We show systematically the relation between a N = 2 nonlinear supersymmetric (NLSUSY) model and a N = 2 SUSY QED theory by means of the superfield formulation in two dimensional spacetime without imposing a priori any special gauge conditions for a gauge superfield.
We study the SUSY breaking of the covariant gauge-fixing term in SUSY QED and observe that this corresponds to a breaking of the Lorentz gauge condition by SUSY. Reasoning by analogy with SUSY's violation of the Wess-Zumino gauge, we argue that the SUSY transformation, already modified to preserve Wess-Zumino gauge, should be further modified by another gauge transformation which restores the Lorentz gauge condition. We derive this modification and use the resulting transformation to derive a Ward identitiy relating the photon and photino propagators without using ghost fields. Our transformat…
We compute the effective actions for the 0+1 dimensional scalar field interacting with an Abelian gauge background, as well as for its supersymmetric generalization at finite temperature.
Within the superfield formalism, we study the ultraviolet properties of the three-dimensional supersymmetric quantum electrodynamics. The theory is shown to be finite at all loops orders in a particular gauge.
We utilise a non-local gauge transform which renders the entire action of SUSY QED invariant and respects the SUSY algebra modulo the gauge-fixing condition, to derive two- and three-point ghost-free SUSY Ward identities in SUSY QED. We use the cluster decomposition principle to find the Green's function Ward identities and then takes linear combinations of the latter to derive identities for the proper functions.
Within the superfield approach, we discuss the three-dimensional supersymmetric (SUSY) pseudo-QED. We prove that it is all-loop renormalizable. We demonstrate that the SUSY pseudo-QED action can be generated as a quantum correction from the coupling of a spinor gauge superfield to a set of $N$ massless complex scalar superfields. Afterwards, we calculate the two-point function of the scalar superfields in the pseudo-QED which displays a divergence vanishing in a certain gauge.
A series of exact BPS solutions are found for single and double domain walls in N=2 supersymmetric (SUSY) QED for finite gauge coupling constants. Vector fields are found to be massive, although it is localized on the wall. Massless modes can be assembled into a chiral scalar multiplet of the preserved N=1 SUSY, after an appropriate gauge choice. The low-energy effective Lagrangian for the massless fields is obtained for the finite gauge coupling. The inter-wall force is found to be much stronger than the known infinite coupling case. The previously proposed expansion in inverse powers of the …
An exact solution of domain wall junction is obtained in N=2 supersymmetric (SUSY) QED with three massive hypermultiplets. The junction preserves two out of eight SUSY. Both a (magnetic) Fayet-Iliopoulos (FI) term and complex masses for hypermultiplets are needed to obtain the junction solution. There are zero modes corresponding to spontaneously broken translation, SUSY, and U(1). All broken and unbroken SUSY charges are explicitly worked out in the Wess-Zumino gauge in N=1 superfields as well as in components. The relation to models in five dimensions is also clarified.
We argue that supersymmetry with its well known advantages, such as naturalness, grand unification and dark matter candidate seems to possess one more attractive feature: it may trigger, through its own spontaneous violation in the visible sector, a dynamical generation of gauge fields as massless Nambu-Goldstone modes during which physical Lorentz invariance itself is ultimately preserved. We consider the supersymmetric QED model extended by an arbitrary polynomial potential of massive vector superfield that breaks gauge invariance in the SUSY invariant phase. However, the requirement of vacu…
The vacuum structure of N = 2 linear supersymmetry (LSUSY) invariant QED, which is equivalent to N = 2 nonlinear supersymmetry (NLSUSY) model, is studied explicitly in two dimensional space-time (d = 2). Two different isometries SO(1,3) and SO(3,1) appear for the vacuum field configuration corresponding to the various parameter regions. Two different field configurations of SO(3,1) isometry describe the two different physical vacua, i.e. one breaks spontaneously both U(1) and SUSY and the other breaks spontaneously SUSY alone.
We review gauge invariant $\mathcal N =1$ supersymmetric massive $U(1)$ gauge theory coupled to matter and Stuckelberg superfields. We focus on the leading order self energy and vertex correction to the matter field in the massless limit of both the $U(1)$ vector superfield and the Stuckelberg superfield. We explicitly verify that the theory is infrared divergence free in the massless limit. Hence the Stuckelberg mechanism appears to be the efficient route to handle infrared divergences seen in supersymmetric quantum electrodynamics.Since these additional particles have very small masses they …
We discuss explicitly the details and some remarkable physical consequences of the NL/L SUSY relation between N = 2 LSUSY QED and N = 2 NLSUSY in two-dimensional space-time, which may show the potential of the SUSY composite model for the theory of everything beyond the SM.
