Efficient representation of Gaussian states for multimode non-Gaussian quantum state engineering via subtraction of arbitrary number of photons
AffiliationUniv Arizona, Dept Elect & Comp Engn
Univ Arizona, Coll Opt Sci
MetadataShow full item record
PublisherAMER PHYSICAL SOC
CitationGagatsos, C. N., & Guha, S. (2019). Efficient representation of Gaussian states for multimode non-Gaussian quantum state engineering via subtraction of arbitrary number of photons. Physical Review A, 99(5), 053816.
JournalPHYSICAL REVIEW A
RightsCopyright © 2019 American Physical Society.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe consider a complete description of a multi-mode bosonic quantum state in the coherent-state basis (which in this paper is denoted as the “K” function), which—up to a phase—is the square root of the well-known Husimi Q representation. We express the K function of any N-mode Gaussian state as a function of its covariance matrix and displacement vector, and also that of a general continuous-variable cluster state in terms of the modal squeezing and graph topology of the cluster. This formalism lets us characterize the non-Gaussian state left over when one measures a subset of modes of a Gaussian state using photon number resolving detection, the fidelity of the obtained non-Gaussian state with any target state, and the associated heralding probability, all analytically. We show that this probability can be expressed as a Hafnian, reinterpreting the output state of a circuit claimed to demonstrate quantum supremacy termed Gaussian boson sampling. As an example application of our formalism, we propose a method to prepare a two-mode coherent-cat-basis Bell state with fidelity close to unity and success probability that is fundamentally higher than that of a well-known scheme that splits an approximate single-mode cat state—obtained by photon number subtraction on a squeezed vacuum mode—on a balanced beam splitter. This formalism could enable exploration of efficient generation of cat-basis entangled states, which are known to be useful for quantum error correction against photon loss.
VersionFinal published version
SponsorsArmy Research Office STIR program [W911NF-18-1-0377]