English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We consider $N_a$ three-level atoms (or systems) interacting with a one-modeelectromagnetic field in the dipolar and rotating wave approximations. Theorder of the quantum phase transitions is determined explicitly for each of theconfigurations $\Xi$, $\Lambda$ and $V$, with and without detuning. Thesemi-classical and exact quantum calculations for both the expectation valuesof the total number of excitations $\cal{M}=\langle \bm{M} \rangle$ and photonnumber $n=\langle \bm{n} \rangle$ have an excellent correspondence as functionsof the control parameters. We prove that the ground state of the collectiveregime obeys sub-Poissonian statistics for the ${\cal M}$ and $n$ distributionfunctions. Therefore, their corresponding fluctuations are not well describedby the semiclassical approximation. We show that this can be corrected byprojecting the variational state to a definite value of ${\cal M}$.

A semi-classical versus quantum description of the ground state of three-level atoms interacting with a one-mode electromagnetic field