1 / 13

Quantum Criticality

Quantum Criticality. Condensed Matter Physics (Lee). Range for CMP. Complexity causes new physics. Classical Phase Transitions. Classical example: Phase diagram of H 2 O Notice: 1 st order and 2 nd order transitions. Experimental Evidence for Phase Transitions. Specific heat.

lakia
Download Presentation

Quantum Criticality

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Quantum Criticality

  2. Condensed Matter Physics(Lee) Range for CMP Complexity causes new physics

  3. Classical PhaseTransitions Classical example: Phase diagram of H2O Notice: 1st order and 2nd order transitions

  4. Experimental Evidence forPhase Transitions Specific heat

  5. The ‘Standard Model’Fermi Liquid Theory and Metals Non-classical ‘sharing’ of e- in ‘cond. band’ Band theory:

  6. … more on metals DOS – density of states cV ~ T, r ~ T2 Metal-insulator transitions; Mott insulators Fermi Liquid Theory (Landau): quasi-particles (excitations) in ‘sea’ of fermions

  7. What is a Quantum Phase Transition? Quantum fluctuations b/c of Heisenberg uncertainty relation: no v=0 at T=0 can cause disruptions Examples: magnetism in metals (FM / AFM) superconductivity (‘pairing’ of electrons) often combined with low dimensionality (constrained motion)

  8. Quantum Criticality Hertz 1976 Steglich 2003

  9. … more examples CV in HF, Steglich Hill 2001, r (T) at high B

  10. … more examples – Heavy Fermions

  11. … more examples - HTSC Lee, CQP AFM vs SC Laughlin etal Adv Phys The bigger picture: HF vs SC phase diagrams

  12. … more examples: fract. QH Eff. Hall Effect: Lorentz force causes drift F= q(E+v x B) Quantum Hall Effect (1994): Quantized ~ h/e2 Fractional QHE quantized in non-integer steps

  13. Comprehensive Literature List Monographs: In Physics and Electronics ed. JMT ThompsonDKK Lee AJ Schofield ‘Metals without Electrons: The Physics of Exotic Quantum Fluids’ Some figures taken from Kittel and from Omar Review Articles: Coleman Schofield Nature 433 2005, Quantum Criticality’ Laughlin, Longzarich, Monthoux, PinesAdv Phys 50(361) Hertz 1976 PRB 14 Research Articles: Nature 425 2003Doiron-Leyraud et al (Longzarich) Nature 424 2003 Custers (Steglich) The break up of heavy electrons at a QCP Nature 414 2001 Hill Breakdown of FL theory in a cuprate SC Nature 441 2006 Sebastian Nature 441 2006 Erwin ‘When is a metal not a metal?’

More Related