Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Theory for continuous quantum measurements of two-mode fields

Tatiana M. Maevskaya, S. Ya. Kilin

Published May 6, 1996• 0 citations

Abstract

A simulation scheme for the photodetection process of two-mode fields with the continuous measurements of one and both modes is presented. Continuous reduction of the two-mode field during the measurement is described. Analytical expressions for statistic characteristics of the monitored radiation are obtained.

DOI: 10.1117/12.239856

Related papers

State preparation via quantum coherence and continuous measurement

G. S. Agarwal, M. Graf, Miguel Orszag +2 more

The theory of continuous measurement is generalized so as to be applicable to a two-mode radiation field whose properties are monitored by using a \ensuremath{\Lambda} system with initial coherence between two ground states. The two-mode system is shown to offer the possibility of generating a number of new quantum states. Quantum statistics of the field following continuous measurements is calculated. Results for the phase distribution, quasiprobability distribution, and the photon-number distribution of the resulting field are also presented.

Physical Review AMay 1, 199435 citations

Generalized Q parameters and their evolution under continuous photodetection

Ching Tsung Lee

The well known Q parameter introduced by Mandel (1958) is generalized to higher orders. The photodetection of a cavity radiation is considered as continuous quantum measurement which consists of one-count and no-count processes. The evolutions of the generalized Q parameters under both the one-count and the no-count processes are studied, emphasizing their relevance to the classical or non-classical characteristics of the radiation.

Quantum Optics Journal of the European Optical Society Part BFeb 1, 19948 citations

Microscopic theory of the continuous measurement of photon number

Nobuyuki Imoto, Masahito Ueda, Tetsuo Ogawa

This paper proposes a microscopic model for the continuous measurement of photon numbers where the continuous measurement is simulated by a sequence of infinitesimal processes. Each process is composed of a unitary evolution for the coupled system, which consists of the field and the measuring apparatus, followed by a projection according to the readout of the measuring apparatus. The proposed model consists of two-level atoms that are coupled one by one with an optical cavity field via the electric-dipole interaction. Each atomic level is then read out after the interaction, causing a nonunitary state reduction of the field. In particular, it is shown that this microscopic model leads to the Srinivas-Davies model that has been postulated for the photodetection process.

Physical Review AApr 1, 199065 citations

Quantum noise reduction in photodetection processes

Martin Wilkens, Maciej Lewenstein

We propose a photodetection scheme, based on an interference between emission and absorption processes. Such a scheme, under specific circumstances, leads to sub-Poissonian statistics of the photocurrent and a reduction of quantum noise.

Physical Review AApr 1, 19897 citations

A Model for Photodetection of Single-mode Cavity Radiation

Terence J. Shepherd

A model for photodetection is presented which permits evolution of the detected field during the detection process. The integrated univariate and bivariate statistics of the photocount are obtained exactly for detection of single-mode thermal, coherent and free-field cavity radiation. The scheme encompasses the results of three hitherto disparate photocounting models, and demonstrates explicitly the relation between the univariate photon counting statistics and the photon statistics of the field. First-order photocount correlation functions are derived and compared with the corresponding cavity photon population correlations. Photocount antibunching is examined and found to be possible in this model.

Optica Acta International Journal of OpticsApr 1, 198142 citations

Quantum theory for continuous photodetection processes

Masahito Ueda, Nobuyuki Imoto, Tetsuo Ogawa

We develop a quantum theory for continuous photodetection processes that describes nonunitary time development of the field under continuous measurement of photon number. Exact expressions are obtained for time evolutions of the photon-field density operator, average and variance of the photon number, and the Fano factor. These are applied to typical quantum states, i.e., number, coherent, thermal, and squeezed states. The continuous photodetection process is made up of two elementary processes in terms of the referring measurement process, that is, one-count and no-count processes. Just after the one-count process in which a photodetector registers one photoelectron, the average photon number 〈n(t)〉 of the remaining field is shown to increase for super-Poissonian states (e.g., thermal state) and decrease for sub-Poissonian states (e.g., number state); for the Poissonian state (e.g., coherent light), 〈n(t)〉 does not change. During the no-count process in which the photodetector registers no photoelectrons, on the other hand, 〈n(t)〉 decreases in time for all states except the number state. The physical origins for these results are clarified from the viewpoint of nonunitary state reduction by continuous measurement of photon number. Furthermore, we introduce a nonreferring measurement process in which the detector registers photocounts, but we discard all readout information. We discuss the difference in the way the photon field evolves in this process compared to the referring measurement process.

Physical Review AApr 1, 199095 citations