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Related papers: Forward scattering amplitudes and the thermal oper…

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We study, in the imaginary time formalism, the relation between loops and on-shell forward scattering tree amplitudes in thermal field theories. This allows for an efficient evaluation, at all temperatures, of Green's functions with causal…

High Energy Physics - Theory · Physics 2023-04-24 F. T. Brandt , J. Frenkel , S. Martins-Filho , D. G. C. McKeon , G. S. S. Sakoda

In this paper, we extend our earlier one loop analysis to two loops and give a simple diagrammatic description for the retarded Greens functions at finite temperature, in terms of forward scattering amplitudes of on-shell thermal particles.…

High Energy Physics - Theory · Physics 2016-08-25 F. T. Brandt , Ashok Das , J. Frenkel

We employ the thermal forward scattering amplitudes technique in order to compute the gluon self-energy in a class of temporal gauges. The leading T^2 and the sub-leading ln(T) contributions are obtained for temperatures high compared with…

High Energy Physics - Theory · Physics 2007-05-23 F. T. Brandt , J. Frenkel , F. R. Machado

In this paper, we give a simple diagrammatic identification of the unique combination of the causal n-point vertex functions in the real time formalism that would coincide with the corresponding functions obtained in the imaginary time…

High Energy Physics - Theory · Physics 2016-08-25 F. T. Brandt , Ashok Das , J. Frenkel , A. J. da Silva

We discuss the high temperature behavior of retarded thermal loops in static external fields. We employ an analytic continuation of the imaginary time formalism and use a spectral representation of the thermal amplitudes. We show that, to…

High Energy Physics - Theory · Physics 2015-06-17 F. T. Brandt , J. Frenkel , J. B. Siqueira

In the context of scalar field theories, both real and complex, we derive the cutting description at finite temperature (with zero/finite chemical potential) from the cutting rules at zero temperature through the action of a simple thermal…

High Energy Physics - Theory · Physics 2008-11-26 F. T. Brandt , Ashok Das , Olivier Espinosa , J. Frenkel , Silvana Perez

Through the application of the thermal operator to the zero temperature retarded Green's functions, we derive in a simple way the well known hard thermal effective action in QCD. By relating these functions to forward scattering amplitudes…

High Energy Physics - Theory · Physics 2008-11-26 Ashok Das , J. Frenkel

We present a simple set of rules for obtaining the imaginary part of a self energy diagram at finite temperature in terms of diagrams that correspond to physical scattering amplitudes.

High Energy Physics - Phenomenology · Physics 2009-11-07 M. E. Carrington , Hou Defu , R. Kobes

An often used rule that the thermal correction to the self-energy is the thermal phase-space times the forward scattering amplitude from target particles is shown to be the leading term in an exact multiple scattering expansion. Starting…

High Energy Physics - Phenomenology · Physics 2008-11-26 Sangyong Jeon , Paul J. Ellis

This is a more detailed version of our recent paper where we proposed, from first principles, a direct method for evaluating the exact fermion propagator in the presence of a general background field at finite temperature. This can, in…

High Energy Physics - Theory · Physics 2010-03-12 Ashok Das , J. Frenkel

We extend to a general class of covariant gauges an approach which relates the thermal Green functions to forward scattering amplitudes of thermal particles. A brief discussion of the non-transversality of the thermal gluon polarization…

High Energy Physics - Theory · Physics 2009-10-30 F. T. Brandt , J. Frenkel

We present, from first principles, a direct method for evaluating the exact fermion propagator in the presence of a general background field at finite temperature, which can be used to determine the finite temperature effective action for…

High Energy Physics - Theory · Physics 2015-05-13 Ashok Das , J. Frenkel

Combining the thermal operator representation with the dispersion relation in QED at finite temperature and chemical potential, we determine the complete retarded photon self-energy only from its absorptive part at zero temperature. As an…

High Energy Physics - Theory · Physics 2008-11-26 Ashok Das , J. Frenkel

We examine the gluon scattering amplitude in N=4 super Yang-Mills at finite temperature with nonzero R-charge densities, and in Non-Commutative gauge theory at finite temperature. The gluon scattering amplitude is defined as a light-like…

High Energy Physics - Theory · Physics 2011-08-17 George Georgiou , Dimitrios Giataganas

By employing retarded and advanced propagators, Aurenche and Becherrawy showed how to rewrite the real-time thermal Feynman rules so that the temperature dependence is removed from the free propagators and transferred to the vertices. The…

High Energy Physics - Phenomenology · Physics 2016-09-06 H. Arthur Weldon

A prescription is presented to construct manifestly gauge invariant tree-level scattering amplitudes with one or two off-shell initial-state gluons for processes with arbitrary particles in the final state, which allows for calculations…

High Energy Physics - Phenomenology · Physics 2013-07-09 A. van Hameren

We show, in the imaginary time formalism, that the temperature dependent parts of all the retarded (advanced) amplitudes vanish in the Schwinger model. We trace this behavior to the CPT invariance of the theory and give a physical…

High Energy Physics - Theory · Physics 2015-06-05 Ashok Das , R. R. Francisco , J. Frenkel

We define form factors and scattering amplitudes in Conformal Field Theory as the coefficient of the singularity of the Fourier transform of time-ordered correlation functions, as $p^2 \to 0$. In particular, we study a form factor…

High Energy Physics - Theory · Physics 2020-12-30 Marc Gillioz , Marco Meineri , Joao Penedones

In this paper, the cross section for the Compton scattering process at finite temperature is calculated. Temperature effects are introduced using the Thermofield Dynamics (TFD) formalism. It is a real-time finite temperature quantum field…

High Energy Physics - Theory · Physics 2023-02-01 D. S. Cabral , A. F. Santos

A conjecture is presented for the thermal one-point function of boundary operators in integrable boundary quantum field theories in terms of form factors. It is expected to have applications in studying boundary critical phenomena and…

High Energy Physics - Theory · Physics 2008-11-26 G. Takacs
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