Experimental analysis of decoherence in continuous-variable bipartite systems

Buono, Daniela; Nocerino, Gaetano; Porzio, Alberto; Solimeno, S.

doi:10.1103/physreva.86.042308

Cited by 48 publications

(59 citation statements)

References 83 publications

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“…On these bases, CV quantum optics has experienced an increasing interest for its application to quantum key distribution (QKD) [5], with many proposals based on both single-mode [6-8] and two-mode squeezed light [9,10]. Entanglement distillation and entanglement swapping schemes for long distance quantum communication have been demonstrated [5,11] and systematic studies have been performed on the robustness of non-classicality against the communication channel losses [12,13]. A further step towards real-world applications of CV quantum communication has been done by generating squeezed light in the telecom C-band of wavelengths, where low-loss optical fibres and high performance standard components are available [14][15][16].…”

Section: Pacs Numbersmentioning

confidence: 99%

A fully guided-wave squeezing experiment for fiber quantum networks

Kaiser¹,

Fedrici²,

Zavatta³

et al. 2016

Optica

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We demonstrate, for the first time, the realization of an entirely guided-wave squeezing experiment at a telecom wavelength. The state generation relies on waveguide non-linear optics technology while squeezing collection and transmission are implemented by using only telecom fibre components. We observe up to −1.83 ± 0.05 dB of squeezing emitted at 1542 nm in CW pumping regime. The compactness and stability of the experiment, compared to free-space configurations, represent a significant step towards achieving out-of-the-lab CV quantum communication, fully compatible with existing telecom fibre networks. We believe that this work stands as a promising approach for real applications as well as for "do-it-yourself" experiments. PACS numbers:Generation and manipulation of continuous variable (CV) non-classical states of light are the object of intense research due to their importance in both fundamental and applied physics [1,2]. Among others, a valuable feature of CV quantum resources is that they can be generated in a deterministic way at the output of non-linear optical media [3]. Moreover, CV entanglement is affected but never vanishes completely for any level of external loss [4]. On these bases, CV quantum optics has experienced an increasing interest for its application to quantum key distribution (QKD) [5], with many proposals based on both single-mode [6-8] and two-mode squeezed light [9,10]. Entanglement distillation and entanglement swapping schemes for long distance quantum communication have been demonstrated [5,11] and systematic studies have been performed on the robustness of non-classicality against the communication channel losses [12,13]. A further step towards real-world applications of CV quantum communication has been done by generating squeezed light in the telecom C-band of wavelengths, where low-loss optical fibres and high performance standard components are available [14][15][16]. In the perspective of implementing quantum networks that exploit optical fibres to connect distant atomic quantum memories, a quantum interface has recently been developed, converting squeezed light from telecom to visible wavelengths compatible with suitable atomic transitions [17]. In the same spirit, a light-matter interface, coupling light guided in a tapered nanofibre to cold atoms, has been demonstrated [18].In this framework, and in order to comply with further out-of-the-lab realizations of CV quantum optics, we demonstrate, for the first time, the feasibility of a full guided-wave approach for both the generation and measurement of squeezed light at a telecom wavelength. In our scheme, single-mode squeezing at 1542 nm is generated by spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate ridge-waveguide (PPLN/RW). At the output of the PPLN/RW, the non-classical beam is measured with a fibre homodyne detector. This configuration allows implementing an extremely easy setup, entirely based on commercially available components, and fully compatible with existing fibre network...

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Section: Pacs Numbersmentioning

confidence: 99%

A fully guided-wave squeezing experiment for fiber quantum networks

Kaiser¹,

Fedrici²,

Zavatta³

et al. 2016

Optica

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“…This does not happen for entanglement witnesses related to the PHS and Duan criteria. 5,6 As for example, at T = 0.01, i.e. 99% of losses, E N (σ) = 0.01 ± 0.02 and E F (σ) = 0.000 ± 0.002; while w P HS = −0.008 ± 0.001 and w DUAN = −0.018 ± 0.001.…”

Section: Resultsmentioning

confidence: 98%

Transmitting continuous variable entangled states over long distances

et al. 2013

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Recently, we experimentally proved that, even in presence of strong decoherence, the bi-partite continuous variable entangled state generated by a sub-threshold type-II optical parametric oscillator (OPO) never disentangles. It keeps breaking the limits for some of the entanglement criteria. In this contribution, we extend our previous analysis by focusing on the behaviour, under decohenrece, of two entanglement measures: Logarithmic Negativity (LN) and Entanglement of Formation (EOF).

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“…In realistic experimental conditions the state | T will be affected by unavoidable sources of decoherence such as cavity output couplings and losses during propagation [50,51]. In this context, the four-mode protostate |ζ 12 |ξ 34 , Eq.…”

Section: B Generation Under Realistic Conditionsmentioning

confidence: 99%

Tunable non-Gaussian resources for continuous-variable quantum technologies

DellʼAnno¹,

Buono²,

Nocerino³

et al. 2013

Phys. Rev. A

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We introduce and discuss a set of tunable two-mode states of continuous-variable systems, as well as a simple, effective scheme for their experimental generation. This class of tunable entangled resources is defined by a general ansatz depending on two experimentally adjustable parameters. It is very ample and flexible as it encompasses Gaussian as well as non-Gaussian states. The latter include, among others, known states such as squeezed number states and de-Gaussified photon-added and photon-subtracted squeezed states, the latter being the most efficient non-Gaussian resources currently available in the laboratory. Moreover, it contains the classes of squeezed Bell states and even more general non-Gaussian resources that can be optimized according to the specific quantum technological task that needs to be realized. The proposed experimental scheme exploits linear optical operations and photon detections performed on a pair of uncorrelated two-mode Gaussian squeezed states. The desired non-Gaussian state is then realized via ancillary squeezing and conditioning. Two independent, freely tunable experimental parameters can be exploited to generate different states and to optimize the performance in implementing a given quantum protocol. As a concrete instance, we analyze in detail the performance of different states considered as resources for the realization of quantum teleportation in realistic conditions. For the fidelity of teleportation of an unknown coherent state, we show that the resources associated with the optimized parameters outperform, in a significant range of experimental values, both Gaussian twin beams and photon-subtracted squeezed states.

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Experimental analysis of decoherence in continuous-variable bipartite systems

Cited by 48 publications

References 83 publications

A fully guided-wave squeezing experiment for fiber quantum networks

A fully guided-wave squeezing experiment for fiber quantum networks

Transmitting continuous variable entangled states over long distances

Tunable non-Gaussian resources for continuous-variable quantum technologies

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