Quantum Technology Initiative Journal Club

Thursday 29 Jan 2026, 16:00 → 17:00 Europe/Zurich

513/R-070 - Openlab Space (CERN)

Michele Grossi (CERN)

Weekly Journal Club meetings organised in the framework of the CERN Quantum Technology Initiative (QTI) to present and discuss scientific papers in the field of quantum science and technology. The goal is to help researchers keep track of current findings and walk away with ideas for their own research. Some previous knowledge of quantum physics would be helpful, but is not required to follow the talks.

To propose a paper for discussion, contact: michele.grossi@cern.ch

16:00 → 17:00 CERN QTI Journal CLUB

Convener: Dr Michele Grossi (CERN)

16:00 Introduction to quantum Boltzmann machines

TITLE: Introduction to quantum Boltzmann machines

Abstract: This tutorial introduces quantum Boltzmann machines (QBMs) as quantum generalizations of classical Boltzmann machines, starting from their energy-based formulation and extending it to Gibbs states of parameterized many-body Hamiltonians. I explain how the non-commuting nature of quantum interactions fundamentally affects both expressivity and learning dynamics. I then present and compare two main classes of models: fully-visible QBMs, for which one obtains convex or near-convex loss landscapes and sample-efficient training, but at the cost of limited expressive power; and QBMs with hidden units, which constitute quantum analogues of restricted Boltzmann machines and are universal approximators, yet suffer from severe trainability and scalability issues due to non-commuting visible–hidden couplings. Throughout the tutorial, I emphasize the trade-off between optimization and representation power, clarify the connection to classical Boltzmann machines, and identify the regimes in which quantum effects can be leveraged while retaining practical and theoretically controlled training procedures.

Speaker: Cenk Tüysüz (CERN)

recording