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Fawen90
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Inequality on matrix trace

Consider the following inequality of Lemma 1 arising in The law of large numbers for quantum stochastic filtering and control of many-particle systems :

$$\Big|tr(L\gamma LB) - \frac{1}{2}tr(B(L\gamma + \gamma L))tr(BL + \gamma L) + tr(B\gamma)tr(BL)tr(\gamma L) \Big| \leq 5||L||^2 tr\big((Id-\gamma)B\big),$$

where $\gamma$ is a ($n\times n$) density matrix of rank one (see https://en.wikipedia.org/wiki/Density_matrix for the definition of density matrix), $B$ is a density matrix and $L$ a hermitian matrix. My question is whether the above inequality holds (up to some constant in front of $tr\big((Id-\gamma)B\big)$) by assuming only that $\gamma$ is a density matrix (with the assumptions on $\gamma, L$ unchanged)?

PS : Without loss of generality we may assume that $\gamma$ is diagonal with its diagonal elements $\gamma_1,\ldots, \gamma_n\in\mathbb R_+$ s.t. $\sum_{i=1}^N \gamma_i=1$.

Fawen90
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