It might be expected that only global symmetries are fundamental symmetries of Nature, whereas local symmetries and associated massless gauge fields could solely emerge due to spontaneous breaking of underlying spacetime symmetries involved, such as relativistic invariance and supersymmetry. This breaking, taken in the form of the nonlinear sigma-model type pattern for vector fields or superfields, puts essential restrictions on geometrical degrees of freedom of a physical field system that makes it to adjust itself in such a way that its global internal symmetry G turns into the local symmetr…
We discuss composite representations of new supersymmetry (SUSY) algebra under nonlinear (NL) SUSY transformations in curved space-time from the viewpoint of nonlinear supersymmetric general relativity (NLSUSY GR)/ SGM scenario. We show in the linearization of NLSUSY how various basic fields in linear SUSY theories/supergravity are expressed as functionals in terms of a vierbein and Nambu-Goldstone fermion fundamental fields in NLSUSY GR.
We argue that a generic trigger for photon and other gauge fields to emerge as massless Nambu-Goldstone modes could be spontaneously broken supersymmetry rather than physically manifested Lorentz violation. We consider supersymmetric QED model extended by an arbitrary polynomial potential of vector superfield that induces the spontaneous SUSY violation in the visible sector. As a consequence, massless photon appears as a companion of massless photino being Goldstone fermion state in tree approximation. Remarkably, the photon masslessness appearing at tree level is further protected against rad…
The relation between a N = 2 nonlinear supersymmetric (SUSY) model and a linear SUSY (free) theory for $N = 2$ vector supermultiplet accompanying the spontaneous SUSY breaking is systematically worked out in two-dimensional superfield formulation.
A nonlinear vector supersymmetry for three-dimensional topological massive Yang-Mills is obtained by making use of a nonlinear but local and covariant redefinition of the gauge field.
We study in two space-time dimensions (d = 2) the relation between N = 2 supersymmetric (SUSY) QED theory and N = 2 nonlinear (NL) SUSY model by linearizing N = 2 NLSUSY generally based upon the fundamental notions of the basic theory. We find a remarkable mechanism which determines theoretically the magnitude of the bare gauge coupling constant from the general structure of auxiliary fields. We show explicitly in d = 2 that the NL/linear SUSY relation (i.e. a SUSY compositeness condition for all particles) determines the magnitude of the bare electromagnetic coupling constant (i.e. the fine s…
We show some consequences of the nonlinear supersymmetric general relativity (NLSUSYGR) theory on particle physics, cosmology and their relations. They may give new insights into the SUSY breaking mechanism, dark energy, dark matter and the low enegy superpartner particles which are compatible with the recent LHC data.
BPS lumps in ${\cal N}=2$ SUSY nonlinear sigma models on hyper-\kahler manifolds in four dimensions are studied. We present new lump solutions with various kinds of topological charges. New BPS equations and a new BPS bound, expressed by the three complex structures on hyper-\kahler manifolds, are found. We show that any states satisfying these BPS equations preserve 1/8 (1/4) SUSY of ${\cal N}=2$ SUSY nonlinear sigma models with (without) a potential term. These BPS states include non-parallel multi-(Q-)lumps.
We study the UV properties of the three-dimensional ${\cal N}=4$ SUSY nonlinear sigma model whose target space is $T^*(CP^{N-1})$ (the cotangent bundle of $CP^{N-1}$) to higher orders in the 1/N expansion. We calculate the $β$-function to next-to-leading order and verify that it has no quantum corrections at leading and next-to-leading orders.
We investigate for N = 3 supersymmetry (SUSY) in D = 2 the algebraic relation between the Volkov-Akulov (VA) model of nonlinear (NL) SUSY and a (renormalizable) SO(3) vector supermultiplet of linear (L) SUSY. We derive SUSY and SO(3) invariant relations between component fields of the vector supermultiplet and Nambu-Goldstone (NG) fermions of the VA model at leading orders by using three arbitrary dimensionless parameters which can be recasted as the vacuum expectation values of auxiliary fields in the vector supermultiplet. Two different irreducible representations of SO(3) super-Poincaré sym…
We construct the {\cal N}=4 supersymmetric nonlinear sigma model in three dimensions which can be expanded in 1/N. We evaluate the effective action at leading order in the 1/N expansion and show the finiteness of the model to this order.
