Namiko Mitarai

Namiko Mitarai

Associate Professor

We use theoretical methods from physics to investigate complex systems and living systems, and in turn use inspirations from those systems to develop new concepts in physics models. We study phenomena in various scales, from intracellular processes, collective behaviours of cells and agents, to species competition in an ecological scale, with tools from dynamical systems, stochastic processes, and individual-based models.

We also perform experiments using bacteria and bacteriophage (viruses that infect bacteria) in our lab. The unique combination of theoretical and experimental research makes our activity truly interdisciplinary. 

Mitarai Lab is part of Biocomplexity group, CMoL (Center for Models of Life), and located at the Niels Bohr Institute, University of Copenhagen. 

Primary fields of research


Growth of viruses of bacteria (phage)

Any life forms are infected by viruses, and bacteria are no exception. We are interested if there are universal, quantitative rules that most, if not all, bacterial viruses follow.  For example, is the virus production rate simply proportional to the bacterial hosts’ growth rate? Or can we categorize different classes of viruses according to how they manipulate the bacterial physiological state, with each class having their quantitative relations between bacterial growth and viral growth?  We search for the universal quantitative laws of viral growth experimentally and establish a theory to explain them.

Phage-Bacteria interaction in space

Phage plaque morphology tells a lot about the phage-bacteria interaction. Through a quantitative modeling with closely related experiments, we reveal how the spatial structures are formed and how the space affects the phage-bacteria interaction. As modeling tools, we use individual based model with mechanical cell-cell interactions as well as reaction-diffusion type models.

Bacterial Physiology and Persistence

When an antibiotic is applied to a large population of antibiotic-sensitive bacterial cells, a subpopulation of cells tolerant to the antibiotic almost always appear, which are called persisters. Persisters are different from antibiotic resistant cells, because the progenies of the persisters are still sensitive to the same antibiotic: persisters are caused by phenotypic heterogeneity, that reflects stochasticity in the system.

Species competition and diversity

We use Lotoka-Volterra equations to stochastic lattice models to address how various types of species competitions affect emergence and coexistence of diversity.

Complex systems and statistical physics

We are interested in various collective phenomena, where rich behaviors emerge from elements or agents interacting with simple rules.


  • Courses
    • Dynamical Models in Molecular Biology (block 2)
    • Diffusive and Stochastic Processes (block 4)

It is strongly recommended to take "Diffusive and Stochastic Processes" if you are interested in doing a master project in Mitalai lab. If you are interested in projects related to biological problems, the course "Dynamical Models in Molecular Biology" is also strongly recommended. 

ID: 12071632