Postdoc Position in Quantum Nanomechanics

Project 1: Gravitational coupling between nonclassical masses

• This project aims to address one of the great unresolved challenges in physics: While quantum mechanics successfully describes low-energy phenomena, it is incompatible with general relativity which governs gravity and huge energies. The interface between these two has remained experimentally elusive, because only the most violent events in the universe have been considered to produce measurable effects due to the plausible quantum behavior of gravity. We aim at detecting gravitational forces for the first time within a quantum system. We use mechanical oscillators loaded by milligram masses and bring two such gravitationally interacting oscillators into nonclassical motional states. The initial phase of the project focuses on measuring the gravitational force between milligram-scale gold particles, representing a new mass scale showing gravitational forces within a system. This work is part of the ERC Advanced Grant project “GUANTUM: Probing the limits of quantum mechanics and gravity with micromechanical oscillators”.

Project 2: Remote connection and strong coupling in coherent electromechanics

• We utilize “microwave optomechanical” devices, where micromechanical membrane oscillators interact with on-chip microwave cavity resonators. Optomechanical techniques allow for both preparing, measuring and manipulation of the mechanical quantum states. So far, true quantum states in such systems have been reached in only in physically adjacent components. We aim to extend this to remotely connected electromechanical systems capable of sharing a quantum state. This opens possibilities for fundamental studies in remote entanglement and quantum teleportation of mechanical states, as well as ultra-sensitive detection of weak, long-range forces—such as those predicted by physics beyond the Standard Model. Distant, coupled microwave optomechanical systems can also be utilized for quantum information transmission. In this project, two electromechanical quantum chips are connected via superconducting cables at millikelvin temperatures. The vibrating membranes will be realized with a phononic crystal radiation shield, enabling ultrahigh mechanical quality factors. In the project we are also interested in increasing the electromechanical coupling by creating a nanometer-size vacuum gap connection to the vibrating membrane via nanopositioning.  This work is part of European Union’s Quantera Program project “MQSens: Quantum Sensing with Nonclassical Mechanical Oscillators”, where opto-/electromechanics is utilized to explore how quantum protocols can be adapted to mechanical sensors in the quantum regime for various applications.

Key responsibilities include:

• The experimental work in all these projects involves design of the samples and of the measurement setups, cleanroom fabrication, performing cryogenic microwave measurements, and data analysis. You are expected to participate in advising and mentoring PhD students.