Vortrag Andreas Wallraff Meter-Scale Microwave Quantum Interconnects: From Fundamental Physics to Applications in Quantum Computing

Meter-Scale Microwave Quantum Interconnects: From Fundamental Physics to Applications in Quantum Computing

Andreas Wallraff
ETH Zurich
http://www.qudev.ethz.ch

Superconducting circuits are a strong contender for realizing quantum computing systems. Constructing such systems with many thousands, possibly millions of superconducting qubits will likely require linking several computing nodes housed in their dedicated cryogenic systems into a larger networked cluster. Such networks could operate at optical frequencies using fiber links but would require large bandwidth and high-fidelity microwave-to-optical conversion. At ETH Zurich, in a radically different approach, we have designed, realized, and tested a first quantum microwave link which allows superconducting-circuit-based quantum processors located in different systems to directly exchange quantum information [1] over distances of up to 30 meters as demonstrated in a loophole-free Bell test [2]. This link, for a quantum computer, takes the role of a network transferring data between computing nodes located in a high-performance computing data center. However, unlike its conventional counterparts, our data link is operated at ultra-low temperatures, close to absolute zero. This allows our quantum data link to directly connect to quantum processors operating at the same temperature [3]. Using this system, we transfer qubit states and generate entanglement on demand with high transfer and target state fidelities. The system we have constructed is the first of its kind in the world and could play an important role in both growing the power of quantum computers in the future and allowing for fundamental quantum science experiments.

[1] P. Magnard et al., Phys. Rev. Lett. 125, 260502 (2020)
[2] S. Storz et al., Nature 617, 265-270 (2023)
[3] P. Kurpiers et al., Nature 558, 264-267 (2018)