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In this work we study the production and swapping of non-gaussian multipartite entanglement in a setup containing a parametric amplifier which generates three photons in different modes coupled to three qubits. We prove that the…

Quantum Physics · Physics 2022-02-07 A. Agustí Casado , C. Sabín

Properties of weak spatio-spectral twin beams in paraxial approximation are analyzed using the decomposition into appropriate paired modes. Numbers of paired modes as well as numbers of modes in the signal (or idler) field in the transverse…

Quantum Physics · Physics 2016-01-05 Jan Perina

Quantum entanglement can manifest itself in the narrowing of wavepackets. We define the phenomenon of phase entanglement and describe its effect on the interpretation of spatial localization experiments.

Quantum Physics · Physics 2007-05-23 K. W. Chan , J. H. Eberly

Quantum fluctuation and quantum entanglement of the pump field reflected from an optical cavity for type II second harmonic generation are theoretically analyzed. The correlation spectra between the quadratures of the reflected subharmonic…

Quantum Physics · Physics 2007-05-23 Zehui Zhai , Yongming Li , Jiangrui Gao

We consider entanglement entropy between two halves of space separated by a plane, in the theory of free photon in 3+1 dimensions. We show how to separate local gauge invariant quantities that belong to the two spatial regions. We calculate…

High Energy Physics - Theory · Physics 2020-08-05 Candost Akkaya , Alex Kovner

We investigate the process of entanglement transfer from a three-mode quantized field to a system of three spatially separated qubits each one made of a two-level atom resonantly coupled to a cavity mode. The optimal conditions for…

Quantum Physics · Physics 2009-11-13 Federico Casagrande , Alfredo Lulli , Matteo G. A. Paris

Photons entangled in their position-momentum degrees of freedom (DoFs) serve as an elegant manifestation of the Einstein-Podolsky-Rosen paradox, while also enhancing quantum technologies for communication, imaging, and computation. The…

The manifestation of entanglement within geometric phase is elucidated for spatially-structured bi-photons. Entanglement parameters are shown to influence holonomy in two distinct ways: through statistical superpositions of separable…

Quantum Physics · Physics 2024-10-21 Mark T. Lusk

We demonstrate the presence of multimode entanglement in the vacuum state of a free, massless scalar quantum field in four-dimensional flat spacetime between two sets of field modes, each contained within a spacetime region that is causally…

We study the entanglement in tripartite quantum systems by using the principal basis matrix representations of density matrices. Using the Schmidt decomposition and local unitary transformation, we first convert the general states to…

Quantum Physics · Physics 2023-10-13 Hui Zhao , Yu-Qiu Liu , Shao-Ming Fei , Zhi-Xi Wang , Naihuan Jing

We show experimentally how noncollinear geometries in spontaneous parametric downconversion induce ellipticity of the shape of the spatial mode function. The degree of ellipticity depends on the pump beam width, especially for highly…

The need for spatial and spectral filtering in the generation of polarization entanglement is eliminated by combining two coherently-driven type-II spontaneous parametric downconverters. The resulting ultrabright source emits photon pairs…

We propose a method for detecting bipartite entanglement in a many-body mixed state based on estimating moments of the partially transposed density matrix. The estimates are obtained by performing local random measurements on the state,…

Multi-mode entanglement is investigated in the system composed of $N$ coupled identical harmonic oscillators interacting with a common environment. We treat the problem very general by working with the Hamiltonian without the rotating-wave…

Quantum Physics · Physics 2015-05-13 Gao-xiang Li , Li-hui Sun , Zbigniew Ficek

We investigate entanglement between collective operators of two wave-packets of finite spectral bandwidth, in two different approximations of the Multimode Parametric-Down Conversion (MPDC) process: the pairwise and the one-to-all…

Quantum Physics · Physics 2012-10-11 Ana M. Martins

Polarization-entangled photon pairs can be efficiently prepared into pure Bell states with a high fidelity via type-II spontaneous parametric down-conversion (SPDC) of narrow-band pump light. However, the use of femtosecond pump pulses to…

Quantum Physics · Physics 2007-05-23 Hou Shun Poh , Chune Yang Lum , Ivan Marcikic , Antia Lamas-Linares , Christian Kurtsiefer

Nonclassical beams in high order spatial modes have attracted much interest but they exhibit much less squeezing and entanglement than the fundamental spatial modes, limiting their applications. We experimentally demonstrate the relation…

Quantum Physics · Physics 2017-04-05 Jun Guo , Chunxiao Cai , Long Ma , Kui Liu , Hengxin Sun , Jiangrui Gao

The dynamics of tripartite entanglement of fermionic system in noninertial frames through linear contraction criterion when one or two observers are accelerated is investigated. In one observer accelerated case the entanglement measurement…

Quantum Physics · Physics 2016-12-09 Salman Khan

We illustrate a procedure to generate a bipartite, entangled compass state, which shows sub-Planck structure. The proposed method uses the interaction of a standing wave laser field, with two, two-level atoms and relies on the ability of…

Quantum Physics · Physics 2015-05-18 Sayan Choudhury , Prasanta K. Panigrahi

Metasurfaces consisting of nano-scale structures are underpinning new physical principles for the creation and shaping of quantum states of light. Multi-photon states that are entangled in spatial or angular domains are an essential…