multi-planet systems; Kozai mechanism. For each specific problem, analytic approximations are available and can be used for comparison with the numerical results.

Methods:

 A handful of numerical integrators is available, covering a set of different algorithms (Bulirsch­-Stoer, Runge-Kutta, Everhart, (hybrid) symplectic) and scenarios. The integrators can be compared with respect to their precision and speed. Simulation results can then be visualized and statistically examined with self-made programs/scripts.

Instructor:    Timothy Pearce

Venue:          Astrophys. Inst. and Unisternwarte, Haus 2 (Schillergässchen 3)

The complex topic can be worked on by one or multiple students. The actual tasks will be adapted.

Navier-Stokes-Equations Eintrag erweitern

Goals and context

Computational Fluid Dynamics (CFD) is a central part of computational physics and has been a driver for the development of modern numerical methods. It involves solving flow mechanical problems that cannot be solved analytically and are expensive to study experimentally by integrating generally nonlinear, partial differential equations.

In this project, the students will apply numerical methods to solve the Navier-Stokes-Equations for the case of an incompressible fluid to study flow within a cavity and flow around obstacles.

Methods

Timestepping schemes for integration of hyperbolic equations as well as a relaxation scheme for solving elliptic equations will be employed to solve the Navier-Stokes-Equations numerically on a staggered grid in two dimensions. The stability and convergence behavior of these schemes will be examinated.

The students will use C/C++, Python or Matlab to implement these methods.

Prerequisites

  • Basic knowledge of partial differential equations
  • Basic knowledge of numerical methods
  • Familiarity with at least one of the suggested programming languages

Organisation

Person in charge: Prof. Dr. Bernd Brügmann

Supervision: Sarah Renkhoff

Place:  Abbeanum, Fröbelstieg 1 or PAF Computerpool

One or two students may work on this project

Wave Equation Eintrag erweitern

Goals and context

  • Basic concept of hyperbolic partial differential equations (PDEs) and the initial-boundary value problem (IVBP)
  • Finite differencing methods for derivative approximation
  • Method-of-line for time-domain PDEs with Runge-Kutta timesteps
  • Numerical implementation of methods to solve multi-D PDEs
  • Concepts of numerical stability and convergence

Methods

The students will solve the IBVP with the wave equation in 1+1 and 2+1 dimensions (one time dimension and one and two spatial dimensions) numerically. The project has different sequential steps:

  • Wave equation and reduction to first order system
  • Characteristic analysis and well-posedness
  • Finite differencing approximation of derivatives and convergence
  • Runge-Kutta time integrators
  • Solution of IBVP withthe 1+1 wave equation and periodic boundaries using the method of lines
  • Stability and convergence
  • IBVP with open boundaries and Sommerfeld boundary conditions
  • Wave equation with a potential: the Regge-Wheeler equation, scattering of graviational waves off a black hole and quasi-normal modes
  • More spatial dimensions: the 2+1 wave equation

Students can code in their preferred language, although Python is strongly recommended (open sources, simple and optimal for visualizations).

Prerequisites

  • Basic knowledge of partial differential equations
  • Basic programming skills

Organisation

Person of charge: Prof. Dr. S. Bernuzzi

Supervision: Alejandra Gonzalez and/or Dr. Boris Daszuta

Place: Abbeanum, Fröbelstieg 1 or PAF Computerpool

Per term, one or two or three students may work on the topic.

Strong Interactions on the Computer: Gauge Theory on the Lattice Eintrag erweitern

The strong interaction that binds the elementary particles in nuclear matter is responsible for most the mass of visible matter. The mass is generated due to the interaction strength and it is hence essential for the formation of our universe. Nevertheless its charges can not be observed at the scales of our everyday live due to confinement: at low energies, a free charge of the theory can not exist and only bound states of fundamental particles are observed. At high enough energies, on the other hand, the theory is rather simple due to a phenomenon called asymptotic freedom. This simple fundamental theory is specified by the guiding principle of local gauge invariance, a generalization of the gauge principle of electrodynamics.

The confinement is an essential property of the theory, but it is not accessible by analytic perturbative methods. Some decades ago, the numerical techniques of Monte Carlo simulations on a space-time lattice have been developed. They are by now the most important methods to investigate the theory especially in the confined regime. This low temperature regime of bound state particles is separated by a deconfinement transition form a high temperature regime at which the fundamental constituents, the quarks and gluons, become relevant degrees of freedom.

