Study of spin states in vacuum pair production via the Dirac-Heisenberg-Wigner formalism

• URL: http://arxiv.org/abs/2510.00455v1
• Date: Wed, 01 Oct 2025 03:08:02 GMT
• Title: Study of spin states in vacuum pair production via the Dirac-Heisenberg-Wigner formalism
• Authors: R. Z. Jiang, Z. L. Li, Y. J. Li,
• Abstract summary: A general spin-resolved momentum distribution of electron-positron pairs produced in strong external fields is derived.<n>The result shows that the spin-resolved and helicity-resolved momentum distributions given in previous literature are actually two special cases of it.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: A general spin-resolved momentum distribution of electron-positron pairs produced in strong external fields is derived by combining the covariant spin projection operator and the Dirac-Heisenberg-Wigner (DHW) formalism. The result shows that the spin-resolved and helicity-resolved momentum distributions given in previous literature are actually two special cases of it. For any spin-direction unit vector, numerical investigations demonstrate that when the $z$-component of the unit vector vanishes, the number density of produced spin-up and spin-down particles is equal, while their momentum distributions have some asymmetry. For a nonzero $z$-component of the unit vector, there is a difference of $1-3$ orders of magnitude in the number density of spin-up and spin-down particles induced by angular momentum transfer in multiphoton absorption. Moreover, as the electric field strength increases and/or the field frequency decreases, the asymmetry between the spin-up and spin-down particle number density decreases rapidly. These results offer an approach to study general spin states in vacuum pair production, and enhance our understanding of angular momentum transfer from fields to matter in extreme environments.

Related papers

• An integrated neural wavefunction solver for spinful Fermi systems [41.99844472131922]
  We present an approach to solving the ground state of Fermi systems that contain spin or other discrete degrees of freedom in addition to continuous coordinates.<n>A transformer achieves both continuous position and discrete spin as inputs universal approximation to spinful generalized orbitals.<n>We validate the method on a range of two-dimensional material problems.
  arXiv  Detail & Related papers  (2025-10-21T13:20:31Z)
• Spin Squeezing via One-Axis Twisting in a Quadrupolar NMR system under relaxation effects [0.0]
  The origin of spin squeezing is attributed to the interaction between the nuclear quadrupole moment and the electric field gradients in the molecular environment.<n>Non-Cartesian angular momentum operators are proposed, with their variances catching the quantum effects during the dynamics.<n>An upper bound for the squeezing parameter and the Heisenberg uncertainty at thermal equilibrium are also predicted for any spin quantum number.
  arXiv  Detail & Related papers  (2025-04-08T16:47:41Z)
• Harnessing Chiral Spin States in Molecular Nanomagnets for Quantum Technologies [44.1973928137492]
  We show that chiral qubits naturally suppress always-on interactions that can not be switched off in weakly coupled qubits.<n>Our findings establish spin chirality engineering as a promising strategy for mitigating always-on interaction in entangling two chiral qubits in molecular quantum technologies.
  arXiv  Detail & Related papers  (2025-01-21T08:23:12Z)
• Spin Effect induced Momentum Spiral and Asymmetry Degree in Pair Production [0.361593752383807]
  We find for the first time that spirals can also be induced due to the particles spin effect even if in a single field. Spin asymmetry degree on the momentum distributions is investigated and found that there exist the effect of spin flip with increasing time delay between two fields.
  arXiv  Detail & Related papers  (2024-02-26T10:48:41Z)
• Scalable spin squeezing in two-dimensional arrays of dipolar large-$S$ spins [0.0]
  We show that spin-spin interactions lead to scalable spin squeezing along the non-equilibrium unitary evolution in a coherent spin state. For sufficiently small quadratic shifts, the spin squeezing dynamics is akin to that produced by the paradigmatic one-axis-twisting (OAT) model. Spin squeezing with OAT-like scaling is shown to be protected by the robustness of long-range ferromagnetic order to quadratic shifts.
  arXiv  Detail & Related papers  (2023-09-11T10:32:24Z)
• Production of twisted particles in magnetic fields [62.997667081978825]
  Quantum states suitable for a production of charged particles in a uniform magnetic field are determined. Experiments allowing one successful discoveries of twisted positrons and positroniums are developed.
  arXiv  Detail & Related papers  (2022-07-28T14:20:36Z)
• Precession of entangled spin and pseudospin in double quantum dots [0.0]
  Quantum dot spin valves are characterized by exchange fields which induce spin precession and generate current spin resonances. We generalize this setup to allow for arbitrary spin and orbital polarization of the leads. We observe for both vectors a delicate interplay of decoherence, pumping and precession which can only be understood by considering the dynamics of the spin-pseudospin correlators.
  arXiv  Detail & Related papers  (2022-02-08T23:00:00Z)
• Rapidly enhanced spin polarization injection in an optically pumped spin ratchet [49.1301457567913]
  We report on a strategy to boost the spin injection rate by exploiting electrons that can be rapidly polarized. We demonstrate this in a model system of Nitrogen Vacancy center electrons injecting polarization into a bath of 13C nuclei in diamond. Through a spin-ratchet polarization transfer mechanism, we show boosts in spin injection rates by over two orders of magnitude.
  arXiv  Detail & Related papers  (2021-12-14T08:23:10Z)
• Measurable fractional spin for quantum Hall quasiparticles on the disk [0.0]
  We study the spin of the localised quasiparticles of lowest-Landau-level quantum Hall states defined on a disk. Since it is related to the quadrupole moment of the quasiparticle charge distribution, it can be measured in an experiment.
  arXiv  Detail & Related papers  (2021-12-06T09:53:54Z)
• Dispersive readout of molecular spin qudits [68.8204255655161]
  We study the physics of a magnetic molecule described by a "giant" spin with multiple $d > 2$ spin states. We derive an expression for the output modes in the dispersive regime of operation. We find that the measurement of the cavity transmission allows to uniquely determine the spin state of the qudits.
  arXiv  Detail & Related papers  (2021-09-29T18:00:09Z)
• Zitterbewegung of massless particles [91.3755431537592]
  Zitterbewegung of massless particles with an arbitrary spin is analyzed in various representations. Zitterbewegung takes place in any representation except for the Foldy-Wouthuysen one.
  arXiv  Detail & Related papers  (2020-08-12T14:16:44Z)
• Spin current generation and control in carbon nanotubes by combining rotation and magnetic field [78.72753218464803]
  We study the quantum dynamics of ballistic electrons in rotating carbon nanotubes in the presence of a uniform magnetic field. By suitably combining the applied magnetic field intensity and rotation speed, one can tune one of the currents to zero while keeping the other one finite, giving rise to a spin current generator.
  arXiv  Detail & Related papers  (2020-01-20T08:54:56Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.