A model of dense-plasma atomic structure for equation-of-state calculations

Jean-Christophe Pain

Home/Archive/arXiv

arXiv · 0706.3592

A model of dense-plasma atomic structure for equation-of-state calculations

Jean-Christophe Pain

View original source ↗Read source document ↗Export metadata ↓

Abstract

A model of dense plasmas relying on the superconfiguration approximation is presented. In each superconfiguration the nucleus is totally screened by the electrons in a Wigner-Seitz sphere (ion-sphere model). Superconfigurations of the same charge are grouped into ions. It is shown that boundary values of the wavefunctions play a crucial role in the form of the Virial theorem from which the pressure formula is derived. Finally, a condition is presented and discussed, which makes the ion-sphere model variational when bound electrons are treated quantum-mechanically and free electrons quasi-classically.

Explore related subjects

physics.atom-ph physics.plasm-ph

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Jean-Christophe Pain. 2007-06-25. A model of dense-plasma atomic structure for equation-of-state calculations. https://arxiv.org/abs/0706.3592

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Single-step SU(3) Hahn Echo in a Qutrit Atom Interferometer

The Hahn echo is a well-known dynamical decoupling method that refocuses the dephasing due to energy inhomogeneities of a spin-1/2 ensemble and is widely used to extend phase coherence in quantum computers and sensors. Extensions of such techniques beyond the spin-1/2 have been reported, but have mainly used SU(2) gates, limiting their scalability. Here, we generalize the Hahn echo to qutrits using single-step SU(3) gates and extend the coherence time by more than an order of magnitude. The gates are generated through optimal control theory and implemented in an ultracold atomic ensemble in free fall. A quantum process tomography procedure benchmarks the gates and yields fidelities of ~ 93%, limited mainly by state preparation and measurement errors. Due to the geometry of the laser beams, the generalized Hahn echo also realizes a three-path Mach-Zehnder atomic interferometer with two independent interferometric phase differences. Our results therefore establish SU(3) control for dynamical decoupling of qutrits and multi-path atom interferometers, with the latter opening the possibility for vector force measurements and interferometric tests of the validity of Born's rule.

physics.atom-ph↗

arXiv2026

A Compact Single-Beam Optically Pumped Magnetometer Based on Absorption Detection

We demonstrate a compact single-beam optically pumped magnetometer (OPM) employing a pure 87Rb microfabricated vapor cell with 500 Torr buffer gas. The residual magnetic field is actively minimized to below 400 pT through a combination of mu-metal magnetic shielding and internal compensation coils. We systematically characterize the OPM response as a function of laser detuning and optical intensity, and derive the magnetic-field sensitivity from the signal slope and noise amplitude spectral density. A best sensitivity of 11 fT/Hz^1/2 is achieved near the resonance transition at an optimal optical intensity, using a small cell volume of only 0.027 cm^3. Furthermore, a miniaturized OPM prototype was developed using a folded flexible printed circuit board (FPCB) to integrate the vapor cell, a compact heater, and magnetic-field coils into a cubic sensing head. Two coil configurations patterned directly on the FPCB were investigated. Under optimized operating conditions, the OPM prototype achieved a sensitivity of 66 fT/Hz^1/2. These results demonstrate that high-buffer-pressure single-beam OPMs can achieve excellent sensitivity, establishing a pathway toward compact and scalable arrays.

physics.atom-ph↗

arXiv2026

A classical trajectory method for diatom-atom-atom ternary association reactions

We introduce a classical trajectory method for calculating direct diatom-atom-atom ternary association re- action rates that incorporates the rotational degrees of freedom of the diatomic reactant. By treating the diatomic molecule as a rigid rotor, we include the effects of the anisotropy of the molecule-atom interaction and the dynamical effects of the rotational motion. We apply this approach to a system of experimental interest, CD+ + He + He, along with the isotopic variant CH+ + He + He -> CHHe+ + He, and examine the role of the internal, rotational degrees of freedom of the diatomic molecule. In particular, we find that in the regime where the collision energy is much smaller than the rotational energy of the entrance channel, the rotational motion leads to deviation from the classical threshold law by violating the assumptions of long-range capture theory models.

physics.atom-ph↗