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Improvement of the polarized neutron interferometer setup demonstrating violation of a Bell-like inequality.

Geppert H, Denkmayr T, Sponar S, Lemmel H, Hasegawa Y - Nucl Instrum Methods Phys Res A (2014)

Bottom Line: For precise measurements with polarised neutrons high efficient spin-manipulation is required.The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state.The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out.

View Article: PubMed Central - PubMed

Affiliation: Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria.

ABSTRACT

For precise measurements with polarised neutrons high efficient spin-manipulation is required. We developed several neutron optical elements suitable for a new sophisticated setup, i.e., DC spin-turners and Larmor-accelerators which diminish thermal disturbances and depolarisation considerably. The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state. The obtained value of [Formula: see text], which is much higher than previous measurements by neutron interferometry, is [Formula: see text] above the limit of S=2 predicted by contextual hidden variable theories. The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out.

No MeSH data available.


Related in: MedlinePlus

Photographs of -spin turner coils made out of aluminium, copper and an empty frame for a coil (right to left).
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f0020: Photographs of -spin turner coils made out of aluminium, copper and an empty frame for a coil (right to left).

Mentions: The peak broadening was measured for different coils made of copper ribbon (0.1× 3 mm2 and 0.1× 4 mm2 in profile), aluminium ribbon (1× 4 mm2 in profile), and aluminium wire (0.5 mm in diameter). In Fig. 4 the aluminium ribbon coil and the copper ribbon coil are shown next to an empty coil frame. Fig. 5 shows the rocking curves for different coils in comparison to the empty coil frame. In Table 1 the peak height and the width of the rocking curves for different coils are given with respect to the empty beam line. One can see that despite the small absorption and the scattering cross-section of aluminium, the wire coil enlarges the width of peak and lowers the peak intensity because of small-angular scattering, whereas within the error there is no evident difference between the three ribbon coils. The rectangular profiled ribbons do not produce significant small-angle scattering and therefore more neutrons fulfil Bragg׳s law. For our measurements we used 3 mm wide copper ribbon for both DC spin-turners. In Fig. 6 one can see the separation of the up-spin peak and the down-spin peak with the π/2-spin turner in the beam line. Between the two main peaks one can see a small peak produced by neutrons that fulfil higher orders of the Bragg condition. The degree of polarisation and the efficiencies of the two DC spin turners can be evaluated using the two-flipper method corresponding to Ref. [23]. Two spin-flippers, which rotate the spin by π when turned on, are necessary, in our case the DC-spin turner in front and behind the IFM are used. Assuming that the polariser and the analyser have the same efficiency, which is justified in our setup, it is possible to calculate the efficiencies of the two spin-flippers (DC 1 and DC 2) and the degree of polarization using(1)effDC1=Ion,on−Ion,offIoff,off−Ioff,on,effDC2=Ion,on−Ioff,onIoff,off−Ion,off,P=(Ioff,off−Ion,off)(Ioff,off−Ioff,on)Ioff,offIon,on−Ion,offIoff,on


Improvement of the polarized neutron interferometer setup demonstrating violation of a Bell-like inequality.

Geppert H, Denkmayr T, Sponar S, Lemmel H, Hasegawa Y - Nucl Instrum Methods Phys Res A (2014)

Photographs of -spin turner coils made out of aluminium, copper and an empty frame for a coil (right to left).
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375610&req=5

f0020: Photographs of -spin turner coils made out of aluminium, copper and an empty frame for a coil (right to left).
Mentions: The peak broadening was measured for different coils made of copper ribbon (0.1× 3 mm2 and 0.1× 4 mm2 in profile), aluminium ribbon (1× 4 mm2 in profile), and aluminium wire (0.5 mm in diameter). In Fig. 4 the aluminium ribbon coil and the copper ribbon coil are shown next to an empty coil frame. Fig. 5 shows the rocking curves for different coils in comparison to the empty coil frame. In Table 1 the peak height and the width of the rocking curves for different coils are given with respect to the empty beam line. One can see that despite the small absorption and the scattering cross-section of aluminium, the wire coil enlarges the width of peak and lowers the peak intensity because of small-angular scattering, whereas within the error there is no evident difference between the three ribbon coils. The rectangular profiled ribbons do not produce significant small-angle scattering and therefore more neutrons fulfil Bragg׳s law. For our measurements we used 3 mm wide copper ribbon for both DC spin-turners. In Fig. 6 one can see the separation of the up-spin peak and the down-spin peak with the π/2-spin turner in the beam line. Between the two main peaks one can see a small peak produced by neutrons that fulfil higher orders of the Bragg condition. The degree of polarisation and the efficiencies of the two DC spin turners can be evaluated using the two-flipper method corresponding to Ref. [23]. Two spin-flippers, which rotate the spin by π when turned on, are necessary, in our case the DC-spin turner in front and behind the IFM are used. Assuming that the polariser and the analyser have the same efficiency, which is justified in our setup, it is possible to calculate the efficiencies of the two spin-flippers (DC 1 and DC 2) and the degree of polarization using(1)effDC1=Ion,on−Ion,offIoff,off−Ioff,on,effDC2=Ion,on−Ioff,onIoff,off−Ion,off,P=(Ioff,off−Ion,off)(Ioff,off−Ioff,on)Ioff,offIon,on−Ion,offIoff,on

Bottom Line: For precise measurements with polarised neutrons high efficient spin-manipulation is required.The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state.The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out.

View Article: PubMed Central - PubMed

Affiliation: Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria.

ABSTRACT

For precise measurements with polarised neutrons high efficient spin-manipulation is required. We developed several neutron optical elements suitable for a new sophisticated setup, i.e., DC spin-turners and Larmor-accelerators which diminish thermal disturbances and depolarisation considerably. The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state. The obtained value of [Formula: see text], which is much higher than previous measurements by neutron interferometry, is [Formula: see text] above the limit of S=2 predicted by contextual hidden variable theories. The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out.

No MeSH data available.


Related in: MedlinePlus