We investigate for N = 1 supersymmetry (SUSY) the relation between a scalar supermultiplet of linear SUSY and a nonlinear (NL) SUSY model including apparently pathological higher derivaive terms of a Nambu-Goldstone (N-G) fermion besides the Volkov-Akulov (V-A) action. SUSY invariant relations with higher derivative terms of the N-G fermion, which connect the linear and NL SUSY models, are constructed at leading orders by heuristic arguments. We discuss a higher derivative action of the N-G fermion in the NL SUSY model, which apparently includes a (Weyl) ghost field. By using this relation, we…
We present the basic features of emergent SUSY gauge theories where an emergence of gauge bosons as massless vector Nambu-Goldstone modes is triggered by the spontaneously broken supersymmetry rather than the physically manifested Lorentz violation. We start considering the supersymmetric QED model extended by an arbitrary polynomial potential of massive vector superfield that induces the spontaneous SUSY violation in the visible sector. As a consequence, a massless photon appears as a companion of a massless photino emerging as a goldstino in the tree approximation, and remains massless due t…
The ${\cal N}=1$ SUSY nonlinear sigma models in four spacetime dimensions are studied to obtain BPS walls and junctions. A nonlinear sigma model with a single chiral scalar superfield is found which has a moduli space of the topology of $S^1$ and admits BPS walls and junctions connecting arbitrary points in moduli space. New BPS junction solutions connecting $N$ discrete vacua are also found for nonlinear sigma models with several chiral scalar superfields. More detailed exposition of our results can be found in Ref.\cite{NNS}.
We show explicitly by the heuristic and practical arguments that for $N = 2$ supersymmetry (SUSY) a SUSY invariant relation between component fields of a vector supermultiplet of linear SUSY and Nambu-Goldstone fermions of the Volkov-Akulov model of nonlinear SUSY is written by using only three arbitrary dimensionless parameters, which can be recasted as the vacuum expectation values of auxiliary fields in the vector supermultiplet.
We discuss further the universality of the Volkov-Akulov (V-A) action of a Nambu-Goldstone (N-G) fermion for the spontaneous breaking of supersymmetry (SUSY). We show general relations between the standard V-A action and nonlinear (NL) SUSY actions including apparently (pathological) higher derivatives of the N-G fermion. Composite fields of the N-G fermions are found, which transform homogeneously under NL SUSY transformations of V-A. Consequently, we obtain NL SUSY invariant constraints which connect our NL SUSY actions with the V-A action. The constraints are explicitly solved and we show e…
We systematically compare the N=1 SUSY QED plasma to its non-supersymmetric counterpart which is QED plasma of electrons, positrons and photons. Collective excitations and collisional processes in the two systems are confronted to each other in a regime of small coupling. The collective and collisional characteristics of supersymmetric plasma are both very similar to those of QED plasma.
We point out the possibility that the magnitude of the bare gauge coupling constant is determined theoretically in a composite model of all particles in SUSY theories. We show explicitly in two space-time dimensions that the NL/L SUSY relation (i.e., a SUSY compositeness condition for all particles) between N = 2 LSUSY QED and N = 2 NLSUSY determines the magnitude of the bare electromagnetic coupling constant (i.e., the fine structure constant) of N = 2 LSUSY QED.
We show explicitly in D = 2 that N = 2 nonlinear supersymmetric (SUSY) Volkov-Akulov model is equivalent to a spontaneously broken N = 2 linear SUSY interacting theory containing the ordinary Yukawa interactions and mass terms, which is renormalizable, by using SUSY invariant relations.
The relation between a nonlinear supersymmetic (NLSUSY) theory and a SUSY Yang-Mills (SYM) theory is studied for N = 3 SUSY in two-dimensional space-time. We explicitly show the NL/L SUSY relation for the (pure) SYM theory by means of cancellations among Nambu-Goldstone fermion self-interaction terms.
We investigate for the N = 2 supersymmetry (SUSY) a relation between a vector supermultiplet of the linear SUSY and the Volkov-Akulov model of the nonlinear SUSY. We express component fields of the vector supermultiplet in terms of Nambu-Goldstone fermion fields at the leading orders in a SUSY invariant way, and show the vector nature of the U(1) gauge field explicitly. A relation of the actions for the two models is also discussed briefly.
