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Michael Gabbay

Senior Principal Physicist






Dr. Gabbay's current research involves the development of mathematical models and computational simulations of network dynamics, focusing on social and political systems. He has also conducted research in the areas of nonequilibrium pattern formation, coupled oscillator dynamics, sensor development, and data analysis algorithms. His work has appeared in physics, engineering, biology, and political science publications. Dr. Gabbay received a B.A. in physics from Cornell University and a Ph.D. in physics from the University of Chicago with a specialization in nonlinear dynamics.


B.A. Physics, Cornell University, 1985

M.S. Physics, University of Chicago, 1987

Ph.D. Physics, University of Chicago, 1997


2000-present and while at APL-UW

Strategies of armed group consolidation in the Afghan civil war (1989–2001)

Erickson, M., and M. Gabbay, "Strategies of armed group consolidation in the Afghan civil war (1989–2001)," Stud. Conflict Terror., EOR, doi:10.1080/1057610X.2021.2013752, 2021.

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20 Dec 2021

What explains the variation in the strategies of consolidation among armed groups? We examine three conditions that can explain the modes of militant consolidation — territorial control, organizational structure, and external support. We test these theoretical conjectures using unique time series data on armed group consolidation in Afghanistan from 1989 to 2001. Using a linear probability model, we find that territorial control, organizational structure, and fungible forms of external support have the most significant impact on explaining consolidation. This article contributes to the study of armed group dynamics by drawing on existing theory and leveraging original data to explain variation in strategies of militant consolidation.

Consolidation of nonstate armed actors in fragmented conflicts: Introducing an emerging research program

Hafez, M.M., M. Gabbay, and E.K. Gade, "Consolidation of nonstate armed actors in fragmented conflicts: Introducing an emerging research program," Stud. Conflict Terror., EOR, doi:10.1080/1057610X.2021.2013751, 2021.

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16 Dec 2021

How do armed groups consolidate power in conflict landscapes packed with rival factions, paramilitary militias, and local warlords? Extant scholarship has studied the causes and consequences of rebel fragmentation, but the reverse process in which power that is dispersed among many armed actors becomes concentrated among a handful of factions is underexplored. In this special issue, we bring together eight case studies to illustrate at least three pathways to militant consolidation. Cooperative consolidation involves organizations growing consensually through alliance formation and mergers. Competitive consolidation entails a gradual process of increasing political and military power by outcompeting rival groups for fighters, popular support, and international sponsors. Coercive consolidation occurs when militant organizations violently eliminate rivals. This framing article considers several factors that may explain the choice of consolidation mode, including the role of territorial control, permeability of group boundaries, and state sponsorship. By investigating this under-examined aspect of civil conflict, we forge fundamentally new theoretical ground in the study of internal wars and weakly-governed societies.

Community detectability and structural balance dynamics in signed networks

Morrison, M., and M. Gabbay, "Community detectability and structural balance dynamics in signed networks," Phys. Rev. E, 102, 012304, doi:10.1103/PhysRevE.102.012304, 2020.

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6 Jul 2020

We investigate signed networks with community structure with respect to their spectra and their evolution under a dynamical model of structural balance, a prominent theory of signed social networks. The spectrum of the adjacency matrix generated by a stochastic block model with two equal-size communities shows detectability transitions in which the community structure becomes manifest when its signal eigenvalue appears outside the main spectral band. The spectrum also exhibits "sociality" transitions involving the homogeneous structure representing the average tie value. We derive expressions for the eigenvalues associated with the community and homogeneous structure as well as the transition boundaries, all in good agreement with numerical results. Using the stochastically generated networks as initial conditions for a simple model of structural balance dynamics yields three outcome regimes: two hostile factions that correspond with the initial communities, two hostile factions uncorrelated with those communities, and a single harmonious faction of all nodes. The detectability transition predicts the boundary between the assortative and mixed two-faction states and the sociality transition predicts that between the mixed and harmonious states. Our results may yield insight into the dynamics of cooperation and conflict among actors with distinct social identities.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center