Project 1. Spin-optomechanics in silicon, PI Professor Juha Muhonen
Donor spins in silicon are known to be excellent qubits with one of the longest single qubit coherence times demonstrated in solid state. This is a significant advantage for both quantum sensing and quantum information applications. However, currently the application potential of silicon donor qubits is hindered by two related obstacles: current readout techniques require nanoelectric connections, millikelvin temperatures and high magnetic fields, and - most importantly - there are no scalable methods to couple multiple qubits.
In this project, you will work in realizing an optomechanical quantum bus for spins in silicon in order to enable optical and mechanical coupling and readout mechanisms for the donor spins and hence overcome all these obstacles. The created quantum bus will allow integrating the spin qubits with existing silicon photonics and NEMS platforms for integrated quantum circuits and optically readable practical quantum sensors.
In the longer term, the purpose of the project is not only to advance the technological applications but also create an on-chip platform where we can start to study the foundational questions of quantum mechanics. Having a system where long coherence times qubits (spins) are coupled to semi-macroscopic objects (mechanical resonators) with quantum level control, opens the experimental space into studying the appearance of unconventional decoherence mechanisms, spontaneous collapse models, and gravitational induced entanglement.
The group
In the Hybrid Quantum Technologies in Silicon Group we study the quantum potential of silicon technologies, concentrating especially on optical interfaces for silicon spin qubits and on optomechanical systems. The motivation comes from both enabling practical quantum sensors and quantum computing components and from studying fundamental physics in these on-chip quantum physics testbeds. Fundamental questions that we aim to investigate include the ultimate quantum coherence limits and possibilities for superposition states in macroscopic systems. The group was started in 2018 when the group leader Prof. Muhonen arrived to Jyväskylä. Since then, a state-of-the-art measurement laboratory has been built, and our experimental infrastructure includes 3K and millikelvin systems with both optical and electrical (DC and microwave) access. We also use extensively the cleanroom facilities at the Nanoscience Center.
What we expect from candidates in this project?
- You have a doctoral degree (or are close to getting one) in physics or related engineering sciences and have research experience in an international environment. We seek an excellent candidate with relevant experience, preferably in experimental quantum information, quantum optics, nanophotonics, low temperature physics or other AMO physics.
- In the project, you will need to combine advanced optical and microwave methods at low temperatures, strong theoretical understanding about the physics involved, and skills in numerical modelling (Python preferred). Preferably, you would already master some of these, but the rest can be learned during the project.
- You will guide PhD and MSc students and can drive the project forward. You have an experimentalist mindset but you are not shy about putting pen to paper for some calculations. Proactivity is a must.
Project 2. Next generation superconducting qubits, PI Professor Ilari Maasilta
Quantum devices, for example superconducting qubits, exploit genuine quantum-mechanical features, such as coherence and entanglement, to create functionalities that are not available classically. Next generation superconducting quantum hardware requires advances in device physics to decrease the complexity of fabrication and interference of ubiquitous and unwanted decoherence mechanisms. Novel ideas for the design and fabrication of such devices must employ latest knowhow from material science and nanotechnology, to provide a scalable platform for studying fundamental physics as well as implementing quantum algorithms. In this project, you will advance such quantum technologies by developing helium-ion beam based fabrication of Josephson junctions in qubits using advanced superconducting materials such as NbTiN, which you will grow in house with pulsed laser deposition (PLD). In addition, you will leverage the existing computational and fab expertise in the group to study a hybrid phononic crystal-qubit device designed to suppress two-level system (TLS) mediated decoherence.
The Thermal Nanophysics and Superconducting Devices Group has been an established research group since early 2000s. It is one of the heaviest users of the NSC nanofab and cryogenic infra. It has currently three main research directions: 1. Development of new superconducting materials and devices, especially superconducting junctions for quantum technology (qubits) and ultrasensitive superconducting radiation detectors (such as TESes); 2. Nanoscale thermal transport, especially focusing on phononic crystals and near-field phonon tunneling across vacuum; 3. Utilizing novel nanofabrication and imaging techniques for interdisciplinary projects, such as nanoscale biological imaging with helium ion microscope (HIM) and 3D laser lithography. The group runs a lab with several dilution refrigerators, one of them containing SQUID amplifiers, and has particular expertise in advanced nanofabrication using pulsed laser deposition, helium ion-beam direct writing and 3D laser lithography.
What we expect from candidates in this project?
- You have a PhD (or are close to getting one) in experimental physics or related engineering sciences and have research experience in an international environment. We seek an excellent candidate with some project-relevant experience, preferably in experimental quantum or other superconducting devices, advanced nanofabrication. (experience with HIM, PLD and/or e-beam lithography is a benefit), low temperature physics, phononic crystals, and/or microwave measurements.
- You are self-motivated with the ability to work independently, drive the project forward and participate creatively in collaborative teams including MSc and PhD students.
- You have an experimentalist mindset but are not shy to do some calculations, including numerical modelling.
The contract
- The contract will be initally for two years, starting on 1 September 2024, or as mutually agreed.
- The annual salary will be approximately 43,300 - 50,400 EUR (gross income, including a holiday bonus), depending on the qualifications and experience of the candidate.
- A six-month trial period will be implemented at the beginning of the employment.
The duties, qualification requirements and language skills of a postdoctoral researcher are stipulated by the University of Jyväskylä Regulations and language skills guidelines. The doctoral degree required for the position must have been completed before starting the position.