1,721,085 research outputs found
Induced quantum gravity from heat kernel expansion
No full textThe asymptotic expansion of the heat kernel is employed
to derive the Einstein action from the matter effective action. The
advantages of this approach are discussed. We point out some problems
arising when scalar fields, nonminimally coupled to the background
geometry, are used as fundamental pregeometric objects
Coleman-weinberg model in Einstein space-time
No full textWe study radiative, symmetry breaking, h ht ('olemav,-
~,Veinb(,r(_,, in the /eometry of a .~tatic Einstein mfivcrsc. \Vc prove that
the syvmnetric gv'om,d state (oi~510 > - . r in a nouminimally coupled mass-
1,,s,~ ).r theory, can l)et'onw, u,,st al)lc at high curvature only if 0 "4 ~ )..;: 1.
As far as mas.sles~ scalar (~I".I) is ('oncerned, we find lhat pha.~c transitions
can already oc('m" at low cttrvature. These conchisions arc improvc(l
by nwans of r,*norm:diz:alion group tcwhniques
Symmetry restoration in conformally flat metrics
No full textWe study symmetry restoration in a curved-background
metric. Massless scalar QED is considered in the de Sitter space-time.
The radius of the cosmological-event horizon corresponding to the critical
temperature turns out to be of the order of the Compton wave-length
of the vector bosom Quite similarly, the Gross-Neveau model in the twodimensional
Schwarzschild background shows symmetry restoration
when the radius of the black-hole horizon becomes comparable with
the Compton wave-length of the spinor
Curvature and symmetry breaking: An induced-action approach
No full textWe recover the general form of the one-loop effective
potential for a Ar 4 theory, nonminimally coupled to a constant-curvature
background geometry, in the low-energy limit, i.e. for small curvature.
Renormalization is carried out and the massless limit of the renormalized
theory is performed. Then we study the symmetry properties of the
vacuum state according to the value of the nonminimal coupling constant
~ and the sign of the curvature
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