Article
History & Philosophy Of Science
Charles T. Sebens
Summary: There is debate over whether quantum field theory is based on fields or particles. This article argues for a field approach and presents three advantages over a particle approach. It also highlights two important tasks facing proponents of a field approach.
Article
Physics, Multidisciplinary
Julien Zylberman, Fabrice Debbasch
Summary: Electric Dirac quantum walks, a discretisation of the Dirac equation for spatial searches, use an electric field coupled with a spinor. These walks partially localize on a point charge after a finite time period, but the localization time scales as vN for small N values and asymptotically converges to a constant for larger N, offering a speed-up compared to conventional methods.
Article
Physics, Particles & Fields
Matthias Wollensak
Summary: This research is based on the formal solutions of the Weyl-Dirac equation in anisotropic planar Bianchi-type-I background spacetimes with power law scale factors. It introduces suitable equivalence classes and shows how exact solutions for all models of a given class can be generated through a special parameter transformation, as well as approximate solutions that exhibit correct behavior at early and late times. The method is explicitly demonstrated for the case of anisotropic Kasner background with axial symmetry.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
Ismail Burak Ates, Senguel Kuru, Javier Negro
Summary: This paper proposes a simple method to obtain analytical solutions of the Dirac-Weyl equation for low energy electrons in graphene under certain electric and magnetic fields, with the assistance of a few numerical calculations. By assuming a displacement symmetry and applying certain conditions on the magnetic and electric fields, the resulting equations can be decoupled and expressed in a form suitable for the technique of supersymmetric quantum mechanics. The example of an electric well with a square profile is worked out in detail to illustrate some interesting features of this method.
Article
Physics, Particles & Fields
Marija Dimitrijevic Ciric, Nikola Konjik, Andjelo Samsarov
Summary: This paper establishes another example of the implicit duality within the structure of noncommutative (NC) theories through perturbation in the first order of the Seiberg-Witten expansion. The model studied relates a noncommutative U(1)(*) gauge field to a noncommutative scalar field and to a classical Reissner-Nordstrom (RN) geometry, and it is shown to be completely equivalent to the commutative U(1) gauge theory coupled to a commutative scalar field and a classical geometry. The results obtained contribute to a deeper understanding of the dynamics of spin 1/2 fields on curved backgrounds with a persistent noncommutative structure.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
History & Philosophy Of Science
Charles T. Sebens
Summary: This article compares the treatments of the Stern-Gerlach experiment in different physical theories, leading to a novel analysis of electron spin measurement within classical Dirac field theory. It discusses how classical Dirac field theory can explain uniqueness and discreteness of electron spin measurements, as well as the limitations of other theories in explaining these features.
Article
Physics, Condensed Matter
Hasna Chnafa, Miloud Mekkaoui, Ahmed Jellal, Abdelhadi Bahaoui
Summary: This study investigates the impact of energy gap on the transmission of fermions in graphene exposed to linearly polarized light as a laser barrier. The research examines the energy spectrum, applies boundary conditions at interfaces, and utilizes the transfer matrix approach to determine transmissions for all energy modes. Results demonstrate that as the energy gap increases, the oscillations of transmissions dramatically decrease until they disappear completely. However, varying the barrier width leads to more significant oscillations with sharp peaks. Additionally, increasing incident energy allows the laser field to suppress Fabry-Perot resonance and shift transmissions to the right when the energy gap is adjusted.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Physics, Multidisciplinary
Y. Concha-Sanchez, E. Diaz-Bautista, A. Raya
Summary: In this study, we construct the exact propagator for Dirac fermions in graphene-like systems immersed in external static magnetic fields with non-trivial spatial dependence. By using a first-order supersymmetric framework and the Ritus eigenfunctions, we are able to express the propagator in a diagonal form in momentum space and expand the number of magnetic field profiles in which the fermion propagator can be expressed in a closed-form. The obtained electric charge and current densities are compared with findings from other methods.
Article
Physics, Multidisciplinary
Stefano Gogioso, Maria E. Stasinou, Bob Coecke
Summary: The paper introduces a compositional algebraic framework to describe the evolution of quantum fields in discretised spacetimes, recovering familiar notions from Relativity and quantum causality purely through the causal order of events. By formulating theory-independent notions of fields and introducing concepts of symmetry and cellular automata, the framework shows potential for new developments in Algebraic Quantum Field Theory, Quantum Cellular Automata, and Quantum Field Theory in general.
FRONTIERS IN PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Francois Fillion-Gourdeau, Emmanuel Lorin, Steve MacLean
Summary: This article models the dynamics of low-energy electrons in general static strained graphene surface using the Dirac equation in curved space-time. Two strategies are introduced to simplify the problem: diagonal metric approximation and change of variables to isothermal coordinates. It is shown that electron wave packets can be focused by local strained regions on Gaussian shaped graphene surface deformations.
Article
Physics, Multidisciplinary
J. W. Moffat
Summary: The boson and fermion particle masses are calculated in a finite quantum field theory, which satisfies certain conditions and uses finite self-energy graphs for mass calculation. The predicted mass of the W boson is determined under a regulating mass scale parameter, and higher order corrections are suppressed for the Higgs boson mass.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Physics, Multidisciplinary
Gregg Jaeger
Summary: The elementary particles in relativistic quantum field theory are not simple field quanta, but rather a supplement to quantum fields, providing consistency and unity between particle physics practice and its basis in quantum field theory.
