2.5D cQED: Multilayer circuit quantum electrodynamics
Publications & Patents
Planar Multilayer Circuit Quantum Electrodynamics [ArXiv]
Z.K. Minev, K. Serniak, I.M. Pop, Z. Leghtas, K. Sliwa, M. Hatridge, L. Frunzio, R. J. Schoelkopf, and M. H. Devoret
Phys. Rev. Applied 5, 044021
* Main manuscript on 2.5D circuit quantum electrodynamics (cQED)
[Patent] Techniques for coupling planar qubits to non-planar resonators and related systems and methods
Z.K. Minev, K. Serniak, I.M. Pop, Y. Chu, T. Brecht, L. Frunzio, R.J. Schoelkopf,
and M.H. Devoret
Priority date: Feb. 27, 2015
International Publication No. WO/2016/138395
Planar superconducting whispering gallery mode resonators (WGMR) [ArXiv]
Z.K. Minev, I.M. Pop, and M.H. Devoret
Appl. Phys. Lett. 103, 142604 (2013)
* Manuscript on multilayer planar superconducting whispering gallery mode resonators (WGMR)
In the field of quantum technologies based on superconducting elements, there are two experimental platforms: the fully planar (2D) approach, which can benefit from the parallel fabrication of integrated circuits, and the machined cavity (3D) approach, which provides record quantum coherence, the crucial ingredient for advanced quantum operations. These two seemingly conflicting approaches raise the question: Is it be possible to reconcile the demand for robust quantum coherence with the demand of modularity and scaling arising from increased complexity?
We demonstrate an intermediate approach that can unite the benefits of both architectures. The experimental platform consists of a stack of 2D circuit layers separated by vacuum gaps. The circuit layers can be fabricated using conventional single-layer fabrication procedures. By properly designing the metallic structures that face each other in different layers, we confine the electromagnetic fields in the vacuum gap, therefore minimizing losses from the substrate and connecting elements.
In order to demonstrate the potential of these design principles, we implemented an integrated, two-cavity-modes, one-transmon-qubit system for cQED experiments. This has been possible by introducing a key concept, namely that of aperture coupling, which provides the manner in which an element patterned in one layer, such as a qubit, links to the electromagnetic fields in-between the layers.
The measured coherence times and coupling energies suggest that the 2.5D platform would be promising for integrated quantum-information-processing and for interfacing with a variety of mesoscopic or atomic systems.