Strongly correlated many-body systems are often formulated as gauge theories where gauge field plays a role of Lagrangian multiplier and fundamental matter field represents a fractional degree of freedom which carries only a fractional quantum number of microscopic particle. Although the fractional particles are prone to be confined at high energy owing to an infinite bare gauge coupling, they can emerge as deconfined degrees of freedom at low/intermediate energy scales as the gauge coupling is renormalized to a finite value by fluctuating matter fields. The resulting dynamics of the gauge field crucially depends on the number and the dynamics of the matter fields. In this talk, I will discuss how a change in the dynamics of matter fields affects the dynamics of gauge field. I will consider a field theory where a 2+1D compact U(1) gauge field is coupled to a large number of fundamental matter fields with an infinite bare gauge coupling and the matter fields are, in turn, subject to an additional strong interaction. This field theory can be realized as a low energy theory of a D-brane configuration and nonperturbative effects of the strong interaction can be studied from the AdS/CFT correspondence. Using the dual gravity theory, I will discuss how the strong interaction between matter fields can drastically modify the dynamics of the U(1) gauge field. Our result suggests that even an unstable brane configuration can define a consistent field theory once tachyonic modes are frozen.