Changing Fock matrix elements of two-mode squeezed vacuum state by employing three conditional operations in one-sided lossy channel
Haoliang Zhang, Hong‐Chun Yuan, Xue-xiang Xu · Physica Scripta · 2019
Abstract This paper focuses on changing Fock matrix elements of two-mode squeezed vacuum state (TMSVS) by employing three conditional operations in one-sided lossy channel. These three conditional operations include one-photon replacement (OPR), one-photon substraction (OPS) and one-photon addition (OPA). Indeed, three conditional quantum states have been generated from the original TMSVS. Using the characteristic function (CF) representation of quantum density operator, we derive the analytical expressions of their Fock matrix elements, which depend on the interaction parameters, including the squeezing parameter of the input TMSVS, the loss factor and the transmissivity of the variable beam splitter. For convenience of discussion, we only give the Fock matrices in the subspace span 00 , 01 , 10 , 02 , 11 , 20 for these two-mode states. Obviously, the TMSVS only has the populations in 00 and 11 in such subspace. By comparing the generated states with the TMSVS, we find that: (1) the generated state after OPR will remain the populations in 00 and 11 , and add the populations in 10 and 20 ; (2) the generated state after OPS will lost the populations in 00 and 11 , but add the populations in 10 and 20 ; (3) the generated state after OPA will remain the population only in 11 and add the population in