Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States

Rodó, Carles; Romero‐Isart, Oriol; Eckert, K.; Sanpera, Anna

doi:10.1007/s11080-007-9030-x

Cited by 12 publications

(14 citation statements)

References 17 publications

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“…Our squeezed-light resonator is a possible source for high-speed quantum key distribution. The source can be used to create two-mode squeezed states and therefore entanglement in the GHz band [20,21,22]. Our current design is capable of producing similarly high squeezing values as state of the art narrow-band squeezing resonators.…”

Section: Discussionmentioning

confidence: 99%

High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity

Ast¹,

Mehmet²,

Schnabel³

2013

Opt. Express

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Abstract:We report the generation of squeezed vacuum states of light at 1550 nm with a broadband quantum noise reduction of up to 4.8 dB ranging from 5 MHz to 1.2 GHz sideband frequency. We used a custom-designed 2.6 mm long biconvex periodically-poled potassium titanyl phosphate (PPKTP) crystal. It featured reflectively coated end surfaces, 2.26 GHz of linewidth and generated the squeezing via optical parametric amplification. Two homodyne detectors with different quantum efficiencies and bandwidths were used to characterize the non-classical noise suppression. We measured squeezing values of up to 4.8 dB from 5 to 100 MHz and up to 3 dB from 100 MHz to 1.2 GHz. The squeezed vacuum measurements were limited by detection loss. We propose an improved detection scheme to measure up to 10 dB squeezing over 1 GHz. Our results of GHz bandwidth squeezed light generation provide new prospects for high-speed quantum key distribution.

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Section: Discussionmentioning

confidence: 99%

High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity

Ast¹,

Mehmet²,

Schnabel³

2013

Opt. Express

View full text Add to dashboard Cite

show abstract

“…The generation of Gaussian entangled states is nowadays quite advanced and, thus, they serve as the main class of states for improving CV-QKD [26][27][28][29][30][31]. Gaussian states are fully characterized by the covariance matrix of their field quadratures or, equivalently, of their complex field amplitudes.…”

Section: Introductionmentioning

confidence: 99%

Gaussian entanglement in the turbulent atmosphere

et al. 2016

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We provide a rigorous treatment of the entanglement properties of two-mode Gaussian states in atmospheric channels by deriving and analyzing the input-output relations for the corresponding entanglement test. A key feature of such turbulent channels is a non-trivial dependence of the transmitted continuous-variable entanglement on coherent displacements of the quantum state of the input field. Remarkably, this allows one to optimize the entanglement certification by modifying local coherent amplitudes using a finite, but optimal amount of squeezing. In addition, we propose a protocol which, in principle, renders it possible to transfer the Gaussian entanglement through any turbulent channel over arbitrary distances. Therefore, our approach provides the theoretical foundation for advanced applications of Gaussian entanglement in free-space quantum communication.

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“…Prepare-and-measure schemes with squeezed states have been considered in [8,9]. The less common entanglement-based schemes do not need signal modulation [10], and instead exploit directly the correlations in the field quadratures of an Einstein-Podolsky-Rosen (EPR) entangled state. EPR entangled states are usually generated by interfering two squeezed beams at a beam splitter [11][12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Gaussian entanglement for quantum key distribution from a single-mode squeezing source

et al. 2013

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We report the suitability of an Einstein-Podolsky-Rosen entanglement source for Gaussian continuous-variable quantum key distribution at 1550 nm. Our source is based on a single continuous-wave squeezed vacuum mode combined with a vacuum mode at a balanced beam splitter. Extending a recent security proof, we characterize the source by quantifying the extractable length of a composable secure key from a finite number of samples under the assumption of collective attacks. We show that distances in the order of 10 km are achievable with this source for a reasonable sample size despite the fact that the entanglement was generated including a vacuum mode. Our security analysis applies to all states having an asymmetry in the field quadrature variances, including those generated by superposition of two squeezed modes with different squeezing strengths.

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Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States

Cited by 12 publications

References 17 publications

High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity

High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity

Gaussian entanglement in the turbulent atmosphere

Gaussian entanglement for quantum key distribution from a single-mode squeezing source

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