Beyond particles: Unparticles in strongly correlated electron

Research output: Chapter in Book/Report/Conference proceedingChapter


I am concerned in these lectures with the breakdown of the particle concept in strongly correlated electron matter. I first show that the standard procedure for counting particles, namely Luttinger's theorem, breaks down anytime pole¬like excitations are replaced by ones that have a divergent self-energy. Such a breakdown obtains in electronic systems whose pole-like excitations do not extend to the edge of the Brillouin zone, as in Fermi arcs in the cuprates. Since any non-trivial infrared dynamics in strongly correlated electron matter must be controlled by a critical fixed point, unparticles are the natural candidate to explain the presence of charged degrees of freedom that have no particle content. The continuous mass formulation of unparticles is recast as an action in anti de Sitter space. Such an action serves as the generating functional for the propagator. This mapping fixes the scaling dimension of the unparticle to beand ensures that the corresponding propagator has zeros with d the spacetime dimension of the unparticle field. The general dynamical mechanism by which bulk operators, such as the Pauli term, cou¬ple to the scaling dimension of the boundary operator and thereby lead to a vanishing of the spectral weight at zero energy is reviewed in the context of unparticles and zeros. The analogue of the BCS gap equations with unparticles indicates that the transition temperature increases as the attractive interac¬tion strength decreases, indicating that unparticles are highly susceptible to a superconducting instability.

Original languageEnglish (US)
Title of host publicationQuantum Criticality In Condensed Matter
Subtitle of host publicationPhenomena, Materials And Ideas In Theory And Experiment - 50th Karpacz Winter School Of Theoretical Physics
PublisherWorld Scientific Publishing Co. Pte Ltd
Number of pages26
ISBN (Electronic)9789814704090
ISBN (Print)9789814704083
StatePublished - Jul 23 2015


  • Anti de Sitter
  • Cuprates
  • Unparticles

ASJC Scopus subject areas

  • General Physics and Astronomy


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