We theoretically investigated how the quantum entanglement between the spin of the photoelectron and the polarization of the emitted X-ray photon depends on the excited core-level, using the 3$d\rightarrow\
2p$ and 3$d\rightarrow\
3p$ SPR-XEPECS (spin- and polarization-resolved XEPECS) processes for
Ti2O3-type system, and the 4$f\rightarrow\
4d$ SPR-XEPECS process for
CeF3-type system. In the calculation for
Ti2O3-type system, we used
TiO6 cluster model with the full-multiplet structure of the Ti ion and the charge-transfer effect between Ti 3
d and ligand O 2
p orbitals. For
CeF3-type system, we used ionic model with the full-multiplet structure of the Ce ion. We found two distinct mechanisms for entanglement generation in the 3$d\rightarrow\
2p$ and 4$f\rightarrow\
4d$ cases. The first is generated by the spin-orbit interaction of the 2
p core electron, whereas the second is generated by the spin-orbit interaction of the 4
f valence electron and strong exchange interaction between the 4
f and 4
d electrons. However, in the 3$d\rightarrow\
3p$ case with the strong 3$d-
3p$ exchange interaction, we found that the entanglement is not generated due to the crystal field effect. These results reveal the existence of two distinct mechanisms for entanglement generation in X-ray inner-shell excitation processes.
We present a theoretical analysis of spin-entanglement between a photoelectron and an Auger electron sequentially ejected from an atom (say,
A) following the absorption of a single photon. Entanglement, both without and with spin-orbit interaction has been analyzed. In the former case, entanglement in a photo-Auger electron pair is generated only by the electrostatic Coulomb forces inside an atom and completely characterized merely by the multiplicities of the electronic states of
A,
A+∗,
A2+ participating in the process, without using any protocols already suggested in the literature for this purpose. The presence of both the Coulomb and spin-orbit interactions, on the other hand, couples the entanglement of this bipartite state with the dynamics and kinematics of the whole process, as well as with the properties of the absorbed photon. In such cases, therefore, it is not possible to predict, a priori, the photo-Auger electron entanglement. These discussions have quantitatively been illustrated by several examples.
X-Ray photoemission (XPS) spectra, which have been used for analyzing the chemical and nano structural characteristics of thin film- gate dielectric of nano devices and optoelectronic devices, need to be studied with considering the Quantum entanglement between photoelectron (pe) and emitted X-ray photon (ph) as an indication of the quantum technology. In the present work, as an innovation in the quantum technology, a three-electron S-P model consisting of a 1s orbital in the inner shell and a XPS 2p3/2, 2p1/2) orbital in the outer shell by writing the wave function and second quantization - based on creation and annihilation operators. Regarding the pe-ph entanglement (PPE) via an optical selection rule, we found that the linear polarization of emitted X-ray photons; ph, to pe (or pe-ph) entanglement transfer, reveled in reduced density matrix in von Neumann approach can be useful equation for exploring PPE transfers and for applications to nano chip devices.
An accessible tabletop source for the production of entangled x rays is crucial for the field of high-energy quantum optics. Here, we present a detailed analysis of the entanglement and polarization of the two photons emitted by an electron in an intense laser wave (nonlinear double-Compton scattering), by working within the framework of strong-field QED. By identifying contributions to the emission probability stemming from the electron being either on-shell or off-shell between the two-photon emissions, we show that the entangled photons are generated via the off-shell contribution for moderate beam energies, which are realizable on a tabletop setup. We propose an experiment to produce and isolate pairs of entangled x rays, through spectral filtering.
Objectives: To study of entanglement between two electronic qubits,without observing spin orbit interaction (SOI), produced by double photo ionization from Xeon atom following the absorption of a photon. Methods: In absence of SOI, Russel-Salunders coupling (L-S coupling) is applicable. As the estimations of entanglement we have considered PeresHorodecki condition and negativity. In case of L-Scoupling, all the properties of electronic qubits are predicted merely with the knowledge of the spins of the target atom, the residual photoion, emitted electrons and the state of polarization of the absorbed photon. Findings: We have found that the electronic qubits may be totally entangled, partially entangled or separable depending on spin states of target Xe, residualdication Xe2+,emitted electrons and the state of polarization of incident photon as well as of the direction sspin quantization and ejection of the photoelectrons. Applications/ Improvements: Studies of quantumen tanglement and its paradoxical properties hold the key to various Quantum information (QI) tasks such as quantum teleportation, quantum cryptography and quantum computer technology. Keywords: Density Operator PACS No. 32.30, L-S Coupling, Negativity, Peres-Horodecki Condition
Abstract A photoelectron, emitted due to the absorption of light quanta as described by the photoelectric effect, is often characterized experimentally by a classical quantity, its momentum. However, since the photoelectron is a quantum object, its rigorous characterization requires the reconstruction of the complete quantum state, the photoelectron’s density matrix. Here we use quantum-state tomography to fully characterize photoelectrons emitted from helium and argon atoms upon absorption of ultrashort, extreme ultraviolet light pulses. While in helium we measure a pure photoelectronic state, in argon, spin–orbit interaction induces entanglement between the ion and the photoelectron, leading to a reduced purity of the photoelectron state. Our work shows how state tomography gives new insights into the fundamental quantum aspects of light-induced electronic processes in matter, bridging the fields of photoelectron spectroscopy and quantum information and offering new spectroscopic possibilities for quantum technology.