We combine hydrodynamic and field theoretic methods to develop a general theory of
phonons as Goldstone bosons in crystals, glasses, and liquids based on nonaffine …

A bstract We study the quasi-hydrodynamics of a system with a softly broken U (1) global
symmetry using effective field theory (EFT) and holographic methods. In the gravity side, we …

A bstract We study the hydrodynamic excitations of backreacted holographic superfluids by
computing the full set of quasinormal modes (QNMs) at finite momentum and matching them …

A bstract We construct effective field theory for SU (2) isospin charge diffusion, based on
holographic Schwinger-Keldysh contour [1]. The holographic model consists of a probe SU …

A bstract We study a nearly critical superfluid system from two complementary approaches.
Within the first approach, we formulate a Schwinger-Keldysh effective field theory (EFT) for …

Active matter consumes energy from the environment and transforms it into mechanical
work. Notable examples from biology include cell division, bacterial swarms, and muscle …

A bstract We consider the superfluid phase of a specific renormalizable relativistic quantum
field theory. We prove that, within the regime of validity of perturbation theory and of the …

We investigate macroscopic behaviors of fluctuating domain walls in nonequilibrium open
systems with the help of the effective field theory based on symmetry. Since the domain wall …

Symmetry has played a crucial role in our understanding of physical systems. In this thesis,
we review several works based on investigating the symmetry properties of theories. We …