Research Interests

Quantum Networks Link to heading

Within the Quantum Internet Alliance (QIA), I work on the modelling of DLCZ-type elementary links for continent-scale entanglement distribution. I focus on an exact, non-perturbative model of such a link, exposing the fundamental trade-off between distribution rate and entanglement quality. Building on this exact modelling, I developed a loss-robust entanglement witness relying only on local operations and classical communication. I also studied a dual-rail full-repeater link, made of two elementary links spanning 500 km, whose hybrid swapping has to reconcile the heterogeneity between physical platforms.

Detailed description of a DLCZ-like elementary link.

Uniting Quantum Processing Nodes of Cavity-Coupled Ions with Rare-Earth Quantum Repeaters Using Single-Photon Pulse Shaping Based on Atomic Frequency Comb P. Cussenot, B. Grivet, et al. · Phys. Rev. Lett. 135, 240803 (2025)

DOI

@article{cussenot2025,
  title = {Uniting {{Quantum Processing Nodes}} of {{Cavity-Coupled Ions}} with {{Rare-Earth Quantum Repeaters Using Single-Photon Pulse Shaping Based}} on {{Atomic Frequency Comb}}},
  author = {Cussenot, P. and Grivet, B. and Feldmann, L. and Wengerowsky, S. and Lanyon, B. P. and Northup, T. E. and family=Riedmatten, given=H., prefix=de, useprefix=true and Sørensen, A. S. and Sangouard, N.},
  date = {2025-12-10},
  journaltitle = {Physical Review Letters},
  shortjournal = {Phys. Rev. Lett.},
  volume = {135},
  number = {24},
  pages = {240803},
  publisher = {American Physical Society},
  doi = {10.1103/hvsx-cx2d},
  url = {https://link.aps.org/doi/10.1103/hvsx-cx2d}
}

Quantum Compilation Link to heading

I work on machine-learning-based quantum compilation. So far this has been at the circuit level: framing exact circuit synthesis as a single-player game and training an AlphaZero-inspired agent to find new decompositions of subroutines. I am now interested in layers closer to the physical hardware, e.g. lattice-surgery compilation and the full toolchain of fault-tolerant quantum error correction.

Learning curriculum of the AlphaZero agent for quantum circuit synthesis.

Unitary Synthesis with AlphaZero via Dynamic Circuits X. Valcarce, B. Grivet, N. Sangouard · arXiv:2508.21217 (2025)

arXiv

@online{valcarce2025,
  title = {Unitary {{Synthesis}} with {{AlphaZero}} via {{Dynamic Circuits}}},
  author = {Valcarce, Xavier and Grivet, Bastien and Sangouard, Nicolas},
  date = {2025-08-28},
  eprint = {2508.21217},
  eprinttype = {arXiv},
  eprintclass = {quant-ph},
  doi = {10.48550/arXiv.2508.21217},
  url = {http://arxiv.org/abs/2508.21217},
  pubstate = {prepublished}
}

Side Project: UNIX Systems & Self-Hosting Link to heading

In my free time, I explore UNIX systems, with a particular interest in NixOS and reproducible workflows, with the longer-term ambition of building an agent-powered workflow running on local LLMs.

Client side: a centralised flake covering all my machines (laptop, Android tablet, WSL, …), both TUI (Neovim, tmux) and GUI (Wayland-based) environments, and per-project dev shells (Python, CUDA, Node), with some attention to ricing (Nixus-Public repo).
Server side: a personal homelab for storage and compute, covering cloud sysadmin basics, self-hosted services (*arr suite, Nextcloud, agents), GPU training pipelines, network architecture, etc.