HAMP-vQED

User Tools

Site Tools

Trace:
public:overview

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
public:overview [2021/05/09 17:27] – tsauepublic:overview [2024/07/18 15:16] (current) – tsaue
Line 1: Line 1:
 +See also [[https://cordis.europa.eu/project/id/101019907|here]].
 +
 === Does chemistry need more physics ? === === Does chemistry need more physics ? ===
-[{{:public:period3.jpg?400 |The period table (1871)}}]The building blocks of chemistry are organized in the periodic table, which requires quantum mechanics for its understanding. In the 1980s it was realized that in order to correctly describe the heavy elements in the lower part of the periodic table, the special theory of relativity had to be invoked. The HAMP-vQED projet will investigate the possible role of quantum electrodynamics (QED) in chemistry. It will provide a protocol for highly accurate calculations of molecular properties, with particular attention to properties that probe the electron density in the close vicinity of atomic nuclei, where the QED-effects associated with the Lamb shift are created. The HAMP-vQED adheres to the general framework of quantum chemistry by seeking a variational (non-perturbative) approach using local (Gaussian) basis functions. +[{{:public:period3.jpg?400 |The periodic table (1871)}}]The building blocks of chemistry are organized in the periodic table, which requires quantum mechanics for its understanding. In the 1980s it was realized that in order to correctly describe the heavy elements in the lower part of the periodic table, the special theory of relativity had to be invoked. The HAMP-vQED projet will investigate the possible role of quantum electrodynamics (QED) in chemistry. It will provide a protocol for highly accurate calculations of molecular properties, with particular attention to properties that probe the electron density in the close vicinity of atomic nuclei, where the QED-effects associated with the Lamb shift are created. The HAMP-vQED project adheres to the general framework of quantum chemistry by seeking a variational (non-perturbative) approach using local (Gaussian) basis functions. 
  
 === Is the vacuum really empty ? === === Is the vacuum really empty ? ===
  
-An ideal sitatution for accurate calculations is a molecule alone in space at 0K. However, is the vacuum really empty ? It has been shown that placing a molecule in an otherwise empty cavity will change its reactivity. This is explained by the coupling of the molecule to the zero-point vibrations of the quantized electromagnetic field. +An ideal situation for accurate calculations is a molecule alone in space at 0K. However, is the vacuum really empty ? It has been shown that placing a molecule in an otherwise empty cavity will change its reactivity [1]. This is explained by the coupling of the molecule to the zero-point vibrations of the quantized electromagnetic field. 
 [{{:public:vacpol_phys.png?&200 |The target QED-effects arise from the polarizable vacuum.}}] In the HAMP-vQED we are particularly interested in the effects leading to the Lamb shift, a splitting between the 2S1/2 and 2P1/2-levels of one-electron atoms, not predicted by the Dirac equation, but observed for the first time in 1947 by Lamb and Retherford. [{{:public:vacpol_phys.png?&200 |The target QED-effects arise from the polarizable vacuum.}}] In the HAMP-vQED we are particularly interested in the effects leading to the Lamb shift, a splitting between the 2S1/2 and 2P1/2-levels of one-electron atoms, not predicted by the Dirac equation, but observed for the first time in 1947 by Lamb and Retherford.
   * **Vacuum polarization**: A charge in space is surrounded by virtual electron-positron pairs. This will contribute to the observed charge.   * **Vacuum polarization**: A charge in space is surrounded by virtual electron-positron pairs. This will contribute to the observed charge.
   * ** Electron self-energy**: A charge drags along its electromagnetic field. This will contribute to the observed mass.   * ** Electron self-energy**: A charge drags along its electromagnetic field. This will contribute to the observed mass.
-The splitting is a mere 4 meV, but for hydrogen-like uranium the splitting has grown to an impressive 468 eV.   +The splitting is a mere 4 μeV, but for hydrogen-like uranium the splitting has grown to an impressive 76 eV.   
 It is therefore legitimate to ask if QED-effects could play a role in the chemistry of heavy elements.  It is therefore legitimate to ask if QED-effects could play a role in the chemistry of heavy elements. 
  
Line 15: Line 17:
   - Develop a variational approach to QED rather than the usual perturbative one (QED without diagrams)   - Develop a variational approach to QED rather than the usual perturbative one (QED without diagrams)
 The most challenging part of the project is to devise ways of handling the divergences of QED using the computational framework of quantum chemistry. The most challenging part of the project is to devise ways of handling the divergences of QED using the computational framework of quantum chemistry.
 +
 +== References ==
 +<fs smaller>
 +[1]. J.A. Hutchison, T. Schwartz, C. Genet, E. Devaux, and T. W. Ebbesen, “Modifying Chemical Landscapes by Coupling to Vacuum Fields”, [[http://dx.doi.org/10.1002/anie.201107033|Angewandte Chemie International Edition 51, 1592–1596 (2012)]].
 +</fs>
public/overview.1620574055.txt.gz · Last modified: 2021/05/09 17:27 by tsaue