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

Conference on Lasers and Electro-Optics

Measurement of two-photon position-momentum EPR-correlation by detecting single-photon correlation

Abhinandan Bhattacharjee, Anand K. Jha

Published Jan 1, 2020• 0 citations
Publisher

Abstract

We propose a technique for measuring position-momentum EPR-correlation by detecting single-photon position and momentum correlation function. Our method does not involve coincidence detection for measuring EPR-correlation.
DOI
10.1364/cleo_at.2020.jtu2a.3

Related papers

Measurement of two-photon position–momentum Einstein–Podolsky–Rosen correlations through single-photon intensity measurements

Abhinandan Bhattacharjee, Nilakantha Meher, Anand K. Jha

Abstract The measurement of the position–momentum Einstein–Podolsky–Rosen (EPR) correlations of a two-photon state is important for many quantum information applications ranging from quantum key distribution to coincidence imaging. However, all the existing techniques for measuring the position–momentum EPR correlations involve coincidence detection and thus suffer from issues that result in less accurate measurements. In this article, we propose and demonstrate an experimental scheme that does not require coincidence detection for measuring the EPR correlations. Our technique works for two-photon states that are pure, irrespective of whether the state is separable or entangled. We theoretically show that if the pure two-photon state satisfies a certain set of conditions then the position–momentum EPR correlations can be obtained by doing the intensity measurements on only one of the photons. We experimentally demonstrate this technique for pure two-photon states produced by type-I spontaneous parametric down-conversion, and to the best of our knowledge, we report the most accurate experimental measurement of position–momentum EPR correlations.

arXiv:2102.04356•New Journal of Physics•Apr 21, 2022•15 citations

Twin-photon correlations in single-photon interference

Mayukh Lahiri, Armin Hochrainer, Radek Łapkiewicz +2 more

The measurement of the correlation between two quantum systems or particles has a broad significance in physics and also plays a central role in the fields of quantum optics and quantum information science. We propose a method of measuring the correlation between the transverse momenta of two photons, in which one only needs to detect one of the photons. We show that it is possible to generate a single-photon fringe pattern by using two spatially separated identical biphoton sources. The fringes are similar to the ones observed in a Michelson interferometer and possess certain remarkable properties. A striking feature of the fringes is that although the pattern is obtained by detecting one photon only of each photon pair, the fringes shift due to a change in the optical path traversed by the undetected photon; the shift is characterized by a combination of wavelengths of both photons. Using this method one can, therefore, measure the wavelength of a photon without detecting it. The visibility of the fringes diminishes as the correlation between the transverse momenta of twin photons decreases: visibility is unity for maximum momentum correlation and zero for no momentum correlation. This dependence allows us to determine the momentum correlation between both photons from the visibility of the fringe pattern obtained by detecting one of the photons only. Our method can potentially be generalized to other quantum entities.

arXiv:1610.04298•Physical Review A•Jul 12, 2017•27 citations

Bidirectional coincidence counting of correlated photons to determine the detection efficiency of a single-photon detector without a reference standard

Akio Yoshizawa, Satoru Odate, Daiji Fukuda +1 more

Bidirectional coincidence counting of correlated photons was adopted to determine the detection efficiency of single-photon detectors operating at 1550 nm without comparing to a reference standard. A self-calibration method best suitable for single-photon detectors was established.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)•Aug 1, 2007•0 citations

Characterizing mixed-state entanglement through single-photon interference

Mayukh Lahiri, Radek Łapkiewicz, Armin Hochrainer +2 more

Entanglement verification and measurement is essential for experimental tests of quantum mechanics and also for quantum communication and information science. Standard methods of verifying entanglement in a bipartite mixed state require detection of both particles and involve coincidence measurement. We present a method that enables us to verify and measure entanglement in a two-photon mixed state without detecting one of the photons, i.e., without performing any coincidence measurement or postselection. We consider two identical sources, each of which can generate the same two-photon mixed state but they never emit simultaneously. We show that one can produce a set of single-photon interference patterns, which contain information about entanglement in the two-photon mixed state. We prove that it is possible to retrieve the information about entanglement from the visibility of the interference patterns. Our method reveals a distinct avenue for verifying and measuring entanglement in mixed states.

arXiv:2009.02829•Physical Review A•Jul 6, 2021•18 citations

The Physics of 2 is not 1+1

Yanhua H. Shih

One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. In an entangled EPR two-particle system, the value of the momentum (position) for neither single subsystem is determined. However, if one of the subsystems is measured to have a certain momentum (position), the other subsystem is determined to have a unique corresponding value, despite the distance between them. This peculiar behavior of an entangled quantum system has surprisingly been observed experimentally in two-photon temporal and spatial correlation measurements, such as ghost interference and ghost imaging. This article addresses the fundamental concerns behind these experimental observations and to explore the nonclassical nature of two-photon superposition by emphasizing the physics of 2 is not 1 + 1.

