Generalized modular values with non-classical pointer states

Abstract

In this study, we investigate the advantages of non-classical pointer states in the generalized modular value scheme. We consider a typical von Neumann measurement with a discrete quantum pointer, where the pointer is a projection operator onto one of the states of the basis of the pointer Hilbert space. We separately calculate the conditional probabilities, Q M factors, and signal-to-noise ratios of quadrature operators of coherent, coherent squeezed, and Schrödinger cat pointer states and find that the non-classical pointer states can increase the negativity of the field and precision of measurement compared with semi-classical states in generalized measurement problems characterized by the modular value.

Amplitude-squared squeezing of Schrödinger cat states via Postselected von Neumann Measurement

“…This kind of measurement is referred to as a postselected von Neumann measurement. The postselected von Neumann measurement can be used in state optimization and precision measurement problems [73][74][75][76][77][78][79]. Recently, one of the authors of this paper investigated the effects of postselected von Neumann measurement on the properties of single-mode radiation fields [78] and found that postselected von Neumann measurement changed the photon statistics and quadrature squeezing of radiation fields for different anomalous weak values and coupling strengths.…”

Studying the squeezing effect and phase space distribution of single-photon-added coherent state using postselected von Neumann measurement

“…Since this state has wide application across many quantum information processes including quantum communication [46], quantum key distribution [47][48][49][50], and * yusufu1984@hotmail.com quantum digital signature [51], the optimization for this state is worthy of study, in particular, it may provide new methods to the implementations related processes. On the other hand, the weak signal amplification technique proposed in 1988 [52] by Aharonov, Albert, and Vaidman is widely used in state optimization and precision measurement problems [53][54][55][56][57][58][59]. Most recently, one of the authors of this paper investigated the effects of postselected von Neumann measurement on the properties of single-mode radiation fields [58,59] and found that postselected von Neumann measurement changed the photon statistics and quadrature squeezing of radiation fields for different anomalous weak values and coupling strengths.…”

Effects of postselected von Neumann measurement on nonclassicality of single-photon-added coherent state

“…In Ref. [59], the authors studied the effects of postselected measurement characterized by modular value [60] to show the properties of semi-classical and non-classical pointer states considering the coherent, coherent squeezed, and Schrodinger cat state as a pointer. Most recently, the author of this paper investigated the effects of postselected von Neumann measurement on the properties of singlemode radiation fields [61], and found that postselected von Neumann measurement really changed the photon statistics and squeezing parameters of radiation fields for different weak values and coupling strengths.…”

“…In this paper, motivated by the previous studies [58,59,61], we investigate the effects of postselected von Neumann measurement on nonclassicality of SPACS. In order to achieve our goal, we take the spatial degree of freedom of SPACS as pointer and its polarization degree of freedom as measured system.…”