Dynamic structure factor of liquid 4He across the normal-superfluid transition

Abstract

We have carried out a microscopic study of the dynamic structure factor of liquid ${}^4$He across the normal-superfluid transition temperature using the path integral Monte Carlo method. The ill-posed problem of the inverse Laplace transform, from the imaginary-time intermediate scattering function to the dynamic response, is tackled by stochastic optimization. Our results show a quasi-particle peak and a small and broad multiphonon contribution. In spite of the lack of strength in the collective peaks, we clearly identify the rapid dropping of the roton peak amplitude when crossing the transition temperature $T_{\lambda }$. Other properties such as the static structure factor, static response, and one-phonon contribution to the response are also calculated at different temperatures. The changes of the phonon-roton spectrum with the temperature are also studied. An overall agreement with available experimental data is achieved.

arXiv comment10 pages

References in corpus (6)

• Worm Algorithm and Diagrammatic Monte Carlo: A New Approach to Continuous-Space Path Integral Monte Carlo Simulations
• Gradient Symplectic Algorithms for Solving the Schroedinger Equation with Time-Dependent Potentials
• Ab-initio low-energy dynamics of superfluid and solid 4He
• High order Chin actions in path integral Monte Carlo
• Spectral Analysis by the Method of Consistent Constraints
• Quantum Monte Carlo estimation of complex-time correlations for the study of the ground-state dynamic structure function

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• Statistical and computational intelligence approach to analytic continuation in Quantum Monte Carlo
• Dynamic structure factor of superfluid He-4 from Quantum Monte Carlo: Maximum Entropy revisited
• Microscopic dynamics of superfluid ${}^4$He: a comprehensive study by inelastic neutron scattering
• Prediction of a roton-type feature in warm dense hydrogen
• Extraction of the frequency moments of spectral densities from imaginary-time correlation function data
• Path-integral Monte Carlo worm algorithm for Bose systems with periodic boundary conditions
• Gapped spectrum in pair-superfluid bosons
• Applying the Liouville-Lanczos Method of Time-Dependent Density-Functional Theory to Warm Dense Matter
• Estimates of the dynamic structure factor for the finite temperature electron liquid via analytic continuation of path integral Monte Carlo data
• Dual formulation of the maximum entropy method applied to analytic continuation of quantum Monte Carlo data
• Maxon and roton measurements in nanoconfined ${}^4$He
• A Parameter-Free Differential Evolution Algorithm for the Analytic Continuation of Imaginary Time Correlation Functions
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• Hole-induced anomaly in the thermodynamic behavior of a one-dimensional Bose gas
• PyLIT: Reformulation and implementation of the analytic continuation problem using kernel representation methods
• The noiseless limit and improved-prior limit of the maximum entropy method and their implications for the analytic continuation problem
• Momentum distribution of liquid 4He across the normal-superfluid phase transition
• Path Integral Monte Carlo Simulations of liquid ${}^3$He without Fixed Nodes: Structural Properties and Collective Excitations