A fully self-consistent treatment of collective fluctuations in quantum liquids

The problem of the equilibrium triplet structures in fluids with quantum behavior is discussed. Theoretical questions of interest to the real space structures are addressed by studying the three types of structures that can be determined via path integrals (instantaneous, centroid, and total thermalizedcontinuous linear response). The cases of liquid para-H 2 and liquid neon on their crystallization lines are examined with path-integral Monte Carlo simulations, the focus being on the instantaneous and the centroid triplet functions (equilateral and isosceles configurations). To analyze the results further, two standard closures, Kirkwood superposition and Jackson-Feenberg convolution, are utilized. In addition, some pilot calculations with path integrals and closures of the instantaneous triplet structure factor of liquid para-H 2 are also carried out for the equilateral components. Triplet structural regularities connected to the pair radial structures are identified, a remarkable usefulness of the closures employed is observed (e.g., triplet spatial functions for medium-long distances, triplet structure factors for medium k wave numbers), and physical insight into the role of pair correlations near quantum crystallization is gained.

Section: Discussionmentioning

confidence: 99%

Section: Computational Detailsmentioning

confidence: 99%

On static triplet structures in fluids with quantum behavior

Sesé

2017

“…(2.6) and also with experimental data [121][122][123][124][125][126] . It will also be an interesting task to use the LSC-IVR to calculate the coherent dynamic structure factor, which reflects the collective behavior of liquids rather than the single-particle motion 72,95,104,127 The integral over gives Eqs. Δx (2.14) and (2.17).…”

Section: Discussionmentioning

confidence: 99%

“…We also note here that the maximum entropy analytic continuation (MEAC) approach developed mainly by Berne and coworkers [84][85][86][87][88][89] and quantum mode-coupling theory (QMCT) approach of Rabani and Reichman [90][91][92][93][94][95][96][97] are also very useful methods to capture accurate short-time behavior of the real time correlation function. Since only the imaginary time information is needed as the input, calculations of these two methods are usually light and are feasible for cases where dynamics are very slow (i.e., glassy liquids), which is the strength of these two methods.…”

Section: Introductionmentioning

confidence: 99%

Test of the consistency of various linearized semiclassical initial value time correlation functions in application to inelastic neutron scattering from liquid para-hydrogen

Liu

Miller

2008

“…As for our EPAC method, the nonlinear operator problem has not been examined yet. In addition to these three methods, a theoretical approach based on the quantum mode-coupling theory has been applied to study the dynamical properties involving nonlinear operators in quantum liquids [8,22].…”

mentioning

confidence: 99%

Effective potential analytic continuation approach for real time quantum correlation functions involving nonlinear operators

Horikoshi

Kinugawa

2005

We apply the effective potential analytic continuation (EPAC) method to the calculation of real time quantum correlation functions involving operators nonlinear in the position operatorq. For a harmonic system the EPAC method provides the exact correlation function at all temperature ranges, while the other quantum dynamics methods, the centroid molecular dynamics and the ring polymer molecular dynamics, become worse at lower temperature. For an asymmetric anharmonic system, the EPAC correlation function is in very good agreement with the exact one at t = 0.When the time increases from zero, the EPAC method gives good coincidence with the exact result at lower temperature. Finally, we propose a simplified version of the EPAC method to reduce the computational cost required for the calculation of the standard effective potential.