Perturbative Construction of Coherent States

Understand

The perturbative consistency of coherent states within interacting quantum field theory requires them to be altered beyond the simple non-squeezed form.

• Building on this point, we perform explicit construction of consistent squeezed coherent states, required by the finiteness of physical quantities at the one-loop order.
• Extending this analysis to two-loops, we demonstrate that a non-Gaussian alteration of squeezed coherent states is necessary.
• The modifications of the coherent state we propose are perturbative in $\hbar$ and may be an indication that coherence must be viewed through a nonlinearly redefined, background-dependent, degree of freedom.