Week 5

Lecture 23, 29 April, 10.00-12.00, FL51

Phase transition into superconducting state, superconducting order parameter. Transition temperature, quasiparticle spectrum, specific heat.
Superconductors - ideal diamagnetics. Current states. Meissner effect.

Reading.

Review questions.

1. How to prove in practice that resistance of a superconductor is zero?
2. What is a critical temperature of a superconductor?
3. What is the Meissner effect? Discuss the London equation for the supercurrent. Derive equation for the penetration depth of the magnetic filed.
4. Derive quantization of the magnetic flux. What is the magnitude of the flux quantum?
5. Explain physical meaning of the module and the phase of the superconducting order parameter. What is a current state of a superconductor. Why superconductivity is destroyed by magnetic field?

Home task.

1. Problem

Lecture 24, 2 May, 13.15-15.00, FL51

More about superconductivity.
Guest lecture of Professor Tord Claeson.

Reading.

Review questions.

1. Write down Ginsburg-Landau free energy functional. Derive equations for the order parameter and current. What is the temperature dependence of the order parameter, gradients of the order parameter, current?
2. What is the superfluid momentum? Discuss Meissner effect and flux quantization.