Quantum-like criticality for a classical transverse Ising model in 4–ε dimensions

摘要

We investigate the low-temperature critical properties of a classical Ising model in a transverse field. This is performed by applying the conventional Wilson renormalization group to the related Ginzburg-Landau functional emerging from a Hubbard-Stratonovich transformation. Results in 4–ε dimensions provide a low temperature critical scenario very similar to that found for the quantum counterpart. Remarkably, we find that the discrimination between the two cases essentially lies on the different values of the shift exponent which characterizes the behavior of the phase boundary close to the zero-temperature critical point. This feature suggests that, decreasing the temperature, the observation of different renormalized critical exponents may signal activation of genuine quantum critical fluctuations.