Decoupling Cross-Quadrature Correlations using Passive Operations
- URL: http://arxiv.org/abs/2004.03105v2
- Date: Wed, 12 Aug 2020 14:17:22 GMT
- Title: Decoupling Cross-Quadrature Correlations using Passive Operations
- Authors: Syed M. Assad, Mile Gu, Xiaoying Li, Ping Koy Lam
- Abstract summary: We show when it is possible to remove correlations between conjugate quadratures using only passive operations.
Such correlations are usually undesired and arise due to experimental cross-quadrature contamination.
Our proof is constructive, and whenever it is possible we obtain an explicit expression for the required passive operation.
- Score: 0.8127364542975234
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Quadrature correlations between subsystems of a Gaussian quantum state are
fully characterised by its covariance matrix. For example, the covariance
matrix determines the amount of entanglement or decoherence of the state. Here,
we establish when it is possible to remove correlations between conjugate
quadratures using only passive operations. Such correlations are usually
undesired and arise due to experimental cross-quadrature contamination. Using
the Autonne--Takagi factorisation, we present necessary and sufficient
conditions to determine when such removal is possible. Our proof is
constructive, and whenever it is possible we obtain an explicit expression for
the required passive operation.
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