Matter fields near quantum critical point in [formula omitted]-dimensional [formula omitted] gauge theory

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We study chiral phase transition and confinement of matter fields in ( 2 + 1 ) -dimensional U ( 1 ) gauge theory of massless Dirac fermions and scalar bosons. The vanishing scalar boson mass, r = 0 , defines a quantum critical point between the Higgs phase and the Coulomb phase. We consider only the critical point r = 0 and the Coulomb phase with r > 0 . The Dirac fermion acquires a dynamical mass when its flavor is less than certain critical value N f c , which depends quantitatively on the flavor N b and the scalar boson mass r. When N f < N f c , the matter fields carrying internal gauge charge are all confined if r ≠ 0 but are deconfined at the quantum critical point r = 0 . The system has distinct low-energy elementary excitations at the critical point r = 0 and in the Coulomb phase with r ≠ 0 . We calculate the specific heat and susceptibility of the system at r = 0 and r ≠ 0 , which can help to detect the quantum critical point and to judge whether dynamical fermion mass generation takes place.