Faculty Profiles

Birrell, J., Katsoulakis, M. A., Rey-Bellet, L., Zhang, B., & Zhu, W. (2025). Nonlinear denoising score matching for enhanced learning of structured distributions. Computer Methods in Applied Mechanics and Engineering. Retrieved from https://www.sciencedirect.com/science/article/pii/S0045782525004980

Birrell, J., & Ebrahimi, R. (n.d.). Optimal Transport Regularized Divergences: Application to Adversarial Robustness. SIAM Journal on Mathematics of Data Science.

Birrell, J., Ahmadi, K., Behnia, R., Ebrahimi, R., Kermani, M. M., Pacheco, J., & Yavuz, A. A. (2025). An Interactive Framework for Implementing Privacy-Preserving Federated Learning: Experiments on Large Language Models. Retrieved from https://ieeexplore.ieee.org/document/11050826

Rafelski, J., Birrell, J., Grayson, C., Steinmetz, A., & Yang, C. T. (2025). Quarks to Cosmos: Particles and Plasma in Cosmological evolution. The European Physical Journal Special Topics. Retrieved from https://link.springer.com/article/10.1140/epjs/s11734-025-01470-w

Birrell, J. (2025). Statistical Error Bounds for GANs with Nonlinear Objective Functionals. Transactions on Machine Learning Research. Retrieved from https://openreview.net/forum?id=ZgjhykPSdU

Birrell, J., Ebrahimi, R., Behnia, R., & Pacheco, J. (2024). Differentially Private Stochastic Gradient Descent with Fixed-Size Minibatches: Tighter RDP Guarantees with or without Replacement. In Advances in Neural Information Processing Systems 37 (NeurIPS 2024). Retrieved from https://neurips.cc/virtual/2024/poster/95041

Birrell, J., Formanek, M., Steinmetz, A., Yang, C. T., & Rafelski, J. (2024). Fermi-Dirac Integrals in Degenerate Regimes: Novel Asymptotic Expansion. International Journal of Theoretical Physics, 63(7). https://doi.org/10.1007/s10773-024-05695-8

Rafelski, J., Birrell, J., Steinmetz, A., & Yang, C. T. (2023). A Short Survey of Matter-Antimatter Evolution in the Primordial Universe. Universe, 9(7). https://doi.org/10.3390/universe9070309

Birrell, J., Pantazis, Y., Dupuis, P., Rey-Bellet, L., & Katsoulakis, M. A. (2023). Function-space regularized Rényi divergences. Retrieved from https://openreview.net/forum?id=89GT-S49mGd

Birrell, J., Katsoulakis, M. A., Rey-Bellet, L., & Zhu, W. (2022). Structure-preserving GANs. In Proceedings of Machine Learning Research (ICML 2022) (Vol. 162, pp. 1982–2020). Retrieved from https://proceedings.mlr.press/v162/birrell22a.html

Birrell, J., Dupuis, P., Katsoulakis, M. A., Pantazis, Y., & Rey-Bellet, L. (2022). (f,Γ)-Divergences: Interpolating between f-Divergences and Integral Probability Metrics. Journal of Machine Learning Research, 23. Retrieved from https://www.jmlr.org/papers/v23/21-0100.html

Birrell, J., Katsoulakis, M. A., & Pantazis, Y. (2022). Optimizing Variational Representations of Divergences and Accelerating Their Statistical Estimation. IEEE Transactions on Information Theory, 68(7), 4553–4572. https://doi.org/10.1109/tit.2022.3160659

Birrell, J., Dupuis, P., Katsoulakis, M. A., Rey-Bellet, L., & Wang, J. (2021). Variational Representations and Neural Network Estimation of Rényi Divergences. SIAM Journal on Mathematics of Data Science, 3(4), 1093–1116. https://doi.org/10.1137/20m1368926

Birrell, J., Katsoulakis, M. A., & Rey-Bellet, L. (2021). Quantification of model uncertainty on path-space via goal-oriented relative entropy. ESAIM: Mathematical Modelling and Numerical Analysis, 55(1), 131–169. https://doi.org/10.1051/m2an/2020070

Birrell, J., & Wehr, J. (2020). Langevin Equations in the Small-Mass Limit: Higher-Order Approximations. Annales Henri Poincaré, 21(6), 1765–1811. https://doi.org/10.1007/s00023-020-00910-8

Birrell, J., & Rey-Bellet, L. (2020). Uncertainty Quantification for Markov Processes via Variational Principles and Functional Inequalities. SIAM/ASA Journal on Uncertainty Quantification, 8(2), 539–572. https://doi.org/10.1137/19m1237429

