[seminar] Jiangyang YouC, 22.05. (petak) 14h (c.t.), predavaona I krila IRB

[Kornelija Passek-Kumericki]

                       SEMINAR  TEORIJSKE  FIZIKE


   (Zajednički seminari Fizičkog odsjeka PMF-a te Zavoda za teorijsku
    fiziku i Zavoda za eksperimentalnu fiziku IRB-a)

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2nd Order Seiberg-Witten Maps and Four Photon Tadpole 
in U_*(1) Gauge Theory on Moyal Space

Jiangyang You

   Datum:  petak, 22. svibnja 2015.
   Vrijeme: 14 sati c.t.
   Mjesto: IRB, predavaona I krila



Sazetak:

We study two distinct $\theta$-exact Seiberg-Witten (SW) map expansions up
to $e^3$ order for the gauge parameter, gauge field and the gauge field
strengths of the noncommutative (NC) $\rm U_\star(1)$ gauge theory on the
Moyal space. We derive explicitly the closed form expression for the SW map
ambiguity between the two as well as identify the additional gauge freedoms
within each of the $e^3$ order field strength expansions. Based on these
results we construct the $\theta$-exact four photon self-coupling vertex and
evaluate the one-loop four photon tadpole diagram of this theory, where we
observe that the NC massless tadpole is solely quadratic IR divergent,
contrary to the vanishing nature of the commutative counterpart. The tensor
structures of NC tadpole remain the same as the photon bubble diagram we
studied before. The anomalous IR divergence (``UV/IR mixing'') from the
tadpole diagram could not be completely done away together with the
pathological contributions from the bubble diagram simultaneously by
fine-tuning the gauge freedom in the action. Certain consideration on how to
regain control over IR divergence will also be discussed.





Voditeljica seminara: Kornelija Passek-Kumericki (passek at irb dot hr)
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