Perturbative non-equilibrium thermal field theory to all orders in gradient expansion

Millington, Peter; Pilaftsis, Apostolos

doi:10.1016/j.physletb.2013.05.044

Cited by 18 publications

(22 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[84] (see ref. [85] for a summary) enables one to proceed in a perturbative loop-wise fashion without encountering so-called pinch singularities [86][87][88][89][90][91][92] or secular terms [78] thought previously to spoil such approaches to non-equilibrium field theory. Quite remarkably, we find exact agreement between these two formulations, illustrating the self-consistency and complementarity of these two approaches.…”

Section: Jhep06(2016)066mentioning

confidence: 99%

Lepton asymmetry from mixing and oscillations

Kartavtsev

Millington

Vogel

2016

J. High Energ. Phys.

View full text Add to dashboard Cite

We show how the two physically-distinct sources of CP -asymmetry relevant to scenarios of leptogenesis: (i) resonant mixing and (ii) oscillations between different flavours can be unambiguously identified within the Kadanoff-Baym formalism. These contributions are isolated by analyzing the spectral structure of the non-equilibrium propagators without relying on the definition of particle number densities. The mixing source is associated with the usual mass shells, whereas the oscillation source is identified with a third intermediate shell. In addition, we identify terms lying on the oscillation shell that can be interpreted as the destructive interference between mixing and oscillation. We confirm that identical shell structure is obtained in both the Heisenberg-and interaction-picture realizations of the Kadanoff-Baym formalism. In so doing, we illustrate the self-consistency and complementarity of these two approaches. The interaction-picture approach in particular has the advantage that it may be used to analyze all forms of mass spectra from quasi-degenerate through to hierarchical.

show abstract

Section: Jhep06(2016)066mentioning

confidence: 99%

Lepton asymmetry from mixing and oscillations

Kartavtsev

Millington

Vogel

2016

J. High Energ. Phys.

View full text Add to dashboard Cite

show abstract

“…Recently, a new perturbative formulation of non-equilibrium thermal field theory [115] (for an overview, see [116]) was developed, which is free of the mathematically ill-defined pinch singularities previously thought to spoil such approaches. Within this framework, one may define a perturbative loopwise truncation scheme for quantum transport equations that is valid to all orders in a gradient expansion, whilst capturing non-Markovian dynamics, memory and threshold effects.…”

Section: Introductionmentioning

confidence: 99%

“…For further details of the diagrammatic representation of non-homogeneous self-energies and, in particular, their double-momentum structure, see[115,116].…”

mentioning

confidence: 99%

Kadanoff–Baym approach to flavour mixing and oscillations in resonant leptogenesis

et al. 2015

Self Cite

View full text Add to dashboard Cite

We describe a loopwise perturbative truncation scheme for quantum transport equations in the KadanoffBaym formalism, which does not necessitate the use of the so-called Kadanoff-Baym or quasi-particle ansaetze for dressed propagators. This truncation scheme is used to study flavour effects in the context of Resonant Leptogenesis (RL), showing explicitly that, in the weakly-resonant regime, there exist two distinct and pertinent flavour effects in the heavy-neutrino sector: (i) the resonant mixing and (ii) the oscillations between different heavy-neutrino flavours. Moreover, we illustrate that Kadanoff-Baym and quasi-particle ansaetze, whilst appropriate for the flavour-singlet dressed charged-lepton and Higgs propagators of the RL scenario, should not be applied to the dressed heavy-neutrino propagators. The use of these approximations for the latter is shown to capture only flavour oscillations, whilst discarding the separate phenomenon of flavour mixing.

show abstract

“…Such an oscillating pattern signifies a non-Markovian evolution of memory effects, which is a distinctive feature governing truly out-of-thermal-equilibrium dynamical systems. A summary of the main results detailed in this article can be found in [86].…”

Section: Introductionmentioning

confidence: 99%

Perturbative nonequilibrium thermal field theory

Millington

Pilaftsis

2013

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

We present a new perturbative formulation of non-equilibrium thermal field theory, based upon non-homogeneous free propagators and time-dependent vertices. Our approach to non-equilibrium dynamics yields time-dependent diagrammatic perturbation series that are free of pinch singularities, without the need to resort to quasi-particle approximation or effective resummations of finite widths. In our formalism, the avoidance of pinch singularities is a consequence of the consistent inclusion of finite-time effects and the proper consideration of the time of observation. After arriving at a physically meaningful definition of particle number densities, we derive master time evolution equations for statistical distribution functions, which are valid to all orders in perturbation theory. The resulting equations do not rely upon a gradient expansion of Wigner transforms or involve any separation of time scales. To illustrate the key features of our formalism, we study out-ofequilibrium decay dynamics of unstable particles in a simple scalar model. In particular, we show how finite-time effects remove the pinch singularities and lead to violation of energy conservation at early times, giving rise to otherwise kinematically forbidden processes. The non-Markovian nature of the memory effects as predicted in our formalism is explicitly demonstrated.

show abstract

Perturbative non-equilibrium thermal field theory to all orders in gradient expansion

Cited by 18 publications

References 62 publications

Lepton asymmetry from mixing and oscillations

Lepton asymmetry from mixing and oscillations

Kadanoff–Baym approach to flavour mixing and oscillations in resonant leptogenesis

Perturbative nonequilibrium thermal field theory

Contact Info

Product

Resources

About