Internship program

Host: Markus Müller, RWTH Aachen/Forschungszentrum Jülich

Quantum neural networks have been proposed as a computational paradigm to combine benefits such as massive parallel information processing in neural networks with advantages like the computational speedup promised by quantum computers. In this theory internship, you will first familiarise yourself with the basics of quantum neural neural networks and machine learning. You will then implement a quantum neural network based on a quantum Hopfield, multi-layer or quantum cellular automaton network architecture, and investigate and benchmark its performance for applications such as information storage and retrieval, or for quantum error correction.

Project-specific requirements:

Completed course in quantum mechanics and solid understanding of quantum mechanics.
Ideally completed course on quantum computing and algorithms, and possibly also in machine learning.
Some knowledge in numerical programming (e.g. in python, matlab, C++).

Host: Markus Müller, RWTH Aachen/Forschungszentrum Jülich

Qubits encoded in electronic states of neutral atoms held in optical tweezer arrays provide a highly promising, quickly developing platform for scalable quantum computing. Atoms can be laser-excited to Rydberg states with strong and long range-interactions, which can be used to realise fast and high-fidelity two- and multi-qubit gate operations between atoms. In this theory internship, you will first familiarize yourself with the basics of quantum computing and algorithms. You will then develop and numerically implement protocols for quantum gate operations between Rydberg atoms and investigate their expected performance under realistic conditions and noise sources, as building blocks of more complex quantum algorithms.

Project-specific requirements:

Completed course in quantum mechanics and solid understanding of quantum mechanics.
Ideally completed course on atomic physics or quantum optics.
Some knowledge in numerical programming (e.g. in python, matlab, C++).

Host: Christoph Stampfer, RWTH Aachen

We assess the potential of bilayer graphene quantum dots as hosts for valley and spin qubits. With our state-of-the-art fabrication technology, we can form quantum dots in bilayer graphene which allow control of the charge carrier occupation and the interdot tunnel coupling. In this type of devices, we studied e.g. spin relaxation times [1] and achieved a spin-valley blockade in an electron/hole double quantum dot [2].

The goal of this project is the characterization of spin and valley relaxation rates. For that purpose, we use devices with capacitively coupled single electron transistors acting as charge sensors. This will allow time-resolved detection of individual spin and valley states. A high-frequency reflectometry measurement technique will be used to enhance the readout fidelity.

Depending on your personal interests, your focus can lie on the device fabrication or on measurements and data analysis. You will gain expertise in high-frequency quantum transport experiments, in the physics of 2D materials and in the relevant fabrication techniques.

[1] Banszerus, Hecker et al., Nature Communications 13, 3637 (2022).

[2] Banszerus, Möller et al., Nature 618, 51 (2023).

Project-specific requirements:

This project requires a background in the field of solid state physics or 2D materials. First experience in quantum transport measurements or programming (python) is beneficial but not required.

Host: Sebastian Hofferberth, Bonn University

Help us design & construct the world-first portable Strontium MOT – which will make ultracold atoms visible by eye in a compact setup to be used in outreach, teaching & student research. In this project you can gain hands-on experience in design & setup of state-of-the-art AMO experiments.

Hosts: Christian Dickel & Daniel Rosenbach (Ando & Bocquillon Groups), University of Cologne

Embedded within the II. Institute of Physics in the University of Cologne we are investigating electromagnetic signals emitted by Josephson junctions. These are nano- to micrometer scaled devices that consist of two superconducting metals interrupted by an insulating or semiconducting material.
In order to measure Josephson radiation from these devices we need cryogenic temperatures, a radio-frequency pick-up, an amplification chain for the measured signal and working devices. Based on your interest and personal background we could discuss how you can contribute to our efforts.
Projects might cover the fabrication of devices in a cleanroom environment, operation and optimization of measurements at cryogenic temperatures, implementation of measurement and analysis routines using python or conceptualizing and testing new components for the measurements setup.

