AQP Seminar: Non-gaussian interactions in optomechanical systems. An easy introduction with realistic applications

Abstract: 

In this seminar, I will give a friendly introduction to non-Gaussian interactions in opto- and electro-mechanical systems. In the last years, several research groups are pushing the boundaries of linear opto-mechanics and proposed several setups that seemingly have a dominant quadratic coupling between the mechanical motion and the light in the cavity. Being able to exploit this quadratic coupling is, in fact, essential if one wants to extend the realm of opto-mechanics to, e.g., quantum computing or more advanced quantum applications. A famous setup for which a quadratic dependence of the optical frequency with respect to a membrane’s motion was experimentally shown, is the so-called membrane-in-the-middle. As it was later demonstrated, however, this quadratic dependence resulted from a hybridization of several optical modes due to the mechanical motion. This also resulted in additional heating of the membrane, that ultimately makes the exploitation of the quadratic coupling extremely challenging, if not impossible. I will summarize the results of mine and others’ researchers in the area, and explain how the detrimental effects of this hybridization can be lowered, ultimately allowing for real exploitation of the quadratic coupling, i.e., of non-Gaussian interactions between the mechanics and the light. I will propose few experiments that are feasible for current technologies, where these non-Gaussian interactions can be used (in the short term) to create nonclassical mechanical states, or (in the longer term) a mechanical qubit that can be coherently manipulated.

References:

[1801.02438] Quantum nondemolition measurement of mechanical motion quanta (arxiv.org)

[2101.01750] Quantum manipulation of a two-level mechanical system (arxiv.org)