Canonical Transformations for Quantum Systems

The following sections are included:

• Interacting Bose System

  • Pseudopotential

  • Special Role of the Ground State

  • Effective Hamiltonian

  • Bogoliubov Transformation

  • Discussion of Results

    • Excitation Spectrum

    • Depletion

    • Ground-State Energy

  • Superfluid ⁴He

• Superconductors

  • Cooper Pairs

  • Bogoliubov-Valatin Transformation

    • Pairing

    • Thermodynamic Potential

    • Wick's Theorem

    • Diagonalization of

    • Gap Equation

  • Discussion of Results

    • Particle Number

    • Ground-State Thermodynamic Potential

    • Ground-State Energy

    • Excitation Spectrum

    • Momentum Operator

    • Quasiparticle Spectrum

    • Calculation of the Energy Gap Δ

    • Quasiparticle Interactions