257 citations · 1.1k across the 71 of their papers we have counts for
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Symmetry restoration, Tunnelling and the Null Energy Condition
Jean Alexandre, Janos Polonyi
A finite volume allows tunnelling between degenerate vacua in Quantum Field Theory, and leads to remarkable energetic features, arising from the competition of different saddle poi…
Tunnelling and dynamical violation of the Null Energy Condition
Jean Alexandre, Janos Polonyi
The Null Energy Condition is considered the most fundamental of the energy conditions, on which several key results, such as the singularity theorems, are based. The Casimir effect…
Boost invariant regulator for field theories
Janos Polonyi
It is shown that by imposing the relativistic symmetries on the cutoff in field theories one rules out all known non-perturbative regulators except the point splitting. The relativ…
Stability and causality of multi-local theories
Janos Polonyi
The regularized theories are non-local at the scale of the cutoff, leading so to the usual difficulties of non-local theories. In this work the conservation laws and causality are…
The Abraham-Lorentz force and electrodynamics at the classical electron radius
Janos Polonyi
The Abraham-Lorentz force is a finite remnant of the UV singular structure of the self interaction of a point charge with its own field. The satisfactory description of such intera…
Irreversibility and decoherence in an ideal gas
Janos Polonyi
Different models are described where non-interacting particles generate dissipative effective forces by the mixing of infinitely many soft normal modes. The effective action is cal…
Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles
Sašo Grozdanov, Janos Polonyi
We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be hig…
Classical and quantum effective theories
Janos Polonyi
A generalization of the action principle of classical mechanics, motivated by the Closed Time Path (CTP) scheme of quantum field theory, is presented to deal with initial condition…
Viscosity and dissipative hydrodynamics from effective field theory
Sašo Grozdanov, Janos Polonyi
With the goal of deriving dissipative hydrodynamics from an action, we study classical actions for open systems, which follow from the generic structure of effective actions in the…
Effective dynamics of a classical point charge
Janos Polonyi
The effective Lagrangian of a point charge is derived by eliminating the electromagnetic field within the framework of the classical closed time path formalism. The short distance…
Yang-Mills-Higgs models with higher order derivatives
Janos Polonyi, Alicja Siwek
Models with higher order derivative terms in the kinetic energy appear not only as effective theories, they can be considered as elementary, renormalizable models in their own righ…
Environment Induced Time Arrow
Janos Polonyi
The spread of the time arrows from the environment to an observed subsystem is followed within a harmonic model. A similarity is pointed out between irreversibility and a phase wit…
Dynamical breakdown of time reversal invariance and causality
Janos Polonyi
Irreversibility and acausality of a sub-system are established in exactly soluble harmonic models with reversible and causal dynamics. It is shown that initial conditions, imposed…
Scattering in an environment
Janos Polonyi, Karima Zazoua
The cross section of elastic electron-proton scattering taking place in an electron gas is calculated within the Closed Time Path method. It is found to be the sum of two terms, on…
Spontaneous breakdown of Lorentz symmetry in scalar QED with higher order derivatives
Janos Polonyi, Alicja Siwek
Scalar QED is studied with higher order derivatives for the scalar field kinetic energy. A local potential is generated for the gauge field due to the covariant derivatives and the…
Gluon confinement and quantum censorship
Janos Polonyi
The dynamical Maxwell-cut, a degeneracy is shown to be a precursor of condensate in the phi4 and the sine-Gordon models. The difference of the way the Maxwell-cut is obtained is po…
Boundary conditions and consistency of effective theories
Janos Polonyi, Alicja Siwek
Effective theories are non-local at the scale of the eliminated heavy particles modes. The gradient expansion which represents such non-locality must be truncated to have treatable…
Sub-classical fields and polarization in electrodynamics
Mathieu Planat, Janos Polonyi
Expectation values of the electromagnetic field and the electric current are introduced at space-time resolution which belongs to the quantum domain. These allow us to approach som…
Generalized universality in the massive sine-Gordon model
S. Nagy, I. Nandori, J. Polonyi +1
A non-trivial interplay of the UV and IR scaling laws, a generalization of the universality is demonstrated in the framework of the massive sine-Gordon model, as a result of a deta…
Renormalizable parameters of the sine-Gordon model
S. Nagy, I. Nandori, J. Polonyi +1
The well-known phase structure of the two-dimensional sine-Gordon model is reconstructed by means of its renormalization group flow, the study of the sensitivity of the dynamics on…
Quantum-classical crossover in electrodynamics
Janos Polonyi
A classical field theory is proposed for the electric current and the electromagnetic field interpolating between microscopic and macroscopic domains. It represents a generalizatio…
Spinodal Instability and Confinement
Janos Polonyi
It is pointed out that inhomogeneous condensates or spinodal instabilities suppress the propagation of elementary excitations due to the absorptive zero mode dynamics. This mechani…
Casimir effect: running Newton constant or cosmological term
Janos Polonyi, Eniko Regos
We argue that the instability of Euclidean Einstein gravity is an indication that the vacuum is non perturbative and contains a condensate of the metric tensor in a manner reminisc…
Lectures on the functional renormalization group method
Janos Polonyi
These introductory notes are about functional renormalization group equations and some of their applications. It is emphasised that the applicability of this method extends well be…