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Quantum Oscillators - O. Henri-Rousseau, et. al., (Wiley, 2011)


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- 11.3 Obtainment of the Dynamics 325.
- 14.5 Quantization of the Electromagnetic Fields 423.
- 6.3 Stabilization of the energy of the eight lowest eigenvalues E k (n.
- 9.2 Progressive stabilization of the eigenvalues appearing in Eq.
- 9.4 Five lowest wavefunctions k (ξ) of the Morse Hamiltonian compared to the five symmetric or antisymmetric lowest wavefunctions n (ξ) of the.
- 9.5 The 40 lowest energy levels of the Morse oscillator.
- (9.103) in terms of the geometric parameters V 1.
- 9.13 Schematic representation of the two wavefunctions (9.120).
- ε γ is the width of the energy cells given by Eq.
- The initial excitation energy of the site k = 1 is α 2 1 = N.
- The initial excitation energy of the site k = 1 is α 2 1 = N .
- 13.3 Temperature evolution of the elongation Q(T ) (in Q.
- The intensities are normalized to the maximum of the curve.
- Figure 9.4 Five lowest wavefunctions k (ξ) of the Morse Hamiltonian compared to the five symmetric or antisymmetric lowest wavefunctions n (ξ) of the harmonic Hamiltonian..
- Consider a linear transformation of the form (1.5).
- Now, the Hermitian conjugate of the linear transformation (1.7) is.
- Consider now an eigenvalue equation of the form (1.6).
- ξ | ξ or, in view of the inequality (1.20).
- of the Hermitian conjugate A † of the linear operator A.
- Moreover, the Hermitian conjugate of the linear transformations (1.40) is |B.
- where A i is the scalar eigenvalue of the operator A.
- In addition, owing to the nullity of the commutator (1.61), we have.
- Next, assume that the inverse U − 1 of the linear operator U is the Hermitian conjugate of U:.
- Invariance of the trace:.
- where | n are the corresponding eigenkets of the eigenvectors of A.
- Owing to the Hermiticity of the observables, their eigenvalues are real:.
- so that due to the orthonormality of the eigenkets of a Hermitian operator A(P k , Q k ) P μη.
- where A 2 is the average of the square of A.
- Let us write the eigenvalue equation of the Hamiltonian H:.
- i of the Hamiltonian, that is,.
- (2.37) is the dispersion of the operator A averaged on the ket.
- If it is normalized, the norm of the ket| (t.
- i (t)|AH| (t) or, in term of the commutator of H and A.
- (2.56) to the product QP of the coordinate and momentum operators Q and P.
- 2.4.4.2 Applications of the virial theorem.
- where k is the force constant of the potential, which is a scalar.
- 2.5.1 Eigenvalue equations of the position and momentum operators.
- Consider the eigenvalue equation of the coordinate operator Q:.
- P|{P} and {P}|P = {P}|P (2.93) Here, |{P} 2 is an eigenket of the momentum operator P with the eigenvalue P..
- Now, calculate the commutator of the operator (2.95) with Q.
- Now, consider the eigenvalue equation of the momentum operator corresponding to the zero eigenvalue, that is,.
- 3.1.4.1 Simple linear transformations Consider the eigenvalue equation of the Hermitian operator B:.
- leading to the following matrix representation of the inverse linear transformation:.
- which, owing to the orthonormality properties (3.28) of the basis.
- l } yielding a matrix representation of the Hamiltonian..
- j u } of the kets | l belonging.
- the action of the operator Q over some ket | reads.
- This representation of the operator is therefore J.
- H| (t) (3.76) where H is the total Hamiltonian of the system.
- First consider that of the Q(t) coordinate.
- H| (t) SP Thus, the time derivative of the IP ket becomes.
- (3.139), the square of the density operator reduces to ρ 2.
- or, because of the orthonormality properties (3.138), to ρ 2.
- where | l(r) is the lth ket | l of the rth particle..
- Finally, owing to the orthonormality properties (3.138) of the basis.
- where C k are the coefficients involved in the expansion of the logarithm.
- the matrix elements of the density operator (3.158) read {Q}| ρ |{Q.
- 3.4.5.2 Momentum representation Now, write the eigenvalue equation of the momentum P as.
- Next, consider a matrix element of the density operator in the basis.
- Thus, write the eigenvalue equation of the Hamiltonian:.
- the matrix representation of the Liouville Eq.
- (4.5) is of the form.
- Then, in terms of the energy units E.
- the diagonal matrix elements of the full Hamiltonian are.
- Now, the eigenvalue equation of the full Hamiltonian (4.37) is.
- the matrix representation of this eigenvalue equation in the basis of the eigenkets of H ◦ being.
- where the square root appears to be of the form.
- 4.3 of the two interacting energy level systems with β negative.
- C where the C k ± are the components of the eigenvectors.
- E − )t (4.84) Furthermore, by aid of the trigonometric relations.
- ω 2 kl (1 − cos ω kl t) Moreover, by aid of the usual trigonometric relations.
- i where the reduced mass m of the oscillator is given by.
- (5.8) leads to the following fundamental expression for the Hamiltonian of the quantum harmonic oscillator:.
- 5.1.2 Resolution of the Hamiltonian eigenvalue.
- Again, consider the action of the commutator (5.15).
- Consider again the action of the commutator (5.16) on |a † {n}:.
- {n}|a † (5.32) Then, owing to the property of the norm, requiring.
- which, with the help of the eigenvalue equation (5.17), transforms to { n } a.
- Now, suppose that the energy of the ground state |{0} is zero.
- n Now, consider the corresponding average value of the momentum, which, according to Eq.
- This is the purpose of the present section..
- (5.9), the average value of the harmonic Hamiltonian is.
- Then, the Hamiltonian of the oscillator yields.
- (3.60), the Hamiltonian of the harmonic oscillator is, therefore, H ˆ.
- Search for a solution of the form.
- C 0 (e − ξ where C 0 is the normalization constant of the wavefunction..
- and where C 0 is the normalization constant of the wavefunction.
- (5.154), that of the position operator reads {n}|Q(t)|{n}.
- the average value of the position coordinate becomes {n}|Q(t)|{n.
- (5.164), the average value of the potential energy is {n}|V(t)|{n.
- (5.181), the matrix representation of the Hermitian operator N f defined by Eq.
- Eigenvalue equation of the harmonic Hamiltonian:.
- Action of the ladder operators on the harmonic Hamiltonian eigenkets:.
- Time dependence of the Boson operators:.
- α } are the eigenkets of the lowering a operator, obeying therefore.
- (6.11), to get the norm of the coherent state { α.
- which, due to the expansion properties of the exponential, yields.
- β } obeying an expression of the same form as Eq.
- Next, consider the corresponding average value of the squared Hamiltonian, that is, H 2 α.
- so that the average value of the squared Hamiltonian given by Eq