Speaker: Guillermo F. Peñas Fernández
Affiliation: IFF-CSIC
Date: Thursday, 13 February 2025 at 11:00
Location: Seminar Room, Serrano 113b
Scaling up quantum computers remains a significant challenge due to their extreme sensitivity to environmental interactions. While early theoretical proposals have led to proof-of-concept quantum computers, the problem of achieving large-scale, fault-tolerant computing is still unresolved. Distributed Quantum Computing (DQC) offers a promising approach by distributing computation and memory across multiple medium-sized nodes, reducing cross-talk and control overhead. However, this introduces the need for fast, reliable, and synchronized quantum state transfer between nodes.
This thesis focuses on quantum state transfer networks, where quantum information is transmitted by mapping stationary qubits onto propagating ones. Superconducting circuits, with their strong and tunable light-matter interactions, provide an ideal platform for implementing these networks. The research has two main objectives: (1) developing a theoretical quantum optical model for state transfer networks based on microwave quantum links, and (2) designing novel protocols and mitigation strategies to address critical challenges in current implementations.
Through detailed modeling, this work identifies often-overlooked error sources in superconducting circuits, such as wavepacket distortion from nonlinear dispersion relations and non-uniform couplings, which compound known issues like slow measurements, limited coherence times, and cryogenic requirements. Additionally, this thesis addresses the challenges of multiplexing quantum information and distributing entanglement across the network, both of which are crucial for scalability.
The results demonstrate that state transfer networks based on microwave quantum links are a viable and scalable solution for quantum information processing, provided that appropriate design protocols and error mitigation strategies are implemented.