8 research outputs found
Dynamics of entanglement of bosonic modes on symmetric graphs
We investigate the dynamics of an initially disentangled Gaussian state on a
general finite symmetric graph. As concrete examples we obtain properties of
this dynamics on mean field graphs of arbitrary sizes. In the same way that
chains can be used for transmitting entanglement by their natural dynamics,
these graphs can be used to store entanglement. We also consider two kinds of
regular polyhedron which show interesting features of entanglement sharing.Comment: 14 pages, 11 figures, Accepted for publication in Physics Letters
Broadband quadrature-squeezed vacuum and nonclassical photon number correlations from a nanophotonic device
We report the first demonstrations of both quadrature squeezed vacuum and
photon number difference squeezing generated in an integrated nanophotonic
device. Squeezed light is generated via strongly driven spontaneous four-wave
mixing below threshold in silicon nitride microring resonators. The generated
light is characterized with both homodyne detection and direct measurements of
photon statistics using photon number-resolving transition edge sensors. We
measure ~dB of broadband quadrature squeezing (~dB inferred
on-chip) and ~dB of photon number difference squeezing (~dB
inferred on-chip). Nearly-single temporal mode operation is achieved, with raw
unheralded second-order correlations as high as measured
(~when corrected for noise). Multi-photon events of over 10 photons
are directly detected with rates exceeding any previous quantum optical
demonstration using integrated nanophotonics. These results will have an
enabling impact on scaling continuous variable quantum technology.Comment: Significant improvements and updates to photon number squeezing
results and discussions, including results on single temporal mode operatio
Simulating realistic non-Gaussian state preparation
We consider conditional photonic non-Gaussian state preparation using
multimode Gaussian states and photon-number-resolving detectors in the presence
of photon loss. While simulation of such state preparation is often
computationally challenging, we show that obtaining the required multimode
Gaussian state Fock matrix elements can be reduced to the computation of matrix
functions known as loop hafnians, and develop a tailored algorithm for their
calculation that is faster than previously known methods. As an example of its
utility, we use our algorithm to explore the loss parameter space for three
specific non-Gaussian state preparation schemes: Fock state heralding, cat
state heralding, and weak cubic-phase state heralding. We confirm that these
schemes are fragile with respect to photon loss, yet find that there are
regions in the loss parameter space that are potentially accessible in an
experimental setting which correspond to heralded states with non-zero
non-Gaussianity.Comment: 12 pages, 6 figs. Source code available at
https://github.com/XanaduAI/realistic-quantum-state