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

Several conceptual aspects of quantum gravity are studied on the example ofthe homogeneous isotropic LQC model. In particular: $(i)$ The proper time ofthe co-moving observers is showed to be a quantum operator {and} a quantumspacetime metric tensor operator is derived. $(ii)$ Solutions of the quantumscalar constraint for two different choices of the lapse function are comparedand contrasted. In particular it is shown that in case of model with maslessscalar field and cosmological constant $\Lambda$ the physical Hilbert spacesconstructed for two choices of lapse are the same for $\Lambda<0$ while theyare significantly different for $\Lambda>0$. $(iii)$ The mechanism of thesingularity avoidance is analyzed via detailed studies of an energy densityoperator, whose essential spectrum was shown to be an interval $[0,\rhoc]$,where $\rhoc\approx 0.41\rho_{\Pl}$. $(iv)$ The relation between thekinematical and the physical quantum geometry is discussed on the level ofrelation between observables.

Physical time and other conceptual issues of QG on the example of LQC