1 / 40

Nuclear Tidal Waves

Explore angular momentum projection and mean field methods in studying low-spin waves and yrast lines in rotating nuclei. Theoretical approaches to describe tidal wave vibrations and the antimagnetic rotor model are discussed.

tdugan
Download Presentation

Nuclear Tidal Waves

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. Nuclear Tidal Waves Daniel Almehed Stefan Frauendorf Yongquin Gu Yang Sun

  2. Classical Quadrupole Surface Vibration

  3. Tidal wave

  4. In the rotating frame: small oscillations around qp. excitations E I Yrast line of 5D-harmonic oscillator Tidal waves

  5. E(5) like I Anharmonic oscillator

  6. I-1/2 rotor tidal wave vibrator

  7. I-1/2 rotor tidal wave vibrator

  8. N= 92 90 88 86 84 No good vibrator!

  9. Theoretical methods Fix the angular momentum or rotational frequency Find the static shape – use a mean field method Angular momentum projection: Projected shell model Cranking model: semiclassical treatment of angular momentum

  10. Low-spin waves

  11. Low-spin waves

  12. F. Courminboeuf et al. PRC 63 (00) 014305

  13. harmonic QQ model +cranking Energy minimum (self-consistency) at:

  14. AMR Tidal wave Cranking model • B(E2,I->I-2)[(eb)^2] • I exp calc • tidal wave • 0.09 0.07 • 0.18 0.17 • 6 0.24 0.22 • antimagnetic rotor • 0.15 0.10 • 0.11 0.10 • 16 0.12 0.10 Experiment: M. Piiparinen et al. NPA565 (93) 671 F. Courminboeuf et al. PRC 63 (00) 014305 R. Clark et al. private communication

  15. Projected shell model

  16. Monopole Pairing+Quadrupole Pairing+QQ model Zero quasiparticle version: Two quasiparticle version: Diagonalize H in the basis Minimize lowest energy

  17. Projected shell model • B(E2,I->I-2)[(eb)^2] • I exp calc • tidal wave • 0.09 0.07 • 0.18 0.13 • 0.24 0.16 • antimagnetic rotor • 0.15 0.14 • 0.11 0.15 • 16 0.12 0.16 AMR Tidal wave

  18. Antimagnetic rotor

  19. Geometrical model for an antimagnetic rotor

  20. A. Simons et al. Phys. Rev. Lett. 91, 162501 (2003)

  21. High-spin waves Combination of Angular momentum reorientation Triaxial deformation

  22. yrast D. Cullen et. al

  23. TAC 25 26 27 28 Line distance: 20keV 29 30

  24. Line distance: 200 keV

  25. Tidal wave Less favored vibrations Mixed with p-h excitations

  26. K=25 i (130 ns) P. Chowdhury et al NPA 484, 136 (1988) o t m s K=0 0 8 14 21 24 i m t s o

  27. Tidal waves Yrast mode in soft nuclei at low and high spin Angular momentum generated by shape change at nearly constant angular velocity. Shape change: Axial, triaxial quadrupole, orientation, octupole … Rotating mean field gives a reliable microscopic description No new parameters Experimental rotational frequency well defined

  28. AMR Tidal wave Cranking model • B(E2,I->I-2)[W.u.] • I exp calc • tidal wave • 23.0 (15) 18 • 46 (6) 43 • 6 62 (20) 56 • antimagnetic rotor • 39 (2) 25 • 29 (3) 25 • 16 25 25

  29. Projected shell model • B(E2,I->I-2)[W.u.] • I exp calc • tidal wave • 23.0 (15) 18 • 46 (6) 33 • 6 62 (20) 41 • antimagnetic rotor • 39 (2) 36 • 29 (3) • 16 25 AMR Tidal wave

More Related