Temporal Klein Model for Particle-Pair Creation

This work considers the creation of electron-positron pairs from intense electric fields in vacuum, for arbitrary temporal field variations. These processes can be useful to study quantum vacuum effects with ultra-intense lasers. We use the quantized Dirac field to explore the temporal Klein model. This model is based on a vector potential discontinuity in time, in contrast with the traditional model based on a scalar potential discontinuity in space. We also extend the model by introducing a finite time-scale for potential variations. This allows us to study the transition from a singular electric field spike, with infinitesimal duration, to the opposite case of a static field where the Schwinger formula would apply. The present results are intrinsically non-perturbative. Explicit expressions for pair-creation as a function of the potential time-scales are derived. This work explores the spacetime symmetry associated with pair creation in vacuum: the space symmetry breaking of the old Klein paradox model, in contrast with the time symmetry breaking of the temporal Klein model.

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Vacuum polarization and particle creation in the presence of a potential step

International Journal of Modern Physics A ◽

10.1142/s0217751x16410311 ◽

2016 ◽

Vol 31 (02n03) ◽

pp. 1641031 ◽

Cited By ~ 2

Author(s):

S. P. Gavrilov ◽

D. M. Gitman

Keyword(s):

Electric Potential ◽

Canonical Quantization ◽

Particle Creation ◽

Pair Creation ◽

Dirac Field ◽

Potential Step ◽

Electron Positron ◽

Physical Impact ◽

Particle Interpretation ◽

Electron Positron Pair

We consider QED with strong external backgrounds that are concentrated in restricted space areas. The latter backgrounds represent a kind of spatial x-electric potential steps for charged particles. They can create particles from the vacuum, the Klein paradox being closely related to this process. We describe a canonical quantization of the Dirac field with x-electric potential step in terms of adequate in- and out-creation and annihilation operators that allow one to have consistent particle interpretation of the physical system under consideration and develop a nonperturbative (in the external field) technics to calculate scattering, reflection, and electron-positron pair creation. We resume the physical impact of this development.

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Electron-positron pair creation in the electric fields generated by micro-bubble implosions

Physics Letters A ◽

10.1016/j.physleta.2020.126854 ◽

2020 ◽

Vol 384 (34) ◽

pp. 126854

Author(s):

James K. Koga ◽

Masakatsu Murakami ◽

Alexey V. Arefiev ◽

Yoshihide Nakamiya ◽

Stepan S. Bulanov ◽

...

Keyword(s):

Electric Fields ◽

Pair Creation ◽

Electron Positron ◽

Micro Bubble ◽

Electron Positron Pair

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Optimization of spatially localized electric fields for electron-positron pair creation

Physical Review A ◽

10.1103/physreva.96.032120 ◽

2017 ◽

Vol 96 (3) ◽

Cited By ~ 8

Author(s):

S. S. Dong ◽

M. Chen ◽

Q. Su ◽

R. Grobe

Keyword(s):

Electric Fields ◽

Pair Creation ◽

Electron Positron ◽

Electron Positron Pair

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Harmonic hybrid inflation

Journal of High Energy Physics ◽

10.1007/jhep12(2020)161 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

Federico Carta ◽

Nicole Righi ◽

Yvette Welling ◽

Alexander Westphal

Keyword(s):

Domain Wall ◽

Symmetry Breaking ◽

Initial Conditions ◽

Scalar Potential ◽

Field Range ◽

Slow Roll ◽

Minimal Form ◽

Wide Range ◽

Hybrid Inflation ◽

Type Iib String Theory

Abstract We present a mechanism for realizing hybrid inflation using two axion fields with a purely non-perturbatively generated scalar potential. The structure of the scalar potential is highly constrained by the discrete shift symmetries of the axions. We show that harmonic hybrid inflation generates observationally viable slow-roll inflation for a wide range of initial conditions. This is possible while accommodating certain UV arguments favoring constraints f ≲ MP and ∆ϕ60 ≲ MP on the axion periodicity and slow-roll field range, respectively. We discuss controlled ℤ2-symmetry breaking of the adjacent axion vacua as a means of avoiding cosmological domain wall problems. Including a minimal form of ℤ2-symmetry breaking into the minimally tuned setup leads to a prediction of primordial tensor modes with the tensor-to-scalar ratio in the range 10−4 ≲ r ≲ 0.01, directly accessible to upcoming CMB observations. Finally, we outline several avenues towards realizing harmonic hybrid inflation in type IIB string theory.

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Electron Symmetry Breaking during Attosecond Charge Migration Induced by Laser Pulses: Point Group Analyses for Quantum Dynamics

Symmetry ◽

10.3390/sym13020205 ◽

2021 ◽

Vol 13 (2) ◽

pp. 205

Author(s):

Dietrich Haase ◽

Gunter Hermann ◽

Jörn Manz ◽

Vincent Pohl ◽

Jean Christophe Tremblay

Keyword(s):

Laser Pulse ◽

Symmetry Breaking ◽

Electric Fields ◽

Quantum Dynamics ◽

Point Group ◽

Laser Pulses ◽

Charge Migration ◽

Laser Control ◽

The One ◽

Superposition States

Quantum simulations of the electron dynamics of oriented benzene and Mg-porphyrin driven by short (<10 fs) laser pulses yield electron symmetry breaking during attosecond charge migration. Nuclear motions are negligible on this time domain, i.e., the point group symmetries G = D6h and D4h of the nuclear scaffolds are conserved. At the same time, the symmetries of the one-electron densities are broken, however, to specific subgroups of G for the excited superposition states. These subgroups depend on the polarization and on the electric fields of the laser pulses. They can be determined either by inspection of the symmetry elements of the one-electron density which represents charge migration after the laser pulse, or by a new and more efficient group-theoretical approach. The results agree perfectly with each other. They suggest laser control of symmetry breaking. The choice of the target subgroup is restricted, however, by a new theorem, i.e., it must contain the symmetry group of the time-dependent electronic Hamiltonian of the oriented molecule interacting with the laser pulse(s). This theorem can also be applied to confirm or to falsify complementary suggestions of electron symmetry breaking by laser pulses.

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Quantum Zeno effects across a parity-time symmetry breaking transition in atomic momentum space

npj Quantum Information ◽

10.1038/s41534-021-00417-y ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Tao Chen ◽

Wei Gou ◽

Dizhou Xie ◽

Teng Xiao ◽

Wei Yi ◽

...

Keyword(s):

Symmetry Breaking ◽

State Of The Art ◽

Cold Atom ◽

Pt Symmetry ◽

Level System ◽

Flexible Control ◽

Time Symmetry ◽

Symmetry Phase ◽

Lattice Quantum ◽

Atomic Momentum

AbstractWe experimentally study quantum Zeno effects in a parity-time (PT) symmetric cold atom gas periodically coupled to a reservoir. Based on the state-of-the-art control of inter-site couplings of atoms in a momentum lattice, we implement a synthetic two-level system with passive PT symmetry over two lattice sites, where an effective dissipation is introduced through repeated couplings to the rest of the lattice. Quantum Zeno (anti-Zeno) effects manifest in our experiment as the overall dissipation of the two-level system becoming suppressed (enhanced) with increasing coupling intensity or frequency. We demonstrate that quantum Zeno regimes exist in the broken PT symmetry phase, and are bounded by exceptional points separating the PT symmetric and PT broken phases, as well as by a discrete set of critical coupling frequencies. Our experiment establishes the connection between PT-symmetry-breaking transitions and quantum Zeno effects, and is extendable to higher dimensions or to interacting regimes, thanks to the flexible control with atoms in a momentum lattice.

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