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Abstract We consider different schemes for the electrodynamic Aharonov-Bohm (AB) effect introduced in Saldanha P. L.,Phys. Rev. A,108(2023) 062218, exploring the phenomenon to enhance the understanding of its topological nature in spacetime. In the treated examples, the electric current in a solenoid varies in time, changing its internal magnetic field and producing an external electric field, while a quantum charged particle is in a superposition state inside two Faraday cages in an interferometer. The Faraday cages cancel the electric field at their interiors, such that the particle is always subjected to null electromagnetic fields. We discuss how the AB phase difference depends on the topology of the electric and magnetic fields in spacetime in the different treated situations. In particular, we discuss interesting results when a conducting wire connects the two Faraday cages, with the AB phase depending on the wire position. We also show an amplification of the AB phase when the wire makes several turns around the solenoid, which could enable an experimental verification of the effect. 

For a continuous beam, particles that arrive at random times show a flat second-order correlation function, g(2), as measured by a flat coincidence spectrum. A reduction in the likelihood for two particles in such a continuous beam to arrive at the same time is called antibunching, observed as a dip in the otherwise flat coincidence spectrum. For a pulsed beam, the coincidence spectrum consists of a series of equal height peaks, where the “dip” manifests as a reduction in the height of the zero-delay time peak. For electrons, such a dip is an experimental signature of Coulomb repulsion and Pauli pressure. This paper discusses another effect that can produce a similar signature but that does not originate from the properties of the physical system under scrutiny. Instead, the detectors and electronics used to measure those coincidences suffer significantly even from weak crosstalk. A simple model that explains our experimental observations is given. Furthermore, we provide an experimental approach to correct this type of crosstalk. 

Multiphoton emission of electrons has been observed from sharp tips of heavily p-doped GaAs caused by laser pulses with, nominally, 800-nm wavelength, 1-nJ/pulse energy, and 90-fs duration. The emission is mostly due to four-photon processes, with some contribution from three-photon absorption as well. When the electron emission current due to two pulses separated by delay 200 fs << τ << 1 ns is integrated over all electron energies, it is less than that observed for the sum of the emission from the two individual pulses. This subadditive behavior is consistent with a fast electron emission process, i.e., one in which the electron emission occurs over a time comparable to the laser pulse width. The subadditivity results from Pauli blocking of electron emission by the second pulse due to a population increase of the GaAs conduction band caused by the first pulse. Such subadditive photoemission is a sensitive probe of excited-carrier dynamics. We employ the use of an excited-level population model to characterize the photon absorption process and give us a clearer understanding of the electron dynamics in GaAs associated with multiphoton electron emission. Possible applications of this subadditivity effect to control photoemitted electron spin are discussed.