Entanglement in condensed matter

As already mentioned above the experimental work on short-lived protonic quantum entanglement in condensed matter has been triggered by earlier theoretical and experimental work of C. A. Chatzidimitriou-Dreismann [Chatzidimitriou-Dreismann 1991 Chatzidimitriou-Dreismann 1997 (b)]. One model for the theoretical interpretation of the NCS results has been put forward by C. A. Chatzidimitriou-Dreismann et al. starting from the van Hove formalism for the scattering process and explicitly taking into account the irreversible dynamics of the decoherence process [Chatzidimitriou-Dreismann 2000 (b)]. This model has experienced a further development and extension [Chatzidimitriou-Dreismann 2003 (b)]. E. B. Karlsson and S. W. Lovesey have proposed another model [Karlsson 2002 (a)] relying on the existence of exchange cor-... 

In addition to the papers presenting the results of the various experimental techniques (e.g., NCS, ECS, elastic neutron scattering, IXS, etc.) applied to investigate protonic quantum entanglement in condensed matter, there are also papers in this part aiming at the theoretical interpretation of the experimental results. Although the theoretical models presented are different from each... 

Table 1. Experimental data that indicates H - H quantum entanglement in condensed matter. Neutron experiments are described in the text. Raman and electron scattering experiments are published in Refs. [Chatzidimitriou-Dreismann 1995 Chatzidimitriou-Dreismann 2003 (a)] respectively. Raman scattering has also a time window in the fs-range.

An interesting example of entanglement in condensed matter is represented by the formation of Cooper pairs in conventional superconductors. It is well known that the electron-phonon interaction in metals can lead to formation of collective quantum states of paired electrons with opposite spins and linear momenta [77]. In the simplest quasispin form, the system can be specified by the Hamiltonian [78,79]... 

To sum up, the contributions described above represent a few chosen examples of the experimental and theoretical work on the subject of quantum entanglement and coherence in condensed matter. This fascinating new field of science has not yet been given a common name. With no doubt it is, however, science "in statu nascendi" and as such needs further development. From the experimental point of view this new field needs new techniques involved. Some examples (NCS, neutron diffraction, ECS, IXS) have already been mentioned above. Further work is also clearly needed to make the theoretical models mentioned above more specific and directly applicable to the experiment. 

Also important is the analogy that every chemical reaction can be regarded as a scattering process with a reaction channel. Bearing this in mind one might appreciate the importance of the above results for the application of the kinetic gas theory to problems in condensed matter physics and chemistry. Also, the experimental and theoretical work of others (see for example Refs. [Prezhdo 1998 Opatrny 2001]) demonstrate that quantum entanglement plays a fundamental role in condensed matter physics and chemistry. 

Abstract We present preliminary experimental results of inelastic X-ray scattering (IXS) on molecular vibrations of liquid H2O, DoO and the equimolar H>0 - D >0 mixture. The data analysis indicates the presence of an anomalous shortfall of scattering intensity from the O//-stretching vibrational modes. This effect has no explanation within the frame of conventional X-ray scattering theory. The possible connection of these observations with recent results of neutron and electron Compton scattering from protons in condensed matter is mentioned, as well as their interpretation in terms of attosecond entanglement. 

This part is focussed on the intriguing question of quantum entanglement in large statistical condensed-matter ensembles and its possible influence on the cross-section of neutron scattering from solids ... 

Therefore, as concerns the determined areas from the VESUVIO data, the argument of Cowley does not play any role and the associated sub-femtosecond quantum entanglement effect found in the metallic hydride is not affected at all. The above results demonstrate that the short-lived quantum entanglement effect revealed in the niobium hydride system [Karlsson 1999 Abdul-Redah 2000 Karlsson 2003 (b)] as well as in the other condensed matter systems studied thus far [Chatzidimitriou-Dreismann 1997 (a) Chatzidimitriou-Dreis-mann 2000 (b) Chatzidimitriou-Dreismann 2001 Chatzidimitriou-Dreismann 2002 (a) Chatzidimitriou-Dreismann 2003 (a)] are real and are not caused by incorrect data reduction. 

There are many different physical realizations of the EPR or entangled states in optics and condensed-matter physics. For example, the creation of two photons with different helicities by a single atom in the process of cascade... 

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