Path-integral formulation of real-time quantum field theories at finite temperature

1989 ◽  
Vol 40 (4) ◽  
pp. 1199-1206 ◽  
Author(s):  
A. Niégawa
Keyword(s):  
Real Time ◽  
Path Integral ◽  
Finite Temperature ◽  
Integral Formulation ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Path Integral Formulation ◽  
Time Quantum

scholarly journals UNITARITY OF NONCOMMUTATIVE FIELD THEORIES FROM STRING THEORY

2003 ◽  
Vol 18 (33n35) ◽  
pp. 2525-2532 ◽  
Author(s):  
ALESSANDRO TORRIELLI
Keyword(s):  
String Theory ◽  
Open String ◽  
Space Time ◽  
Bosonic String ◽  
Field Theories ◽  
Noncommutative Space ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Superstring Theory ◽  
Time Quantum

We improve the study of the lack of perturbative unitarity of noncommutative space-time quantum field theories derived from open string theory in electric backgrounds, enforcing the universality of the mechanism by which a tachyonic branch cut appears when the Seiberg-Witten limit freezes the string in an unstable vacuum. The main example is realized in the context of the on-shell four-tachyon amplitude of the bosonic string, and the dependence of the phenomenon on the brane-worldvolume dimension is analysed. We discuss the possibility of a proof in superstring theory, and finally mention the NCOS limit in this framework.

scholarly journals CURRENT ALGEBRA IN THE PATH INTEGRAL FRAMEWORK

1998 ◽  
Vol 13 (27) ◽  
pp. 2193-2198
Author(s):  
V. CÁRDENAS ◽  
S. LEPE ◽  
J. SAAVEDRA
Keyword(s):  
Path Integral ◽  
Current Algebra ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Integral Formalism ◽  
Path Integral Formalism ◽  
Current Algebras

In this letter we describe an approach to the current algebra based on the path integral formalism. We use this method for Abelian and non-Abelian quantum field theories in (1+1) and (2+1) dimensions and the correct expressions are obtained. Our results show the independence of the regularization of the current algebras.

An equivalence class of quantum field theories at finite temperature

1984 ◽  
Vol 25 (10) ◽  
pp. 3076-3085 ◽  
Author(s):  
H. Matsumoto ◽  
Y. Nakano ◽  
H. Umezawa
Keyword(s):  
Equivalence Class ◽  
Finite Temperature ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field

scholarly journals THERMOFIELD DYNAMICS FOR TWISTED POINCARÉ-INVARIANT FIELD THEORIES: WICK THEOREM AND S-MATRIX

2011 ◽  
Vol 26 (15) ◽  
pp. 2569-2589 ◽  
Author(s):  
MARCELO LEINEKER ◽  
AMILCAR R. QUEIROZ ◽  
ADEMIR E. SANTANA ◽  
CHRYSTIAN DE ASSIS SIQUEIRA
Keyword(s):  
Field Theory ◽  
Finite Temperature ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
S Matrix ◽  
Scalar Quantum ◽  
Wick Theorem ◽  
Wick’S Theorem ◽  
Invariant Quantum

Poincaré invariant quantum field theories can be formulated on noncommutative planes if the statistics of fields is twisted. This is equivalent to state that the coproduct on the Poincaré group is suitably twisted. In the present work we present a twisted Poincaré invariant quantum field theory at finite temperature. For that we use the formalism of thermofield dynamics (TFD). This TFD formalism is extend to incorporate interacting fields. This is a nontrivial step, since the separation in positive and negative frequency terms is no longer valid in TFD. In particular, we prove the validity of Wick's theorem for twisted scalar quantum field at finite temperature.

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