Nonlinear theory for a quantum diode in a dense Fermi magnetoplasma

Localization effects in disordered quantum batteries

We investigate the effect of localization on the local charging of quantum batteries (QBs) modeled by disordered spin systems. Two distinct schemes based on the transverse-field random Ising model are considered, with Ising couplings defined on a Chimera graph and on a linear chain with up to next-to-nearest-neighbor interactions. By adopting a low-energy demanding charging process driven by local fields only, we obtain that the maximum extractable energy by unitary processes (ergotropy) is highly enhanced in the ergodic phase in comparison with the many-body localization (MBL) scenario. As we turn off the next-to-nearest-neighbor interactions in the Ising chain, we have the onset of the Anderson localization phase. We then show that the Anderson phase exhibits a hybrid behavior, interpolating between large and small ergotropy as the disorder strength is increased. We also consider the splitting of total ergotropy into its coherent and incoherent contributions. This incoherent part implies in a residual ergotropy that is fully robust against dephasing, which is a typical process leading to the self-discharging of the battery in a real setup. Our results are experimentally feasible in scalable systems, such as in superconducting integrated circuits.

Enhancing self-discharging process with disordered quantum batteries

One of the most important devices emerging from quantum technology are quantum batteries. However, self-discharging, the process of charge wasting of quantum batteries due to decoherence phenomenon, limits their performance, measured by the concept of ergotropy and half-life time of the quantum battery. The effects of local field fluctuation, introduced by the disorder term in the Hamiltonian of the system, on the performance of the quantum batteries is investigated in this paper. The results reveal that the disorder term could compensate disruptive effects of the decoherence, i.e., self-discharging, and hence improve the performance of the quantum battery via "incoherent gain of ergotropy" procedure. Adjusting the strength of the disorder parameter to a proper value and choosing a suitable initial state of the quantum battery, the amount of free ergotropy, defined with respect to the free Hamiltonian, could exceed the amount of initial stored ergotropy. In addition harnessing the degree of the disorder parameter could help to enhance the half-life time of the quantum battery. This study opens perspective to further investigation of the performance of quantum batteries that explore disorder and many-body effects.

Oblique collision of ion acoustic solitons in a relativistic degenerate plasma

The interaction (oblique collision) of two ion acoustic solitons (IASs) in a magnetized relativistic degenerate plasma with relativistic degenerate electrons and non-degenerate cold ions is studied. The extended Poincaré–Lighthill–Kuo (PLK) method is used to obtain two Korteweg deVries (KdV) wave equations that describe the interacting IASs, then the phase shifts due to interaction are calculated. We studied influence of the fluid number density on the interaction process, interacting solitons phase shifts and also phase velocities. The introduced model is valid for astrophysical objects with high density matter such as white dwarfs, neutron stars, degenerate electrons gas in metals and laboratory degenerate plasma. An inverse proportionality between the phase shifts, phase velocity and the equilibrium electron fluid number density \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n_{eo}$$\end{document}neo was established in the range \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10^{35}\,{\text {m}}^{-3}>n_{eo}>10^{38}\,{\text {m}}^{-3}$$\end{document}1035m-3>neo>1038m-3. We found that the soliton waves get sharper (narrower) and higher with increasing the electrons fluid number density \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n_{eo}$$\end{document}neo, and hence less spacial occupying. The phase shifts and the phase velocity remain approximately unchanged in the range of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10^{35}\,{\text {m}}^{-3}<n_{eo}<10^{38}\,{\text {m}}^{-3}$$\end{document}1035m-3<neo<1038m-3. The impact of the obliqueness angle \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\theta $$\end{document}θ on the soliton interaction process is also studied.

Relativistic theory for localized electrostatic excitations in degenerate electron-ion plasmas

A self-consistent relativistic two-fluid model is proposed for electron-ion plasma dynamics. A one-dimensional geometry is adopted. Electrons are treated as a relativistically degenerate fluid, governed by an appropriate equation of state. The ion fluid is also allowed to be relativistic, but is cold, nondegenerate, and subject only to an electrostatic potential. Exact stationary-profile solutions are sought, at the ionic scale, via the Sagdeev pseudopotential method. The analysis provides the pulse existence region, in terms of characteristic relativistic parameters, associated with the (ultrahigh) particle density.

Theory for large-amplitude electrostatic ion shocks in quantum plasmas

We present a generalized nonlinear theory for large-amplitude electrostatic (ES) ion shocks in collisional quantum plasmas composed of mildly coupled degenerate electron fluid of arbitrary degeneracy and nondegenerate strongly correlated ion fluid with arbitrary atomic number. For our purposes, we use the inertialess electron momentum equation including the electrostatic force, pressure gradient, and relevant quantum forces, as well as a generalized viscoelastic ion momentum (GVIM) equation for strongly correlated nondegenerate ions. The ion continuity equation, in the quasineutral approximation, then closes our nonlinear system of equations. When the electric field force is eliminated from the GVIM equation by using the inertialess electron momentum equation, we then obtain a GVIM and ion continuity equations, which exhibit nonlinear couplings between the ion number density and the ion fluid velocity. The pair of nonlinear equations is numerically solved to study the dynamics of arbitrarily-large-amplitude planar and nonplanar ES shocks arising from a balance between harmonic generation nonlinearities and the ion fluid viscosity for a wide range of plasma mass densities and ion atomic numbers that are relevant for the cores of giant planets (viz., Jupiter) and compact stars (viz., white dwarfs). Our numerical results reveal that the ES shock density profiles strongly depend on the plasma number density and composition (the atomic-number) parameters. Furthermore, ion density perturbations propagate with Mach numbers which significantly depend on the studied plasma fractional parameters. It is concluded that the dynamics of the ES shocks in the superdense degenerate plasma is quite different in the core of a white dwarf star from that in the lower density crust region.

Phase-space structures in quantum-plasma wave turbulence

The quasilinear theory of the Wigner-Poisson system in one spatial dimension is examined. Conservation laws and properties of the stationary solutions are determined. Quantum effects are shown to manifest themselves in transient periodic oscillations of the averaged Wigner function in velocity space. The quantum quasilinear theory is checked against numerical simulations of the bump-on-tail and two-stream instabilities. The predicted wavelength of the oscillations in velocity space agrees well with the numerical results.