ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarVarró SándorWigner FK SZFI; ELI-ALPSAberrations of parametric 
down-conversion probabilities in generation of entangled photon 
pairs.Tuesday, 18 April 2023, 10:00, KFKI Campus, Bldg. 1, 2nd floor, 
Conference RoomThe quantum states of light have long been playing an 
important role in the physics of lasers and parametric processes in quantum 
optics, e.g. in noise reduction in measurements. Concerning quantum imaging 
[1] or quantum information science [2], the application of entangled photon 
pairs has become a part of everyday practice. The subject of the talk belongs 
to this quite broad area of research, and the results to be presented may be 
useful in several sub-areas.As an introduction, a brief summary of some basic 
photon correlation experiments will be given. Then, we shall discuss the 
photon statistics of the entangled photon pairs in a close connection with 
the quantum phase formalism already introduced earlier [3]. Recently we have 
derived the probability amplitudes of general squeezing transitions [4] and 
the photon statistics of a degenerate parametric amplifier. In the meantime, 
we have used an analogous mathematical procedure and [3] for describing the 
non-degenerate down-conversion process, resulting in ‘Einstein-Podolsky-Rosen 
(EPR)-type entangled photon pairs’. We will show that in a special case, the 
derived probability amplitudes reduce to the Zernike functions, well-known in 
the classical theory of aberration in optical imaging [5]. In the case under 
discussion, the ‘aberration’ stems from induced emission, so it quantifies 
the deviation from the spontaneous process. The derived ‘quantum  Zernike 
polynomials’ form a complete set of orthogonal aberration functions of the 
phase-space variables of the photons. Finally, we point out that, though 
these functions do not depend on the coordinates in real space where the 
electromagnetic wave propagates, they likely leave ‘fingerprints’ of noise on 
the wavefront. Thus, the ‘quantum Zernike moments’ may be used for 
quality-assessment of parametric sources.References.[1] Lugiato L A, Gatti A 
and Brambilla E, Quantum imaging. J. Opt. B: Quantum Semiclass. Opt. 4 (2002) 
S176–S183.[2] > The Royal Swedish Academy of Sciences has decided to award 
the Nobel Prize in Physics 2022 to Alain Aspect, John F. Clauser and Anton 
Zeilinger; “for experiments with entangled photons, establishing the 
violation of Bell inequalities and pioneering quantum information science”. < 
 https://www.nobelprize.org/uploads/2022/10/press-physicsprize2022-2.pdf  [3] 
Varró S : Regular phase operator and SU(1,1) coherent states of the harmonic 
oscillator. Physica Scripta 90, 074053 (2015).[4] Varró S, Coherent and 
incoherent superposition of transition matrix elements of the squeezing 
operator. New Journal of Physics 24, 053035 (2022). [5] Born M and Wolf E, 
Principles of Optics (Cambridge University Press, Cambridge, 2002). 
&nbsp;Minden érdeklődőt szívesen látunk! - Everyone is welcome to 
attend.Attila Nagysem-admin AT szfki.hu