v0.4.0

TNRKit v0.4.0

Diff since v0.3.0

TNRKit v0.4.0 adds a bunch of new features!

One of the main changes in this version is the update to TensorKit v0.16.
This brings a couple of internal and interface changes.

The projectors in HOTRG are now finally calculated with a truncated hermitian eigenvalue decomposition (eigh_trunc).
The TensorKit.TruncationSchemes like truncdim and truncbelow are now MatrixAlgebraKit.TruncationStrategys like truncrank and trunctol.

New Methods

2D Triangular CTM Methods

• c6vCTM_triangular: C6v symmetric Corner Transfer Matrix for triangular lattices (#109)
• CTM_triangular: Corner Transfer Matrix for triangular lattices (#128)

New Models

XY Models (#130)

• classical_XY_U1_symmetric: XY model with U(1) symmetry
• classical_XY_O2_symmetric: XY model with O(2) symmetry

Triangular Lattice Models

• classical_ising_triangular: Ising model on triangular lattice
• classical_ising_triangular_symmetric: Symmetric Ising model on triangular lattice with ℤ₂ grading
• New constants: ising_βc_triangular and f_onsager_triangular

φ⁴ theory models (#134)

Real φ⁴:

• phi4_real: Partition function tensor
• phi4_real_symmetric: Partition function with explicit ℤ₂ symmetry
  Corresponding impurity tensors have also been added.

Complex φ⁴:

• phi4_complex: Partition function tensor
• phi4_complex_symmetric: Partition function with explicit U(1) symmetry
  Corresponding impurity tensors have also been added.

Clock Model (#129)

• classical_clock_symmetric: Clock model with explicit ℤq symmetry on each space

Added Functionality

CFT Analysis (#123)

• ground_state_degeneracy: Calculate GSD from fixed-point tensors using Shannon entropy
• gu_wen_ratio: Calculate Gu-Wen ratios (X1 and X2) related to GSD and scaling dimensions
• New finalizers: GSDegeneracy_Finalizer and guwenratio_Finalizer

API Changes

• Breaking: Renamed cft_data! to cft_data (no longer mutates scheme)
• TensorKit v0.16.2 is now required, users should now use it's TruncationStrategy interface for truncation.

Bugfixes

• Fixed arrow direction checks in LoopTNR implementation (#127)

Merged pull requests:

• Add C6 symmetric CTMRG for triangular lattice (#109) (@sanderdemeyer)
• Clarify loop-TNR CFT calculation (#120) (@Yue-Zhengyuan)
• Make all cft_data non-mutating (#122) (@Yue-Zhengyuan)
• Ground state degeneracy (#123) (@Adwait-Naravane)
• normalize! (#124) (@lkdvos)
• coner_spectrum with symmetries (#125) (@lkdvos)
• declare globals as const (#126) (@lkdvos)
• Preserve arrows in loop-TNR (#127) (@Yue-Zhengyuan)
• Add general CTMRG for triangular lattice (#128) (@sanderdemeyer)
• Add Zq symmetric classical clock model (#129) (@dartsushi)
• Added XY model protected by U(1) and O(2) symmetries (#130) (@Chenqitrg)
• Update to TensorKit 0.16 (#133) (@VictorVanthilt)
• Add phi^4 models (#134) (@JaridPiceu)
• Remove double definitions of HOTRG steps (#136) (@VictorVanthilt)
• Use svd_compact instead of svd_full (#137) (@VictorVanthilt)
• Version 0.4.0 (#138) (@VictorVanthilt)

Closed issues:

• Two site update in Loop TNR (#101)
• Possibility of implementing symmetry provided by TensorKit.jl (#117)
• Arrows in loop-TNR (#121)
• Using Linsolve instead of Gradient descent in SloopTNR. (#132)