Schwinger Mechanism Research Articles

Catastrophic emission of charges from near-extremal Nariai black holes

Using both the in-out formalism and the monodromy method, we study the emission of charges from near-extremal charged Nariai black holes with the black hole event and cosmological horizons close to each other, whose near-horizon geometry is dS2×S2. The emission becomes catastrophic for a charge with energy greater than its chemical potential, whose leading exponential factor increases inversely proportional to the separation of two horizons. This effect may prevent near-extremal Nariai black holes with large charges that evaporate dominantly through the charge emission from evolving to black holes with a naked singularity, in analog to near-extremal RN-dS black holes that have the Breitenlohner-Friedman bound, below which they become stable against Hawking radiation and Schwinger effect of charge emission. The near-extremal Nariai black holes with small charges, which are close to near-extremal Schwarzschild-de Sitter black holes, emit dominantly charge-neutral particles and evolve to black holes with increasing charge to mass ratio. We illuminate the origin of the catastrophic emission in the phase-integral formulation and monodromy method by comparing near-extremal charged Nariai black holes with near-extremal Reissner-Nordtröm-dS black holes. Published by the American Physical Society 2024

Schwinger vs Unruh (Mini-review)

It is shown that the temperatures which characterise the Unruh effect, the Gibbons-Hawking radiation from the de Sitter cosmological horizon and the Hawking radiation from the black hole horizon acquire the extra factor 2 compared with their traditional values. The reason for that is the coherence of different processes. The combination of the coherent processes also allows us to make the connection between the Schwinger pair production and the Unruh effect.

Roles of electric field/time-dependent Wilson line in toroidal compactification with or without magnetic fluxes

We discuss the effects of electric fields along compact directions within (supersymmetric) gauge theory in ℝ1,3×T2×T2×T2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\mathbb{R}}^{1,3}\ imes {\\mathbbm{T}}^2\\left(\ imes {\\mathbbm{T}}^2\ imes {\\mathbbm{T}}^2\\right) $$\\end{document}. The electric field along compact directions is equivalent to time-dependent homogeneous configuration of Wilson line moduli, which would be relevant to physics in the early universe. In particular, we consider models with and without background magnetic fluxes, which lead to completely different effects of the electric field due to the difference in the Kaluza-Klein (KK) level structure. We show that, in the case without magnetic fluxes, the deceleration of KK momenta may cause non-perturbative KK particle production dubbed as the KK Schwinger effect, whereas in the case with magnetic flux such KK particle production does not take place but flavor structure of low energy effective theory may be affected.

Schwinger dark matter production

Building on recently constructed inflationary vector dark matter production mechanisms as well as studies of magnetogenesis, we show that an inflationary dark Schwinger mechanism can generate the observed dark matter relic abundance for `dark electron' masses as light as ∼ 0.1 eV and as heavy as 1012 GeV. The dark matter can interact very weakly via the exchange of light dark photons with a power spectrum which is peaked at very small scales, thus evading isocurvature constraints. This mechanism is viable even when (purely) gravitational particle production is negligible. Thus dark matter can be produced solely via the Schwinger effect during inflation including for light masses.

The Schwinger pair production method in the framework of non-commutative phase space coordinates and its applications

In noncommutative phase space (NCPS), we investigate the pair creation rate for the problem of scalar and spinorial particles emerging from a vacuum under the influence of uniform external electromagnetic fields using the Schwinger formal technique. It is demonstrated that under specific conditions, where the speed of light c approaches the Fermi velocity [Formula: see text] and [Formula: see text] (with [Formula: see text] representing the cyclotron frequency), the behavior of the Dirac oscillator problem in a uniform electromagnetic field within NCPS is akin to the monolayer graphene problem in NCPS. In addition, the production probability per unit volume per unit time is discussed, along with the limits of parameter deformations.

