Application of optimized quantum Monte-Carlo simulation method in study of complex magnetic systems

Abstract

The invention provides an optimized quantum Monte-Carlo method, which is used for studying magnetic material, belonging to that field of computational physics and computational materials science. Themethod includes: S1, calculating all the physical quantities, including the spin or magnetic moment in the Hamiltonian of the system is a quantum mechanical operator, according to the quantum theory;2, simulating the random orientation of all spins at the initial time; 3, randomly selecting a spin in each step and rotating that spin by a random solid angle; S4, judging whether the new orientation of the spin is accepted or not according to the Metropolis algorithm; S5, if accepted, updating the energy state of the nearest neighbor; 6, judging whether that current cycle is end or not, otherwise, returning to S3; 7, judging whether that current cycle satisfy the convergence condition or the cycle number is greater than an integer, otherwise, returning to S3; S8, calculating and outputtingmagnetic structures and other physical quantities. Because of the application of quantum theory and the optimization of algorithm, the computational speed is greatly improved, and the difficulty thatthe classical simulation method can not solve is overcome.

Description

technical field [0001] The present invention belongs to the field of computational physics and computational materials science. Its theory, model, method and related software developed will be used to simulate the microscopic magnetic structure of the magnetic system, and calculate its magnetization, magnetic susceptibility, hysteresis loop, heat capacity and other macroscopic physical quantity. Background technique [0002] For decades, researchers at home and abroad have generally used two numerical methods, Classical Monte Carlo (Classical Monte Carlo) [1-5] and Micromagnetics (Micromagnetics) [6-9], to simulate the microscopic magnetic structure of magnetic materials. their macroscopic physical properties. [0003] However, both methods are based on classical physics, that is, in the simulation, the spin and magnetic moment in the magnetic system are treated as classical vectors with constant length but rotating in space. Obviously, such a simple processing method will...

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Problems solved by technology

However, these expedient measures greatly slow down the calculation speed, and the author found in recent research that for magnetic systems with complex interactions (such as Dzyaloshinsky-Moriya interaction), the expedient methods may not guarantee the correct magnetic structure simulation

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