With τ=1.0 the target softmax(E_Q/τ) was too peaked, causing entropy
collapse despite SAC α=2.0. At τ=5.0 the target is soft enough for
the entropy term to maintain equilibrium.
Entropy: STABLE at 0.78-0.81 from step 1000 to 5000 (was declining
to 0.10 at τ=1.0). Hold: 56-100% oscillating. wr: 0.38.
The τ-α balance controls the explore-exploit tradeoff:
high τ + high α = explore (soft target + entropy bonus)
low τ + low α = exploit (sharp target + no entropy)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>