Skip to main content Accessibility help
×
  1. Home
  2. Browse subjects
  3. Physics and Astronomy
  4. Condensed Matter Physics, Nanoscience and Mesoscopic Physics
  5. Content listing

Refine search

Refine search

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

6943 results in Condensed Matter Physics, Nanoscience and Mesoscopic Physics

Page 123 of 348

  • 3 - Second quantization

  • Radi A. Jishi, California State University, Los Angeles
  • Book:
    Feynman Diagram Techniques in Condensed Matter Physics
    Published online:
    05 April 2013
    Print publication:
    25 April 2013, pp 37-64

  • Summary

    Nothing can be made out of nothing.

    William Shakespeare, King Lear

    Historically, quantization of the motion of particles was developed first. The state was described by a wave function and observables by operators. When dealing with interactions between particles and fields, such as the electromagnetic field, the fields were treated classically. Classical field equations look like the quantum mechanical equations for the wave function of the field quanta. For example, the Klein–Gordon classical field equation is similar to the quantum mechanical wave equation for a relativistic spinless particle. Quantizing the fields, leading to quantum field theory, appears to be quantizing a theory that has already been quantized; hence the name “second quantization.” In reality, there is only one quantization and one quantum theory.

    The method of second quantization is important in the study of many-particle systems. It enables us to express many-body operators in terms of creation and annihilation operators, thus rendering calculations less cumbersome. Moreover, the method makes it possible to treat systems with a variable number of particles; that is why the method initially emerged in the context of quantum field theory.

    In Chapter 1 we indicated that any one-particle wave function may be expanded in a complete set of states. In this chapter, we show that products of single-particle states, when properly symmetrized, form an orthonormal basis for the expansion of the wave function of an N-particle system.

  • 12 - Superconductivity

  • Radi A. Jishi, California State University, Los Angeles
  • Book:
    Feynman Diagram Techniques in Condensed Matter Physics
    Published online:
    05 April 2013
    Print publication:
    25 April 2013, pp 284-330

  • Summary

    False friends are common. Yes, but where True nature links a friendly pair, The blessing is as rich as rare.

    -From the Panchatantra Translated by Arthur W. Ryder

    The magnet of their course is gone, or only points in vain The shore to which their shiver'd sail shall never stretch again.

    -Lord Byron, Youth and Age

    Superconductivity was discovered in 1911 by H. Kamerlingh Onnes soon after he succeeded in liquefying helium (Onnes, 1911). He observed that the resistivity of mercury dropped suddenly as its temperature was lowered below a certain critical value TC (for Hg, TC = 4.2 K). Over the years, it was found that many additional elements and compounds similarly transition to a superconducting state. In this state, materials exhibit properties that are strikingly different from the normal state. Below we discuss the most important features of superconductors.

    Properties of superconductors

    The first important property of a material that undergoes a superconducting transition is that its resistivity drops to zero belowa critical temperature (see Figure 12.1). In a superconducting ring, a persistent electric current flows without any observable attenuation for as long as one is willing to watch.

Feynman Diagram Techniques in Condensed Matter Physics
  • Radi A. Jishi
  • Published online:
    05 April 2013
    Print publication:
    25 April 2013
  • A concise introduction to Feynman diagram techniques, this book shows how they can be applied to the analysis of complex many-particle systems, and offers a review of the essential elements of quantum mechanics, solid state physics and statistical mechanics. Alongside a detailed account of the method of second quantization, the book covers topics such as Green's and correlation functions, diagrammatic techniques and superconductivity, and contains several case studies. Some background knowledge in quantum mechanics, solid state physics and mathematical methods of physics is assumed. Detailed derivations of formulas and in-depth examples and chapter exercises from various areas of condensed matter physics make this a valuable resource for both researchers and advanced undergraduate students in condensed matter theory, many-body physics and electrical engineering. Solutions to exercises are available online.

Page 123 of 348