Jastrow Correlated Wave Function Research Articles

Electronic origin of the volume collapse in cerium

The cerium $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\gamma}$ phase transition is characterized by means of a many-body Jastrow-correlated wave function, which minimizes the variational energy of the first-principles scalar-relativistic Hamiltonian, and includes correlation effects in a nonperturbative way. Our variational ansatz accurately reproduces the structural properties of the two phases, and proves that even at temperature $T=0\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ the system undergoes a first-order transition, with ab initio parameters which are seamlessly connected to the ones measured by experiment at finite $T$. We show that the transition is related to a complex rearrangement of the electronic structure, with a key role played by the $p\ensuremath{-}f$ hybridization. The underlying mechanism unveiled by this work can hold in many Ce-bearing compounds, and more generally in other $f$-electron systems.

Jastrow-correlated wave functions for flat-band lattices

The electronic band structure of many compounds, e.g., carbon-based structures, can exhibit essentially no dispersion. Models of electrons in flat-band lattices define non-perturbative strongly correlated problems by default. We construct a set of Jastrow-correlated ansatz wavefunctions to capture the low energy physics of interacting particles in flat bands. We test the ansatz in a simple Coulomb model of spinless electrons in a honeycomb ribbon. We find that the wavefunction accurately captures the ground state in a transition from a crystal to a uniform quantum liquid.

ENTANGLEMENT PROPERTIES OF QUANTUM MANY-BODY WAVE FUNCTIONS

The entanglement properties of correlated wave functions commonly employed in theories of strongly correlated many-body systems are studied. The variational treatment of the transverse Ising model within correlated-basis theory is reviewed, and existing calculations of the one- and two-body reduced density matrices are used to evaluate or estimate established measures of bipartite entanglement, including the Von Neumann entropy, the concurrence, and localizable entanglement, for square, cubic, and hypercubic lattice systems. The results discussed in relation to the findings of previous studies that explore the relationship of entanglement behaviors to quantum critical phenomena and quantum phase transitions. It is emphasized that Jastrow-correlated wave functions and their extensions contain multipartite entanglement to all orders.

Fermi hypernetted-chain calculation of the half-diagonal two-body density matrix of model nuclear matter

The half-diagonal two-body density matrix ρ2h(r1,r2,r1′) is a key quantity in theoretical descriptions of nucleon knockout reactions at intermediate energies, due to its central role in treatments of the propagation and final-state interactions of ejected nucleons in the nuclear medium. This quantity is calculated for a simple model of the ground state of infinite symmetrical nuclear matter, based on a Jastrow-correlated wave function and a Fermi hypernetted-chain analysis. The dependence of ρ2h on the variables r11′=|r1−r1′|, r12=|r1−r2|, and the angle θ between r1−r1′ and r1−r2 is investigated in some detail. Significant departures from ideal Fermi gas behavior in certain domains reflect the importance of short-range correlations and their interplay with statistical correlations. The quality of approximations to ρ2h proposed by Gersch et al., Rinat, and Silver is assessed by comparison with the Fermi hypernetted-chain results.

Translationally invariant treatment of pair correlations in nuclei II. Tensor correlations

We study the extension of our translationally invariant correlated-cluster treatment of few-body nuclear systems to include tensor forces and correlations. It is shown that a direct application of our method is not as successful for realistic V6 interactions as our previous results for V4 potentials suggested. We investigate the cause in detial for the case of 4He, and show that a combination of the method of translationally invariant configuration interactions truncated at second order with that of Jastrow-correlated wave functions seems to be a lot more powerful, thereby suggesting that for mildly to strongly repulsive forces such a hybrid procedure may be an appropriate description.

Variational methods for nuclear systems with dynamical mesons

We derive a model Hamiltonian whose ground state expectation value of any two-body operator coincides with that obtained with the Jastrow correlated wave function of the many-body Fermi system. Using this Hamiltonian we show that the variational principle can be extended to treat systems with dynamical mesons, even if in this case the concept of wave function looses its meaning.

Boson-boson mixtures and triplet correlations

The hypernetted-chain formalism for boson-boson mixtures described by an extended Jastrow correlated wave function is derived, taking into account elementary diagrams and triplet correlations. The energy of an ideal boson /sup 3/He-/sup 4/He mixture is computed for low values of the /sup 3/He concentration. The zero-/sup 3/He-concentration limit provides a /sup 3/He chemical potential in good agreement with the experimental value, when a McMillan two-body correlation factor and the Lennard-Jones potential are adopted. If the Euler equations for the two-body correlation factors are solved in presence of triplet correlations, the agreement is again improved. At the experimental /sup 4/He equilibrium density, the /sup 3/He chemical potential turns out to be -2.58 K, to be compared with the experimental value, -2.79 K.

Density matrices and momentum distributions inHe3-He4mixtures

We report variational calculations, in the hypernetted-chain (HNC)-Fermi-HNC scheme, of one-body density matrices and one-particle momentum distributions for $^{3}\mathrm{He}$-$^{4}\mathrm{He}$ mixtures described by a Jastrow correlated wave function. The $^{4}\mathrm{He}$ condensate fractions and the $^{3}\mathrm{He}$ strength poles are examined and compared with the Monte Carlo available results. The agreement has been found to be very satisfactory. Their density dependence is also studied.

Coherent ρ-Meson photoproduction in nuclei by means of jastrow correlated wave functions

Coherent ρ-Meson photoproduction in nuclei by means of jastrow correlated wave functions

Short-range correlations in high-energy hadron collisions

High-energy collisions of hadrons on nuclei are studied by means of Glauber multiple scattering theory, using Jastrow correlated wave functions. To this end a cluster expansion is derived, and its convergence properties are studied. Calculations have been carried out for 4He and 16O nuclei, and they are compared with experimental data.

Diagrammatic Analysis of the Method of Correlated Basis Functions

The weakly interacting Bose gas is studied on the one hand with the independent-particle perturbation formalism of Hugenholtz and Pines, and on the other hand by a perturbation theory using a set of correlated basis functions. We find by comparison that up to fourth order in energy, a Jastrow correlated wave function sums all rings and ladders, and other diagrams in part; and the simplest correlated basis functions perturbation correction accounts for all remaining discrepancies.