Quantum metrology of Schwinger effect

We propose a scheme for the quantum metrology of the Schwinger effect and the dynamics of Gaussian interference power (GIP). The ongoing reliability of the estimation strategy for the probe state prepared in particle–particle modes is demonstrated. Although the GIP sensitively depends on the strength of the external electric field and the transverse momentum, the advantage of quantum parameter estimation is still maintained even in the limit of an infinite electric field and zero transverse momentum. It is shown that the entanglement between the particle–particle modes provides a guarantee for obtaining higher precision for the black-box estimation. In contrast, for the probe state prepared in particle–antiparticle modes, the advantage of quantum parameter estimation can also be ensured even though there is no entanglement in the probe state. Put differently, some non-entanglement quantum correlations play the role of quantum resources in the estimation for particle–antiparticle modes.

Band structure for relativistic charged particles immersed in a structurally chiral electromagnetic field

In this paper, we determine the band structure of an electromagnetic space-time crystal. We construct a coordinate transformation in which the matrix elements of the Dirac equation are constant. Consequently, their corresponding band structure is recovered analytically. The band structure is fragmented into three different energy regions. In the center, there is a region prohibited for all particles (universal band gap), which is symmetrically enveloped by two energy regions of the same width. These regions allow the passage of particles with a specific spin (discriminatory band gaps). Furthermore, we demonstrate that, through the appropriate combination of the refractive index, the length of the electromagnetic wave, and the amplitude of the electric field, it is possible to shorten the bandwidth of the universal gap and replace it with a discriminatory band gap. In that sense, the proposed system constitutes an alternative procedure to observe the Schwinger mechanism experimentally.

Nonlinear Schwinger mechanism in QCD, and Fredholm alternatives theorem

We present a novel implementation of the Schwinger mechanism in QCD, which fixes uniquely the scale of the effective gluon mass scale and streamlines considerably the procedure of multiplicative renormalization. The key advantage of this method stems from the nonlinear nature of the dynamical equation that generates massless poles in the longitudinal sector of the three-gluon vertex. An exceptional feature of this approach is an extensive cancellation involving the components of the integral expression that determines the gluon mass scale; it is triggered once the Schwinger–Dyson equation of the pole-free part of the three-gluon vertex has been appropriately exploited. It turns out that this cancellation is driven by the so-called Fredholm alternatives theorem, which operates among the set of integral equations describing this system. Quite remarkably, in the linearized approximation this theorem enforces the exact masslessness of the gluon. Instead, the nonlinearity induced by the full treatment of the relevant kernel evades this theorem, allowing for the emergence of a nonvanishing mass scale. The numerical results obtained from the resulting equations are compatible with the lattice findings, and may be further refined through the inclusion of the remaining fundamental vertices of the theory.

MoEDAL Search in the CMS Beam Pipe for Magnetic Monopoles Produced via the Schwinger Effect.

We report on a search for magnetic monopoles (MMs) produced in ultraperipheral Pb-Pb collisions during Run 1 of the LHC. The beam pipe surrounding the interaction region of the CMS experiment was exposed to 184.07 μb^{-1} of Pb-Pb collisions at 2.76TeV center-of-mass energy per collision in December 2011, before being removed in 2013. It was scanned by the MoEDAL experiment using a SQUID magnetometer to search for trapped MMs. No MM signal was observed. The two distinctive features of this search are the use of a trapping volume very close to the collision point and ultrahigh magnetic fields generated during the heavy-ion run that could produce MMs via the Schwinger effect. These two advantages allowed setting the first reliable, world-leading mass limits on MMs with high magnetic charge. In particular, the established limits are the strongest available in the range between 2 and 45 Dirac units, excluding MMs with masses of up to 80GeV at a 95% confidence level.

Kaluza–Klein Schwinger Effect

Abstract We show that electric fields in compactified spaces may produce Kaluza–Klein (KK) particles even when the energy of the electric fields is smaller than the KK scale. As an illustrative example, we consider a charged massless complex scalar coupled to U(1) gauge theory in $\mathbb {R}^{1,3}\times {\mathbb {S}}^1$ and discuss the effect of background gauge potential along a compact direction. The electric field produces the charged KK particle nonperturbatively, which we call the KK Schwinger effect. We quantitatively show that KK modes can be produced even when the electric field energy is far below the KK scale. The mechanism is rather general and similar phenomena would occur in any compactification models when a gauge potential along a compact direction evolves in time and experiences a large enough field excursion. We also discuss the subtlety of 4D effective theory truncated by KK modes at an initial time, when the electric field is turned on.

