This paper surveys the evidence that nuclear matter can undergo a first-order liquid–gas phase transition. "Nuclear matter" here means an idealized, infinite collection of protons and neutrons that ignores surface and electric (Coulomb) effects. Like ordinary fluids, the force between two nucleons (protons or neutrons) has a short-range repulsive core and a longer-range attraction. That mix of forces can produce a familiar liquid-to-vapor change, at least in the infinite system. In real, finite nuclei the same physics shows up as instabilities and the breaking up of an excited nucleus into many pieces.

The authors summarize how experiment and theory have been used to find the critical point that ends the liquid–vapor coexistence region. Experimentally, researchers look at multifragmentation in intermediate-energy nuclear collisions. By measuring many charged fragments and correcting for finite-size and Coulomb effects, they extract temperatures and other thermodynamic signals. The paper focuses on excitations up to about 30 MeV per nucleon, which correspond to temperatures up to about 25 MeV and to densities below the usual saturation density of nuclear matter, n0 ≃ 0.16 fm−3.

Several concrete experimental results are described. Fragment production grows with excitation energy, rising from roughly 3 MeV per nucleon and peaking around 9 MeV per nucleon, a value close to the typical binding energy of nuclei. The INDRA detector studies of 36Ar + 58Ni collisions at 95 MeV per nucleon identified a vaporized, gas-like phase. A quantum statistical model that treats the system as a gas of fermions and bosons in thermal and chemical equilibrium reproduces the measured compositions and average kinetic energies of the emitted particles.

On the theory side, the review compares the empirical findings with models. A Van der Waals–style equation of state gives a simple analogy: the long-range attraction in nuclear matter has a dominant two‑pion exchange component that plays a role similar to the attractive term in a Van der Waals fluid. More detailed microscopic approaches include self-consistent Hartree–Fock and variational calculations. The paper also discusses Chiral Effective Field Theory (ChEFT), the low-energy effective form of quantum chromodynamics (QCD), and how it informs nuclear thermodynamics for both symmetric matter and neutron-rich matter. Critical exponents for the transition have been reported in the literature and are discussed.