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The standard model problem of a three-dimensional fully interacting electron gas in a uniform compensating background is shown to result from a procedure starting at the operator leval with a fully quantum mechanical two-component system of electrons and countercharge (e.g. nuclei), and following a dual limiting process involving the division of charge and the scaling of mass. The bifurcation method provides insight into other aspects of the corresponding many-body problem, two examples of which are given. 8 50 11023 11028

We develop a variational many-body description of low-density three-dimensional paired electron crystals. Among the ground states of such crystals we find that coherent paired supersolids (resonant spin states) and true paired crystals (fixed spin states) can both be favored at intermediate densities (100rs200) relative to the well-known conventional (Bravais lattice) Wigner crystals. The stabilization of this pairing is largely exchange driven and if it persists at higher densities (even beyond melting) then we show that for an intermediate density electron fluid an evolution into a superconducting state of unusual character can occur. © 1993 The American Physical Society. 48 16 11646 11665 Cited By :22

A variational method shows that for a range of densities the compensated low density interacting electron system possesses a ground-state crystalline phase with L=0 spin-singlet pairs and with an energy lower than the Wigner crystal. The physical origin of the additional binding is intrapair exchange resulting from wave-function overlap and cooperative anharmonic behavior. © 1992 The American Physical Society. 69 17 2555 2558 Cited By :28

We present a general theory of the metal-insulator transition based on the formal introduction of an auxiliary irrotational gauge field and the subsequent behavior of the system in response to it. Correspondingly general scaling relations are derived which determine the point of transition at a critical value of the controlling density in terms of a series expansion with respect to a coupling constant. Functional integral techniques are also used to show the relation of this transition to a density-fluctuation instability. Finally, an interpretation is given of the transition in terms either of condensation of gauge bosons or, alternatively, in terms of the appearance of an additional geometric phase, an interpretation that is valid for quite general condensed-matter systems. © 1992 The American Physical Society. 45 20 11518 11526

Starting with a view of condensed matter as a neutral assembly of electrons and nuclei, with mutual Coulomb interactions, a coherent-state functional-integral approach gives a first-principles theory of pairing phases that requires no adiabatic separation of time scales. For electrons and protons, both fermions, we show that an interdependent pairing of electrons and of protons can arise at low temperature with effective pairing interactions. A critical point for this system is identified, which is discussed in the light of recent experiments on dense hydrogen. © 1991 The American Physical Society. 66 22 2915 2918 Cited By :38

We report a general method for evaluating the partial chemical potentials of a dense neutral multicomponent system of charged particles. The results of this analysis can be directly applied to the evaluation of chemical potentials and partial chemical potentials for the electron gas, for a neutral two-component charged system such as the metallic phase of hydrogen, and even for a three-component system such as a metal hydride. © 1991 The American Physical Society. 43 4 1685 1700 Cited By :2

We present a static recursive method that can straightforwardly be applied to variational treatments of canonical many-body systems whose ground states generally exhibit pairing or higher clustering correlations. We illustrate the utility of the method by applying it to an electron system with pairing interactions where we obtain, as expected, a smooth transition between a Bose condensate of tightly bound electron pairs and a superconducting ground state. The method also reproduces the mean-field results for the electron-hole liquid problem as well as the antiferromagnetic insulator ground state of the Hubbard model but in a simpler way. We give a nontrivial application to a model of dense molecular hydrogen consisting of condensed generalized molecules. We show that the effective interaction between identical particles is of such a form that the state undergoes a dielectric catastrophe at a certain finite density. The competition between this abrupt transition and a smooth transition of atomic pairs in the spinless and translationally invariant version of the problem is also discussed. © 1990 The American Physical Society. 42 13 7855 7868

We derive exact scaling relations for the energy and pair-correlation functions of a neutral two-component system of charged nonrelativistic particles in its ground state. These are obtained under general conditions through the use of the virial theorem, and the use of the Hellmann-Feynman theorem with respect to masses and charges, and they are independent of symmetry. For a dense system of charged fermions of disparate masses, where Born-Oppenheimer separation is valid, these results are used to obtain the ground-state energy by scaling from known electron-gas results and evaluating terms from cross interactions by response and effective-mass theory. The results, which require very little numerical work, agree well with the quantum Monte Carlo simulations for metallic hydrogen. © 1990 The American Physical Society. 41 10 6500 6519