Showing that operators follow SU(2) algebra

In summary, there is a question about whether the raising and lowering operators and number operator for two quantum oscillators follow the commutation relations of the SU(2) algebra. The basis transformations can be found at the given link, with the operators N, T_+, T_-, T_1, T_2, and T_3 corresponding to H, X, Y, U, V, and W respectively.
  • #1
graviton_10
5
1
For two quantum oscillators, I have raising and lowering operators
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and
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, and the number operator
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. I need to check if operators below follow
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commutation relations.

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Now as far as I know, SU(2) algebra commutation relation is [T_1, T_2] = i ε^ijk T_3. So, should I just get T_1 and T_2 in terms of T_- and T_+ and then try to check if I get they follow the SU(2) commutation relation?
 
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  • #3
Just a pedantic comment but ##SU(2)## is a group, and ##\mathfrak{su}(2)## is an algebra.
 
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FAQ: Showing that operators follow SU(2) algebra

What is SU(2) algebra?

SU(2) algebra refers to the Lie algebra associated with the special unitary group SU(2). It consists of all 2x2 complex matrices with zero trace and is characterized by three generators that satisfy specific commutation relations. These generators often correspond to the Pauli matrices in quantum mechanics.

What are the commutation relations for SU(2) generators?

The commutation relations for the SU(2) generators \( J_i \) (where \( i = 1, 2, 3 \)) are given by \( [J_i, J_j] = i \epsilon_{ijk} J_k \), where \( \epsilon_{ijk} \) is the Levi-Civita symbol. These relations define the structure constants of the SU(2) Lie algebra.

How do Pauli matrices relate to SU(2) algebra?

The Pauli matrices \( \sigma_x, \sigma_y, \sigma_z \) are a set of three 2x2 complex matrices that serve as the generators of the SU(2) algebra. They satisfy the same commutation relations as the SU(2) generators: \( [\sigma_i, \sigma_j] = 2i \epsilon_{ijk} \sigma_k \). Thus, they provide a concrete representation of the SU(2) algebra.

Why is SU(2) algebra important in quantum mechanics?

SU(2) algebra is fundamental in quantum mechanics because it underpins the mathematical structure of spin and angular momentum. The generators of SU(2) correspond to the components of angular momentum operators, and their commutation relations reflect the intrinsic properties of spin-1/2 particles and other quantum systems.

How can one show that a set of operators follows SU(2) algebra?

To show that a set of operators follows SU(2) algebra, you need to demonstrate that they satisfy the commutation relations \( [J_i, J_j] = i \epsilon_{ijk} J_k \). This typically involves calculating the commutators of the operators and verifying that they match the expected form dictated by the SU(2) algebra. If the operators are matrices, this can be done through explicit matrix multiplication and subtraction.

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