1. Quantum tunneling by Hyperfine interaction Origin of adiabatic change of the magnetization and the symmetry of the molecules
Seiji Miyashita,
Hans de Raedt and Kristel Michielsen
Univ. of Tokyo and Groningen Univ.

2. Nonadiabatic Transition
Quantum Dynamics in Discrete Energy Levels
Landau-Zener-Stueckelberg
Mechanism
C. Zener, Proc. R. Soc. (London)
Ser. A137 (1932) 696.
Adiabatic change, i.e. Resonant Tunneling
Change in Sweeping Field
SM, JPSJ 64(1995) 3207, 65(1996) 2734.
H. De Raedt et al, PRB56 (1997) 2734

3. Control of Quantum State Adiabatic Transition
Smooth Change of Magnetization
I. Chiorescu, W. Wernsdorfer, A. Mueller, H. Boegge, B. Barbara,
Phys. Rev. Lett. 84 (2000) 3454.
K. Saito & SM. JPSJ (2001) 3385.

4. DM interaction Extra-degeneracy + Dzyloshinskii-Moriya interaction
S: odd (S=1/2) V15
Kramers doublet
No tunneling?
Extra-degeneracy +
Dzyloshinskii-Moriya
interaction
SM, &. N. Nagaosa,
. Theor. Phys. 106 (2001) 533

5. Energy structure with DM
|3/2,3/2>
|3/2,-1/2>
|1/2,a>
|1/2,b>
No adiabatic change
at H=0

6. Directionally Independent Energy Gap due to Hyperfine interaction
SM, H.de Raedt and K. Michielsen:
Prog. Thor. Phys (2003) No.11

7. Change of state

8. Triangle system

9. M(t) from the ground state
Apparent LZS relation

10. Finite temperature

11. M(t) under a sweeping field

12. Finite temperature

13. Apparent LZS transition

14. Effects of doubly degenerate structure
Transition from 1/ /2

15. Hysteresis in field sweep

16. Hidden Conservation Law?
Equilibrium
process
Adiabatic change
SM, &. N. Nagaosa, Prog. Theor. Phys. 106 (2001) 533

17. Coherence at the crossing

18. Resonance on the AC field Non-trivial Resonance
Y. Kayamuma, PRB 47 (1993) 9940
SM, K. Saito, H. De Daedt,
Phys. Rev. Lett. 80 (1998) 1525.

19. Nontrivial resonance

20. Decoherence

21. Dissipation Effect Thernal Bath：Quantum Master equation
I. Chiorescu, W. Wernsdorfer,
A. Mueller, H. Boegge, B. Barbara,
Phys. Rev. Lett. 84 (2000) 3454.
Random Noise： Quantum Schroedinger equation

22. Quantum Master EquationH0 HB HI
e.g. Photon dissipation and pumping :
(SM., H. Ezaki, and E. Hanamura PRA 57 (1998) 2046)
Lindblad form  Stochastic Schrodinger Equation　　(antibunching, squeezing
photo emission)

23. General formulation Independent phonon bath
K. Saito, S. Takesue and SM. Phys. Rev. B61 (2000) 2397
No feedback effects

24. Field sweeping with thermal bath
Fast sweeping
Slow sweeping
Magnetic
FoehnEffect
LZS
K. Saito & SM.
JPSJ (2001) 3385.

25. Effects of environments

26. Phonon-bottleneck effect (MFE) Electron spin system + DM Hx sweeping
No noise
Symmetric Noise
Nonsymmetric Noise

27. Effects on the Phonon-bottleneck effect (Magnetic Foehn effect) Hz:sweep

28. 45-degree

29. Reaction to the nuclear spin

30. Temperature effect

31. Fe ring Fe3+ plays a role of a localized spin with S=5/2 and L=0. Fe10
n= n=10
n= n=12
Fe10
[NaFe6(OCH3)12 (dmb)6] : monoclinic 単斜晶系 a \ne b \ne c, alpha=gamma=90degree \ne beta
[NaFe6(OCH3)12 (pmdbm)6]+ : trigonal 　菱面体晶系 a=b=c, alpha=beta=gamma \le 120degree or \ne 90degree
Fe : monoclinic
Fe : monoclinic
Fe : trigonal

32. 2 1
Fe10 10 3 4 9
+Reflection 5 8
Mirror symmetry 6 7

33. A set of D vectors from static regular structure
<yM|HDM|yM+1>=0
The DM interaction of the above D vectors is not
the origin of the peaks in dM/dH.

34. Anisotropy of g-tensor
Hg-tensor=SiSab mBgabiSibHa
<yM|Hg-tensor|yM+1>=0
Anisotropy of single ion
Hsingle-ion=SiSab DabiSibSia
<yM|Hsingle-ion|yM+1>=0
Inversion symmetry should be broken.

35. Oscillation of methyl groups
Structure is measured at Tst=226 K.
Each ellipsoid shows 50% possibility.
Oblong thermal ellipsoids
with the longer radius a
Elastic constant of an elastic energy of a methyl group
is briefly estimated as K ～ kBTst/a2.
H. Nakano and SM: JPSJ 71 (2002) 2580

36. Thank you for your attention

37. Quantum Control of state: Non AdiabaticTransitions
Non-monotonic magnetization process
SM, &. N. Nagaosa, Prog. Theor. Phys. 106 (2001) 533

38. Quantum Switching Memory： 2-values＋Metastability Quantum : Dynamics
Classical：Hysteresis　
Dissipation
Nondiabatic change
Memory
Switch
Adiabatic change
No Hysteresis loss

39. 1. Gap control Transverse field Nontrivial control
Quantum interference
Berry phase
W.Wernsdorfer & R. Sessoli:
Science 284 (1999) 133

40. 2. Sweeping velocity control
Switching between different S values

41. 3.Rotation of the field (or sample)
Rosen-Zener
process

42. Effect of dissipation

43. Noise of uniform field does not contribute to the transition between
Fluctuation of uniform field
does not contribute to the transition
between
S=0 and S=1

44. Singlet-triplet transition
Light emission
Spin flip
No emission

45. 4. Anisotropy control
Spin control in semiconductors by voltage