Quantum-state engineering assisted by entanglement

Paris, Matteo G. A.; Cola, Mary M.; Bonifacio, R.

doi:10.1103/physreva.67.042104

Cited by 38 publications

(36 citation statements)

References 41 publications

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“…As already considered in Refs. [14,16], in order to give meaning to the obtained probability distribution, that must be defined on discrete values, we assume a finite binning of size η for the output probability density of CVS circuits [23]. This allows for the definition of a set of indicesb = (b…”

Section: Definition Of the Circuit Familymentioning

confidence: 99%

Continuous-variable sampling from photon-added or photon-subtracted squeezed states

et al. 2017

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We introduce a new family of quantum circuits in continuous variables and we show that, relying on the widely accepted conjecture that the polynomial hierarchy of complexity classes does not collapse, their output probability distribution cannot be efficiently simulated by a classical computer. These circuits are composed of input photon-subtracted (or photon-added) squeezed states, passive linear optics evolution, and eight-port homodyne detection. We address the proof of hardness for the exact probability distribution of these quantum circuits by exploiting mappings onto different architectures of sub-universal quantum computers. We obtain both a worst-case and an average-case hardness result. Hardness of Boson Sampling with eight-port homodyne detection is obtained as the zero squeezing limit of our model. We conclude with a discussion on the relevance and interest of the present model in connection to experimental applications and classical simulations.

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Section: Definition Of the Circuit Familymentioning

confidence: 99%

Continuous-variable sampling from photon-added or photon-subtracted squeezed states

et al. 2017

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“…Basically, they may be divided into two main categories: those based on non-linear interaction of order higher than two [56,57], as for example the Kerr effect [58][59][60]), and those based on conditional measurements. Indeed, the nonlinear dynamics induced by conditional measurements has been analyzed for a large variety of schemes [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75], also including, besides photon addition and subtraction schemes, optical state truncation of coherent states [64], state filtering by active cavities [65,66], synthesis of arbitrary unitary operators [67] and generation of optical qubit by conditional interferometry [68]. Conditional state generation has been achieved in the low energy regime [45,49,50] by using single-photon detectors, and also in the mesoscopic domain [51][52][53].…”

Section: Introductionmentioning

confidence: 99%

Quantifying non-Gaussianity for quantum information

2010

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We address the quantification of non-Gaussianity of states and operations in continuous-variable systems and its use in quantum information. We start by illustrating in details the properties and the relationships of two recently proposed measures of non-Gaussianity based on the Hilbert-Schmidt (HS) distance and the quantum relative entropy (QRE) between the state under examination and a reference Gaussian state. We then evaluate the non-Gaussianities of several families of non-Gaussian quantum states and show that the two measures have the same basic properties and also share the same qualitative behaviour on most of the examples taken into account. However, we also show that they introduce a different relation of order, i.e. they are not strictly monotone each other. We exploit the non-Gaussianity measures for states in order to introduce a measure of non-Gaussianity for quantum operations, to assess Gaussification and de-Gaussification protocols, and to investigate in details the role played by non-Gaussianity in entanglement distillation protocols. Besides, we exploit the QRE-based non-Gaussianity measure to provide new insight on the extremality of Gaussian states for some entropic quantities such as conditional entropy, mutual information and the Holevo bound. We also deal with parameter estimation and present a theorem connecting the QRE non-Gaussianity to the quantum Fisher information. Finally, since evaluation of the QRE non-Gaussianity measure requires the knowledge of the full density matrix, we derive some experimentally friendly lower bounds to non-Gaussianity for some class of states and by considering the possibility to perform on the states only certain efficient or inefficient measurements.

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“…The early works for SPE are focused on the nolocality of the single photon [16][17][18]. In the recent ten years, the SPE has been proved to be a valuable resource for cryptography [19,20], state engineering [21], and tomography of states and operations [22,23]. Especially, Duan et al proposed a quantum repeater protocol using the single-photon entanglement and cold atomic ensembles in 2001 [24].…”

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confidence: 99%

Distilling single-photon entanglement from photon loss and decoherence

Zhou

Sheng

2013

J. Opt. Soc. Am. B

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Single-photon entanglement may be the simplest type of entanglement but it is of vice importance in quantum communication. Here we present a practical protocol for distilling the single-photon entanglement from both photon loss and decoherence. With the help of some local single photons, the probability of single photon loss can be decreased and the less-entangled state can also be recovered to maximally entangled state simultaneously. It only requires some linear optical elements which makes it feasible in current experiment condition. This protocol might find applications in current quantum communications based on the quantum repeaters.

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Quantum-state engineering assisted by entanglement

Cited by 38 publications

References 41 publications

Continuous-variable sampling from photon-added or photon-subtracted squeezed states

Continuous-variable sampling from photon-added or photon-subtracted squeezed states

Quantifying non-Gaussianity for quantum information

Distilling single-photon entanglement from photon loss and decoherence

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