[seminar] Seminar Dr. Ivan Dadic (srijeda, 04.07., 15:30 sati c.t)

[Kornelija Passek]

INSTITUT "Ruder Boskovic"
ZAVOD ZA TEORIJSKU FIZIKU
Bijenicka c. 54, Zagreb, Hrvatska

  ----------------------------------------------------------------------

                SEMINAR TEORIJSKE  FIZIKE
  (Zajednicki seminari Zavoda za fiziku PMF-a i
       Zavoda za teorijsku fiziku  IRB-a)

  ----------------------------------------------------------------------

Ivan Dadic

   Zavod za teorijsku fiziku, IRB, Zagreb


"Manifestly Retarded formalism for
Out-of-equilibrium Thermal Field Theories"


  Datum: 4. srpnja 2007. (srijeda)
  Vrijeme: 15:30 sati c.t.
  Mjesto: IRB, predavaonica I krila


  Sažetak:
We define perturbation expansion in finite time out-of-equilibrium
TFT expressed exclusively in retarded and advanced propagators and
represented by Feynman-like diagrams.
The physical quantities are represented by equal-time-limit
of multi-point Greens functions.
In the diagrams there are "normal" vertices in which energy is
conserved, "sink" vertices (only incoming retarded and outgoing advanced
propagators) in which energy cannot be conserved (at least 
in the equal-time limit), and "source" vertices 
(only outgoing retarded and incoming advanced propagators) 
which are absent from expansion, thus leading to the
absence of closed diagram contributions to physical quantities.
The "sink" vertices are naturally regulated, and no illdefined 
expressions ("pinching") appear.
The safe time-to-infinity limit is enabled.
The naive Keldysh time-path formulation is clearly out.
Other functions e.g. higher retarded propagator make sense only
as a subgraph of equal-time-limit of multi-valued Greens function.



  2007-06-28

  Voditeljica seminara:
  dr. Kornelija Passek-Kumericki (passek at thphys.irb.hr)



--
--------------------------------------------------------------------
Kornelija Passek-Kumericki
  E-mail: passek at thphys.irb.hr
Theoretical Physics Division
Rudjer Boskovic Institute
Bijenicka c. 54, P.O.B. 180
HR-10002 Zagreb, Croatia
Tel: ++385-1-4561-133
Fax: ++385-1-4680-223
--------------------------------------------------------------------