Evaporation of Primordial Charged Black Holes: Timescale and Evolution of Thermodynamic Parameters

The evolution of primordial black holes formed during the reheating phase is revisited. For reheating temperatures in the range of 1012–1013 GeV, the initial masses are respectively of the order of 1010–108MP, where MP is the Planck mass. These newborn black holes have a small charge-to-mass ratio of the order of 10−3, a consequence of statistical fluctuations present in the plasma constituting the collapsing matter. Charged black holes can be rapidly discharged by the Schwinger mechanism, but one expects that, for very light black holes satisfying the condition M/MP<<MP/mW (mW is the mass of the heaviest standard model charged W-boson), the pair production process is probably strongly quenched. Under these conditions, these black holes evaporate until attaining extremality with final masses of about 107–105MP. Timescales to reach extremality as a function of the initial charge excess were computed, as well as the evolution of the horizon temperature and the charge-to-mass ratio. The behavior of the horizon temperature can be understood in terms of the well-known discontinuity present in the heat capacity for a critical charge-to-mass ratio Q/GM=3/2.

Nonextensivity and temperature fluctuations of the Higgs boson production

We determine the temperature fluctuations associated with the Higgs boson pT spectrum through the derivation of the string tension distribution corresponding to the QCD-based Hagedorn function, frequently used to fit the transverse momentum distribution (TMD). The identified string tension fluctuations are heavy tailed, behaving similarly to the q-Gaussian distribution. After the convolution with the Schwinger mechanism, both approaches correctly describe the entire TMD. This approach leads to the nonthermal description of the particle production in ultrarelativistic pp collisions. By analyzing the data of pp collisions at s=13 TeV, we found that the average temperature associated with the Higgs boson differential cross section is around 85 times greater than the estimated value for the charged particle TMD. Our results show that the Higgs boson production exhibits the largest deviation from the thermal description. Published by the American Physical Society 2024

Complete analysis of the Landau-gauge three-gluon vertex from lattice QCD

Several continuum and lattice investigations of the QCD three-gluon vertex have recently exposed its key properties, some intimately connected with the low-momentum behavior of the two-point gluon Green’s function and especially relevant for the emergence of a mass scale in this latter, via the Schwinger mechanism. In the present study, we report on a lattice determination of the Landau-gauge, transversely projected three-gluon vertex, particularly scrutinizing an outstanding one of these properties, termed , exploring its implications and capitalizing on it to gain further insight on the low-momentum running of both the three-gluon vertex and its associated strong coupling. Published by the American Physical Society 2024

Schwinger mechanism of magnon-antimagnon pair production on magnetic field inhomogeneities and the bosonic Klein effect

Schwinger mechanism of magnon-antimagnon pair production on magnetic field inhomogeneities and the bosonic Klein effect

Hidden conformal symmetry and Schwinger effect in extremal magnetized Kerr black holes

This paper explores the near-extremal and extremal magnetized Kerr black hole, revealing the Schwinger effect in the absorption cross section at the spacetime's extremal limit. The agreement with CFT2 hints at hidden conformal symmetry. The analysis uncovers SL(2,R)L×SL(2,R)R symmetry for the massless scalar near the black hole, suggesting the Kerr/CFT correspondence for the magnetized Kerr black holes. Cardy formula of the conformal field theory is used to reproduce the black hole entropy in both extremal and near-extremal cases.

