I am a PhD student in the Mesoscopic Physics group lead by Prof. Peter Samuelsson.

I am interested in questions within Quantum Thermodynamics and Open Quantum systems. In particular the process of measurements on quantum systems and utilizing this for feedback control.

Pop Sci summary:

The number of applications of control theory today is nearly countless, with applications in fields as diverse as the stock market and telecommunications. However, due to the constant advancement of technology, new types of systems have emerged that require control and regulation, systems that differ somewhat from what we are used to in our everyday "classical" world: namely, quantum mechanical systems.

When controlling quantum mechanical systems, one encounters some unexpected challenges. One of the strange predictions of quantum mechanics is that the system and the measurement instrument are not decoupled from one another; a measurement on a quantum system will affect the state of the system. To measure the state of the system and then use this information to control it, we necessarily disturb the system, thus influencing its state. This interaction between measurement and system is called back-action. To avoid back-action while still being able to control quantum systems, a method known as weak measurements has been developed. Weak measurements extract only a small amount of information from the system and therefore do not disturb it significantly. The price we pay is that we may not necessarily perform accurate feedback given the incomplete information about the system's state.

Recently, a new type of equation was published within the group that allows for the description of a quantum mechanical system controlled by weak measurements. Similar equations have been published before but have required computers to solve them (aside from a few special cases). What is exciting about this new equation is that it enables one to calculate the effects of control for these systems by hand, using pen and paper, for a much larger class of feedback situations than was previously possible