Historical Review of Dressed Photons: Experimental Progress and Required Theories

Motoichi Ohtsu

Hirofumi Sakuma, Izumi Ojima, Motoichi Ohtsu

This article reviews recent progress in theoretical studies of dressed photons. For providing concrete physical images of dressed photons, several experimental studies are demonstrated. They are applications of dressed photons to novel optical functional devices, nano-fabrication technologies, energy conversion technologies, and photon breeding devices. After these experimental demonstrations, as the main part of this review, quantum-field theoretical formulation of dressed photons is attempted in use of the newly introduced Clebsch-dual variable of electromagnetic field. The reason for introducing the new formulation will be explained in the final section from the viewpoint to exhibit the contrast between free and interacting quantum fields in regard to their energy-momentum supports which are seldom touched upon (or forgotten) in the common physical discussions about quantum fields.

Motoichi Ohtsu, Hirofumi Sakuma

After reviewing the nature of off-shell field and creation/measurement processes of DP, nanometer-sized optical logic gate devices are demonstrated that triggered rapid development of off-shell science. Next, two technologies are reviewed that exhibit novel phenomena of Table 1.1 . One is the nanofabrication technology. Its essential by-product is the successful estimation of the maximum size of the DP. The other is silicon light-emitting devices. It is pointed out that a cluster of photons emitted from these devices behaves as if it is a single photon. Portions of Chap. 2 have been reproduced from Ref. [15] (an open access article published under a CC BY license (Creative Commons Attribution 4.0 International License)), from Ref. [47] with permission from Elsevier, and from Sakuma, H., Ojima, I. and Ohtsu, M., Perspective on an Emerging Frontier of Nanoscience Opened up by Dressed Photon Studies. Nanoarchitectonics, 1, 1–23 (2024) (an open access article distributed under a CC BY license (Creative Commons Attribution 4.0 International License)).

Motoichi Ohtsu, Hirofumi Sakuma

Kazuya Okamura

Keiichi Edamatsu

Entanglement is one of the essential resources of quantum information and communication technology. Photons are the most popular and promising media to manipulate entanglement. In this review article, concepts and progress in the generation, observation, and characterization of entangled photons are presented. Starting from underlying theoretical concepts, a historical review on the generation of entangled photons is given. Particularly, recent results on the generation of polarization-entangled photons from semiconductor sources are reviewed and discussed.