We focus on a nonlinear supersymmetry (NL SUSY) in curved spacetime introduced in the superon-graviton model (SGM) towards a SUSY composite unified model based on SO(10) super-Poincaré symmetry, and we consider for $N = 1$ SUSY a systematic procedure to linearize the NL SUSY. By introducing modified superspace translations of superspace coordinates and their specific coordinate transformations both depending on a Nambu-Goldstone fermion, we show a homogeneous transformation's law of superfields which is important in the relation between linear (L) and NL SUSY. Furthermore, as a preliminary to …
BPS wall solutions are obtained for N=2 supersymmetric nonlinear sigma model with Eguchi-Hanson target manifold in a manifestly supersymmetric manner. The model is constructed by a massive hyper-Kahler quotient method both in the N=1 superfield and in the N=2 superfield (harmonic superspace). We describe the model in simple terms and give relations between various parameterizations which are useful to describe the model and the solution. Some more details can be found in our previous paper [hep-th/0211103]. This article is dedicated to Professor Hiroshi Ezawa on the occasion of his seventieth …
Auxiliary field methods in D=2 (or 3), N=2 supersymmetric (SUSY) nonlinear sigma models (NLSMs) are studied. For these models auxiliary fields as Lagrange multipliers belong to a vector or a chiral superfield, which gives a Kahler quotient of complexified gauge group or a holomorphic constraint on it, respectively. Using these, NLSMs on all Hermitian symmetric spaces were formulated previously. In this paper, we formulate new SUSY NLSMs on some rank-two Kahler coset spaces as SUSY gauge theories with two Fayet-Iliopoulos parameters.
The limits of linear electrodynamics are reviewed, and possible directions of nonlinear extension are explored. The central theme is that the qualitative character of the empirical successes of quantum electrodynamics must be used as a guide for understanding the nature of the nonlinearity of electrodynamics at the subatomic level. Some established theories of nonlinear electrodynamics, namely, those of Mie, Born, and Infeld are presented in the language of the modern geometrical and topological methods of mathematical physics. The manner by which spacetime curvature and topology can affect el…
We show in two dimensional space-time (d = 2) the relation between a N = 2 nonlinear supersymmetric (NLSUSY) model and a N = 2 linear (L) SUSY Yang-Mills (SYM) theory with matter (N = 2 LSUSY QCD theory). We give a new interpretation of four Nambu-Goldstone fermion (superon) contact terms, which emerge from a N = 2 general SUSY QCD (composite) action, as mass terms for LSUSY supermultiplets and discuss the possible SUSY breaking mechanism in NL/L SUSY relation for SUSY gauge theories in d = 2.
The spontaneous breakdown of 4-dimensional Lorentz invariance in the framework of QED with the nonlinear vector potential constraint A_μ^{2}=M^{2}(where M is a proposed scale of the Lorentz violation) is shown to manifest itself only as some noncovariant gauge choice in the otherwise gauge invariant (and Lorentz invariant) electromagnetic theory. All the contributions to the photon-photon, photon-fermion and fermion-fermion interactions violating the physical Lorentz invariance happen to be exactly cancelled with each other in the manner observed by Nambu a long ago for the simplest tree-order…
BPS walls and junctions are studied in ${\cal N}=1$ SUSY nonlinear sigma models in four spacetime dimensions. New BPS junction solutions connecting N discrete vacua are found for nonlinear sigma models with several chiral scalar superfields. A nonlinear sigma model with a single chiral scalar superfield is also found which has a moduli space of the topology of $S^1$ and admits BPS walls and junctions connecting arbitrary points in moduli space. SUSY condition in nonlinear sigma models are classified either as stationary points of superpotential or singularities of the Kähler metric in field sp…
We give a proof of the equivalence of the electric-magnetic duality on one side and helicity conservation of the tree level amplitudes on the other side within general models of nonlinear electrodynamics. Using modified Feynman rules derived from generalized normal ordered Lagrangian we discuss the interrelation of the above two properties of the theory also at higher loops. As an illustration we present two explicit examples, namely we find the generalized normal ordered Lagrangian for the Born-Infeld theory and derive a semi-closed expression for the Lagrangian of the Bossard-Nicolai model (…
We linearize nonlinear supersymmetry in the Volkov-Akulov (VA) theory for extended SUSY in two dimensional spacetime ($d = 2$) based on the commutator algebra. Linear SUSY transformations of basic component fields for general vector supermultiplets are uniquely determined from variations of functionals (composites) of Nambu-Goldstone (NG) fermions, which are represented as simple products of powers of the NG fermions and a fundamental determinant in the VA theory. The structure of basic component fields with general auxiliary fields in the vector supermultiplets and transitions to $U(1)$ gauge…
A brief overview is given of recent developments and fresh ideas at the intersection of PT and/or CPT-symmetric quantum mechanics with supersymmetric quantum mechanics (SUSY QM). We study the consequences of the assumption that the "charge" operator C is represented in a differential-operator form. Besides the freedom allowed by the Hermiticity constraint for the operator CP, encouraging results are obtained in the second-order case. The integrability of intertwining relations proves to match the closure of nonlinear SUSY algebra. In an illustration, our CPT-symmetric SUSY QM leads to non-Herm…
We focus on a spin-3/2 supersymmetry (SUSY) algebra of Baaklini in D = 3 and explicitly show a nonlinear realization of the SUSY algebra. The unitary representation of the spin-3/2 SUSY algebra is discussed and compared with the ordinary (spin-1/2) SUSY algebra.
