Pfaff, Wolfgang

Plug&Play Quantum Circuits

Wolfgang Pfaff - University of Illinois Urbana-Champaign, United States

Abstract: Mediating interactions and generating entanglement between separated qubits is a fundamental physics problem, as well as an important ingredient for scalable quantum technology. On one hand, the ability to create entanglement between qubits that are not immediate neighbors enables modular quantum devices and high connectivity in quantum processors. On the other hand, it is an intriguing fundamental question to ask what the limits are for creating pure entangled states between non-interacting qubits.

I will discuss ongoing efforts in my group that are targeting both practical and fundamental aspects, using the circuit QED platform: For one, we have realized two-qubit gates with high fidelities through detachable and reconfigurable cable connections; this effort is geared towards developing means to scale quantum processors beyond single wafers. Next, we are developing routing schemes that will enable all-to-all connectivity for 'plug & play' connected networks. Finally, we have developed a driven-dissipative protocol with which we aim to show experimentally steady-state remote entanglement between qubits that do not interact coherently. This effort can be understood as a way of using bath engineering to mediate interactions.

Through these approaches we aim to advance scaling of superconducting quantum devices, and shed light on the question how distributed quantum states may be preserved in open systems.