Abstract

In this talk, I outline the on-going projects and recent results from QCD Labs. I begin with a brief overview of our demonstrations of magnetic-monopole analogues [1,2] and quantum-mechanical knots [3] in superfluids. Subsequently, I focus on our development of engineered environments for quantum-mechanically behaving superconducting circuits. In this context, I present our recent results on quantum-limited heat conduction over macroscopic distances [4] and the quantum circuit refrigerator. In the future, we aim to develop these concepts into in-situ-tunable components that can be use to conveniently cool down quantum devices at will. Such components can potentially be applied in the initialization of quantum registers in a quantum computer and in the enhancement quantum annealers. Finally, I introduce a thermal detector for propagating microwave photons [5] and demonstrate that it can distinguish between single zeptojoule microwave pulses using electrothermal feedback [6]. To our knowledge, this is an order-of-magnitude improvement over previous thermal detectors.

[1] M. Ray et al., Nature 505, 657 (2014). [2] M. Ray et al., Science 348, 544 (2015). [3] D. S. Hall et al., Nature Phys. doi:10.1038/nphys3624 (2016). [4] M. Partanen et al. Nature Phys. doi:10.1038/nphys3642 (2016). [5] J. Govenius et al. Phys. Rev. B 90 , 064505 (2014). [6] J. Govenius et al. arXiv:1512.07235 (2015).