Purity in the QTMS radar

Abstract

In this paper, we analyze the purity and decoherence effects in quantum two-mode squeezed (QTMS) radar as a function of the squeezing parameter and temperature, using quantum information processing tools. The squeezing parameter is an important key to improving the performance of the QTMS radar. We investigate the response to the squeezing parameter controlling to system state of the QTMS radar. In this work, we deal with the QTMS radar with two cases of the transmitted signal, the presence or the absence of the target. The squeezing parameter controls the power of the generated signal and idler, the correlation between signal and idler, as well as the coherence and state of the system. We show that the decoherence effects are low at low temperatures, low squeezing parameters, and low power. In addition, we demonstrate that the purity and, consequently, the coherence of the QTMS radar are better when the target is absent than when it is present. However, the coherence and purity are maintained at high temperatures in both cases. In addition, by calculating the entropy of formation as a tool to investigate the qualitative behavior of entanglement in QTMS radar, we show that the behaviors of purity and entropy are similar. Finally, we show that the proportion of received photons in the QTMS radar is an important factor in improving the radar performance.