The aim of this project is to understand the theoretical foundations of gauge theories and explore properties of the theory in numerical simulations.

Goals of the project

  • obtain understanding of theoretical foundations of gauge theories and strong interactions
  • understand the basics of lattice Monte Carlo simulations in quantum field theory
  • derive a program code for the simulation of SU(2) pure gauge theory (some skeleton code and examples are provided)
  • investigate the deconfinement transition
  • optional extensions: improved algorithms, static quark-antiquark potential and further observables

Prerequisites:

  • basic knowledge of quantum field theory
  • programming skills (C++, C, Fortran)

Contact:

Supervision: Dr. Georg Bergner, Theoretisch-Physikalisches Institut

Where: Theoretisch-Physikalisches Institut, Fröbelstieg 1 (Abbeanum)

Per term, one or two students may work on the project

Hydrostatic Models of Planet Interiors and Atmospheres (not available) Eintrag erweitern

Goals and context:

Most of what we know about the internal structure of planets in the solar system ( and elsewhere) is based on observations of their external properties - and on models. Such models need to cover an extreme range of physical conditions and states, from low-pressure gas to high-pressure liquids and solids, including "exotic" material succh as liquid hydrogen. In this project, simple models of planet interiors and atmospheres are constructed and tested against more refined models and observational constraints. Possible examples for specific goals include:

  • test of the limits of simple models (When do they work? When and how do they fail?)
  • implementaion and test of more advanced analytic approximations of equations of state or tabulated material properties (When und where are they useful?)
  • construction of more complex models (What role do internal enegy souces and the temperature gradient play?)
  • etc.

Methods:

 Available analytic and numerical prescriptions for hydrostatic equilibrium, equations of state, and heat transfer are used to construct a new model or modify an existing one. Additional material properties and constraints are extracted from the literature. Possible languages for programming (and in most cases also visualization of the results) include C++, Wolfram Mathematica, Phyton, Mathlab.

Instructor:      Dr. Torsten Löhne

Venue:          online and/or Astrophys. Inst. and Unisternwarte, Haus 2 (Schillergässchen 3)

The complex topic can be worked on by one or multiple students. The actual tasks will be adapted. Supervision is possible in English and German.

Modern Topics in Quantum and Gravitational Theories Eintrag erweitern

Possible topics within this project are:

  • Entanglement and its entropy measures in quantum mechanics
  • Supersymmetric quantum mechanics
  • Magnetic monopoles and quantization of electric charge
  • Magnetic monopoles in theoretical condensed matter physics: From the Berry phase in quantum mechanics to the field theoretical description of Weyl semimetals
  • Do particles exist interpolating between a fermionic and a bosonic behaviour? Anyons and their description in terms of Chern-Simons theory.
  • Hawking radiation and evaporating quantum black holes*

    *basic knowledge of general relativity and quantum field theory required.

Contact

Supervision: Prof. Dr. Martin Ammon

Venue: Theoretisch-Physikalisches Institut, Fröbelstieg 1 (Abbeanum)

One or two students may work on this topic per term.

Modelling of Nanooptical Structures Eintrag erweitern

Goals and context

The strong coupling of light to quantum systems relies on the confinement of electromagnetic fields to sub-wavelength volumes. This can be achieved by hybrid nanophotonic quantum systems in which photonic nanostructures support tightly confined electromagnetic resonances. Computer simulations are an essential part of this research since the fabrication of nanoscopic structures is challenging and the experimental characterization of optical fields at the few photon level with nanometer resolution is equally complicated. Therefore, reliable simulation methods are required to calculate the electromagnetic response of nanostructured matter in advance. Since we are dealing with structures in the sub-wavelength range, "rigorous" methods are needed, which solve Maxwell´s equations without any approximation. Different approaches have become popular and important for certain classes of nanophotonic structures (micro and nano cavities, metasurfaces, nanoantennas).

Methods

The students will implement and use a rigorous numerical numerical method (FMM, FDTD, FEM, or BPM) for the solution of electrodynamic problems. They will either use one of the existing professional implementations of such methods or will be working on their own implementation in a programming language suitable for high-performance computing. The method will be used to simulate the behavior of a nanophotonic structure and to investigate the coupling to quantum systems.

