Coupling hybrid quantum systems: from atomic to solid-state qubits

Donghun Lee, Se‐Jong Kahng, Mahn‐Soo Choi

Dirk Englund, Luozhou Li, J. S. Hodges +6 more

Optical nanocavities enable a strong interaction between single photons and single emitters. An appealing application is the construction of a quantum interface for photonic and solid state qubits. Since the material of the solid state qubit is often dierent from the nanocavity, there has been considerable interest in combining the two in a hybrid architecture. We describe our recent development of such a hybrid interface based a Gallium Phosphide photonic crystal nanocavity that is scanned and deterministically coupled to single emitters on a surface. The technique is used to couple the cavity to the nitrogen vacancy center in diamond, an emitter system with optically accessible electron spins and the ability to transfer electronic spin states to nuclear spins.

O. P. de Sá Neto, M. C. de Oliveira

Solid state superconducting devices coupled to coplanar transmission lines offer an exquisite architecture for quantum optical phenomena probing as well as for quantum computation implementation, being the object of intense theoretical and experimental investigation lately. In appropriate conditions the transmission line radiation modes can get strongly coupled to a superconducting device with only two levels -for that reason called artificial atom or qubit. Employing this system we propose a hybrid two-quantum bit gate encoding involving quantum electromagnetic field qubit states prepared in a coplanar transmission line capacitively coupled to a single charge qubit. Since dissipative effects are more drastic in the solid state qubit than in the field one, it can be employed for storage of information, whose efficiency against the action of an ohmic bath show that this encoding can be readily implemented with present day technology. We extend the investigation to generate entanglement between several solid state qubits and the field qubit through the action of external classical magnetic pulses.

Janos Storcz, Mathematisch-naturwissenschaftlichen Fakultät I

Cleaven Chia, Ding Huang, Victor Leong +2 more

Abstract The development of single‐platform qubits, predominant for most of the last few decades, has driven the progress of quantum information technologies but also highlighted the limitations of various platforms. Some inherent issues, such as charge/spin noise in materials hinder certain platforms, while increased decoherence upon attempts to scale up severely impacts qubit quality and coupling on others. In addition, a universal solution for coherent information transfer between quantum systems remains lacking. By combining one or more qubit platforms, one could potentially create new hybrid platforms that might alleviate significant issues that current single‐platform qubits suffer from, and in some cases, even facilitate the conversion of static to flying qubits on the same hybrid platform. While nascent, this is an area of rising importance that could shed new light on robust and scalable qubit development and provide new impetus for research directions. Here, the requirements for hybrid systems are defined with artificial atoms in the solid state, exemplified with systems that are proposed or attempted, and conclude with the outlook for such hybrid quantum systems.

D. V. Averin