BERKLELEY AMO/QI SEMINAR: Wolfgang Pfaff, UIUC

Entanglement between separated qubits is a key ingredient for quantum networks and modular quantum processors. The photonic channels used to distribute quantum states are typically lossy, however, demanding strategies and protocols that allow faithful entanglement distribution in open systems.

Here, I will present two complementary experimental directions tackling this challenge, building on the development of low-loss interconnect hardware for superconducting qubits [1].

First, I will discuss our efforts to autonomously stabilize remote entanglement in an open network [2]. To this end, we have realized a low-loss cascaded system in which interference of unidirectionally propagating photons acts as a nonlocal, correlated bath. With this approach we have observed driven-dissipatively stabilized remote entanglement.

Second, I will discuss an approach for loss-detection inspired by quantum error correction. Using higher-dimensional logical qubit encodings, we are able to utilize leakage levels outside the logical subspace to herald photon loss through a so-called erasure conversion.

These approaches set the stage for noise-resilient and scalable multi-node networks.

[1] M. Mollenhauer, A. Irfan, X. Cao, et al., Nat Electron 8, 610 (2025)[2] A. Irfan, K. Singirikonda, et al., Phys. Rev. X 16, 031004 (2026)