getMatrix

Matrix representation of observable

Since R2024b

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    Installation Required: This functionality requires MATLAB Support Package for Quantum Computing.

    Syntax

    H = getMatrix(o)

    Description

    H = getMatrix(o) returns the sparse Hermitian matrix representation of the specified observable. For more information, see Matrix Representation of Observable.

    example

    Examples

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    This example uses:

    Open Live Script

    Create an observable from a two-qubit Pauli basis measurement where the X measurement basis is observed on the first and second qubits with weight 2.4 and the Z measurement basis is observed on the first qubit with weight –1.2.

    o = observable(["XX" "ZI"],[2.4 -1.2]);

    Get the sparse Hermitian matrix representation of the observable.

    H = getMatrix(o)
    H = 4×4 sparse double matrix (8 nonzeros)
   (1,1)      -1.2000
   (4,1)       2.4000
   (2,2)      -1.2000
   (3,2)       2.4000
   (2,3)       2.4000
   (3,3)       1.2000
   (1,4)       2.4000
   (4,4)       1.2000

    Input Arguments

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    Observable, specified as an observable object.

    Output Arguments

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    Matrix representation of the observable, returned as a sparse Hermitian matrix. The size of the matrix is 2n-by-2n, where n is the number of qubits in the quantum circuit or state.

    Limitations

    • As the number of qubits n increases, the size of the matrix grows exponentially as 2n-by-2n. So, using getMatrix is practical only when n is less than about 15.

    More About

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    Version History

    Introduced in R2024b

    See Also

    Functions

    Objects

    Topics