Lipkin

Lipkin is a surname of Jewish origin. It may refer to various people in science, arts, and public life. In physics, the name is widely associated with the Lipkin-Meshkov-Glick (LMG) model, a solvable quantum many-body system introduced in 1965 by Lipkin, Meshkov, and Glick to test the reliability of approximations in many-body theory. The model describes a system of N spin-1/2 particles with all-to-all interactions, captured by a collective spin description. It has become a standard benchmark for analytical and numerical techniques, including mean-field theory, semiclassical approaches, and exact diagonalization.

The LMG model exhibits a quantum phase transition in the thermodynamic limit as interaction strengths or external fields are varied, separating distinct ground states. It also features rich finite-size effects and nontrivial entanglement properties, making it relevant in quantum information research and the study of symmetry breaking. Beyond its original nuclear-physics context, the model has become a common topic of study in condensed matter and quantum optics, illustrating how simple collective interactions can produce complex collective behavior.

In general, Lipkin as a surname appears in various contexts; the name has been borne by researchers and public figures across disciplines. See also Lipkin-Meshkov-Glick model; Lipkin model.