Introduction

Quantum information theory deals with quantum noise in order to protect physical quantum bits (qubits) from its effects. A single electron is an emblematic example of a qubit, and today it is possible to experimentally produce polarized ensembles of electrons. It is well known that an electron beam initially not polarized, i.e. composed of equal numbers of particles polarized parallel and antiparallel to the incidence direction, due to the scattering becomes polarized. Such a result can be demonstrated within the theory of the spin-polarization of electron beams elastically scattered by atoms, which will be briefly summarized.

Methods

The POLARe program suite will be described. POLARe is a set of computer codes aimed at the calculation of the spin-polarization parameters of electron beams elastically interacting with atomic targets [1].

Results and Discussion

Selected outputs of the program will be shown, demonstrating that POLARe provides results in agreement with those of another code (ELSEPA) [2] and with experimental data [3] down to very small energies (see Fig. 1).

Figures

Fig. 1. Left-right asymmetry function S(θ) of 10 eV polarized electrons from Xe atoms. Solid line: POLARe calculations [1]. Dashed line: ELSEPA calculations [2]. Symbols: Berger and Kessler experimental data [3].

References

[1] Dapor, M. Polarized electron beams elastically scattered by atoms as a tool for testing fundamental predictions of quantum mechanics, *Scientific Reports* 8, Article number: 5370 (2018).

[2] Salvat, F., Jablonski, A., Powell, C. J. ELSEPA - Dirac partial-wave calculation of elastic scattering of electrons and positrons by atoms, positive ions and molecules. *Comp. Phys. Comm.* 165, 157 (2005).

[3] Dümmler, M., Hanne, G. F., Kessler, J. Left-right asymmetry in elastic and inelastic scattering of polarized electrons from argon, krypton and xenon atoms. *J. Phys. B: Atom. Molec. Phys. *28, 2985 (1995).

Quantum simulation , Fundamental science for quantum technologies