
Neural networks used as a statistical estimator for the equation of state.Neural network regression is a machine learning technique where an artificial neural network is trained to predict a continuous numerical output from input features. In physics, it is increasingly used as a statistical estimator for complex relationships, such as the equation of state (EoS) of matter — the function linking pressure, temperature, and volume. Instead of relying on analytical formulas, a neural network learns the EoS directly from experimental or simulation data, capturing nonlinearities that are hard to model by hand.
Neural networks were conceptualized in the 1940s, but their use in physics for regression became widespread in the 2010s with the rise of deep learning and powerful GPUs. Specific applications to equations of state emerged in nuclear physics and astrophysics around that time.
A neural network consists of layers of interconnected 'neurons' (mathematical functions). During training, the network adjusts its internal weights to minimize the difference between its predictions and known data points (e.g., from nuclear experiments or simulations). Once trained, it can interpolate or extrapolate to predict the EoS for new conditions. The network's flexibility allows it to approximate any smooth function, given enough data and neurons.
Used to model equations of state for neutron stars, nuclear matter, and materials under extreme conditions, where traditional analytical forms are inadequate.
A neural network with just one hidden layer can approximate any continuous function on a compact domain — a result known as the universal approximation theorem.



















