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Physlib.QuantumMechanics.DDimensions.Hydrogen.LaplaceRungeLenzVector

Laplace-Runge-Lenz vector

In this file we define - The (regularized) LRL vector operator for the quantum mechanical hydrogen atom, `𝐀(ε)ᵢ ≔ ½(𝐩ⱼ𝐋ᵢⱼ + 𝐋ᵢⱼ𝐩ⱼ) - mk·𝐫(ε)⁻¹𝐱ᵢ`. - The square of the LRL vector operator, `𝐀(ε)² ≔ 𝐀(ε)ᵢ𝐀(ε)ᵢ`.

The main results are - The commutators `⁅𝐋ᵢⱼ, 𝐀(ε)ₖ⁆ = iℏ(δᵢₖ𝐀(ε)ⱼ - δⱼₖ𝐀(ε)ᵢ)` in `angularMomentum_commutation_lrl` - The commutators `⁅𝐀(ε)ᵢ, 𝐀(ε)ⱼ⁆ = -iℏ 2m 𝐇(ε)𝐋ᵢⱼ` in `lrl_commutation_lrl` - The commutators `⁅𝐇(ε), 𝐀(ε)ᵢ⁆ = iℏε²(⋯)` in `hamiltonianReg_commutation_lrl` - The relation `𝐀(ε)² = 2m 𝐇(ε)(𝐋² + ¼ℏ²(d-1)²) + m²k² + ε²(⋯)` in `lrlOperatorSqr_eq`

11 declarations

definition

Regularized Laplace-Runge-Lenz operator Ai(ε)A_i(\varepsilon) for the hydrogen atom

For a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the ii-th component of the regularized Laplace-Runge-Lenz (LRL) vector operator Ai(ε)A_i(\varepsilon) is a continuous linear operator on the Schwartz space S(Rd,C)\mathcal{S}(\mathbb{R}^d, \mathbb{C}) defined as: Ai(ε)=12j=1d(pjLij+Lijpj)mk1r(ε)xiA_i(\varepsilon) = \frac{1}{2} \sum_{j=1}^d (p_j L_{ij} + L_{ij} p_j) - mk \frac{1}{r(\varepsilon)} x_i where pjp_j is the jj-th component of the momentum operator, LijL_{ij} is the ijij-component of the angular momentum operator, xix_i is the ii-th component of the position operator, and r(ε)1r(\varepsilon)^{-1} is the regularized inverse radial distance operator.

definition

Square of the regularized Laplace-Runge-Lenz operator A(ε)2\mathbf{A}(\varepsilon)^2

For a dd-dimensional quantum mechanical hydrogen atom with regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the square of the regularized Laplace-Runge-Lenz (LRL) vector operator, denoted as A(ε)2\mathbf{A}(\varepsilon)^2, is a continuous linear operator on the Schwartz space S(Rd,C)\mathcal{S}(\mathbb{R}^d, \mathbb{C}). It is defined as the sum of the squares of the individual components of the LRL operator: A(ε)2=i=1dAi(ε)2\mathbf{A}(\varepsilon)^2 = \sum_{i=1}^d A_i(\varepsilon)^2 where Ai(ε)A_i(\varepsilon) is the ii-th component of the regularized LRL vector operator.

theorem

Ai(ε)=xip2(jxjpj)pi+i(d1)2pimkr(ε)1xiA_i(\varepsilon) = x_i p^2 - (\sum_j x_j p_j) p_i + \frac{i\hbar(d-1)}{2} p_i - mk r(\varepsilon)^{-1} x_i

In a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, for a given regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the ii-th component of the regularized Laplace-Runge-Lenz (LRL) operator Ai(ε)A_i(\varepsilon) can be expressed in terms of the position operators xjx_j and momentum operators pjp_j as: Ai(ε)=xip2(j=1dxjpj)pi+i(d1)2pimk1r(ε)xiA_i(\varepsilon) = x_i p^2 - \left(\sum_{j=1}^d x_j p_j\right) p_i + \frac{i\hbar(d-1)}{2} p_i - mk \frac{1}{r(\varepsilon)} x_i where p2=j=1dpj2p^2 = \sum_{j=1}^d p_j^2 is the momentum squared operator, \hbar is the reduced Planck constant, ii is the imaginary unit, and r(ε)1r(\varepsilon)^{-1} is the regularized inverse radial distance operator.