Programming can be done in any language preferred by the students, but Python and Matlab are supported by existing implementations.

Prerequisites

  • Basic knowledge of partial differential equations
  • Basic knowledge of optics
  • Basic knowledge of numerical methods
  • Familiar with at least one programming language supporting numerical simulations (preferred Python or Matlab)

Organization

Person in charge: Prof. Dr. Thomas Pertsch

Supervisor: Dr. Ángela Barreda and/or Dr. Tobias Vogl

Place: Abbe Center of Photonics, Computer Pools

Per term, up to two groups of one or two students may work on the topic.

Quantum Simulation of Particle Tunneling Eintrag erweitern

Goals and Context

The tunneling of a wave through a potential barrier is one of the fundamental experiments in quantum physics and arguably one of the most studied effects thereof. It has contributed greatly to our understand of the quantum world and is, as such, an ideal experiment to test new simulation methods. The one in question for this project are quantum computers. These utilize interference as a resource for algorithmic problems and are thus exceptionally well-suited to study interference phenomena with almost exponential speedup in scaling over their classical counterparts. Based on a newly developed method to efficiently solve wave equations in QCs we would like to re-investigate quantum tunneling both as a test-case of the method and also as a benchmark on real state-of-the-art quantum computers.

Methods

The students will use a newly developed method to solve Schrödinger’s Equation on a Quantum Computer and implement efficient ways to model various types of potential barriers. They will then analyze the statistical nature of the Quantum Simulation to derive precision boundaries for observables. The programming is done with Python and involves the execution of code on a real quantum computer, accessed via the QISKIT interface.

Prerequisites

  • Basic knowledge of partial differential equations
  • Basic knowledge of programming (Python)
  • Basic knowledge of Quantum Physics

Organization

Person in charge: Dr. Falk Eilenberger

Supervisor: Dr. Falk Eilenberger / Siavash Davani

Place: Abbe Center of Photonics, Computer Pools

Per term, up to two groups of one or two students may work on the topic.

Astronomy

Historical Novae (not available) Eintrag erweitern

Problem:

In the last two millennia, astronomers (as well as citizen scientists) from Far East (China, Korea, Japan), Arabia and Europe have observed some 100 new objects on sky ("new stars" or "guest stars"). These objects could be novae or supernovae, if neither a tail nor motion relative to the stars is reported (which would be typical for comets). Novae (non-final explosions) and supernovae (final explosions) were visible for several days to some months and their date and position, as well as brightness and colors were recorded. Nine of them were identified as Galactic supernovae. Among the remaining "guest stars", there could be more supernovae, but also several novae. Historical novae and supernovae are important for modern astrophysics: (a) Since in those historical cases, the date of the explosion is known, the age of the products are precisely known and not as uncertain as astrophysical measurements would allow to determine - the latter have large error bars for gaseous shells, the (super-)nova remnants as well as for white dwarfs and neutron stars. (b) The historical light curve can be used to determine the type of the supernova (e.g. core-collapse or thermo-nuclear). (c) If a runaway star is found (from a supernova in a binary stellar system), its parallax gives an accurate distance for the (super-)nova remnants (e.g. neutron star), more precise than otherwise possible.

Tasks (e.g.):

  • identification of nova candidates from historical texts,
  • follow-up observations at the AIU Jena telescope,
  • compilation of a light curve and best fit solution to typical light curves of different supernova types, or
  • search for runaway stars in the database of the Gaia satellite.

The project can contain the analysis of historical texts (Terra-Astronomy), possibly own astronomical observations, data reduction, statistics (best fit solution etc.) and astronomical interpretation.

Special language knowledge can be an advantage (like Chinese, Arabic, Latin, etc.), but is not required.

Supervision: Prof. Dr. Ralph Neuhäuser

Location: Astrophysikalical Institute, Schillergäßchen 2

The project can be undertaken by 1 to 2 students (or several teams). 

Observation of Exoplanets (not available) Eintrag erweitern

Contents and learning objectives

Since the discovery of the first planet outside our solar system some 20 years ago, more than 1000 of these exoplanets have been detected around distant stars. Several dozens of planets could be imaged directly next to their host star, using modern observing techniques on large telescopes of the 8 to 10m class. The vast majority of exoplanets, however, were detected indirectly by accurate spectrophoto-metric measurement of the light of their host stars. The transit method is today the most successfully used method for the planet search.

