中央研究院數學研究所

Photon-number cumulants of Gaussian states

2026/02/25 (Wed.) 15:30~16:30

Date : 2026/02/25 (Wed.) 15:30~16:30
Location : Seminar Room 617, Institute of Mathematics (NTU Campus)
Speaker : Yanic Cardin (Polytechnique Montréal)
Organizer : Colin McSwiggen (AS)
Abstract :
Gaussian Boson Sampling (GBS) is a leading model of sub-universal quantum computation realizable with current photonic technologies. Despite recent experimental progress, the validation of GBS devices remains an open problem. In this talk, I present results on photon-number cumulants of multimode Gaussian states and discuss how these quantities can be used as experimentally accessible tools for device validation. After a brief overview of the GBS framework, I introduce a matrix-based approach for computing photon-number cumulants of general Gaussian states, drawing on graph-theoretic structures. By averaging these cumulants over Haar-random interferometers, device-specific details are eliminated, allowing the universal statistical behavior of photon-number distributions to be analyzed as a function of the number of modes. I conclude by highlighting the role of Haarpy, a Python library developed to automate the Weingarten calculus underlying these results.
**No quantum physics background is required for the talk.