EPJB Colloquium - Fulfillment of sum-rules and Goldstone modes in many body theories

Schematic representation of the two body mean field

This EPJ B Colloquium article explores applications of the Self-Consistent Random Phase Approximation (SCRPA) approach to Fermi systems with a continuously broken symmetry. Correlations beyond those considered by standard Random Phase Approximation (RPA) are summed up, thereby correcting for the quasi-boson approximation in standard RPA.

Desirable properties of standard RPA, such as fulfilment of the energy-weighted sum rule and the appearance of Goldstone (zero) modes, are preserved. The authors show theoretically as well as numerically, for a model case, that SCRPA maintains all the properties of standard RPA for practically all instances of spontaneously-broken symmetries. A simpler approximate form of SCRPA, the so-called renormalised RPA, also exhibits these properties. The SCRPA equations are first outlined as an eigenvalue problem, and then it is shown how an equivalent many-body Green’s function approach can be formulated.

This was our first experience of publishing with EPJ Web of Conferences. We contacted the publisher in the middle of September, just one month prior to the Conference, but everything went through smoothly. We have had published MNPS Proceedings with different publishers in the past, and would like to tell that the EPJ Web of Conferences team was probably the best, very quick, helpful and interactive. Typically, we were getting responses from EPJ Web of Conferences team within less than an hour and have had help at every production stage.
We are very thankful to Solange Guenot, Web of Conferences Publishing Editor, and Isabelle Houlbert, Web of Conferences Production Editor, for their support. These ladies are top-level professionals, who made a great contribution to the success of this issue. We are fully satisfied with the publication of the Conference Proceedings and are looking forward to further cooperation. The publication was very fast, easy and of high quality. My colleagues and I strongly recommend EPJ Web of Conferences to anyone, who is interested in quick high-quality publication of conference proceedings.

On behalf of the Organizing and Program Committees and Editorial Team of MNPS-2019, Dr. Alexey B. Nadykto, Moscow State Technological University “STANKIN”, Moscow, Russia. EPJ Web of Conferences vol. 224 (2019)

ISSN: 2100-014X (Electronic Edition)

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