Tensor Product Calculator

A ⊗ B Kronecker product

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About Tensor Product Calculator

A tensor (Kronecker) product calculator for matrices. Computes A ⊗ B where each entry aᵢⱼ is replaced by aᵢⱼ·B. Result is (m₁m₂) × (n₁n₂). Shows the expanded matrix. Select from preset pairs. All calculations are client-side. Essential for quantum computing and multilinear algebra.

Tensor Product Calculator Features

  • A ⊗ B
  • Expanded matrix
  • Properties
  • Quantum gates
  • Presets
Kronecker product: (A ⊗ B)ᵢⱼ block = aᵢⱼ·B. If A is m₁×n₁ and B is m₂×n₂, result is m₁m₂ × n₁n₂. Properties: (A⊗B)(C⊗D) = (AC)⊗(BD). det(A⊗B) = det(A)^n₂ · det(B)^n₁. Eigenvalues: λᵢμⱼ.

How to Use

Select matrices:

  • A, B: Input matrices
  • A ⊗ B: Result
  • Size: Product dimensions

Quantum Computing

Two-qubit states: |ψ⟩ ⊗ |φ⟩. Gate on qubit 1: U ⊗ I. CNOT, SWAP are NOT tensor products (they create entanglement). Tensor product = no entanglement.

Properties

  • (A⊗B)ᵀ = Aᵀ⊗Bᵀ
  • (A⊗B)⁻¹ = A⁻¹⊗B⁻¹
  • tr(A⊗B) = tr(A)·tr(B)
  • Not commutative: A⊗B ≠ B⊗A

Step-by-Step Instructions

  1. 1Select preset matrices.
  2. 2View A and B.
  3. 3Compute A ⊗ B.
  4. 4Check dimensions.
  5. 5Examine properties.

Tensor Product Calculator — Frequently Asked Questions

How is tensor product used in quantum computing?+

Multi-qubit state spaces are tensor products: H₁⊗H₂. A 2-qubit system lives in C²⊗C² = C⁴. Operations on qubit 1 only: U⊗I. Entangled states CANNOT be written as tensor products — that's what makes entanglement special.

What are the eigenvalues of A ⊗ B?+

If λᵢ are eigenvalues of A and μⱼ are eigenvalues of B, then the eigenvalues of A⊗B are all products λᵢμⱼ. The eigenvectors are vᵢ⊗wⱼ. This makes spectral analysis of tensor products easy.

How big does the result get?+

A is m₁×n₁, B is m₂×n₂ → A⊗B is m₁m₂ × n₁n₂. Two 2×2 matrices give 4×4. Three 2×2 matrices give 8×8. Growth is exponential — this is why quantum computers with n qubits have 2ⁿ-dimensional state spaces.

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