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Related papers: Gaussian-State Theory of Two-Photon Imaging

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We model spontaneous parametric down-conversion (SPDC) as classical difference frequency generation (DFG) of the pump field and a hypothetical stochastic "vacuum" seed field. We analytically show that the second-order spatiotemporal…

Entangled two-mode Gaussian states constitute an important building block for continuous variable quantum computing and communication protocols. In this work, we theoretically study two-mode bipartite states which are extracted from…

Quantum Physics · Physics 2026-01-21 Denis A. Kopylov , Torsten Meier , Polina R. Sharapova

We demonstrate a silicon-chip biphoton source with an unprecedented quantum cross correlation up to ${\rm g_{si}^{(2)}(0) = (2.58 \pm 0.16) \times 10^4}$. The emitted biphotons are intrinsically single-mode, with self correlations of ${\rm…

Optics · Physics 2016-03-02 Xiyuan Lu , Wei C. Jiang , Jidong Zhang , Qiang Lin

We consider travelling-wave parametric down-conversion in the high-gain regime and present the experimental demonstration of the quantum character of the spatial fluctuations in the system. In addition to showing the presence of sub-shot…

Quantum Physics · Physics 2009-11-11 O. Jedrkiewicz , E. Brambilla , M. Bache , A. Gatti , L. A. Lugiato , P. Di Trapani

We investigate how the entanglement characteristics of a non-Gaussian entangled state are increased or decreased by a local photon subtraction operation. The non-Gaussian entangled state is generated by injecting a single-mode non-Gaussian…

Quantum Physics · Physics 2015-06-16 Su-Yong Lee , Se-Wan Ji , Chang-Woo Lee

The complete measurement of the quantum state of two correlated photons requires reconstructing the amplitude and phase of the biphoton wavefunction. We show how, by means of spatially resolved single photon detection, one can infer the…

Quantum Physics · Physics 2025-06-26 Nazanin Dehghan , Alessio D'Errico , Francesco Di Colandrea , Ebrahim Karimi

Spontaneous parametric down-conversion (SPDC) is a widely used process to prepare entangled photon pairs. In SPDC, a second-order nonlinear crystal is pumped by a coherent laser beam to generate photon pairs. The photon pairs are usually…

Quantum Physics · Physics 2024-09-16 Richard Bernecker , Baghdasar Baghdasaryan , Stephan Fritzsche

The multiphoton states generated by high-gain spontaneous parametric down-conversion (SPDC) in presence of large losses are investigated theoretically and experimentally. The explicit form for the two-photon output state has been found to…

Photon addition and subtraction render Gaussian states non-Gaussian. We provide a quantitative analysis of the change in nonclassicality produced by these processes by analyzing the Wigner negativity and quadrature coherence scale (QCS) of…

Quantum Physics · Physics 2023-05-10 Anaelle Hertz , Stephan De Bièvre

We directly observe far-field correlations of x-ray photon pairs generated by spontaneous parametric down-conversion (SPDC). Using an energy-resolved, two-dimensional photon counting detector we record the full ring-shaped emission of both…

The two modes of the Einstein-Podolsky-Rosen quadrature entangled state generated by parametric down-conversion interfere on a beam splitter of variable splitting ratio. Detection of a photon in one of the beam splitter output channels…

Quantum Physics · Physics 2014-12-16 Nitin Jain , S. R. Huisman , Erwan Bimbard , A. I. Lvovsky

Imaging systems measuring intensity in the far field succumb to Rayleigh's curse, a resolution limitation dictated by the finite aperture of the optical system. Many proof-of-principle and some two-dimensional imaging experiments have shown…

Quantum non-Gaussian states of photons and phonons are conclusive and direct witnesses of higher-than-quadratic nonlinearities in optical and mechanical processes. Moreover, they are proven resources for quantum sensing, communication and…

Quantum Physics · Physics 2025-03-14 Lukáš Lachman , Radim Filip

The measurement of joint signal-idler photon-number distribution of a field obtained from spontaneous parametric downconversion using an intensified CCD camera is presented. It is shown that a classicality criterion is violated directly by…

Quantum Physics · Physics 2015-05-13 Ondrej Haderka , Jan Perina , Martin Hamar

The quantum illumination is examined by making use of the three-mode maximally entangled Gaussian state, which involves one signal and two idler beams. It is shown that the quantum Bhattacharyya bound between $\rho$ (state for target…

Quantum Physics · Physics 2022-03-15 Eylee Jung , DaeKil Park

Photon pairs generated via spontaneous parametric down-conversion (SPDC) can exhibit entanglement in the Laguerre-Gaussian (LG) mode basis, which enables high-dimensional free-space quantum communication by exploiting the high-dimensional…

Quantum Physics · Physics 2025-07-03 Jungmo Lee , Kyungdeuk Park , Dongkyu Kim , Yonggi Jo , Dong-Gil Im , Yong Sup Ihn

Continuous-variable (CV) photonic states are of increasing interest in quantum information science, bolstered by features such as deterministic resource state generation and error correction via bosonic codes. Data-efficient…

Quantum Physics · Physics 2022-11-22 Joseph C. Chapman , Joseph M. Lukens , Bing Qi , Raphael C. Pooser , Nicholas A. Peters

We report the first experimental demonstration of two-photon imaging with a pseudo-thermal source. Similarly to the case of entangled states, a two-photon Gaussian thin lens equation is observed, indicating EPR type correlation in position.…

Quantum Physics · Physics 2009-11-10 Alejandra Valencia , Giuliano Scarcelli , Milena D'Angelo , Y. Shih

The signal half of an entangled twin-beam, generated using spontaneous parametric downconversion, interrogates a region of space that is suspected of containing a target, and has high loss and high (entanglement-breaking) background noise.…

Quantum Physics · Physics 2009-11-11 Saikat Guha , Baris I. Erkmen

Coincidence imaging, also known as ghost imaging, is a technique that exploits correlations between two particles to reconstruct information about a specimen. The particle that relays the spatial information about the object remains…

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