theorem

Ai(ε)=jLijpj+i(d1)2pimkr(ε)1xiA_i(\varepsilon) = \sum_j L_{ij} p_j + \frac{i\hbar(d-1)}{2} p_i - mk r(\varepsilon)^{-1} x_i

For a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the ii-th component of the regularized Laplace-Runge-Lenz (LRL) operator Ai(ε)A_i(\varepsilon) can be expressed in terms of the angular momentum operators LijL_{ij} and momentum operators pjp_j as: Ai(ε)=j=1dLijpj+i(d1)2pimk1r(ε)xiA_i(\varepsilon) = \sum_{j=1}^d L_{ij} p_j + \frac{i\hbar(d-1)}{2} p_i - mk \frac{1}{r(\varepsilon)} x_i where LijL_{ij} is the ijij-component of the angular momentum operator, pip_i is the ii-th component of the momentum operator, xix_i is the ii-th component of the position operator, \hbar is the reduced Planck constant, ii is the imaginary unit, and r(ε)1r(\varepsilon)^{-1} is the regularized inverse radial distance operator.

theorem

Ai(ε)=jpjLiji(d1)2pimkr(ε)1xiA_i(\varepsilon) = \sum_j p_j L_{ij} - \frac{i\hbar(d-1)}{2} p_i - mk r(\varepsilon)^{-1} x_i

For a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the ii-th component of the regularized Laplace-Runge-Lenz (LRL) operator Ai(ε)A_i(\varepsilon) can be expressed in terms of the momentum operators pjp_j and angular momentum operators LijL_{ij} as: Ai(ε)=j=1dpjLiji(d1)2pimk1r(ε)xiA_i(\varepsilon) = \sum_{j=1}^d p_j L_{ij} - \frac{i\hbar(d-1)}{2} p_i - mk \frac{1}{r(\varepsilon)} x_i where pjp_j is the jj-th component of the momentum operator, LijL_{ij} is the ijij-component of the angular momentum operator, xix_i is the ii-th component of the position operator, \hbar is the reduced Planck constant, ii is the imaginary unit, and r(ε)1r(\varepsilon)^{-1} is the regularized inverse radial distance operator.

theorem

Commutator [Lij,Ak(ε)]=i(δikAj(ε)δjkAi(ε))\left[L_{ij}, A_k(\varepsilon)\right] = i\hbar (\delta_{ik} A_j(\varepsilon) - \delta_{jk} A_i(\varepsilon))

For a dd-dimensional quantum mechanical hydrogen atom, let LijL_{ij} be the component of the angular momentum operator and Ak(ε)A_k(\varepsilon) be the kk-th component of the regularized Laplace-Runge-Lenz operator with regularization parameter εR×\varepsilon \in \mathbb{R}^\times. For any indices i,j,k{1,,d}i, j, k \in \{1, \dots, d\}, the commutator between these operators satisfies: [Lij,Ak(ε)]=i(δikAj(ε)δjkAi(ε))\left[L_{ij}, A_k(\varepsilon)\right] = i\hbar (\delta_{ik} A_j(\varepsilon) - \delta_{jk} A_i(\varepsilon)) where ii is the imaginary unit, \hbar is the reduced Planck's constant, and δ\delta is the Kronecker delta.

theorem

Commutator [Lij,A(ε)2]=0\left[L_{ij}, \mathbf{A}(\varepsilon)^2\right] = 0

For a dd-dimensional quantum mechanical hydrogen atom, let LijL_{ij} be the ijij-component of the angular momentum operator and A(ε)2\mathbf{A}(\varepsilon)^2 be the square of the regularized Laplace-Runge-Lenz operator with regularization parameter εR×\varepsilon \in \mathbb{R}^\times. For any indices i,j{1,,d}i, j \in \{1, \dots, d\}, the commutator between these operators vanishes: [Lij,A(ε)2]=0\left[L_{ij}, \mathbf{A}(\varepsilon)^2\right] = 0 where [,][\cdot, \cdot] denotes the commutator bracket.

