Nonlinear quantum optics in microwave circuits
Photons generally do not interact with each other unless many of them fly through a special material (like certain crystals). These interactions can be useful for preparing interesting quantum states of light, including single photons or entanglement. Nonlinear interactions between photons can be much stronger for microwave photons in superconducting quantum circuits. I want to find out what interesting states we can prepare in these circuits and how we can efficiently verify their existence. Read more
Optomechanical levitation with coherent scattering
The main limitation of optomechanical systems are mechanical losses. Mechanical resonators are clamped to substrates which destroys their fragile quantum states. A solution to this problem is to trap the mechanical resonator (a small particle) using light, which confines its motion to a narrow region around the intensity maximum. The motion can then be precisely controlled by scattering the trapping light into an optical cavity. I study how these techniques can be used to control the motion of one or more particles in one cavity.
Cavity optomechanics with hybrid mirrors
I analyse hybrid optomechanical systems formed by dielectric membranes doped with two-level quantum emitters or patterned with photonic crystal structures. Such hybrid mirrors strongly reflect light around a particular wavelength, leading to a modified response to light. I am trying to find out what interesting applications such devices might have. On the one hand, some existing optomechanical experiments (such as optomechanical cooling) can be improved with this approach; there are also novel effects that I want to understand.
Mechanical oscillators can couple to a broad range of external forces and are thus suitable for conversion of signals between different carriers. One particular—and important—example is the conversion between microwaves and light which can be used improve detection of weak microwave signals or for conversion of quantum signals between superconducting quantum computers (operating at microwave frequencies) and light (suitable for long-distance quantum communication).
Gaussian entanglement of light
Gaussian states of light are an important subclass of all quantum states of light owing to their easy creation and manipulation. Most importantly, entangled Gaussian states can be prepared deterministically, unlike entangled states based on single photons. An important topic of research is finding states best suited for a specific task (such as quantum teleportation) or developing efficient protocols involving non-Gaussian operations (which are necessary, for instance, for entanglement concentration and distillation).