arXiv:0706.2097•Jun 14, 2007•0 citations

Photon-pair characterization using one single-photon detector by time multiplexing

Yulin Zheng, Jiakun He, Chen Zhou +2 more

We experimentally demonstrate coincidence measurements as well as g(2) ( nτ ) correlation function measurements with only one single-photon detector (SPD) with the aid of field-programmable gate array and 2 × 2 fast optical switches. Both experiments produced similar results compared to conventional experimental methods, requiring more than one SPD. When detecting correlations between multiple single photons, this technique can be employed to reduce demands for the number of SPDs and potentially would be able to offer new options to researchers and institutions requiring coincidence measurement systems with lower complexity as well as smaller form factors.

Optical Engineering•Oct 30, 2019•0 citations
Abstract The measurement of the position–momentum Einstein–Podolsky–Rosen (EPR) correlations of a two-photon state is important for many quantum information applications ranging from quantum key distribution to coincidence imaging. However, all the existing techniques for measuring the position–momentum EPR correlations involve coincidence detection and thus suffer from issues that result in less accurate measurements. In this article, we propose and demonstrate an experimental scheme that does not require coincidence detection for measuring the EPR correlations. Our technique works for two-photon states that are pure, irrespective of whether the state is separable or entangled. We theoretically show that if the pure two-photon state satisfies a certain set of conditions then the position–momentum EPR correlations can be obtained by doing the intensity measurements on only one of the photons. We experimentally demonstrate this technique for pure two-photon states produced by type-I spontaneous parametric down-conversion, and to the best of our knowledge, we report the most accurate experimental measurement of position–momentum EPR correlations.
The measurement of the correlation between two quantum systems or particles has a broad significance in physics and also plays a central role in the fields of quantum optics and quantum information science. We propose a method of measuring the correlation between the transverse momenta of two photons, in which one only needs to detect one of the photons. We show that it is possible to generate a single-photon fringe pattern by using two spatially separated identical biphoton sources. The fringes are similar to the ones observed in a Michelson interferometer and possess certain remarkable properties. A striking feature of the fringes is that although the pattern is obtained by detecting one photon only of each photon pair, the fringes shift due to a change in the optical path traversed by the undetected photon; the shift is characterized by a combination of wavelengths of both photons. Using this method one can, therefore, measure the wavelength of a photon without detecting it. The visibility of the fringes diminishes as the correlation between the transverse momenta of twin photons decreases: visibility is unity for maximum momentum correlation and zero for no momentum correlation. This dependence allows us to determine the momentum correlation between both photons from the visibility of the fringe pattern obtained by detecting one of the photons only. Our method can potentially be generalized to other quantum entities.
Entanglement verification and measurement is essential for experimental tests of quantum mechanics and also for quantum communication and information science. Standard methods of verifying entanglement in a bipartite mixed state require detection of both particles and involve coincidence measurement. We present a method that enables us to verify and measure entanglement in a two-photon mixed state without detecting one of the photons, i.e., without performing any coincidence measurement or postselection. We consider two identical sources, each of which can generate the same two-photon mixed state but they never emit simultaneously. We show that one can produce a set of single-photon interference patterns, which contain information about entanglement in the two-photon mixed state. We prove that it is possible to retrieve the information about entanglement from the visibility of the interference patterns. Our method reveals a distinct avenue for verifying and measuring entanglement in mixed states.
One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. In an entangled EPR two-particle system, the value of the momentum (position) for neither single subsystem is determined. However, if one of the subsystems is measured to have a certain momentum (position), the other subsystem is determined to have a unique corresponding value, despite the distance between them. This peculiar behavior of an entangled quantum system has surprisingly been observed experimentally in two-photon temporal and spatial correlation measurements, such as ghost interference and ghost imaging. This article addresses the fundamental concerns behind these experimental observations and to explore the nonclassical nature of two-photon superposition by emphasizing the physics of 2 is not 1 + 1.
We experimentally demonstrate coincidence measurements as well as g(2) ( nτ ) correlation function measurements with only one single-photon detector (SPD) with the aid of field-programmable gate array and 2 × 2 fast optical switches. Both experiments produced similar results compared to conventional experimental methods, requiring more than one SPD. When detecting correlations between multiple single photons, this technique can be employed to reduce demands for the number of SPDs and potentially would be able to offer new options to researchers and institutions requiring coincidence measurement systems with lower complexity as well as smaller form factors.