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Microwave-optical quantum transduction can be achieved via quantum teleportation using microwave-optical photon Bell pairs. The standard spontaneous parametric down-conversion (SPDC) has to trade off between generation fidelity and…

Quantum Physics · Physics 2025-05-05 Fangxin Li , Ming Yuan , Zhaoyou Wang , Changchun Zhong , Liang Jiang

We study theoretically how high-gain effects affect the measurement outcome of visible signal spectra in undetected photon measurement schemes. We consider two interferometric configurations: firstly, the SU(1,1) interferometer where the…

Quantum Physics · Physics 2026-02-02 Martin Houde , Franz Roeder , Christine Silberhorn , Benjamin Brecht , Nicolás Quesada

We numerically and experimentally show that all photons generated by spontaneous parametric down-conversion (SPDC) follow a transverse amplitude similar to that of the pump. This amplitude transfer from pump to SPDC is revealed in the…

Quantum Physics · Physics 2018-04-04 Ali Anwar , Pravin Vaity , Chithrabhanu Perumangatt , R. P. Singh

We have developed a rigorous quantum model of spontaneous parametric down-conversion in a nonlinear 1D photonic-band-gap structure based upon expansion of the field into monochromatic plane waves. The model provides a two-photon amplitude…

Quantum Physics · Physics 2009-11-13 Jan Perina , Marco Centini , Concita Sibilia , Mario Bertolotti , Michael Scalora

A scheme for the enhanced generation of higher photon-number states is realized, using an optical time-multiplexing setting that exploits a parametric down-conversion source for an iterative state generation. We use a quantum feedback…

Quantum Physics · Physics 2021-05-11 M. Engelkemeier , J. Sperling , J. Tiedau , S. Barkhofen , I. Dhand , M. B. Plenio , B. Brecht , C. Silberhorn

We introduce a sufficient and necessary condition for the separability of a specific class of $N$ $d$-dimensional system (qudits) states, namely special generalized Werner state (SGWS): $W^{[d^N]}(v)=(1-v)\frac{I^{(N)}}{d^N}+v|\psi…

Quantum Physics · Physics 2011-03-10 Dong-Ling Deng , Jing-Ling Chen

We use a variational approach to gain insight into the strongly correlated d-wave superconducting state of the high Tc cuprates at T=0. We show that strong correlations lead to qualitatively different trends in pairing and phase coherence:…

Superconductivity · Physics 2009-11-10 Arun Paramekanti , Mohit Randeria , Nandini Trivedi

Optomechanical gradient forces arise from evanescent fields of guided waves in parallel photonic waveguides. When designed to be of attractive nature, they increase exponentially as the gap between the waveguides decreases. Moreover, the…

We present a theoretical treatment of conditional preparation of one-photon states from a continuous-wave non-degenerate optical parametric oscillator. We obtain an analytical expression for the output state Wigner function, and we maximize…

Quantum Physics · Physics 2014-10-09 Anne E. B. Nielsen , Klaus Mølmer

Quantum entanglement, the non-separability of a multipartite wave function, became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality can be demonstrated on impressively large length scales, as…

High-efficient and high-purity photon sources are highly desired for quantum information processing. We report the design of a chip-scale hybrid SixNy and thin film periodically-poled lithium niobate waveguide for generating high-purity…

Correlated photon pairs produced by a spontaneous parametric down conversion (SPDC) process can be used for secure quantum communication over long distances including free space transmission over a link through turbulent atmosphere. We…

In the field of continuous-variable quantum information processing, non-Gaussian states with negative values of the Wigner function are crucial for the development of a fault-tolerant universal quantum computer. While several non-Gaussian…

We investigate entangled Schr\"odinger cat-like states (SCLSs) in degenerate and non-degenerate spontaneous parametric down-conversion (SPDC) with a fully quantized, depleted pump. Our fully quantum treatment, visualized via Wigner…

Quantum Physics · Physics 2026-04-03 Ranjit Singh , Alexander E. Teretenkov

We propose a model of a nonlinear double-well potential (NDWP), alias a double-well pseudopotential, with the objective to study an alternative implementation of the spontaneous symmetry breaking (SSB) in Bose-Einstein condensates (BECs)…

Other Condensed Matter · Physics 2009-11-13 Thawatchai Mayteevarunyoo , Boris A. Malomed , Guangjiong Dong

In this report, a scheme different from the PT and Wootters concurrence is developed to acquire a criterion to investigate the bipartite separability of the Werner state.

Quantum Physics · Physics 2013-10-29 Ming-Chung Tsai , Po-Chung Chen , Wei-Chi Su , Zheng-Yao Su

Non-phase-matched spontaneous parametric down-conversion (SPDC) in atomically thin materials provides new degrees of freedom and enhanced quantum information capacity compared to conventional phase-matched sources. These systems emerged as…

We analyze the resilience under photon loss of the bi-partite entanglement present in multi-photon states produced by parametric down-conversion. The quantification of the entanglement is made possible by a symmetry of the states that…

Quantum Physics · Physics 2009-11-10 G. A. Durkin , C. Simon , J. Eisert , D. Bouwmeester

We report, for the first time, the generation of entangled photon pairs via type-0 spontaneous parametric down conversion in an ultra-thin wafer of lithium niobate in which momentum between the pump photon and daughter photons is not…

Quantum Physics · Physics 2020-01-08 C. Okoth , A Cavanna , T. Santiago-Cruz , M. V. Chekhova

Partially spatially coherent qubits are more immune to turbulent atmospheric conditions than coherent qubits, which makes them excellent candidates for free-space quantum communication. In this article, we report the generation of partially…

Quantum Physics · Physics 2023-07-26 Preeti Sharma , Sakshi Rao , Bhaskar Kanseri