  We investigate the continuous quantum phase transition from an
antiferromagnetic metal to a heavy fermion liquid based on the Kondo lattice
model in two dimensions. We propose that antiferromagnetic spin fluctuations
and conduction electrons fractionalize into neutral bosonic spinons and charged
spinless fermions at the quantum critical point. This deconfined quantum
criticality leads us to establish a critical field theory in terms of the
fractionalized fields interacting via emergent U(1) gauge fields. The critical
field theory not only predicts non-Fermi liquid physics near the quantum
critical point but also recovers Fermi liquid physics away from the quantum
critical point.
