Study of entanglement of continuous variables by photoinduced processes |
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| Uwe Becker | |
| Fritz-Haber-Institut der MPG, Berlin | |
| Decades since the famous paper of Einstein, Podolsky and Rosen and of John Bell’s quantitative reformulation of their critique of the completeness of quantum mechanics, this problem has reemerged in the scientific limelight with unexpected intensity. Its implications range from epistemological questions in quantum physics to information theory. This dramatic development, however, has concentrated on the entanglement of discrete variables only. In this case the complementary systems of non-commutative variables are on equal footing and both allow correlation analysis in form of coincidence measurements between the corresponding entangled partners. This situation is different for the continuous variables position and momentum, originally used by Einstein, Podolsky and Rosen. The scenario for these variables has, however, never been experimentally realized and analyzed in full depth. In this talk the first evidence for this kind of entanglement will be presented and shown that entanglement of singular positions in ordinary space is not possible in a strict sense. Instead, such entanglement requires “double- positions” as basis states in form of gerade and ungerade eigenstates of the parity operator. This entanglement can be projected onto the complementary variables, which are the eigenstates of the momentum operator. This process appears in the time domain as an oscillation between the corresponding eigenstates. Electrons ejected from a homonuclear diatomic molecule, however, exhibit forward / backward oscillations also due to variation of the phase between them in ordinary space. In a way this makes this system unique for the study of entanglement in all its forms of appearances. |