theorem

Commutator [L2,A(ε)2]=0\left[L^2, \mathbf{A}(\varepsilon)^2\right] = 0

For a dd-dimensional quantum mechanical hydrogen atom, let L2L^2 be the square of the angular momentum operator and A(ε)2\mathbf{A}(\varepsilon)^2 be the square of the regularized Laplace-Runge-Lenz operator with regularization parameter εR×\varepsilon \in \mathbb{R}^\times. The commutator of these two operators vanishes: [L2,A(ε)2]=0\left[L^2, \mathbf{A}(\varepsilon)^2\right] = 0

theorem

[Ai(ε),Aj(ε)]=(2imH(ε)+imkε2r(ε)3)Lij[A_i(\varepsilon), A_j(\varepsilon)] = (-2i\hbar m H(\varepsilon) + i\hbar mk \varepsilon^2 r(\varepsilon)^{-3}) L_{ij}

For a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the commutator of the ii-th and jj-th components of the regularized Laplace-Runge-Lenz (LRL) vector operator Ai(ε)A_i(\varepsilon) and Aj(ε)A_j(\varepsilon) is given by: [Ai(ε),Aj(ε)]=(2imH(ε)+imkε2r(ε)3)Lij\left[A_i(\varepsilon), A_j(\varepsilon)\right] = \left(-2i\hbar m H(\varepsilon) + i\hbar mk \varepsilon^2 r(\varepsilon)^{-3}\right) L_{ij} where H(ε)H(\varepsilon) is the regularized Hamiltonian operator, LijL_{ij} is the ijij-component of the angular momentum operator, \hbar is the reduced Planck constant, ii is the imaginary unit, and r(ε)3r(\varepsilon)^{-3} is the regularized inverse cubed radial distance operator.

theorem

Commutator [H(ε),Ai(ε)]=ikε2r(ε)3pi322kε2r(ε)5xi[H(\varepsilon), A_i(\varepsilon)] = i\hbar k \varepsilon^2 r(\varepsilon)^{-3} p_i - \frac{3}{2} \hbar^2 k \varepsilon^2 r(\varepsilon)^{-5} x_i

For a dd-dimensional quantum mechanical hydrogen atom with coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times and a component index ii, the commutator of the regularized Hamiltonian H(ε)H(\varepsilon) and the ii-th component of the regularized Laplace-Runge-Lenz (LRL) operator Ai(ε)A_i(\varepsilon) is given by: [H(ε),Ai(ε)]=ikε2r(ε)3pi322kε2r(ε)5xi[H(\varepsilon), A_i(\varepsilon)] = i\hbar k \varepsilon^2 r(\varepsilon)^{-3} p_i - \frac{3}{2} \hbar^2 k \varepsilon^2 r(\varepsilon)^{-5} x_i where \hbar is the reduced Planck's constant, pip_i is the ii-th component of the momentum operator, xix_i is the ii-th component of the position operator, and r(ε)nr(\varepsilon)^{-n} denotes the operator corresponding to the regularized inverse nn-th power of the radial distance.

theorem

Relation for the square of the regularized LRL operator A(ε)2\mathbf{A}(\varepsilon)^2 in terms of H(ε)H(\varepsilon) and L2\mathbf{L}^2

For a dd-dimensional quantum mechanical hydrogen atom with mass mm and coupling constant kk, given a regularization parameter εR×\varepsilon \in \mathbb{R}^\times, the square of the regularized Laplace-Runge-Lenz (LRL) vector operator A(ε)2\mathbf{A}(\varepsilon)^2 is related to the regularized Hamiltonian H(ε)H(\varepsilon) and the square of the angular momentum operator L2\mathbf{L}^2 by the following identity: A(ε)2=2mH(ε)(L2+2(d1)24)+m2k2(1ε2r(ε)2)12(d1)mk2ε2r(ε)3\mathbf{A}(\varepsilon)^2 = 2m H(\varepsilon) \left( \mathbf{L}^2 + \frac{\hbar^2 (d-1)^2}{4} \right) + m^2 k^2 (1 - \varepsilon^2 r(\varepsilon)^{-2}) - \frac{1}{2} (d-1) m k \hbar^2 \varepsilon^2 r(\varepsilon)^{-3} where \hbar is the reduced Planck constant and r(ε)r(\varepsilon) is the regularized radial distance. The operators are understood to act on the Schwartz space S(Rd,C)\mathcal{S}(\mathbb{R}^d, \mathbb{C}).