Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Ideal and destructive state reductions of correlated light fields and the continuous measurement of photon number

Vlasta Peřinová, A. Lukš, J. Křepelka

Published Jan 1, 1996• 4 citations
Publisher

Abstract

A continuous photon-number measurement has been assumed in the idler mode output from parametric down-conversion for an initial coherent state. The states generated in the signal mode due to the mode entanglement and the effects of both the destructive and the ideal reduction are described in terms of a quasidistribution of the complex field amplitude as well as of the density-matrix elements. The resulting near-number states in the ideal case are suitable for the study of the dynamics of phase and quadrature distributions rotated by the actual preferred phase. These states exhibit both number and quadrature squeezing. \textcopyright{} 1996 The American Physical Society.

DOI
10.1103/physreva.53.525

Related papers

State Reduction for Correlated Photons and Eigenstates of Unitarily and Non-unitarily Displaced Number Operator

A. Lukš, Vlasta Peřinová, J. Křepelka

The number-quadrature minimum-uncertainty states after rotation and displacement emerge in the parametric down-conversion followed by photon number measurement in the idler mode when the coherent state inputs. Again, the state generated in the signal mode by the reduction is described by the principally measurable quantum-statistical tools.

Journal of Modern Optics•Dec 1, 1994•20 citations

Conditional generation of special states using continuous measurements

Vlasta Peřinová, A. Lukš, J. Křepelka

The theory of continuous measurement of the photon number has been applied to a two-mode light field and it has been assumed that the second mode is being measured. An entanglement of the two-mode state has been supposed. The destructive and nondemolition continuous photon-number measurements have been compared according to their response in the first mode to the parameters of the quantum correlation and the detection time. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Jul 1, 1996•6 citations

Quantum correlation and state reduction of photon twins produced by a parametric amplifier

Kimitaka Watanabe, Y. Yamamoto

Signal and idler waves produced by a nondegenerate parametric amplifier feature strong positive correlation between their photon numbers, or in-phase amplitudes. They feature equally strong negative correlation between their phases, or quadrature-phase amplitudes. These photon twins can produce arbitrarily squeezed states via state reduction by appropriate measurements of an idler wave. When the quadrature amplitude of an idler wave is measured, the signal wave is collapsed to a quadrature-amplitude squeezed state. When the two-quadrature amplitudes of an idler wave are measured simultaneously, the signal wave becomes a coherent state.

Physical Review A•Oct 1, 1988•43 citations

Quantum correlations of quadrature amplitudes in nondegenerate parametric downconversion

Silvania F. Pereira, K. C. Peng, Harry J. Kimble

For measurements describable by a discrete set of possibilities, numerous demonstrations of the violation of Bell's inequalities have been reported in optical physics based on observations of polarization correlations for photon pairs. By contrast for observables with a continuous spectrum, there appears to be no general inequalities corresponding to those of Bell and no experimental realization of the original Einstein-Podolsky-Rosen paradox. Following Reid and Drummond,1 we are attempting to demonstrate the EPR paradox in the context of the measurement of continuous quantum variables with a subthreshold optical parametric oscillator operated in a frequency degenerate but polarization nondegenerate mode. In this case, the EPR paradox is formulated in terms of two sets of quadrature phase amplitudes for the spatially separated signal and idler fields. As the parametric gain is increased toward threshold, the quadrature amplitudes of the signal and idler beams become increasingly faithful quantum copies of one another. Our measurements of quadrature amplitudes are carried out using independent balanced homodyne detectors at two sites. When operated for the detection of squeezing at one site, noise reductions of 4 dB relative to the vacuum state limit are observed, which is most encouraging since noise reductions >3 dB in the difference photocurrent from the two sites are sufficient for inference at a distance of a signal observable from a measurement of the corresponding idler variable.

Annual Meeting Optical Society of America•Jan 1, 1989•0 citations

Number-phase properties of correlated chaotic fields

Vlasta Peřinová, A. Lukš, J. Křepelka +1 more

We study the arrangement of two down-conversion crystals with aligned and partially aligned idler beams in the quasimonochromatic approximation. Treating the signal fields as correlated chaotic modes, we arrive at a detailed description and illustration of their mathematically well defined state in terms of number and phase properties. We show it to be a mixed partial phase-difference state. We derive the closed formulae for the phase-difference distributions in this state derived from the phase-space distributions related to the normal, symmetrical and antinormal orderings of field operators and show that such distributions depend exclusively on measures of correlation which are variants of the modulus of the familiar degree of coherence. Quantum correlation influences fluctuations of photon-number sum, photon-number difference and quantum phase difference. Starting from a quasidistribution which carries the same information as the statistical operator, we arrive at the joint distributions of number sum and phase difference and the quasidistribution of number difference and phase difference.

