Complex path simulations of geometrically frustrated ladders

Abstract

Quantum systems with geometrical frustration remain an outstanding challenge for numerical simulations due to the infamous numerical sign problem. Here, we overcome this obstruction via complex path integration in a geometrically frustrated ladder of interacting bosons at finite density. This enables studies of the many-body ground state properties, otherwise inaccessible with standard quantum Monte Carlo methods. Specifically, we study a chemical potential tuned quantum phase transition, along which we track the emergence of quasi-long-range order and critical softening of the single particle gap. We chart future methodological improvements and applications in generalized geometrically frustrated lattice models.

10 pages, 9 figures, published version

References in corpus (9)

• Computational complexity and fundamental limitations to fermionic quantum Monte Carlo simulations
• Feedback-optimized parallel tempering Monte Carlo
• Sign-problem-free quantum Monte Carlo of the onset of antiferromagnetism in metals
• Schwinger-Keldysh on the lattice: a faster algorithm and its application to field theory
• Deep Learning Beyond Lefschetz Thimbles
• Monte Carlo calculations of the finite density Thirring model
• Method for simulating O(N) lattice models at finite density
• Exponential reduction of the sign problem at finite density in the 2+1D XY model via contour deformations
• Lefschetz Thimble Quantum Monte Carlo for Spin Systems