Fermion bag approach to the sign problem in strongly coupled lattice QED with Wilson fermions

Abstract

We explore the sign problem in strongly coupled lattice QED with one flavor of Wilson fermions in four dimensions using the fermion bag formulation. We construct rules to compute the weight of a fermion bag and show that even though the fermions are confined into bosons, fermion bags with negative weights do exist. By classifying fermion bags as either simple or complex, we find numerical evidence that complex bags with positive and negative weights come with almost equal probabilities and this leads to a severe sign problem. On the other hand simple bags mostly have a positive weight. Since the complex bags almost cancel each other, we suggest that eliminating them from the partition function may be a good approximation. This modified partition function suffers only from a mild sign problem. We also find a simpler model which does not suffer from any sign problem and may still be a good approximation at small and intermediate values of the hopping parameter. We also prove that when the hopping parameter is strictly infinite all fermion bags are non-negative.

arXiv comment17 pages, 4 figures, 5 tables

References in corpus (14)

• Computational complexity and fundamental limitations to fermionic quantum Monte Carlo simulations
• String Theory, Quantum Phase Transitions and the Emergent Fermi-Liquid
• Probing Cold Dense Nuclear Matter
• Meron-Cluster Solution of Fermion Sign Problems
• Can stochastic quantization evade the sign problem? -- the relativistic Bose gas at finite chemical potential
• Probing Interactions between Ultracold Fermions
• The fermion bag approach to lattice field theories
• Chiral Limit of Strongly Coupled Lattice Gauge Theories
• Method for simulating O(N) lattice models at finite density
• Efficient simulation of relativistic fermions via vertex models
• Cluster simulation of relativistic fermions in two space-time dimensions
• Simulating the All-Order Hopping Expansion II: Wilson Fermions
• Fermion loop simulation of the lattice Gross-Neveu model
• Modeling pion physics in the $\epsilon$-regime of two-flavor QCD using strong coupling lattice QED

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• Gauge and matter fields as surfaces and loops - an exploratory lattice study of the Z(3) Gauge-Higgs model
• New developments for dual methods in lattice field theory at non-zero density
• Monte Carlo studies of the spontaneous rotational symmetry breaking in dimensionally reduced super Yang-Mills models
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• Anomaly and a QCD-like phase diagram with massive bosonic baryons
• Baryon bags in strong coupling QCD
• Abelian color cycle and abelian color flux dualization methods for non-abelian lattice field theories