Journal of Optics B Quantum and Semiclassical Optics•Nov 21, 2000•3 citations

Number states, twin beams, and photon duplication

Horace P. Yuen

It has been known for a while that coherent high-intensity photon number eigenstate fields can be generated through nonlinear optical parametric processes,1 the same ones that give rise to quadrature squeezing.2,3 In contrast to quadrature squeezing which is essentially a single-mode phenomenon, although it is widely misunderstood that it is a two-mode phenomenon, the generation of single-mode number states through three- or four-wave mixing depends on two separate signal and idler modes that are perfectly correlated in photon numbers, in other words a twin beam. The nature of such twin beams is elucidated in both the Schrodinger and the Heisenberg pictures. In particular, it is shown that strong photon number correlation in a twin beam can still be obtained in an amplifier rather than an oscillator configuration, another widely missed point.

Annual Meeting Optical Society of America•Jan 1, 1991•0 citations
A continuous photon-number measurement has been assumed in the idler mode output from parametric down-conversion for an initial coherent state. The states generated in the signal mode due to the mode entanglement and the effects of both the destructive and the ideal reduction are described in terms of a quasidistribution of the complex field amplitude as well as of the density-matrix elements. The resulting near-number states in the ideal case are suitable for the study of the dynamics of phase and quadrature distributions rotated by the actual preferred phase. These states exhibit both number and quadrature squeezing. \textcopyright{} 1996 The American Physical Society.
Signal and idler waves produced by a nondegenerate parametric amplifier feature strong positive correlation between their photon numbers, or in-phase amplitudes. They feature equally strong negative correlation between their phases, or quadrature-phase amplitudes. These photon twins can produce arbitrarily squeezed states via state reduction by appropriate measurements of an idler wave. When the quadrature amplitude of an idler wave is measured, the signal wave is collapsed to a quadrature-amplitude squeezed state. When the two-quadrature amplitudes of an idler wave are measured simultaneously, the signal wave becomes a coherent state.
For measurements describable by a discrete set of possibilities, numerous demonstrations of the violation of Bell's inequalities have been reported in optical physics based on observations of polarization correlations for photon pairs. By contrast for observables with a continuous spectrum, there appears to be no general inequalities corresponding to those of Bell and no experimental realization of the original Einstein-Podolsky-Rosen paradox. Following Reid and Drummond,1 we are attempting to demonstrate the EPR paradox in the context of the measurement of continuous quantum variables with a subthreshold optical parametric oscillator operated in a frequency degenerate but polarization nondegenerate mode. In this case, the EPR paradox is formulated in terms of two sets of quadrature phase amplitudes for the spatially separated signal and idler fields. As the parametric gain is increased toward threshold, the quadrature amplitudes of the signal and idler beams become increasingly faithful quantum copies of one another. Our measurements of quadrature amplitudes are carried out using independent balanced homodyne detectors at two sites. When operated for the detection of squeezing at one site, noise reductions of 4 dB relative to the vacuum state limit are observed, which is most encouraging since noise reductions >3 dB in the difference photocurrent from the two sites are sufficient for inference at a distance of a signal observable from a measurement of the corresponding idler variable.
We study the arrangement of two down-conversion crystals with aligned and partially aligned idler beams in the quasimonochromatic approximation. Treating the signal fields as correlated chaotic modes, we arrive at a detailed description and illustration of their mathematically well defined state in terms of number and phase properties. We show it to be a mixed partial phase-difference state. We derive the closed formulae for the phase-difference distributions in this state derived from the phase-space distributions related to the normal, symmetrical and antinormal orderings of field operators and show that such distributions depend exclusively on measures of correlation which are variants of the modulus of the familiar degree of coherence. Quantum correlation influences fluctuations of photon-number sum, photon-number difference and quantum phase difference. Starting from a quasidistribution which carries the same information as the statistical operator, we arrive at the joint distributions of number sum and phase difference and the quasidistribution of number difference and phase difference.
It has been known for a while that coherent high-intensity photon number eigenstate fields can be generated through nonlinear optical parametric processes,1 the same ones that give rise to quadrature squeezing.2,3 In contrast to quadrature squeezing which is essentially a single-mode phenomenon, although it is widely misunderstood that it is a two-mode phenomenon, the generation of single-mode number states through three- or four-wave mixing depends on two separate signal and idler modes that are perfectly correlated in photon numbers, in other words a twin beam. The nature of such twin beams is elucidated in both the Schrodinger and the Heisenberg pictures. In particular, it is shown that strong photon number correlation in a twin beam can still be obtained in an amplifier rather than an oscillator configuration, another widely missed point.