Birrell, J., & Wehr, J. (2019). A Homogenization Theorem for Langevin Systems with an Application to Hamiltonian Dynamics. In Sojourns in Probability Theory and Statistical Physics - I (pp. 89–122). Springer Singapore. https://doi.org/10.1007/978-981-15-0294-1_4

Birrell, J. (2018). Entropy Anomaly in Langevin–Kramers Dynamics with a Temperature Gradient, Matrix Drag, and Magnetic Field. Journal of Statistical Physics, 173(6), 1549–1586. https://doi.org/10.1007/s10955-018-2162-2

Birrell, J., & Wehr, J. (2018). Homogenization of dissipative, noisy, Hamiltonian dynamics. Stochastic Processes and Their Applications, 128(7), 2367–2403. https://doi.org/10.1016/j.spa.2017.09.005

Birrell, J., & Wehr, J. (2018). Phase Space Homogenization of Noisy Hamiltonian Systems. Annales Henri Poincaré, 19(4), 1081–1114. https://doi.org/10.1007/s00023-018-0646-x

Birrell, J., Hottovy, S., Volpe, G., & Wehr, J. (2017). Small Mass Limit of a Langevin Equation on a Manifold. Annales Henri Poincaré, 18(2), 707–755. https://doi.org/10.1007/s00023-016-0508-3

Rafelski, J., & Birrell, J. (2016). The hot Hagedorn Universe. Presented at the ICFNP2015 meeting, August 2015. In L. Bravina, Y. Foka, & S. Kabana (Eds.), EPJ Web Conf. Volume 126, 2016 4th International Conference on New Frontiers in Physics (Vol. 126, p. 03005). EDP Sciences. https://doi.org/10.1051/epjconf/201612603005

Birrell, J. (2015). A posteriori error bounds for two point boundary value problems: A Green’s function approach. Journal of Computational Dynamics, 2(2), 143–164. https://doi.org/10.3934/jcd.2015001

Rafelski, J., & Birrell, J. (2015). Dynamical emergence of the Universe into the false vacuum. Journal of Cosmology and Astroparticle Physics, 2015(11). https://doi.org/10.1088/1475-7516/2015/11/035

Birrell, J., & Rafelski, J. (2015). Proposal for resonant detection of relic massive neutrinos. The European Physical Journal C, 75(2). https://doi.org/10.1140/epjc/s10052-015-3310-3

Birrell, J., & Rafelski, J. (2015). Quark–gluon plasma as the possible source of cosmological dark radiation. Physics Letters B, 741, 77–81. https://doi.org/10.1016/j.physletb.2014.12.033

Birrell, J., Wilkening, J., & Rafelski, J. (2015). Boltzmann equation solver adapted to emergent chemical non-equilibrium. Journal of Computational Physics, 281, 896–916. https://doi.org/10.1016/j.jcp.2014.10.056

Birrell, J., Yang, C. T., & Rafelski, J. (2015). Relic neutrino freeze-out: Dependence on natural constants. Nuclear Physics B, 890, 481–517. https://doi.org/10.1016/j.nuclphysb.2014.11.020

Rafelski, J., & Birrell, J. (2014). Traveling Through the Universe: Back in Time to the Quark-Gluon Plasma Era. In Journal of Physics: Conference Series, Volume 509, 14th International Conference on Strangeness in Quark Matter (Vol. 509, p. 012014). IOP Publishing. https://doi.org/10.1088/1742-6596/509/1/012014

Birrell, J., Yang, C.-T., Chen, P., & Rafelski, J. (2014). Relic neutrinos: Physically consistent treatment of effective number of neutrinos and neutrino mass. Physical Review D, 89(2). https://doi.org/10.1103/physrevd.89.023008

Birrell, J., Yang, C. T., Chen, P., & Rafelski, J. (2013). Fugacity and Reheating of Primordial Neutrinos. Modern Physics Letters A, 28(40). https://doi.org/10.1142/s0217732313501885

Rafelski, J., Labun, L., & Birrell, J. (2013). Compact Ultradense Matter Impactors. Physical Review Letters, 110(11). https://doi.org/10.1103/physrevlett.110.111102

Birrell, J., Herzog, D. P., & Wehr, J. (2012). The transition from ergodic to explosive behavior in a family of stochastic differential equations. Stochastic Processes and Their Applications, 122(4), 1519–1539. https://doi.org/10.1016/j.spa.2011.12.014