We investigate the effect of many-body correlations on the ground-state properties of two coupled charged Bose quantum wires. The intrawire and interwire correlations are treated on the same footing within the self-consistent mean-field theory of Singwi, Tosi, Land and Sjölander. Static properties, viz. , pair-correlation functions, local-field correction factors, screened interactions and susceptibilities, are calculated for a range of wire spacings d , wire radii , and boson density parameters . We find that the qualitative dependence of intrawire correlations on and remains the same as found for an isolated wire, except that they become slightly weaker with the decreasing spacing d . The interwire correlations, on the other hand, depend strongly on d and are found to grow in magnitude with decreasing d . Further, we find no evidence for the existence of a charge-density-wave ground state in the density range investigated, , in the close proximity of wires. A comparison with the similar studies on the coupled electron quantum wires reveals that the charge-density-wave instability observed there may be an artifact of the neglect of interwire correlation effects.
The ground state of a double-layer charged Bose system is investigated beyond the random-phase approximation by including the many-body correlation effects. The correlations within the layer are accounted for within the self-consistent theory of Singwi, Tosi, Land, and Sj\"olander, while we have neglected the effect of interlayer correlations. The static susceptibility, the elementary excitation spectrum, and the static screened potentials are calculated and their dependence on the boson number density and the layer spacing is examined. Results are compared with the recent work of Tanatar and Das where correlations are not included. It is found that the inclusion of correlation effects combined with the interlayer interactions can significantly alter the nature of the ground state and, in particular, can favor an inhomogeneous charge-density-wave ground state. A comparison is also made in terms of screened potentials with the double-layer electron system that enables one to have a deeper insight into the role played by the exchange and Coulomb correlations separately.
We have investigated the effect of many-body correlations on properties of coupled electron-hole quantum wires using a Singwi-Tosi-Land-Sj\"olander approach. At
rs=4 the acoustic collective mode traverses the single-electron excitation region as a narrow resonance peak and reemerges in the undamped region on the high-
q side of the excitation region. The acoustic collective mode, but not the optic mode, is sensitive to the separation between the wires. For
rs>2.5 the effective interaction acting between the electrons which is mediated by the heavier holes becomes attractive when the separation between the wires drops to a critical value. For
0.8< rs< 2.5 we detect a charge-density-wave ground state for small wire separations.
The correlation between electrons in different quantum wires is expected to affect the electronic properties of quantum electron-electron biwire systems. Here, we use the variational Monte Carlo method to study the ground-state properties of parallel, infinitely thin electron-electron biwires for several electron densities (
rs) and interwire separations (
d). Specifically, the ground-state energy, the correlation energy, the interaction energy, the pair-correlation function (PCF), the static structure factor (SSF), and the momentum distribution (MD) function are calculated. We find that the interaction energy increases as
ln(d) for $d\ensuremath{\rightarrow}0$ and it decreases as ${d}^{\ensuremath{-}2}$ when $d\ensuremath{\rightarrow}\ensuremath{\infty}$. The PCF shows oscillatory behavior at all densities considered here. As two parallel wires approach each other, interwire correlations increase while intrawire correlations decrease as evidenced by the behavior of the PCF, SSF, and MD. The system evolves from two monowires of density parameter
rs to a single monowire of density parameter
rs/2 as
d is reduced from infinity to zero. The MD reveals Tomonaga-Luttinger (TL) liquid behavior with a power-law nature near
kF even in the presence of an extra interwire interaction between the electrons in biwire systems. It is observed that when
d is reduced the MD decreases for
k<kF and increases for
k>kF, similar to its behavior with increasing
rs. The TL liquid exponent is extracted by fitting the MD data near
kF, from which the TL liquid interaction parameter ${K}_{\ensuremath{\rho}}$ is calculated. The value of the TL parameter is found to be in agreement with that of a single wire for large separation between the two wires.
We evaluate the ground-state properties of a charged Bose gas at
T=0 within the quantum version of the self-consistent field approximation of Singwi, Tosi, Land, and Sj\"olander. The dynamical nature of the local- field correction is retained to include dynamic correlation effects. The resulting static structure factor
S(q) and the local-field factor
G(q) exhibit properties not described by other mean-field theories.
We describe correlation effects in the charged quasi-one-dimensional Bose condensate with parabolic confinement. Many-body effects are calculated with the sum-rule version of the Singwi, Tosi, Land, and Sj\"olander theory. We give numerical and analytical results for the local-field correction, the pair-distribution function, the correlation energy, and the compressibility of the Bose condensate. The results are given as a function of the Wigner-Seitz parameter
rs and the wire-width parameter
b. The exact long-wavelength behavior of the plasmon dispersion is investigated using the compressibility sum rule.
The ground state of a charged Bose gas is studied throughout a large range of densities in a self-consistent-field approximation formalism which includes the short-range correlations between bosons through a local-field correction. Numerical self-consistent calculations have been carried out in order to determine the static structure factor $S(\stackrel{\ensuremath{\rightarrow}}{\mathrm{q}})$. Hence, from $S(\stackrel{\ensuremath{\rightarrow}}{\mathrm{q}})$ we have obtained the pair-correlation functions, the ground-state energy which essentially is the correlation energy, the pressure of the gas, and, from Feynman's relation, the energy spectrum of elementary excitations. The response of the system to a static impurity charge has also been investigated. In the high-density limit our calculations show the same results as those given by Bogoliubov's perturbation theory. In the intermediate-density region, corresponding to the strongly coupled system, our results are in very good agreement with recent calculations based on the hypernetted-chain integral equation as well as Monte Carlo computations.