Intermittent Multi-Mode Memory Gate
Implementation & benchmark of arXiv:2608.12784 — Thermodynamic formalism for intermittent maps with multiple neutral fixed points and phase transitions
Source paper: Thermodynamic formalism for intermittent maps with multiple neutral fixed points and phase transitions arXiv:2608.12784 ⓘ · analyzed Sep 1, 2026
AI-generated research hypothesis, automatically tested. Not peer-reviewed.
Idea description
Add a bounded routing state to an RNN, state-space model, or mixture-of-experts layer, with several neutral fixed points representing persistent modes. The state moves between modes when far from a fixed point but escapes each mode only polynomially when close to it, creating controllable long memory without setting a linear eigenvalue arbitrarily close to one. A temperature parameter selects between an entropy-rich phase using many modes and a low-entropy phase concentrated near one preferred mode.
Formulas
Mathematical statement
For each mode k, use a local map T_k with fixed point xi_k, T_k(xi_k)=xi_k, unit derivative T_k'(xi_k)=1, and local displacement |T_k(s)-s| approximately b_k|s-xi_k|^(1+alpha_k), where b_k>0 and alpha_k>0. If u_t=|s_t-xi_k| is small and the map moves outward, then u_(t+1)-u_t approximately b_k u_t^(1+alpha_k), giving escape time tau_k(u_0) approximately (b_k alpha_k)^(-1)u_0^(-alpha_k), so residence times have a power-law tail. Let p_j be empirical occupancy of mode j, H(p)=-sum_j p_j log p_j its entropy, and r_j a learned preference score. The pressure analogue is P(beta)=sup_p[H(p)-beta sum_j p_j r_j], where beta is inverse temperature. A phase transition occurs when two competing mode families A and B have equal pressure; below the crossing occupancy is distributed across modes, whereas above it one mode family dominates.
Implementation notes
1. Integration point: place the gate before an RNN update or MoE expert selection. Maintain a scalar state s_t in [0,1] for each sequence, head, or token, and choose K mode centers xi_k. For the nearest center k, set u=s_t-xi_k and apply s_new=clip(xi_k+u+gamma*b_k*sign(u)*(abs(u)+epsilon)^(1+alpha_k)+sigma*g(h_t),0,1), where g is a bounded projection of the current hidden state, gamma is the integration scale, sigma is input noise, and epsilon prevents zero-gradient numerical issues. Form routing logits ell_j=-q*(s_new-xi_j)^2+r_j and use p=softmax(ell/tau) to interpolate expert or residual updates. 2. Pseudocode: initialize s; at each step find k=argmin_j abs(s-xi_j); compute u=s-xi_k; update s with the intermittent formula; compute p; then update h_(t+1)=sum_j p_j RNN_j(h_t,x_t). Detach s only if backpropagation through long trajectories is unstable. 3. The power-law exponent is designed by alpha_k and b_k; estimate the realized exponent by collecting mode residence times and fitting the survival curve Pr(tau>n) on log-log axes. Estimate pressure branches using blockwise H(p)-beta times the empirical mean preference. 4. First cheap experiment: compare a GRU and this gate-augmented GRU on the adding task, sequential MNIST, and a synthetic two-regime sequence with controllable dwell times. Use K=2 and alpha_1=alpha_2=1 while sweeping gamma. The predicted signature is tau proportional to u_0^(-1), with fitted log-log slope -1 plus or minus 0.2. On the two-regime task, sweep beta or routing temperature and predict a kink in mode occupancy and entropy at beta_c=(H_A-H_B)/(R_A-R_B), with the measured transition within 20 percent of the estimated crossing. Long-context accuracy should improve specifically for power-law dwell-time data, while exponential-dwell controls should show substantially less benefit.
Verification
This idea has not been verified yet.
Verification happens in two stages: Stage 1 — a mechanism check on a toy system confirms the claimed mathematical phenomenon reproduces; Stage 2 — a benchmark implements the idea on a real (small) neural network task and compares it against a tuned baseline over 8 paired seeds with a permutation test.
Artifacts
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