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CATEGORIES:CQIF Seminar
SUMMARY:Hong-Ou-Mandel effect under partial time reversal:
a destructive interference effect in the amplific
ation of light - Nicolas J. Cerf (Universite Libre
de Bruxelles
DTSTART;TZID=Europe/London:20190509T141500
DTEND;TZID=Europe/London:20190509T151500
UID:TALK123997AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/123997
DESCRIPTION:In the usual\, predictive approach of quantum mech
anics\, one deals with the preparation of a quantu
m system followed by its time evolution and ultima
tely its measurement. In the retrodictive approach
of quantum mechanics\, one postselects the instan
ces where a particular measurement outcome was obs
erved and considers the probability of the prepara
tion variable conditionally on this outcome. This
can be interpreted as if the actually measured sta
te had propagated backwards in time to the prepare
r. I will present an intermediate picture\, called
_partial time reversal_\, where a composite syste
m propagates partly forwards and partly backwards
in time. As a striking application\, I will focus
on the simplest 2-mode linear-optical component\,
namely a beam splitter\, and show that it transfor
ms into a two-mode squeezer under partial time rev
ersal. More generally\, by building on the generat
ing function of the matrix elements of Gaussian un
itaries in Fock basis\, I will build simple recurr
ence equations that are obeyed by the multiphoton
transition probabilities (both for the passive and
active linear coupling between two bosonic modes)
. These recurrence equations exhibit an interferom
etric suppression term which generalizes the Hong-
Ou-Mandel effect for more than two indistinguishab
le photons impinging on a beam splitter of transmi
ttance 1/2. It also exhibits an unexpected 2-photo
n suppression effect in an optical parametric ampl
ifier of gain 2 originating from the _timelike_ in
distinguishability between the input and output ph
otons (it is the partial time-reversed version of
the usual _spacelike_ indistinguishability that is
at work in the Hong-Ou-Mandel effect).
LOCATION:MR13\, Centre for Mathematical Sciences\, Wilberfo
rce Road\, Cambridge
CONTACT:Johannes Bausch
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