PEPSKit.jl: A Julia package for projected entangled-pair state simulations
Pith reviewed 2026-05-20 04:06 UTC · model grok-4.3
The pith
A package supplies high-level algorithms for infinite projected entangled-pair state simulations of two-dimensional quantum many-body systems that handle multiple symmetries and fermions.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The package provides high-level algorithms for iPEPS simulations that support both Abelian and non-Abelian symmetries, as well as fermionic systems, for ground-state, time-evolution, and finite-temperature simulations in systems with different physical symmetries and lattice geometries.
What carries the argument
High-level iPEPS contraction and optimization routines that operate on tensor representations while preserving symmetries during the simulations.
If this is right
- Ground-state calculations become available for models with non-Abelian symmetries on two-dimensional lattices.
- Real-time evolution of fermionic systems can be tracked without separate low-level implementations for each symmetry type.
- Finite-temperature properties can be extracted for a range of lattice geometries using the same algorithmic framework.
- Simulations of systems with mixed symmetries no longer require users to code contraction routines from scratch.
Where Pith is reading between the lines
- The availability of these tools may shorten the time needed to explore candidate quantum phases in two-dimensional materials.
- Direct comparisons with other numerical techniques on identical models could clarify accuracy limits for moderate bond dimensions.
- Extensions to dynamical correlation functions or response properties would follow naturally from the existing time-evolution routines.
Load-bearing premise
The tensor computations and optimization routines remain numerically stable and correctly enforce the chosen symmetries without introducing errors that would distort the physical results.
What would settle it
A benchmark run on a square-lattice Heisenberg antiferromagnet that produces ground-state energies deviating beyond statistical error bars from established reference values would indicate a problem with the claimed capabilities.
Figures
read the original abstract
We present PEPSKit.jl, a Julia package for simulating two-dimensional quantum many-body systems with infinite projected entangled-pair states (iPEPS). PEPSKit.jl builds on the TensorKit.jl package for tensor computations and provides high-level algorithms for iPEPS simulations that support both Abelian and non-Abelian symmetries, as well as fermionic systems. This work gives an overview of the main package features, which include support for ground-state, time-evolution, and finite-temperature simulations in systems with different physical symmetries and lattice geometries. These capabilities are illustrated through various examples and technical benchmarks.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper presents PEPSKit.jl, a Julia package for simulating two-dimensional quantum many-body systems with infinite projected entangled-pair states (iPEPS). It builds on TensorKit.jl for tensor computations and provides high-level algorithms supporting Abelian and non-Abelian symmetries as well as fermionic systems. The package enables ground-state, time-evolution, and finite-temperature simulations across different physical symmetries and lattice geometries, with capabilities illustrated through examples and technical benchmarks.
Significance. If the package implements the described functionality correctly, it would offer a valuable addition to the tensor-network toolkit in condensed-matter physics by providing symmetry-aware iPEPS simulations in the Julia language. The high-level interface and support for non-Abelian and fermionic cases address practical needs in the community and could improve accessibility and reproducibility of such simulations.
major comments (2)
- Technical Benchmarks section: the manuscript refers to technical benchmarks but supplies no quantitative validation data, error analysis, convergence metrics, or comparisons against known results or other codes; this is load-bearing for substantiating the claimed numerical stability and performance for non-Abelian symmetries and fermionic systems.
- Examples section: the provided examples illustrate usage for ground-state and time-evolution tasks but omit explicit checks such as energy convergence with bond dimension or agreement with exact diagonalization on small clusters, which is needed to confirm correctness of the newly implemented contraction and optimization routines.
Simulated Author's Rebuttal
We thank the referee for their positive evaluation of the manuscript and for the constructive comments on the benchmarks and examples sections. We address each point below and have revised the manuscript to incorporate additional quantitative data and validation checks.
read point-by-point responses
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Referee: Technical Benchmarks section: the manuscript refers to technical benchmarks but supplies no quantitative validation data, error analysis, convergence metrics, or comparisons against known results or other codes; this is load-bearing for substantiating the claimed numerical stability and performance for non-Abelian symmetries and fermionic systems.
Authors: We agree that more detailed quantitative validation is necessary to fully substantiate the claims regarding numerical stability and performance, particularly for the non-Abelian and fermionic cases. In the revised manuscript we have expanded the Technical Benchmarks section with explicit convergence metrics, error analyses, and direct comparisons against known analytical results as well as outputs from established codes for both symmetry sectors. revision: yes
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Referee: Examples section: the provided examples illustrate usage for ground-state and time-evolution tasks but omit explicit checks such as energy convergence with bond dimension or agreement with exact diagonalization on small clusters, which is needed to confirm correctness of the newly implemented contraction and optimization routines.
Authors: We appreciate the referee highlighting the value of these explicit validation checks. The revised Examples section now includes energy convergence plots versus bond dimension for the ground-state and time-evolution cases, together with direct comparisons to exact diagonalization results on small clusters, thereby confirming the correctness of the contraction and optimization routines. revision: yes
Circularity Check
No significant circularity in software package description
full rationale
This is a software-package description paper rather than a theoretical derivation. The central claims concern the implementation of iPEPS algorithms with symmetry and fermionic support in PEPSKit.jl, illustrated via examples and benchmarks. No equations, predictions, or first-principles results are presented that could reduce to inputs by construction. There are no self-definitional steps, fitted parameters renamed as predictions, or load-bearing self-citations invoking uniqueness theorems. The manuscript is self-contained; functionality is externally verifiable through the released code and independent benchmarks, yielding no circularity.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption TensorKit.jl correctly implements tensor operations and symmetry handling for Abelian and non-Abelian groups.
- domain assumption Standard iPEPS contraction and optimization algorithms remain numerically stable when extended to the supported symmetries and fermionic statistics.
Lean theorems connected to this paper
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IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
PEPSKit.jl provides high-level algorithms for iPEPS simulations that support both Abelian and non-Abelian symmetries, as well as fermionic systems, for ground-state, time-evolution, and finite-temperature simulations
-
IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
approximate contraction algorithms... corner transfer matrix renormalization group (CTMRG)
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
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