Quantum Modeler · Learn
From binary variables to Ising spins
The same objective can be expressed with binary variables or spin values.
Understand
The Modeler uses x = (1 − z) / 2: bit 0 corresponds to spin +1, and bit 1 to spin −1. Substitution produces an Ising offset, linear Z terms and ZZ couplings.
Keep the offset and convention with the coefficients. The Compiler also exports an Ocean convention using x = (s + 1) / 2; its linear fields have the opposite sign. Coefficients from different conventions are not interchangeable.
The fixture was verified by the native mathematical tests. This lesson displays its coefficients and recorded QUBO energies; it does not run a second Ising evaluator in the browser.
Visualize
Read the original QUBO beside its native Ising coefficients. Energy scale is execution normalization metadata, not permission to discard the original objective.
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Experiment
Select 000 and then 111. Translate the bits into spins using the correspondence, and identify which linear terms change sign. Compare another recorded state with the exact reference.
Apply
Open Custom QUBO to inspect a fresh formulation and its exports. Keep the convention, offset and variable order together when using another solver.
Check your understanding
Under x = (1 − z) / 2, which spin represents bit 0?