In the transit method, the occultation of the host star by its exoplanet is observed. By means of precise photometric measurements, the light curve of the star is measured during the transit of the planet, which allows the determination of the orbital period, the inclination of the planetary orbital plane and the planetary radius.

From the combination of the obtained results with available spectroscopic measurements (msin (i), minimum mass of the planet), the mean density of the exoplanet can be determined, which allows conclusions about its internal structure.

In this project, the students should use the observing method described above for the detection of planets in order to determine the properties of exoplanets, as well as their actual orbital parameters. The students learn the important basics for the reduction and analysis of photometric data of stars, which they themselves have recorded with the modern instruments, operated at the University Observatory in Großschwabhausen (see Fig. 1 & 2). Each exoplanet can be processed by 1 up to 3 students. The specific task will be adjusted depending on the observed exoplanet.

Technology

The photometric observations are carried out by the students at night at the University Observatory in Großschwabhausen (see Fig. 2) with the CCD-cameras, which are operated at the individual telescopes of the observatory.

Supervisor: Dr. Markus Mugrauer

Location (night observation): University Observatory in Großschwabhausen

Location (data reduction and analysis): Astrophysical Institute, Schillergäßchen 2, Jena

Observation of Binary Stars (not available) Eintrag erweitern

Contents and learning objectives

Since the discovery of the first binaries, visual, photometric and spectrometric observations have shown that most stars observable in the night sky are indeed stellar systems of two or even more stars. These binary or multiple star systems, which are bound together by their gravitational force, follow the laws of celestial mechanics, which were first empirically described by Kepler and then later astrophysically explained by Newton. Thanks to the classical mechanics, it is possible with observations to precisely determine the properties of the stars in these stellar systems, in particular their masses.

Since the mass of stars determines their evolution significantly, the observation and characterization of binary star systems is astrophysically very important. While wide binaries can still be observed directly with a telescope, more closer systems can be investigated spectroscopically by means of the Doppler effect. The movement of the components around their center of gravity reveals itself as a shift of the spectral lines in the common spectrum of the stellar system. The precise analysis of the radial velocities of the stars yields an exact characterization of the orbital parameters of the stellar system (e.g. period and orbital eccentricity) as well as its mass function or the mass ratio of its components.

In this project the students use the observing method described above for the detection and characterization of spectroscopic binary stars in order to determine the properties of these systems, as well as their actual orbital parameters. The students learn the important basics for the reduction and analysis of spectroscopic data of stars, which they themselves have taken with the modern instruments, operated at the University Observatory in Großschwabhausen (see Figs. 1 & 2).

Each spectroscopic binary system can be processed by 1 up to 3 students. The specific task will be adjusted depending on the observed stellar system.

Technology

The spectroscopic observations are carried out by the students at night at the University Observatory in Großschwabhausen (see Fig.2) with the Échelle spectrograph FLECHAS, which is operated at the 90cm reflector telescope of the observatory.

Supervisor: Dr. Markus Mugrauer

Location (night observation): University Observatory in Großschwabhausen

Location (data reduction and analysis): Astrophysical Institute, Schillergäßchen 2, Jena

 

Observation of Asteroids (not available) Eintrag erweitern

Contents and learning objectives

With Johannes Kepler's discovery of the laws of planetary motion, the true dimension of our solar system was revealed for the first time. Since the orbital periods of the known planets were already very well known at that time from celestial observations, with the 3rd Kepler's law also the semi-major axes of the orbits of the planets around the Sun could be described relative to the Earth's orbit. It showed that the then outermost planet of the solar system Saturn is about ten times farther from the Sun than the Earth. Furthermore, already Kepler noticed a remarkably large gap between Mars and Jupiter in the solar system, in which another planet was suspected.

After the by chance discovery of the planet Uranus in 1781 by Wilhelm Herschel, the Titius Bode series, which was already developed in the mid of the 18th century, appeared as a law to describe the semi-major axes of the planets in the solar system. This series also predicts a planet located in the large gap between Mars and Jupiter at a = 2.8au. At the end of the 18th century numerous astronomers then went in search for this unknown planet. On New Year's Eve in 1801, Giuseppe Piazzi discovered a point-like object in the sky that he could observe for several nights until mid-February and measure its movement. Further observations of the planet, named after the Roman goddess of agriculture Ceres, were no longer possible and so the newly found planet was lost again. Only thanks to the method of orbit determination based on celestial observations, developed by Carl Friedrich Gauss, the orbit of Ceres could be determined from the observations of Piazzi and so the position of the planet in the sky became predictable. Thus succeeded in December 1801 the rediscovery of Ceres.

