1 / 28

Spectral function in Holographic superconductor

Explore the relationship between spectral function and retarded Green function in holographic superconductor models, analyzing spin-0 and spin-1/2 fields. Investigate the holographic non-Fermi liquid behavior probed by Dirac fermions in AdS2 near-horizon geometries. Develop gravity models for high-Tc superconductors using phenomenological and microscopic approaches. Investigate the State-Operator correspondence and phase transitions in AdS black holes. Study Bosonic and Fermionic condensation in strongly correlated systems. Analyze numerical results and gaps in the spectral function dynamics to enhance the understanding of high-Tc superconductors. Explore possibilities for hard gap solutions and new phases in holographic superconductors.

lonniei
Download Presentation

Spectral function in Holographic superconductor

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. Spectral function in Holographic superconductor Wen-Yu Wen (NTU) Taiwan String Theory Workshop 2010

  2. Hightlight Bi2Sr2CaCu2O8+δ HHTSC Chen-Kao-Wen, arXiv:0911.2821 Norman, et al, Phys. Rev. Lett. 79

  3. Angle Resolved PhotoEmission Spectroscopy A direct exp technique to observe distribution of electrons (single electron excitation)

  4. Spectral function v.s.Retarded Green function Spectral function: Density of states:

  5. AdS/CFT correspondence φ • Consider a correspondence pair (O, ) • Retarded Green function of operator O can be seen as reflection coefficient of by imposing in-falling boundary condition at horizon. φ O φ

  6. Example 1:Spin-0 field

  7. Example 2:Spin-1/2 field

  8. Holographic non-fermi liquid • Extremal charged AdS-BH always has AdS2 as its near horizon geometry • Dirac fermion probed in AdS2 might be related to the non-fermi liquid at quantum critical point. (Sung-Sik Lee, Hong Liu, etc.) • What if a new phase appears before critical point is reached? Normal Phase SC Phase QC Point

  9. Holographic superconductor • To build a gravity model for HTSC ? ○ a phenomenological model: Ginzburg-Landau type ? a microscopic model: BCS type • Essential ingredients: Finite temperature T Chemical potential μ Condensate φ (3+1) Gravity model (2+1) HTSC

  10. Abelian Higgs model in AdS black holea.k.a hairy black hole solution • Ginzburg-Landau feels curvature from AdS-BH • AdS-BH metrics receives no back reaction from GL sector in probe limit AdS-BH T increases with BH mass GL A: abelian gauge field U(1) φ: Higgs Mass term has no explicit T dependence V has no other higher order term

  11. instability BH in flat space BH in AdS space Charged AdS-BH 0 Boundary Horizon

  12. State-Operator correspondence: Scalar field (Higgs) with mass m AdS bulk x Boundary QFT Operator of dimension Δ

  13. Time component gauge potential encodes the message of chemical potential and charge density at the boundary AdS Bulk Boundary QFT

  14. GR problem: Solving equation of motion for GL with given boundary conditions at horizon and infinity. Existence of two solutions implies a second order phase transition between them. Multiple solutions due to nonlinearity

  15. Tc[Hartnoll,Herzog,Horowitz, 08] Bosonic condensation Fermionic condensation strongly correlated? usual BCS ~ 3.5

  16. Hc [Nakano,Wen,Phys.Rev.D78 (08)]

  17. Holographic superconducting vacuum • Operational definition:continue lowering temperature below Tc, where condensate forms, untill it reaches absolute zero • Thanks to condensate, it has to be different from trivial vacuum, and different from nontrivial vacuum of extremal charged black hole AdS vacuum Final state of SSBH AdS + condensate Final state of cBH + Higgs Extremal AdS-RN Final state of RNBH

  18. Through backreaction, our geometry now encodes the information of condensate, which mostly deforms IR physics. [Horowitz-Roberts,09] HTSC in SC vacuum

  19. Numerical result • Spin average spectral function is imaginary part of trace of retarded Green function (ΔB=2ΔF=3) Chen-Kao-Wen, arXiv:0911.2821

  20. Peak Hump Dip

  21. q<2.6 • Dynamics of peak and hump ω/k<0.15 kF q>2.6 Gap ω/k<1

  22. More story…

  23. Prospects • A hard gap solution exists for s-wave HSC only by introducing Majorana coupling for the probed fermion. Any better/smarter way? • Will a probed fermion in p-wave HSC also show a hard gap? • Can we realize d-wave HSC, which is closer to High-Tc SC?

More Related