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Nuclear Tidal Waves

Nuclear Tidal Waves. Daniel Almehed Stefan Frauendorf Yongquin Gu Yang Sun. Classical Quadrupole Surface Vibration. Tidal wave. In the rotating frame: small oscillations around. qp. excitations. E. I. Yrast line of 5D-harmonic oscillator. Tidal waves. E(5) like. I.

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Nuclear Tidal Waves

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  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

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