Einstein-Podolsky-Rosen experiment

P. R. Holland and J. P. Vigier, The quantum potential and signaling in the Einstein-Podolsky-Rosen experiment, Found. Phys. 18(7), 741-750 (1988). 

The Einstein-Podolsky-Rosen experiment aimed at falsifying the Heisenberg uncertainty principle ... 

While this above state of affairs is decidedly counterintuitive, it has the virtue of simply and easily - at least in principle - accounting for one of the deep mysteries of quantum mechanics namely, an apparent noidocality as expressed by the Einstein-Podolsky-Rosen gcdarikcn experiment [ein35] and Bell s theorem [bell64] (see discussion box). Finite nature implies that any system that is allowed to evolve from some distant initial state possesses causality in all space-time directions. This implies, in particular, that no part of space can be considered to be causally separated from another, and that therefore the DM universe will always harbor effects that cannot be attenuated by distance. 

This chapter is organized as follows In Section 2, quantum states are briefly described. Section 3 presents aspects of standard quantum measurement model. Section 4 includes double-slit, Einstein-Podolsky-Rosen, and Tonomura s experiments. Section 5 illustrates calculations of quantum states for quantum measurements. In Section 6, atom interferometer experiment of Scully et al. is analyzed. A detailed discussion is presented in Section 7, emphasizing a physical perception of quantum mechanics. 

In the case that a particle with spin 0 decays into two electrons, observing the spin of one electron determines the spin of the second electron. Since this indicates that information transmits faster than light, it violates the relativistic theory Einstein-Podolsky-Rosen paradox) (Einstein et al. 1935). Bohr could not provide a counterargument to this. Later, this paradox was resolved by Bell s inequality, which limits the correlation of subsequent measurements of particles that have interacted and then separated on the local hidden-variable theory (Bell 1964), and Aspect s experiment, which proves the violation of this inequality (Aspect et al. 1982). 

A. Aspect, P. Grangier, G. Roger, Experimental reaUzation of Einstein-Podolsky-Rosen-Bohm Gedanken-experiment A new violation of Bell s inequalities, Phys. Rev. Lett. 49 (1982) 91. 

The progress undergone in recent years toward a solution of the problem raised by Einstein 1927 has become possible because of two developments (1) A few experimental techniques, in particular, the methods for measuring very short times with good accuracy, have permitted in recent years the execution of several experiments which in their essence are practical versions of the thought experiment proposed and discussed in 1935 by Einstein, Podolski, and Rosen.39 (2) A procedure of analysis of their results has been made possible by the work of Bell40 who has derived in the frame of local realism a relation (the Bell inequality) obeyed by local realistic theories but violated by quantum mechanics. 

The above mentioned paper by Einstein, Podolsky, and Rosen represented a severe critique of quantum mechanics in the form that has been presented by its fathers. After its publication, Erwin Schrddinger published a series of works showing some other problematic issues in quantum mechanics. In particular, he described a Gedanken experiment, later known as the Schrddinger s cat paradox. According to Schrddinger, this paradox shows some absurd consequences of quantum mechanics. 

We conclude this chapter by going back to Albert Einstein, whose work was instrumental in the evolution of the quantum theory. Einstein was unable to tolerate the limitations on classical determinism that seem to be an inevitable consequence of the developments outlined in this chapter, and he worked for many years to construct paradoxes which would overthrow it. For example, quantum mechanics predicts that measurement of the state of a system at one position changes the state everywhere else immediately. Thus the change propagates faster than the speed of light—in violation of at least the spirit of relativity. Only in the last few years has it been possible to do the appropriate experiments to test this ERPparadox (named for Einstein, Rosen and Podolsky, the authors of the paper which proposed it). The predictions of quantum mechanics turn out to be correct. 

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