Quantum Monte Carlo estimation of complex-time correlations for the study of the ground-state dynamic structure...

Area of Science:

• Quantum mechanics
• Computational physics
• Statistical mechanics

Background:

• Calculating ground-state time correlation functions in quantum systems is crucial.
• Traditional methods like inverse Laplace transforms have limitations.

Purpose of the Study:

• To develop a more accurate method for calculating ground-state time correlation functions.
• To improve the inference of spectral functions from quantum system data.

Main Methods:

• Utilizing path integral Monte Carlo formalism.
• Treating time as a complex variable with an adjustable phase parameter (δ).
• Employing high-order approximations for the quantum propagator.

Main Results:

• Successfully obtained Monte Carlo data across a range of complex time values.
• Accurately inferred spectral functions using simple inversion algorithms.
• Demonstrated clear improvement in dynamic response calculations for model systems (harmonic and quartic oscillators).

Conclusions:

• The complex time method offers superior accuracy for spectral function inference compared to traditional inverse Laplace transform methods.
• This approach enhances the calculation of dynamic structure functions in quantum systems.
• The method shows significant promise for advancing quantum system analysis.