Statistical Field Theory

The STELLAR Lab (Statistical Field Theory, Hydrodynamics, and Holography) at the University of Genoa brings together researchers working at the intersection of statistical physics, fluid dynamics, and gauge/gravity dualities. Our mission is to understand collective behavior – both equilibrium and non-equilibrium – through theoretical models, numerical simulations, and novel theoretical approaches. Currently we categorise our work into the following six project areas.

Simulating Herds, Flocks and Swarms

We seek to understand active matter systems such as ensembles of animals, robots, or self-propelled particles that exhibit collective motion. STELLAR develops continuum field-theory models that replace individual agents with interacting fields, enabling the study of large-scale behavior, pattern formation, and emergent dynamics. Our focus includes, but is not limited to, leveraging “boost-agnostic” formalisms that respect observer-independence of velocity as powerful frameworks to quantify non-equilibrium systems. We subsequently test these approaches against numerical simulation.

Relaxation and Driven Steady States in Holography and Beyond

Investigating how systems relax to equilibrium, or sustain steady states when driven, is key to understanding many states of matter. This research stream often delves into holographic dualities (AdS/CFT) which enable us to describe perturbations of strongly-coupled quantum field theories. Such models are ideal testbeds for (quasi-) hydrodynamic behaviour. By mapping complex non-equilibrium dynamics onto simpler gravitational problems in higher dimensions, our group can calculate correlation functions, transport properties, and thermalization processes in regimes where perturbative methods fail.

The Superconductive Field Effect

Our lab also studies how external electric fields modulate superconductivity in thin films, a previously unexpected phenomenon. By employing BCS theory in the presence of such electric fields we aim to understand how they can suppress the supercurrent. Such a result will contribute a key theoretical insight necessary for applications to devices where superconductivity is controlled externally.

Critical Phenomena and Quantum Field Theory

This research line delves into phase transitions – especially second-order ones – and the principles underpinning universality and scale invariance in quantum field theories. Using renormalization-group methods, STELLAR lab explores how critical exponents emerge, how fluctuations near critical points can be characterized, and how quantum fields behave near phase transitions.

Multi‑scale Analysis of Flows

Focusing on fluid dynamics, this project analyzes flows that feature multiple interacting scales – like turbulence or quasi-hydrodynamic regimes where conservation laws are only approximately true. Building on their theoretical expertise, we develop multi-scale models that capture the slow decay or approximate conservation of quantities (e.g., vorticity), bridging microscopic and hydrodynamic descriptions to understand realistic fluid behavior.

Fractonic effective field theories

Fractonic field theories explore systems where the elementary excitations, known as fractons, cannot move freely but only under constrained, often collective, dynamics. The group research focuses on formulating unconventional gauge theories, featuring higher-rank symmetries and extended conservation laws, such as dipole and multipole charges. These models open new perspectives on exotic phases of matter, linking strongly correlated condensed matter to topological structures and potential applications in quantum information.

For further information, please visit the group webpage.

Staff
Andrea Amoretti
Daniel Keith Brattan
Nicola Maggiore
Nicodemo Magnoli

Postdocs
Alkistis Zervou

PhD students
Matteo Anselmi
Daniel Sacco Shaikh
Jonas Rongen