Since many other celestial bodies in Ceres-like orbits around the Sun were soon discovered and all appeared point- or star-like in the sky as Ceres, these objects were henceforth referred to as asteroids (Greek for star-like) and also as minor planets or as planetoids. Ceres is the largest body in the asteroid belt between Mars and Jupiter in which more than 690000 asteroids are currently known. Because of its size and round shape, Ceres is nowadays called a dwarf planet.

In this project, the students will first observe asteroids, whose orbits are not sufficiently well known, using the CCD cameras installed at the telescopes of the University Observatory in Großschwabhausen. In the taken imaging data, the positions and magnitudes of the asteroids are then precisely measured. By means of modern orbit determination methods, the orbits of the asteroids and their absolute brightnesses are determined, which also enables an estimate of their sizes.

In this practical course, the students learn the important basics of the reduction and analysis of astrometric and photometric data, which they themselves have recorded with the modern instruments, operated at the University Observatory in Großschwabhausen (see Fig. 1 & 2). One asteroid each can be processed by 1 up to 3 students. The specific task will be adjusted depending on the observed asteroid.

Technology

The observations are carried out by the students at night at the University Observatory in Großschwabhausen (see Fig.2).

Supervisor: Dr. Markus Mugrauer

Comet Orbits (not available) Eintrag erweitern

Problem

The very fact that comets appear periodically was discovered and published 1705 by Edmund Halley. The comet for which he found the periodicity and for which he predicted the next appearance was later named after him: 1P/Halley (1 means first, P means periodic). In addition to this comet, there are many shorter period and non-periodic comets known. Most recently, even an extra-solar comet was observed to fly through the solar system.

(1) Observe new comets with our 90-cm telescope near Jena, reduce all the data, in particular for astrometry (exact position on sky), and then solve for the orbital elements. This has been done previously for several comets and other small solar system bodies (Mugrauer et al.).

(2) Interpretation of historical (mostly pre-telescopic) observations of comets in order to obtain a sufficient number of dated celestial coordinates, so that we can solve or improve their orbits and identify the comet (like E. Halley for 1P/Halley). This approach was recently tested by us for two perihelion passages of comets in AD 760 and 837, which were both comet 1P/Halley, for which we could then improve the orbital solution (using historical observations from East Asia, Arabia, and Europe, where positions on sky and dates were mentioned), by Neuhäuser and Mugrauer (et al.). The historical records are available in English translation.

(3) From one perihelion to the next, the orbital elements change slightly (e.g. the period of comet Halley sometimes by more than one year). This is due to gravitational interaction with other bodies in the solar system and also due to so-called “non-gravitational” forces, which is mainly due to outgassing (mass loss) of the comet during its close approach with the Sun. Such processes are not yet well understood, so that we try to improve comet orbit elements  by taking into account these outgassing processes. NB: A possible side-project could be to try to repeat the calculations of E. Halley: He did the calculation of the orbital elements “by hand”, while today we use software with our inputs (dated positions). It would be of high interest, to compare these two approaches, here also for aspects of the history of astronomy.

Tasks (e.g.)

  • Follow-up observations of new comets at the AIU Jena telescope,
  • data reduction of AIU Jena telescope data: astrometry, i.e. precise positions,
  • solving the orbit for a comet with dated positions,
  • interpretation of historical observations to obtain dated positions and then to solve for the orbit and to identify the comet, or
  • studying the light curve of a comet depending on its orbit (distance from Earth and Sun) and its activity parameters to learn about comet activity (outgassing).

Supervision: Prof. Dr. Ralph Neuhäuser and/or Dr. Markus Mugrauer

Location: Astrophysical Institute, Schillergäßchen 2

The project can be undertaken by 1 to 2 students (or several teams).

