MARVEL Junior Seminar — March 2026

Each seminar consists of two presentations of 25 minutes each, allowing to present on a scientific question in depth, followed by time for discussion. The discussion is facilitated and timed by the chair.

Pizzas will be served after the seminars in order to facilitate discussions based on the talks just presented. 

Onsite participation

12:15 — Seminars take place in EPFL room Coviz2 (MED 2 1124)

~13:15 — Pizzas will be served in the MED building atrium, second floor

Online participation

Starting at 12:15:

https://epfl.zoom.us/j/62524680392
Password: 805442

Abstracts

Talk 1 — Pump-induced out-of-equilibrium magnetism in the Mott insulator CuO 

Katja Sophia Moos , Yun Yen, Gian Parusa, Arnau C. Romaguera, Elia 
Razzoli, Hiroki Ueda, and Michael Schüler
Center for Scientific Computing, Theory and Data, PSI

Understanding ultrafast magnetism requires tracking energy flow among coupled electronic, spin, and lattice subsystems. Using time-resolved resonant diƯuse scattering combined with complementary X-ray techniques and quantum-kinetic simulations, we reveal microscopic pathways of pump-induced demagnetization in the antiferromagnetic Mott insulator CuO. Above-bandgap photoexcitation creates non-thermal magnons across the Brillouin zone within tens of femtoseconds, followed by magnon-magnon scattering driving quasi-thermalization within picoseconds. Magnetic recovery occurs via magnon[1]phonon coupling on nanoseconds, constrained by dispersion mismatches imposing intrinsic bottlenecks. Our momentum-resolved quantum Boltzmann simulations establish a hierarchical energy transfer framework beyond phenomenological multi-temperature models, reproducing key features of the experiments. This approach provides design principles for controlling non-equilibrium magnetic states and highlights time-resolved resonant diƯuse scattering as a power tool for ultrafast quantum materials researc

Talk 2 — Pauli and Majorana Propagation for Ground-State Preparation of Quantum Many-Body Problems

Julia Gerecke, Zoë Holmes
Laboratory of Quantum Information and Computation - QIC, EPFL

Quantum simulations are promising for studying quantum many-body problems, with the ultimate goal of advancing materials discovery. For efficient use of quantum hardware, classical ground-state preparation frameworks are required that can both provide inputs to and serve as benchmarks for quantum hardware simulations. 
We implement and benchmark variational ground-state preparation using the classical simulation method Pauli Propagation [1] for spin systems and emphasize the algorithmic principles underlying this propagation framework. We further introduce Majorana Propagation [2], a classical simulation method for fermionic systems that shares key algorithmic features with Pauli Propagation. 
In both operator-propagation methods, expectation values are computed in the Heisenberg picture by back-propagating observables through quantum circuits. Although the methods rely on truncations to remain computationally feasible and scalable, they have proven accurate across many applications. Building on this framework, we adapt the iterative ADAPT-VQE ansatz to a fully classical setting and employ an operator-pool tiling strategy to scale to larger 1D and 2D spin systems.

^{[1] M. S. Rudolph et al., arXiv:2505.21606 (2025)
[2] A. Miller et al., arXiv:2503.18939 (2025)}

Check the list of the next MARVEL Junior Seminars here.