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Nuclear Tidal Waves Daniel Almehed Stefan Frauendorf Yongquin Gu Yang Sun
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Classical Quadrupole Surface Vibration
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Tidal wave
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Yrast line of 5D-harmonic oscillator E I In the rotating frame: small oscillations around qp. excitations Tidal waves
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I Anharmonic oscillator E(5) like
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I-1/2 rotor vibratortidal wave
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I-1/2 rotor vibrator tidal wave
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No good vibrator! N= 92 90 88 86 84
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Theoretical methods Fix the angular momentum or rotational frequency Find the static shape – use a mean field method Cranking model: semiclassical treatment of angular momentum Angular momentum projection: Projected shell model
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Low-spin waves
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F. Courminboeuf et al. PRC 63 (00) 014305
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Energy minimum (self-consistency) at: QQ model +cranking harmonic
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Cranking model Tidal wave AMR B(E2,I->I-2)[(eb)^2] Iexpcalc tidal wave 20.090.07 40.180.17 60.240.22 antimagnetic rotor 120.150.10 140.110.10 160.120.10 Experiment:M. Piiparinen et al. NPA565 (93) 671 F. Courminboeuf et al. PRC 63 (00) 014305 R. Clark et al. private communication
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Projected shell model
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Monopole Pairing+Quadrupole Pairing+QQ model Zero quasiparticle version: Two quasiparticle version: Diagonalize H in the basis Minimize lowest energy
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Projected shell model B(E2,I->I-2)[(eb)^2] Iexpcalc tidal wave 20.090.07 40.180.13 60.240.16 antimagnetic rotor 120.150.14 140.110.15 160.120.16 Tidal wave AMR
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Antimagnetic rotor
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Geometrical model for an antimagnetic rotor
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A. Simons et al. Phys. Rev. Lett. 91, 162501 (2003)
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High-spin waves Combination of Angular momentum reorientation Triaxial deformation
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yrast D. Cullen et. al
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25 26 27 28 29 30 Line distance: 20keV TAC
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Line distance: 200 keV
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Tidal wave Less favored vibrations Mixed with p-h excitations
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s ot i m K=25 i (130 ns) s o t m K=0 0 8 14 21 24 P. Chowdhury et al NPA 484, 136 (1988)
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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
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Cranking model Tidal wave AMR B(E2,I->I-2)[W.u.] Iexpcalc tidal wave 223.0 (15)18 446 (6)43 662 (20)56 antimagnetic rotor 1239 (2)25 1429 (3) 25 1625 25
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Projected shell model Tidal wave AMR B(E2,I->I-2)[W.u.] Iexpcalc tidal wave 223.0 (15)18 446 (6)33 662 (20)41 antimagnetic rotor 1239 (2)36 1329 (3) 1625
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