Posts by Collection

Families of periodic delay orbits

Published in Journal of Differential Equations, 410, 228-250, 2024

Peter Albers, Philipp Aretz, Irene Seifert

DOI: 10.1016/j.jde.2024.07.021 | arXiv: 2304.07550

This paper provides examples of periodic solutions to a certain class of two dimensional differential delay equations. We further investigate geometric properties of the families of solutions.

Recommended citation: Albers, P., Aretz, P., and Seifert, I. (2024). "Families of periodic delay orbits." Journal of Differential Equations, 410, 228-250. https://doi.org/10.1016/j.jde.2024.07.021
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A rigorous Keldysh functional integral for fermions

Published in Journal of Statistical Physics, 193(2), Article 28, 2026

Philipp Benjamin Aretz, Manfred Salmhofer

DOI: 10.1007/s10955-026-03583-5 | arXiv: 2508.01787

We give a mathematically precise foundation for the Keldysh formalism and show that it produces stable, controlled predictions for non-equilibrium fermionic systems.

Recommended citation: Aretz, P. B. and Salmhofer, M. (2026). "A rigorous Keldysh functional integral for fermions." Journal of Statistical Physics, 193(2), 28. https://doi.org/10.1007/s10955-026-03583-5
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Diffraction across Colliders

Published: February 01, 2026

An expanded version of my conference talk for graduate students at MIT.

Diffraction across Colliders

Published: March 01, 2026

Factorization of diffraction and universality across colliders.

Classical Mechanics (8.01)

Undergraduate course, MIT, Department of Physics, 2025

Grad TA for classical Mechanics (8.01) at MIT.