Thread by @fgrosshans

Now at #IWQNS, @vparigi81 from @lkb_lab on Engineering non-Gaussian entangled complex photonic graph states .
#LTQI

@vparigi81 @lkb_lab Recent #LTQI threads from me on simlar talks by @vparigi81 :

https://twitter.com/fgrosshans/status/1098964327548272640

,and

https://twitter.com/fgrosshans/status/996325413273120770

(includes link to a video)

@vparigi81 @lkb_lab .@vparigi81’s networks’ nodes are frequency/temporal modes of e.m. fields, made thorugh quantum frequency combs. That is merging optical frequency combs (OFC), with 10⁶ modes with quantum optics by pumping a parametric oscilaltorwith an OFC #LTQI #IWQNS

@vparigi81 @lkb_lab .@vparigi81 : characterizes the states via (frequency resolved) homodyne detection. She doesn’t resolve the 10⁶ modes, but still a few of them. In the good basis (the supermode basis), the system looks like independent squeezers. (it can be shown by Bloch Messiah ) #LTQI #IWQNS

.@vparigi81 : With a vacuum input, any Syplectic transformation can be written, through Bloch Messiah decomposition R₁^T Δ, with R₁ passive and Δ diagonal squeezers. Current setup allows to plays with R₁ at will, leading to cluster states of arbitrary topology #LTQI #IWQNS

@vparigi81 .@vparigi81 : Given a cluster state, it can be described by several differnt graphs / R₁. The least dense graphs are easier to optimize.
#LTQI #IWQNS

@vparigi81 .@vparigi81 : The mapping also works for complex networks of harmonic oscillators with spring-link coupling (Collab. with Sabrina Maniscalco and Roberta Zambrini). A graph can be realized experimentally via pump shaping
#LTQI #IWQNS

@vparigi81 .@vparigi81 Now wants a quantum advantage, and needs therefore a non-Gaussian process: photon subtraction. With a χ⁽²⁾ crystal, and a shped idler beam, one can subtract a photon for an arbitrary superposition of modes, e.g. a cluster #LTQI #IWQNS

@vparigi81 @threadreaderapp kindly unroll