A careful estimation of photon rescatterig in atomic-cascade experimental tests of Bell's inequality

1985 ◽  
Vol 5 (1) ◽  
pp. 23-39 ◽  
Author(s):  
S. Pascazio
2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Johan Hansson

Bell's theorem, and its experimental tests, has shown that the two premises for Bell's inequality—locality and objective reality—cannot both hold in nature, as Bell's inequality is broken. A simple test is proposed, which for the first time may decide which alternative nature actually prefers on the fundamental, quantum level. If each microscopic event is truly random (e.g., as assumed in orthodox quantum mechanics) objective reality is not valid whereas if each event is described by an unknown but deterministic mechanism (“hidden variables”) locality is not valid. This may be analyzed and decided by the well-known reconstruction method of Ruelle and Takens; in the former case no structure should be discerned, in the latter a reconstructed structure should be visible. This could in principle be tested by comparing individual “hits” in a double-slit experiment, but in practice a single fluorescent atom, and its (seemingly random) temporal switching between active/inactive states would possibly be better/more practical, easier to set up, observe, and analyze. However, only imagination limits the list of possible experimental setups.


1972 ◽  
Vol 5 (2) ◽  
pp. 177-181 ◽  
Author(s):  
L. de la Peña ◽  
A. M. Cetto ◽  
T. A. Brody

2010 ◽  
Vol 12 (8) ◽  
pp. 083051 ◽  
Author(s):  
Marcin Pawłowski ◽  
Johannes Kofler ◽  
Tomasz Paterek ◽  
Michael Seevinck ◽  
Časlav Brukner

2006 ◽  
Vol 97 (17) ◽  
Author(s):  
Yu-Ao Chen ◽  
Tao Yang ◽  
An-Ning Zhang ◽  
Zhi Zhao ◽  
Adán Cabello ◽  
...  

2001 ◽  
Vol 1 (Special) ◽  
pp. 113-123
Author(s):  
D. Kielpinski ◽  
A. Ben-Kish ◽  
J. Britton ◽  
V. Meyer ◽  
M.A. Rowe ◽  
...  

We review recent experiments on entanglement, Bell's inequality, and decoherence-free subspaces in a quantum register of trapped {9Be+} ions. We have demonstrated entanglement of up to four ions using the technique of Molmer and Sorensen. This method produces the state ({|\uparrow\uparrow\rangle}+{|\downarrow\downarrow\rangle})/\sqrt{2} for two ions and the state ({\downarrow}{\downarrow}{\downarrow}{\downarrow} \rangle + | {\uparrow}{\uparrow}{\uparrow}{\uparrow} \rangle)/\sqrt{2} for four ions. We generate the entanglement deterministically in each shot of the experiment. Measurements on the two-ion entangled state violates Bell's inequality at the 8\sigma level. Because of the high detector efficiency of our apparatus, this experiment closes the detector loophole for Bell's inequality measurements for the first time. This measurement is also the first violation of Bell's inequality by massive particles that does not implicitly assume results from quantum mechanics. Finally, we have demonstrated reversible encoding of an arbitrary qubit, originally contained in one ion, into a decoherence-free subspace (DFS) of two ions. The DFS-encoded qubit resists applied collective dephasing noise and retains coherence under ambient conditions 3.6 times longer than does an unencoded qubit. The encoding method, which uses single-ion gates and the two-ion entangling gate, demonstrates all the elements required for two-qubit universal quantum logic.


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