Quantum Mechanics II

Spring 2004

Lecturer: Paul Hoyer C321  191 50681 
Assistant: Matti Järvinen  C311  191 50702 
Lectures: Mo 12-14  A315 
We 12-14  A315  
Exercises: Mo 16-18 E205
Problem solutions should be put in the box on the 2nd floor of the A-wing by Friday at 14.00.

Exams: 1. Friday 5 March 14-18 E204
2. Tuesday 18 May 10-14 D101

Course description:

An advanced course in quantum mechanics:
Review of basic formalism. Quantum information. Path integrals. Gauge invariance. The rotation group and angular momentum.
Parity and time reversal. Density matrix. Quantum statistical mechanics. Field ('second') quantization. Relativistic quantum dynamics.

Recommended for 3rd year theoretical physics students, 4th-5th year experimental physics students.
The course Quantum mechanics I (or equivalent) is a prerequisite.

Textbooks: J. Niskanen: Kvanttimekaniikka II (Limes 2003)  [N]
J. J. Sakurai: Modern Quantum Mechanics (Addison Wesley 1994)  [S]
B. H. Bransden and C. J. Joachain: Quantum Mechanics (Prentice Hall 2000)  [BJ]
D. J. Griffiths: Introduction to Quantum Mechanics (Prentice Hall)  [G]
I. J. R. Aitchison and A. J. G. Hey: Gauge Theories in Particle Physics, Vol. I:
From Relativistic Quantum Mechanics to QED (IOP Publishing, 3rd Edition, 2003)  [AH]

Table of Clebsch-Gordan coefficients, spherical harmonics and gradients.

The first partial examination on Friday 5.3 covers the material that was presented at the lectures up to and including Wednesday 25 February.
Note that problem set #7 covers material which is included in the first partial examination.

Problems of partial exam 1/2003         1/2004
Problems of partial exam 2/2003         2/2004
Problems of final exams: 16.5.2003     4.6.2003     13.8.2003     2.4.2004 2.6.2004 16.6.2004 11.8.2004

 

NOTE:  You are encouraged to give feedback on the course on this form.

 

Problems

26.1
Exercise_1.pdf
Exercise_1.ps
2.2
Exercise_2.pdf
Exercise_2.ps
9.2
Exercise_3.pdf
Exercise_3.ps
16.2
Exercise_4.pdf
Exercise_4.ps
23.2
Exercise_5.pdf
Exercise_5.ps
1.3
Exercise_6.pdf
Exercise_6.ps
 
15.3
Exercise_7.pdf
Exercise_7.ps
Workload.pdf
22.3
Exercise_8.pdf
Exercise_8.ps
29.3
Exercise_9.pdf
Exercise_9.ps
5.4
Exercise_10.pdf
Exercise_10.ps
13.4 D106 at 16-18
Exercise_11.pdf
Exercise_11.ps
19.4
Exercise_12.pdf
Exercise_12.ps
26.4
Exercise_13.pdf
Exercise_13.ps
3.5.
Exercise_14.pdf
Exercise_14.ps

Lecture notes: p1-146.pdf

Lecture topics:

19.1
Organization.
Basic notions of Quantum Mechanics. Operators, expectation values, commutators. The uncertainty principle. Projection and unitary operators. Applications to the spin 1/2 system using the Pauli matrix representation.

21.1
Applications to the spin 1/2 system using the Pauli matrix representation. The time evolution operator. Electron spin precession in a magnetic field. General solution for the eigenstates and eigenvalues of a two-state system. The non-crossing of levels and adiabatic mixing of states.

26.1
Applications to solar neutrinos and the neutral kaon system. The time-energy uncertainty relation.
Quantum information. Private key cryptography. Secure transmission using random polarization axes. Principles of public key (RSA) cryptography. Quantum computing.

28.1
Quantum teleportation. The Heisenberg picture. The time dependence of position and momentum operators in the Heisenberg picture. Non-commutation of an operator taken with itself at different times. Classical equations of motion for the expectation values of operators (Ehrenfest's theorem).

2.2
Definition of the propagator K and its differential equation. The trace of the propagator and its connection with statistical physics in imaginary time (Euclidean space). The Fourier transformation of the propagator trace. The propagator as a transition amplitude.