(Topics: observations, data reduction, astrometry, celestial mechanics, orbit analysis)

Detection and observation of runaway stars Eintrag erweitern

Contents and learning objectives:

Runaway stars are young, hot, massive or intermediate-mass stars showing a peculiarly high velocity with respect to the host cluster or OB association.They are moving away from their birth place, while the majority of others remain in their birth cluster.The high velocity nature of runaway stars is explained by two independent mechanisms: i) Dynamical ejection scenario (DES) proposes that the stars are ejected by gravitational interaction within the dense cores of the young clusters.ii) Binary supernova scenario (BSS) brings an alternative explanation that the star is ejected by its orbital velocity due to the supernova of the binary companion.Kinematic studies and observations of the young clusters have proven that the DES is working.On the other hand, high space velocities of isolated neutron stars imply that BSS is also viable.However, the star HD37424 is the only BSS runaway star which has been proven by observations.Finding BSS runaway stars provide us with great information on the supernova, supernova remnants (SNR) and neutron stars.The type of supernova, distance, age and all dependent parameters of the supernova remnant, the mass of the progenitor star and the kick given to the neutron star can be found.Therefore, exploring BSS runaways is now an important task in astrophysics.

The BSS runaways can be found inside the supernova remnants (e.g. Spaghetti Nebula) and nearby the young open clusters. The astrometry by the Gaia Satellite gives us precisedistances and transverse motion vectors of the stars.A star having a significantly higher transverse velocity w.r.t the galactic neighborhood and moving away from an SNR or a young open cluster is a potential candidate.These candidates can be detected through publicastrometry and photometry data and be confirmed by spectroscopic observations.For bright stars (V<11 mag), the observations can be performed at the University Observatory in Grosschwabhausen.The project aims to teach students using astronomical catalogs, stellar evolution models, stellar kinematics, observations and data reduction and analysis.

Tasks (e.g.):

  •   Selection of stars within a certain position and distance range
  •   Calculating the peculiar transverse velocity from proper motion of the stars
  •   Age estimates and tracing back the stellar motion in time
  •   Temperature and evolutionary stage estimation from photometry
  •   Spectroscopic observations of good candidates in Grosschwabhausen
  •   Data reduction and analysis

Supervision: Dr. Baha Dincel

Location: Astrophysikalical Institute, Schillergäßchen 2

The project can be undertaken by 1 to 3 students (also in several teams).

Gamma-Ray Burst Afterglows Eintrag erweitern
Content

From the discovery of the first Gamma-Ray Burst (GRBs) in 1967, it took nearly 30 years to discover an optical transient related to a GRB, which allowed to place them at cosmologic distances. Since the 90’s our knowledge of those cataclysmic events (emitted energy in gamma-rays: ~1051 – 1053 erg) has drastically expanded. We know today that these short-time gamma-ray sources (duration: a few 0.1 sec to several 100000 sec) can be found at redshifts z = 0.0085 to 9.4 (correlates to light travel time of 0.12 Gly to 13 Gly) and can be divided into two categories (long and short burst). Whereas long bursts (duration > 2 sec) are related to a special variant of type Ic supernova and short bursts (duration < 2 sec) are produced by the merger of two compact objects (preferably two neutron stars). The creation of the gamma-ray burst itself can be described within the fireball model by the collision of multiple shells traveling at high-relativistic velocities. After the burst, one can observe the afterglow of the GRB (from X-Ray to the Radio), which arises from the interaction of the shells and the interstellar material (ISM) and can be observed for several days to weeks.

The Project will focus on diffent aspects and caracteristics of the optical/NIR transients that follows the appearance of a GRB and the porperties of their host galaxies.  Up to 4 students can work on different topics within this project (several teams with 1 to 2 students).

Tasks and Learning goals
  • Reduction of photometric data in the VIS and NIR
  • Analysis (photometry and astrometry) of photometric data
  • Modelling of Afterglow light curves to derive the main properties (time and spectral evolution)
  • search and modelling of Supernova components that can be found in the light curve
  • investigating the properties of the GRB host galaxies (e.g. mass, age of the dominant stellar population, star formation rate)
  • search within public archives for additonal data 
  • deepening the understanding of relativistic outflows, Supernovae and the host galaxies of those events
  • Observations at the TLS Tautenburg with the 2m Schmidt Telescope, if weather conditions are acceptable
Organisation:

Supervision: Dr. habil Sylvio Klose; Dipl. Phys. Sebastian Schmidl

Location: Thüringer Landessternwarte Tautenburg (TLS Tautenburg) and/or F-Pranktikum (please contact S. Schmidl for further informations)

Students should consider, to spend one day every two weeks in Tautenburg to work on the project.