Uni.Wien,

1
Uni.Wien, ÖPG Tagung, FAKT 27.September, 2005
2
Conventional two-photon EPR-experiment
A. Einstein, B. Podolsky and N. Rosen, Phys. Rev.
47 (1935) 777.
3
Two-particle vs. two-space entanglement

Nature, Vol. 425, Sept. 4, 2003
4
Poincare/Bloch-sphere description
5
Quantum state tomography (1)
D.F. James et al., Phys. Rev. A 64 (2001) 052312.
6
Quantum state tomography (2)
A.G. White et al., Phys. Rev. Lett. 83 (1999)
3103.
7
Background Mathematics (1)
since
8
Background mathematics (2)
9
Background mathematics (3)
D.F. James et al., Phys. Rev. A 64 (2001) 052312.
10
Experimental setup
11
Typical results --- c oscillations at
12
Typical results --- a oscillations at
13
Analysis
14
Quantum state tomography of neutrons Bell-state
imaginary part
real part
F0.79
15
Schematic view of the experiment
16
Quantum state tomography --- two Bell-states
F0.79
F0.75
real part
17
Quantum state tomography --- polarized incidence
imaginary part
real part
F0.91
18
Quantum state tomography --- comparison
real part
F0.91
imaginary part
F0.79
F0.75
19
Summary future perspectives

• Quantum state tomography of two Bell-like states
• of neutron was carried out F0.75, 0.79.
• Tomographical representation of the polarized
  neutron beam was presented four-pillars
  F0.91.
• These tomographical technique will be applied
  to,
• decoherence/depolarization process,
• characterization of robustness of geometric
  phase,
• non-unitary evolution of neutrons entangled
  state,
• etc.
• especially from the polarized incident!

20
Fin !
21
Neutron interferometry
22
Neutron interferometers
23
Various two-level system
gtgt Described by SU(2)
24
Two-particle vs. two-space entanglement
(Non-)Contextuality gtgt Bell-like
inequality (In)Dependent Results for commuting
Observables
25
Violation of a Bell-like inequality
Cf. Max. violaion S2.81gt2

Y. Hasegawa et al., Nature Vol. 425, Sept. 4, 2003
26
Publications and reactions
Nature, Vol. 425, 4. Sept. 2003
Frankfurter Allgemeine Zeitung 10.Sept. 2003