  In the context of the U(1) slave boson theory we derive a critical field
theory near the quantum critical point of the Kondo lattice model in two
spatial dimensions. First we argue that strong gauge fluctuations in the U(1)
slave boson theory give rise to confinement between spinons and holons, thus
causing "neutralized" spinons in association with the slave boson U(1) gauge
field. Second we show that critical fluctuations of Kondo singlets near the
quantum critical point result in a new U(1) gauge field. This emergent gauge
field has nothing to do with the slave boson U(1) gauge field. Third we find
that the slave boson U(1) gauge field can be exactly integrated out in the low
energy limit. As a result we find a critical field theory in terms of
renormalized conduction electrons and neutralized spinons interacting via the
new emergent U(1) gauge field. Based on this critical field theory we obtain
the temperature dependence of specific heat and the imaginary part of the
self-energy of the renormalized electrons. These quantities display non-Fermi
liquid behavior near the quantum critical point.