4.2
The Feynman path integral: Intuitive derivation and check of the Schrödinger equation. Quantum interference in a gravitational field.

9.2
Application of path integral to neutron interference in a gravitational field. Gauge symmetry in electrodynamics. Kinetic momentum. Gauge transformations.

11.2
The Aharonov-Bohm effect. Magnetic monopoles and the quantization of electric charge.

16.2
Theory of angular momentum. Basics of group theory. SU(2) vs. SO(3).

18.2
Euler angles, rotation operators and matrix elements. Orbital angular momentum. Relation between spherical harmonics Y_\ell^m and rotation matrices D_{m_1 m_2}^{(j)}. Addition of angular momenta.

23.2
Identities following from the completeness and orthogonality of the D_{m_1 m_2}^{(j)} and Y_\ell^m. Transformation of operators under rotations. Cartesian vs spherical tensors. Commutation rules of spherical tensors with the generators J_i of rotations.

25.2
Multiplication of spherical tensors. The Wigner-Eckart theorem. The projection theorem. Spin correlations and Bell's inequality.

1.3
Symmetries in quantum mechanics. Energy degeneracy. Parity transformation of operators, states and matrix elements. The double well potential and handed molecules.

3.3
Parity selection rule. Parity violation in the weak interactions: left-handed neutrinos. Time reversal symmetry. Antiunitary operators. Transformation of operators, states and matrix elements under time reversal.

No lectures or problem sessions during week 11 (8.3 and 10.3)

15.3
Time reversal (cont). Selection rule for matrix elements of spherical tensors. Neutron dipole moment. Kramers degeneracy.

17.3
Density matrix. [Sakurai, Sec. 3.4] Pure and mixed ensembles. Ensemble average. Time evolution. Thermal equilibrium.

22.3
Wave functions of identical bosons and fermions. Statistical quantum mechanics for distinguishable particles vs. identical bosons and fermions. The Fermi-Dirac and Bose-Einstein distributions.

24.3
The Fermi-Dirac and Bose-Einstein distributions. Black-body spectrum.
Introduction to quantum fields. Creation and annihilation operators for bosons and fermions. Fock states. Commutation and anticommutation relations.

29.3
Normal ordering. Wick's theorem. Field operators. Commutation and anticommutation of field operators.

31.3
Hamiltonian and density operators. Time dependence. Propagator.
Introduction to relativistic quantum mechanics. [Niskanen 4, Aitchison and Hey 4]

5.4
Lorentz transformations and connection to the SL(2,C) group. The Klein-Gordon equation, density and current. The Dirac equation, the alpha and beta matrices. Plane wave solutions to the Dirac equation.

7.4
Lie algebra of the Lorentz group and its equivalence to SU(2) x SU(2). Probability density and current for the Dirac equation. Spin, precession and helicity.

14.4
Lorentz covariant notation. Dirac matrices and their anticommutation relatios. The u and v Dirac spinors and their normalization. Lorentz transformation of the Dirac wave function.

19.4
Lorentz transformation of the Dirac bilinears. Interaction with an electromagnetic potential. Gauge invariance.

21.4
Magnetic moment of the electron. The Dirac sea and negative energy solutions as backward moving antiparticles. Crossing symmetry. Lagrangian density and equations of motion for relativistic scalar fields. The QED lagrangian. The Dirac and Maxwell equations. U(1) gauge invariance with derivatives: The connection (gauge) field.

26.4
The uniqueness of the QED lagrangian, given locality, U(1) gauge and lorentz invariance, P and T invariance and renormalizability. Non-abelian gauge invariance. The Yang-Mills lagrangian for SU(2) and SU(N). QCD.

28.4
Symmetries of the lagrangian: Chiral symmetry and its spontaneous breaking. Isospin invariance. Scale invariance broken by renormalization. The Higgs mechanism.
Quantization using functional integrals vs. the Hamilotonian formulation using operators.
The free scalar field operator. Its conjugate momentum and their canonical commutation relation. The hamiltonian.

3.5
The propagator. The Dirac lagrangian and field operator. The conjugate Dirac field and hamiltonian. Interactions.

5.5
Review of the course. Please prepare questions!