The Finnish Quantum Flagship is looking for Doctoral Researchers. The Quantum Flagship is a national initiative to promote quantum science and technology and develop researcher training.  At Tampere University, we are looking for 5 Doctoral Researchers in the area of theoretical and computational physics to work on projects motivated by quantum science and technology. Successful candidates will pursue a doctoral degree at Tampere University. The positions are full-time and for three years, during which doctoral studies are expected to be completed.

The research projects are: 

Project 1: Theory of many-body physics in quantum devices

Traditionally, many-body systems studied in physics are found in naturally occurring or man-made materials. Today, the whole concept of “material” can be generalized to include virtual materials that only exist within a simulation in quantum devices and quantum computers. In contrast to the traditional materials, the properties digital quantum materials are flexibly tuned and probed. In fact, the present and near-future quantum devices offer one of the richest and most exciting realizations of quantum materials, exhibiting massive quantum entanglement between their constituents. In this project, we theoretically study novel many-body phenomena which has been recently discovered in quantum computing platforms. In particular, the project focusses on entanglement phase transitions, measurement-induced dynamics and preparation of exotic states of matter. The project combines advanced theoretical and numerical methods.

Project 2: Quantum information aspects of many-body systems

Effective simulation of correlated quantum systems is, in general, intractable for traditional computers. The root cause of the difficulty is the exponentially scaling of computational resources in the system size. While there exist many powerful algorithms that can circumvent the exponential bottleneck, it is widely believed that only simulations with quantum hardware can efficiently accommodate the complexity of many-body systems. In this project we study theoretically the underlying quantum information patterns of many-body systems and quantify the complexity of physically relevant many-body systems. Besides popular partition entanglement entropies, there exists alternative measures to characterize different aspects of the complexity and multiparticle entanglement in a many-body state. These can be employed to shed light on the possibilities and limitations of quantum simulation and quantum information processing.  The project combines advanced theoretical and numerical methods.

Project 3: Towards quantum accuracy in multiscale modelling of defects in ferromagnets

Crystalline ferromagnetic materials typically have a disordered microstructure due to the presence of various lattice defects such as dislocations, grain boundaries, vacancies and solute atoms which crucially affect the properties of the material. Many key magnetization processes such as domain wall motion that are of both theoretical and practical importance depend on details of the interaction between the magnetic degrees of freedom and structural defects of the material. Yet, accurately modelling the effects of the microstructure in larger-scale computational models such as micromagnetic simulations remains an outstanding problem. In this PhD project, a new multiscale modelling framework will be developed where the atomic scale magnetic properties as induced by defects are extracted using accurate quantum mechanical density functional theory (DFT) calculations. The resulting information is then fed to larger-scale semi-classical micromagnetic simulations, making it possible to simulate disordered magnets at the micron scale with near-quantum accuracy.

Project 4: Branched flow and quantum scarring in two-dimensional systems

Two-dimensional (2D) electronic systems show fascinating physical phenomena and have novel applications in next-generation quantum electronics. Examples of such systems contain, for example, different semiconductor devices, superlattices and heterostructures, quantum wells and dots, quantum Hall systems, topological insulators, as well as graphene and other layered materials.  Recent studies have revealed that depending on the material and the energy scale, electrons in 2D systems may show complex branched flow resembling tsunami waves, quantum scarring with regular trajectories among chaos, or abrupt and anomalous diffusion properties. These novel phenomena are not yet well understood nor exploited in realistic experimental settings including disorder or other perturbations. In this project we examine these phenomena with comprehensive classical and quantum simulations. Alongside physical understanding, our goal is to develop a transport scheme, where electronic motion in two-dimensional systems can be controlled at will, even in the presence of disorder.

Project 5: Modelling surface chemistry and defects in quantum devices

Semiconductor device manufacturing and engineering is approaching single-atom precision. Here, a deterministic and repeatable placement of substituent atoms opens new opportunities for quantum materials and devices where the engineered solid-state dopant lattices exhibit characteristic (tunable) electronic band structures and topological states. This enables manufacturing large-scale artificial atomic arrays of dopant atoms in silicon which will provide building blocks (qubits) for emerging quantum information technologies. In practice, the manufacturing process involves a hydrogen terminated surface [e.g. Si(001)] where dopants (e.g. As) can be selectively placed prior encapsulation. The purpose of this PhD project work is to provide theoretical insight for the atomistic phenomena which take place during the manufacturing process, and especially, the role of hydrogen and defects. For this purpose, we shall perform DFT simulations of surfaces, interfaces and defects to simulate hydrogen formation energetics and migration paths.

The projects will be carried out at Computational Physics Laboratory in the Faculty of Engineering and Natural Sciences at Tampere University.

For more information and how to submit an application, please see:

https://tuni.rekrytointi.com/paikat/?o=A_RJ&jgid=1&jid=2278