We show a low energy physical meaning of nonlinear supersymmetric general relativity (NLSUSY GR) in asymptotic Riemann-flat space-time by studying the vacuum structure of N = 2 linear supersymmetry (LSUSY) invariant QED, which is equivalent to N = 2 NLSUSY model, in two dimensional space-time. Two different vacuum field configurations of SO(3,1) isometry describe the two different physical vacua, i.e. one breaks spontaneously both U(1) and SUSY and the other breaks spontaneously SUSY alone, where the latter elucidates the mysterious relations between the cosmology and the (low energy) particle…
Collisional processes in ultrarelativistic N=1 SUSY QED plasma are studied and compared to those in an electromagnetic plasma of electrons, positrons and photons. Cross sections of all binary interactions which occur in the supersymmetric plasma at the order of e^4 are computed. Some processes, in particular the Compton scattering on selectrons, appear to be independent of momentum transfer and thus they are qualitatively different from processes in an electromagnetic plasma. It suggests that transport properties of the SUSY plasma are different than those of its non-supersymmetric counterpart…
We examine wave propagation and the formation of shocks in strongly magnetized plasmas by applying a variational technique and the method of characteristics to the coupled magnetohydrodynamic (MHD) and quantum-electrodynamic (QED) equations of motion. In sufficiently strong magnetic fields such as those found near neutron stars, not only is the plasma extremely relativistic but the effects of QED must be included to understand processes in the magnetosphere. As Thompson & Blaes [1] find, the fundamental modes in the extreme relativistic limit of MHD coupled with QED are two oppositely directed…
Quantum electrodynamics (QED) fixed in the 't~Hooft-Veltman gauge is renormalized to three loops in the MSbar scheme. The beta-functions and anomalous dimensions are computed as functions of the usual QED coupling and the additional coupling, xi, which is introduced as part of the nonlinear gauge fixing condition. Similar to the maximal abelian gauge of quantum chromodynamics, the renormalization of the gauge parameter is singular.
We study flux tubes on Higgs branches with curved geometry in supersymmetric gauge theories. As a first example we consider N=1 QED with one flavor of charges and with Higgs branch curved by adding a Fayet-Iliopoulos (FI) term. We show that in a generic vacuum on the Higgs branch flux tubes exist but become ``thick''. Their internal structure in the plane orthogonal to the string is determined by ``BPS core'' formed by heavy fields and long range ``tail '' associated with light fields living on the Higgs branch. The string tension is given by the tension of ``BPS core'' plus contribution comin…
Nonlinear (Polynomial, N-fold) SUSY approach to preparation of quantum systems with pre-planned spectral properties is reviewed. The full classification of ladder-reducible and irreducible chains of SUSY algebras in one-dimensional QM is given. Possible extensions of SUSY in one dimension are described. They include (no more than) ${\cal N} =2$ extended SUSY with two nilpotent SUSY charges which generate the hidden symmetry acting as a central charge. Embedding stationary quantum systems into a non-stationary SUSY QM is shown to yield new insight on quantum orbits and on spectrum generating al…
Nonlinear SUSY approach to preparation of quantum systems with pre-planned spectral properties is reviewed. Possible multidimensional extensions of Nonlinear SUSY are described. The full classification of ladder-reducible and irreducible chains of SUSY algebras in one-dimensional QM is given. Emergence of hidden symmetries and spectrum generating algebras is elucidated in the context of Nonlinear SUSY in one- and two-dimensional QM.
