# MY RESEARCH

My current research is focused on understanding how structure is created in systems of active matter, liquid-like droplets in the cell, and in population growth. The backbone of my work has focused on the development of large deviation theory, which is a natural extension of statistical mechanics to out-of-equilibrium systems, to make predictions.

Publications:

[1] GrandPre, T., Levien, E., Amir, A. (2022). Finite time corrections to the population growth rate estimator (in preparation)

[2] Sun, S., GrandPre, T., Limmer, D.T., Groves, J. (2021). Kinetic Constraints Control Membrane Localized Protein Condensation

BioRxiv preprint

[3] Omar, A., Klymko, K., GrandPre, T., Geissler, P. L., & Brady, J. F. (2021). Tuning Nonequilibrium Phase Transitions with Inertia. arXiv preprint arXiv:2108.10278.

[4] Omar, A., Klymko, K., GrandPre, T., Geissler, P.L. (2021). Phase Diagram of Active Brownian Spheres: Crystallization and the Metastability of Motility-Induced Phase Separation. Phys. Rev. Lett. 126, 188002

[5] GrandPre, T., Klymko, K., Mandadapu, K.K., Limmer, D.T. (2020). Entropy fluctuations encode collective behavior in active matter. Phys. Rev. E 103, 012613

[6] Levien, E.*, GrandPre, T.* , Amir, A. (2020). A large deviation principle linking lineage statistics to fitness. Phys. Rev. Lett. 125, 048102

[7] GrandPre, T., & Limmer, D. T. (2018). Current fluctuations of interacting active Brownian particles. Phys. Rev. E, 98(6), 060601.

*denotes first co-author

## Active Matter

In out-of-equilibrium systems, structure can be created by dissipating energy. This is the case for active matter. On the microscopic level each particle dissipates energy to move. Without any attraction, there is macroscopic phase separation strictly from the self propulsion. Understanding these types of processes required developing new physics in the field of large deviation theory.

## Liquid Phase Separation

Within the cell there are liquidlike substructures such as Cajal bodies, germ granules, and centrosomes. It is a mystery how these substructures can coexist and not mix. On the cell membrane there is a protein complex called LAT that phase separates to moderate T-cell signalling. My simulations help elucidate the physics and dynamics of this process.

## Population Growth

Understanding how to predict and control population growth of populations of cells such as E. Coli can help us create general principles of nonequilibrium systems. In my latest collaboration with Ethan and Ariel at Harvard, we develop a general theory to measure population growth.