Aleph - 0.34.0

🚀 Highlights

• Expanded the library of symbolic Fermionic operators in Aleph with new multi-site and parameterized interactions. See the New Features section for details.
• Forge scripts can now declare arguments.

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✨ New Features

• Significant expansion of symbolic Fermionic operators in Aleph, adding standardized factory functions for several interactions:
  • NumberNumber(i, j): Two-site density-density interaction $n_{i} n_{j} = f_{i}^\dagger f_{i} f_{j}^\dagger f_{j}$.
  • TransferNumber(i, j, k): $f_{i}^\dagger f_{j} n_{k}$ interaction.
  • HopNumber(i, j, k): $(f_{i}^\dagger f_{j} + f_{j}^\dagger f_{i}) n_{k}$ interaction.
  • NumberSum(sites): Total occupancy on a set of sites $\sum_{i \in \mathrm{sites}} n_{i}$.
  • NearestNumberSum(sites): Nearest-neighbor density interaction $\sum_{i} n_{i} n_{i+1}$.
  • NextNearestNumberSum(sites): Next-nearest-neighbor density interaction $\sum_{i} n_{i} n_{i+2}$.
  • PairTransfer(i, j, k, l): Directed pair transfer operator $f_{i}^\dagger f_{j}^\dagger f_{k} f_{l}$.
  • PairHop(i, j, k, l): Pair hopping operator $f_{i}^\dagger f_{j}^\dagger f_{k} f_{l} + \mathrm{h.c.}$.
  • PhaseHop(angle, i, j): Complex phase-hop operator $e^{i \phi} f_{i}^\dagger f_{j} + e^{-i \phi} f_{j}^\dagger f_{i}$.
  • NumberPhase(angle, i): Site-specific phase operator $\exp(i \phi n_i)$.
  • NumberNumberPhase(angle, i, j): Two-site phase operator $\exp(i \phi n_{i} n_{j})$.
  • ModeRotation(angle, i, j): Givens rotation operator $\exp(i \theta (f_{i}^\dagger f_{j} + f_{j}^\dagger f_{i}))$.
  • PairRotation(angle, i, j): Bogoliubov rotation operator $\exp(i \theta (f_{i}^\dagger f_{j}^\dagger + f_{j} f_{i}))$.
  • NumberPotential(coefficients [, sites]): Efficient representation of weighted density sums $\sum_{i \in \mathrm{sites}} \alpha_i n_i$.
  • CoulombSum(tensor): General Coulomb interaction $\sum_{i,j,k,l,\sigma,\sigma'} V_{ijkl} a_{i\sigma}^\dagger a_{j\sigma'}^\dagger a_{k\sigma'} a_{l\sigma}$ on interleaved spin-orbitals.
• Unified Fermionic operator naming conventions and added legacy aliases (FourBody, DoubleExcitation, NumberN, NumberNumberNN, NumberNumberNNN) for backward compatibility.
• Added Discrete Cosine Transform (DCT) and Discrete Sine Transform (DST) functions with support for types I-IV, custom normalization, and orthonormal scaling. Both transforms support 1D and 2D operations on Matrix and Array types.
• Forge scripts can now declare arguments and retrieve them with get_arg(name, type[, default]), enabling typed inputs to be provided when launching executions or scheduling jobs.
• Added function to compute the specific heat from the order estimator sse_specific_heat(order).
• The history of an SSE simulation can now be recorded and read/written from/to an HDF5 file allowing for checkpointing of simulations and for post processing.

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🐛 Fixes

• Added string parsing support for complex conversion in Aleph, so expressions like complex("2 + 1i") and "2 + 1i".complex() now work.
• Fixed LSP semantic token locations for interpolated member access (for example ${ab.first}), avoiding invalid and overlapping semantic tokens in editors.
• Mixed-complexity operator expressions that previously caused errors now work correctly. For example, 2.0 * X(0) + 3.0i * Y(1) is now a valid expression.
• Fbit and Qbit can faithfully represent BasisStates with up to 64 sites, and will throw an error if an attempt is made to create a BasisState with more than 64 sites. This prevents silent truncation of states that was previously occurring.

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⚠️ Breaking Changes

• Failed string-to-number conversions now throw an error instead of defaulting to 0. This affects conversions like real("abc") and integer("abc"). Loss-of-precision conversions still behave as before, e.g. integer("5.3") -> 5.

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