Article
Physics, Multidisciplinary
Z. Bentalha
Summary: The (2+1)-dimensional Dirac equation for an electron in a constant magnetic field is examined, and exact solutions and energy spectrum of the equation are derived. It is found that the lowest Landau level wavefunction corresponds to a negative energy anti-electron, which arises due to the existence of negative energy solutions allowed by special relativity.
Article
Materials Science, Multidisciplinary
Pablo A. Morales, Patrick Copinger
Summary: The massless Dirac equation is studied in curved space-time on the (2+1)-dimensional graphene sheet in time-dependent geometries. Emergent pseudogauge fields are found in both the adiabatic and nonadiabatic regimes, extending the conventional understanding of homogeneous pseudogauge fields to include temporal inhomogeneities. By utilizing Floquet theory, a new class of emergent pseudogauge fields is identified, potentially providing a condensed matter realization of cosmological high-frequency geometries.
Article
Astronomy & Astrophysics
Matthias Diez, Reinhard Alkofer, Christian Kohlfuerst
Summary: Particle production by ultra-strong electric fields is a well-studied research field, but the formation time of a particle remains mysterious. In this study, we provide an interpretation of a particle distribution at finite times and identify the relevant time scales for particle formation in quantum physics within and beyond perturbation theory.
Article
Physics, Multidisciplinary
M. Bordag
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2020)
Article
Astronomy & Astrophysics
M. Bordag
MODERN PHYSICS LETTERS A
(2020)
Article
Astronomy & Astrophysics
J. M. Munoz-Castaneda, M. Bordag, L. Santamaria-Sanz
MODERN PHYSICS LETTERS A
(2020)
Article
Physics, Particles & Fields
M. Bordag, J. M. Munoz-Castaneda, L. Santamaria-Sanz
EUROPEAN PHYSICAL JOURNAL C
(2020)
Article
Physics, Multidisciplinary
M. Bordag
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2020)
Article
Astronomy & Astrophysics
Michael Bordag
Summary: The vacuum energy of a scalar field with phi(4) self-interaction in (1 + 1) dimensions was calculated non-perturbatively, considering both massive and massless fields under different boundary conditions. The results showed that for strong coupling, the vacuum energy is negative, indicating potential instability.
Article
Physics, Particles & Fields
M. Bordag, V Skalozub
Summary: In this paper, the spontaneous generation of the A(0)-background field in QCD at finite temperature and a quark chemical potential is studied, considering real and imaginary chemical potential analytically within the two-loop gauge-fixing independent effective potential. Gauge independence is realized through Nielsen's identity and expressing the potential in terms of Polyakov's loop. The study shows that the chemical potential weakly changes the values of the condensate fields, but significantly deepens the minima of the effective potential.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Review
Multidisciplinary Sciences
Michael Bordag
Summary: This article reviews the instabilities that arise from the coupling of spin-one fields to a magnetic background in a non-Abelian theory. The coupling contributes to the effective potential due to asymptotic freedom in a negative quantum. The Savvidy vacuum emerges in QCD, but its instability caused by the tachyonic mode leaves the true ground state of QCD still open. In the electroweak model, the corresponding instability is postponed to very large background fields and may be relevant in the early universe.
Article
Physics, Nuclear
M. Bordag
Summary: In this paper, the issue of chromomagnetic vacuum in SU(2) is studied, revealing a minimum below zero in the effective Lagrangian in the one-loop approximation, leading to the spontaneous generation of a magnetic field. However, this minimum is unstable due to the presence of an imaginary part in the effective action. Numerous attempts have been made to address this issue, all of which have been unsatisfactory to some extent. A new solution is proposed by considering the condensate formation of the tachyonic mode at low temperature, resulting in a phase transition similar to the Higgs model. The approximation with only the tachyonic mode and an O(2)-model with quartic self-interaction in two dimensions is considered. The CJT (2PI) formalism in Hartree approximation is applied, revealing a minimum of the effective action at a certain value of the condensate and background fields at zero and low temperatures, with no imaginary part. As the temperature increases, this minimum becomes shallower, and at a critical temperature, the perturbative state with lower effective potential becomes dominant, restoring the symmetry. The physically interpreted mechanism states that the unstable mode creates tachyons until they reach equilibrium through repulsive self-interactions and form a condensate. The relation to the Mermin-Wagner theorem is discussed.
EUROPEAN PHYSICAL JOURNAL A
(2023)
Article
Physics, Particles & Fields
M. Bordag, V Skalozub
Summary: This paper investigates the behavior of the effective action or free energy in SU(2) gluodynamics at finite temperature, when both A(0) background and magnetic background are present. The results show that the imaginary part is still present at the two-loop level, and the real part exhibits an unnatural singularity in the region where the imaginary part sets in.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Materials Science, Multidisciplinary
M. Bordag, I Fialkovsky, N. Khusnutdinov, D. Vassilevich
Summary: Bulk polarization tensor and dielectric functions for Dirac materials are computed using quantum field theory methods in the presence of a mass gap, chemical potential, and finite temperature. The characteristic features of dielectric functions and their influence on Casimir pressure in Dirac materials are described in detail.
Article
Materials Science, Multidisciplinary
Mauro Antezza, Ignat Fialkovsky, Nail Khusnutdinov
Article
Physics, Mathematical
Ignat Fialkovsky, Maria Perel
JOURNAL OF MATHEMATICAL PHYSICS
(2020)
Article
Astronomy & Astrophysics
I. Fialkovsky, M. Kurkov, D. Vassilevich
