Berlin 2024 – wissenschaftliches Programm
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QI: Fachverband Quanteninformation
QI 3: Quantum Communication
QI 3.11: Vortrag
Montag, 18. März 2024, 12:15–12:30, HFT-TA 441
Where are the photons in a transmission-line pulse? — •Evangelos Varvelis1,2, Debjyoti Biswas3, and David P. DiVincenzo1,2,4 — 1Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany — 2Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technologies, 52425 Jülich, Germany — 3Department of Physics, IIT Madras, Chennai 600036, India — 4Peter Grünberg Institute, Theoretical Nanoelectronics, Forschungszentrum Jülich, 52425 Jülich, Germany
It is now common to say that photons can be transmitted along optical fibers or transmission lines. But in many cases the transmission pulse is defined by a time-profile of the field strength, i.e., the electric field or voltage V(t), at the transmission point. How does this turn into a precise description of the arrival profile of the photons in the pulse? We show that there is a highly nontrivial mathematical relation between the function V(t) and the arrival function of the photons. Paradoxically, even if V(t) is strictly limited in time, the photon arrival profile cannot be. This, and the counterintuitive relation between V(t) and the expected number of arriving photons, has consequences for the security of quantum cryptography.
Keywords: coherent state photons; Paley-Wiener theorem; quantum cryptography