We re-examine the perturbative properties of four-dimensional non-commutative QED by extending the pinch techniques to the theta-deformed case. The explicit independence of the pinched gluon self-energy from gauge-fixing parameters, and the absence of unphysical thresholds in the resummed propagators permits a complete check of the optical theorem for the off-shell two-point function. The known anomalous (tachyonic) dispersion relations are recovered within this framework, as well as their improved version in the (softly broken) SUSY case. These applications should be considered as a first ste…
In the relation between the linear (L) supersymmetry (SUSY) representation and the nonlinear (NL) SUSY representation we discuss the role of the Wess-Zumino gauge. We show in two dimensional spacetime that a spontaneously broken LSUSY theory with mass and Yukawa interaction terms for a minimal off-shell vector supermultiplet is obtained from a general superfield without imposing any special gauge conditions in N = 2 NL/L SUSY relation.
We examine a new application of the Holstein-Primakoff realization of the simple harmonic oscillator Hamiltonian. This involves the use of infinite-dimensional representations of the Lie algebra $su(2)$. The representations contain nonstandard raising and lowering operators, which are nonlinearly related to the standard $a^†$ and $a$. The new operators also give rise to a natural family of two-oscillator couplings. These nonlinear couplings are not generally self-adjoint, but their low-energy limits are self-adjoint, exactly solvable, and stable. We discuss the structure of a theory involving …
We discuss the linearization of vector-spinor (spin-3/2) nonlinear supersymmetry (vsNLSUSY) transformations for both $N = 1$ and $N$-extended SUSY in flat spacetime based on the commutator algebra by using functionals (composites) of spin-3/2 Nambu-Goldstone (NG) fermions, which are expressed as simple products of powers of the spin-3/2 NG fermions and a fundamental determinant in the vsNLSUSY theory. We define basic component fields by means of those functionals in a linearized vsSUSY theory including spin-3/2 fields, general auxiliary ones and a $D$-term. The general forms of linear (rigid) …
We consider a simple nonlinear (quartic in the fields) gauge-invariant modification of classical electrodynamics, which possesses a regularizing ability sufficient to make the field energy of a point charge finite. The model is exactly solved in the class of static central-symmetric electric fields. Collation with quantum electrodynamics (QED) results in the total field energy about twice the electron mass. The proof of the finiteness of the field energy is extended to include any polynomial selfinteraction, thereby the one that stems from the truncated expansion of the Euler-Heisenberg local …
We analyze the ground state structure of the supersymmetric sine-Gordon model via the lattice regularization. The nonlinear integral equations are derived for any values of the boundary parameters by the analytic continuation and showed three different forms depending on the boundary parameters. We discuss the state that each set of the nonlinear integral equations characterizes in the absence of source terms. Four different pictures of the ground state are found by numerically studying the positions of zeros in the auxiliary functions. We suggest the existence of two classes in the SUSY sine-…
We show that QED in the Coulomb gauge can be considered as a low energy linear approximation of a non-linear $σ$-type model where the photon emerges as a vector Goldstone boson related to the spontaneous breakdown of Lorentz symmetry down to its spatial rotation subgroup at some high scale $M$. Starting with a general massive vector field theory one naturally arrives at this model if the pure spin-1 value for the vector field $A_μ(x)$ provided by the Lorentz condition $\partial_μA_μ(x)=0$ is required. The model coincides with conventional QED in the Coulomb gauge in the limit of M going to inf…
We examine the behavior of the non-linear interactions between electromagnetic fields at high temperature. It is shown that, in general, the log(T) dependence on the temperature of the Green functions is simply related to their UV behavior at zero-temperature. We argue that the effective action describing the nonlinear thermal electromagnetic interactions has a finite limit as T tends to infinity. This thermal action approaches, in the long wavelength limit, the negative of the corresponding zero-temperature action.
Nonlinear QED interactions induce different polarization properties on a given probe beam. We consider the polarization effects caused by the photon-photon interaction in laser experiments, when a laser beam propagates through a constant magnetic field or collides with another laser beam. We solve the quantum Boltzmann equation within the framework of the Euler-Heisenberg Lagrangian for both time-dependent and constant background field to explore the time evolution of the Stokes parameters Q, U, and V describing polarization. Assuming an initially linearly polarized probe laser beam, we also c…