Pair Correlation Functions in Classical and Quantal Electron Gases

Pair-correlation function in two-dimensional lattice gases.

The pair-correlation function in two-dimensional lattice gases is computed by means of three discretized classical equations for the structure of liquids: the hypernetted-chain, the Percus-Yevick, and the crossover integral equations. The equations are numerically solved by an iteration procedure. Two different systems are considered: the Ising-Peierls lattice gas with nearest-neighbor interact...

Pair-correlation function in 2-dimensional lattice gases

“Quantal” behavior in classical probability

Phenomena generally believed specific to quantum mechanics — the incompatibility and valueindeterminacy of variables, the non-existence of dispersion-free states, the failure of the standard marginal-probability formula, and the failure of the distributive law of disjunction (“interference”) — are exemplified in a fully non-quantal setting: Sequences of events in a nondeterministic system of mo...

Quantum correlation functions and the classical limit

We study the transition from the full quantum mechanical description of physical systems to an approximate classical stochastic one. Our main tool is the identification of the closed-time-path (CTP) generating functional of Schwinger and Keldysh with the decoherence functional of the consistent histories approach. Given a degree of coarse-graining in which interferences are negligible, we can e...

Correlation Functions in Open Quantum-Classical Systems

Quantum time correlation functions are often the principal objects of interest in experimental investigations of the dynamics of quantum systems. For instance, transport properties, such as diffusion and reaction rate coefficients, can be obtained by integrating these functions. The evaluation of such correlation functions entails sampling from quantum equilibrium density operators and quantum ...