Determinism: Stochastic
All systems with determinism: stochastic
Systems (18)
Belousov-Zhabotinsky (BZ) reaction computer
f(x) = boolean logic / reaction-diffusion computation (via chemical wave collisions)
The BZ reaction is an oscillating chemical system that produces propagating excitation waves in a thin layer of reagent (typically ferroin or ruthenium catalyst in acidified bromate/malonate). Signals...
Biological brain
f(x) = general intelligence / perception, memory, reasoning, motor control
The human brain contains ~86 billion neurons connected by ~10¹⁵ synapses. Each neuron integrates thousands of synaptic inputs and fires a spike when its membrane potential crosses threshold — a leaky ...
Boson sampler
f(x) = sampling from the permanent of a unitary matrix (classically #P-hard)
Identical single photons enter an m-mode linear optical network (beam splitters and phase shifters implementing a unitary U). Detectors at the outputs sample from a distribution whose probabilities ar...
Coherent Ising machine (OPO network)
f(x) = Ising Hamiltonian ground state / combinatorial optimization (MAX-CUT, QUBO)
A network of degenerate optical parametric oscillator (DOPO) pulses circulating in a fiber ring cavity. Each pulse can oscillate in one of two phase states (0 or π), encoding a spin. Measurement-feedb...
Coupled oscillator network (Kuramoto / XY model)
f(x) = MAX-CUT / graph partitioning (approximate)
A network of identical oscillators — pendula, LC circuits, or CMOS ring oscillators — coupled to their neighbours by springs or resistive links. The Kuramoto model describes how each oscillator's phas...
DNA computer (Adleman 1994)
f(x) = Hamiltonian path via strand hybridization
Leonard Adleman's 1994 demonstration solved the directed Hamiltonian path problem using DNA strand hybridization. Cities encoded as DNA sequences, flight connections as complementary strands. Massivel...
DNA strand-displacement computer
f(x) = boolean logic / neural network inference (via hybridization cascades)
Single-stranded DNA molecules in solution compute via toehold-mediated strand displacement: a short single-stranded 'toehold' on a partially double-stranded gate complex allows an input strand to inva...
DishBrain (in-vitro neural culture)
f(x) = closed-loop sensorimotor control / game-playing (via biological learning)
~800,000 human iPSC-derived or mouse cortical neurons are plated onto a high-density multi-electrode array (HD-MEA). The DishBrain system (Kagan et al., 2022, Neuron) embeds the culture in a simulated...
Galton board (bean machine)
f(x) = Gaussian / binomial distribution
Balls dropped through a triangular array of pegs deflect left or right at each level. The distribution of balls in the output bins converges to a Gaussian as N→∞. Each peg is an independent Bernoulli ...
Gate-based quantum computer
f(x) = unitary quantum computation / quantum algorithms (Shor factoring, Grover search, VQE)
A register of qubits — typically superconducting transmons cooled to ~10 mK — whose state is manipulated by sequences of microwave pulses implementing one- and two-qubit unitary gates. Any computation...
Memristive Hopfield network optimizer
f(x) = optimization via chaotic annealing / transient dynamics
Memristive circuits implementing Hopfield network topology where the intrinsic nonlinearity of memristors creates transient chaotic annealing processes. The chaotic dynamics enable escape from local m...
Neuromorphic chip (Intel Loihi / IBM TrueNorth)
f(x) = spiking neural network computation
Silicon chips that mimic neural computation using spiking neurons and synaptic connections. Intel Loihi and IBM TrueNorth implement event-driven, asynchronous processing with on-chip learning capabili...
Physarum polycephalum (slime mold)
f(x) = Steiner tree / shortest transport network (approximate)
The plasmodial slime mold extends filaments toward nutrient sources and progressively reinforces paths that carry more flow, pruning inefficient routes. Toshiyuki Nakagaki showed it reproduces the Tok...
Quantum and quantum-inspired annealers
f(x) = Ising model energy minimization / QUBO optimization
Quantum and quantum-inspired systems for solving combinatorial optimization problems through annealing processes. Includes true quantum annealers (D-Wave) using superconducting qubits and quantum-insp...
Repressilator (synthetic gene oscillator)
f(x) = limit-cycle oscillation / biological clock (via negative-feedback transcription loop)
Elowitz & Leibler (2000, Nature) constructed a synthetic oscillator in E. coli from three mutual repressor genes wired in a ring: LacI represses tetR; TetR represses cI; CI represses lacI. No gene pro...
Simulated annealing (thermal)
f(x) = argmin of energy / cost landscape
A physical system coupled to a heat bath at slowly decreasing temperature explores its energy landscape. At high temperature it escapes local minima; as T→0 it settles into a global minimum — if cooli...
Thermodynamic computer
f(x) = sampling from Boltzmann distributions
Uses thermal noise in analog circuits to sample from Boltzmann distributions. Thermal fluctuations provide natural randomness that follows statistical mechanics principles. The Normal Computing SDE (S...
Thermodynamic computer (Normal Computing SPU)
f(x) = probabilistic sampling / linear algebra via thermal equilibration
Analog physics-based computers using thermodynamic principles for computation. Normal Computing's Stochastic Processing Unit (SPU) uses RLC circuits as unit cells with all-to-all coupling via switched...