Holographic Schwinger effect with higher derivative corrections in presence of string cloud

Holographic Schwinger effect with higher derivative corrections in presence of string cloud

Gluon mass generation from renormalons and resurgence

We establish a link between the concepts of infrared renormalons, infrared fixed point, and dynamical nonperturbative mass generation of gluons in pure Yang-Mills theories. By utilizing recent results in the resurgent analysis of renormalons through non-linear ordinary differential equations, we develop a new description for the gluon propagator, thereby realizing the Schwinger mechanism. Specifically, this approach leads to a nonperturbative, dynamic mass generation for Yang-Mills gauge bosons in the deep infrared region, a phenomenon closely associated with color confinement. Furthermore, we present arguments about the limit of applicability of the Borel-Ecalle resummation of the renormalons by comparing it with the Kallen-Lehman representation of the gluon propagator.

Resummed heat kernel and effective action for Yukawa and QED

In this letter, we prove the existence of resummed expressions for the diagonal of the heat kernel and the effective action of a quantum field which interacts with a scalar or an electromagnetic background. Working in an arbitrary number of spacetime dimensions, we propose an Ansatz beyond the Schwinger–DeWitt proposal, effectively resumming an infinite number of invariants which can be constructed from powers of the background, as well as its first and second derivatives in the Yukawa case. This provides a proof of the recent conjecture that all terms containing the invariants FμνFμν and F˜μνFμν in the proper-time series expansion of the SQED effective action can be resummed. Possible generalizations and several applications are also discussed—in particular, the existence of an analogue of the Schwinger effect for Yukawa couplings.

Spinning pairs: Supporting P03 quark-pair creation from Landau-gauge Green’s functions

Abundant phenomenology suggests that strong decays from relatively low-excitation hadrons into other hadrons proceed by the creation of a light quark-antiquark pair with zero total angular momentum, the so called P03 mechanism originating from a scalar bilinear. Yet the quantum chromodynamics (QCD) interaction is perturbatively mediated by gluons of spin one, and QCD presents a chirally symmetric Lagrangian. Such scalar decay term must be spontaneously generated upon breaking chiral symmetry. We attempt to reproduce this with the help of the quark-gluon vertex in Landau gauge, whose nonperturbative structure has been reasonably elucidated in the last years, and insertions of a uniform, constant chromoelectric field. This is akin to Schwinger pair production in quantum electrodynamics (QED), and we provide a comparison with its two field-insertions diagram. We find that, the symmetry being cylindrical, the adequate quantum numbers to discuss the production are rather Σ30, Σ31, and Π30 as in diatomic molecules, and we indeed find a sizeable contribution of the third decay mechanism, which may give a rationale for the P03 phenomenology, as long as the momentum of the produced pair is at or below the scale of the bare or dynamically generated fermion mass. On the other hand, ultrarelativistic fermions are rather ejected with Σ31 quantum numbers. In QED, our results suggest that Σ30 dominates, whereas the constraint of producing a color singlet in QCD leads to Π30 dominance at sub-GeV momenta. Published by the American Physical Society 2024

Entropy and heat capacity of the transverse momentum distribution for pp collisions at RHIC and LHC energies

We investigate the transverse momentum distribution (TMD) statistics from three different theoretical approaches. In particular, we explore the framework used for string models, wherein the particle production is given by the Schwinger mechanism. The thermal distribution arises from the Gaussian fluctuations of the string tension. The hard part of the TMD can be reproduced by considering heavy tailed string tension fluctuations, for instance, the Tsallis q-Gaussian function, giving rise to a confluent hypergeometric function that fits the entire experimental TMD data. We also discuss the QCD-based Hagerdon function, another family of fitting functions frequently used to describe the spectrum. We analyze the experimental data of minimum bias pp collisions reported by the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) experiments (from s=0.2 TeV to s=13 TeV). We extracted the corresponding temperature by studying the behavior of the spectra at low transverse momentum values. For the three approaches, we compute all moments, highlighting the average, variance, and kurtosis. Finally, we compute the Shannon entropy and the heat capacity through the entropy derivative with respect to the temperature. We found that the q-Gaussian string tension fluctuations lead to a monotonically increasing heat capacity as a function of the center-of-mass energy, which is also observed for the Hagedorn fitting function. This behavior is consistent with the experimental observation that the temperature slowly rises with increments of the collision energy. Published by the American Physical Society 2024