A Relativistic toy model for back-reaction

Aug, 2004
8 pages
Published in:
  • Class.Quant.Grav. 24 (2007) 4361-4376
e-Print:

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Abstract: (arXiv)
We consider a quantized massless and minimally coupled scalar field on a circular closed string with a time-dependent radius R(t)R(t), whose undisturbed dynamics is governed by the Nambu-Goto action. Within the semi-classical treatment, the back-reaction of the quantum field onto the string dynamics is taken into account in terms of the renormalized expectation value of the energy-momentum tensor including the trace anomaly. The results indicate that the back-reaction could prevent the collapse of the circle R0R\downarrow0 -- however, the semi-classical picture fails to describe the string dynamics at the turning point (i.e., possible bounce) at finite values of RR and R˙\dot R. The fate of the closed string after that point (e.g., oscillation or eternal acceleration) cannot be determined within the semi-classical picture and thus probably requires the full quantum treatment. PACS: 04.62.+v, 03.70.+k, 11.15.Kc, 04.60.-m.
  • 04.60.-m
  • 11.15.Kc
  • 04.62.+v
  • 03.70.+k
  • string model
  • field theory: scalar
  • massless
  • coupling: minimal
  • back reaction
  • dimension: 2