Project-specific requirements:
Completed course on electromagnetism.
At least one practical course in experimental physics.
Experience in numerical programming, especially with Python, would be preferable

Hosts: Boris Stanchev, Erwann Bocquillon Group, University of Cologne

Thanks to their unique quantum mechanical properties, thin-film quantum anomalous Hall insulators are a building block for an emerging class of microelectronic devices. Electrons in these materials flow along one-dimensional edge channels, giving us a unique way of engineering quantum systems in these devices. In the Bocquillon group, we study the fundamental electronic transport properties of devices based on these films. For this project, focus lies in the control of the flow of electric currents along the edge channels. The direction of this current depends on the direction of the magnetization of these thin films. We will study how to reverse the magnetization by applying large current pulses, which will then let us create co-propagating edge channels at the interface between two magnetic domains.

A potential intern may choose to focus on cleanroom microfabrication, characterization of devices at the mK temperature scale, as well as engineering/modifying electronic measurement setups.

Project-specific requirements:

Completed course on quantum mechanics and on electromagnetism
At least one practical course in experimental physics

Host: Dr. David Edward Bruschi, Forschungszentrum Jülich

Controlling the dynamics of quantum systems is key to understanding physical processes and phenomena. Quantum dynamics are defined abstractly via the celebrated Schrödinger equation provided in the theory of quantum mechanics. Application of this tool to simple problems provides clear and immediate evidence of the stark difference between the classical and the quantum world. Nevertheless, obtaining explicit expressions once a Hamiltonian that governs the evolution and an initial state of the system are given is usually an extremely hard task. Among the tools available to tackle this problem one finds Lie theory of groups and algebras, which has been recently employed with some success.

In this project we explore the formal aspects of Lie algebraic approaches to time evolution, focusing on mathematical methods and analytical tools. The goal is to investigate the scope of validity of these approaches, with particular attention to finding explicit solutions and expressions for the dynamics. The starting point is the collection of results obtained to date by the project supervisor. While it might be difficult to obtain concrete closed formulas, pushing the boundaries of our understanding in this area providing no-go theorems, or partial and approximate solutions can still be seen as a successful endeavour.

Project-specific requirements:

Strong mathematical physics background, and an aptitude for analytical and independent work.

Host: Vincent Mourik, Forschungszentrum Jülich

Hole spin qubits in electrically defined quantum dots inGermanium quantum wells are a great platform for future quantum technologies. One of reasons for its fast success are the lowered fabrication requirements, especially useful is the ability to form electrical contacts to holes using interdiffused metal contacts. In Germanium, distances between the actual spin qubits and the interdiffused contacts is often as low as a few hundreds of nanometers. Since interface defects can be a dominant noise source in spin qubits, investigating the noise spectral density on differently far retracted Ohmic contacts will be investigated in this project.

Project-specific requirements:

A good understanding of quantum mechanics. Background in quantum mechanics necessary.
A basic understanding of DC transport measurements and solid state physics.
Willingness to work with python and homebrewed python libraries.

Host: Vincent Mourik, Forschungszentrum Jülich

Two dimensional hole gases like in strained Germanium have shown recent promise in gated electronics, both with the superconducting and spin community. With the low effective mass, high carrier mobility, spin-orbit coupling, and fermi-level pinning, we open a new toolbox of experiments to be done with proximitized planar Josephson junctions with Germanium. Depending on the properties of the hole gas, we can study exotic versions of existing junction phenomena and try to understand the physics behind few-mode superconducting transport. Through this project, we aim to optimize junction characterization at milli-Kelvin temperatures and gain insight on the effects of junction geometry on the physics of Andreev Bound States in nanoscale devices.

Project-specific requirements:

A good understanding of quantum mechanics. Background in quantum mechanics and electronics necessary.
A basic understanding of DC transport measurements and Josephson junctions.
Willingness to work with python and homebrewed python libraries.