Exact critical exponents for the antiferromagnetic quantum critical metal in two dimensions
Abstract
Unconventional metallic states which do not support well defined
single-particle excitations can arise near quantum phase transitions as strong
quantum fluctuations of incipient order parameters prevent electrons from
forming coherent quasiparticles. Although antiferromagnetic phase transitions
occur commonly in correlated metals, understanding the nature of the strange
metal realized at the critical point in layered systems has been hampered by a
lack of reliable theoretical methods that take into account strong quantum
fluctuations. We present a non-perturbative solution to the low-energy theory
for the antiferromagnetic quantum critical metal in two spatial dimensions.
Being a strongly coupled theory, it can still be solved reliably in the
low-energy limit as quantum fluctuations are organized by a new control
parameter that emerges dynamically. We predict the exact critical exponents
that govern the universal scaling of physical observables at low temperatures.