How a single photon can mediate entanglement between two others

Sang-Kyung Choi, Hee Su Park

Li-Ping Yang, Chinmay Khandekar, Tongcang Li +1 more

Abstract We show that a single photon pulse incident on two interacting two-level atoms induces a transient entanglement force between them. After absorption of a multi-mode Fock state pulse, the time-dependent atomic interaction mediated by the vacuum fluctuations changes from the van der Waals interaction to the resonant dipole–dipole interaction (RDDI). We explicitly show that the RDDI force induced by the single photon pulse fundamentally arises from the two-body transient entanglement between the atoms. This single photon pulse induced entanglement force can be continuously tuned from being repulsive to attractive by varying the polarization of the pulse. We further demonstrate that the entanglement force can be enhanced by more than three orders of magnitude if the atomic interactions are mediated by graphene plasmons. These results demonstrate the potential of shaped single photon pulses as a powerful tool to manipulate this entanglement force and also provides a new approach to witness transient atom–atom entanglement.

Yoon-Ho Kim

Bertúlio de Lima Bernardo, Askery Canabarro, Sérgio Azevedo

The concept of wave-particle duality, which is a key element of quantum theory, has been remarkably found to manifest itself in several experimental realizations as in the famous double-slit experiment. In this specific case, a single particle seems to travel through two separated slits simultaneously. Nevertheless, it is never possible to measure it in both slits, which naturally appears as a manifestation of the collapse postulate. In this respect, one could as well ask if it is possible to "perceive" the presence of the particle at the two slits simultaneously, once its collapse could be avoided. In this article, we use the recently proposed entanglement mediation protocol to provide a positive answer to this question. It is shown that a photon which behaves like a wave, i.e., which seems to be present in two distant locations at the same time, can modify two existing physical realities in these locations. Calculations of the "weak trace" left by such photon also enforce the validity of the present argumentation.

Hyunseok Jeong, Minsu Kang, Seungwoo Lee +1 more

Carlos Gonzalez-Ballestero, Esteban Moreno, Francisco José García-Vidal

We study the possibility of using guided photons to generate, control, and measure the entanglement of two qubits that is mediated by a one-dimensional waveguide. We show how entanglement can be generated both with single-photon and with two-photon wave packets. The introduction of a second photon allows for a manipulation of the entanglement between the qubits, and phenomena such as sudden death and revival of entanglement appear. Finally, we propose a procedure for entanglement detection via the scattering output of a single photon over a qubit state.