Manipulating the quantum information of the radial modes of trapped ions: linear phononics, entanglement generation, quantum state transmission and non-locality tests

Serafini, Alessio; Retzker, Alex; Plenio, Martin B.

doi:10.1088/1367-2630/11/2/023007

Cited by 45 publications

(51 citation statements)

References 62 publications

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“…Depending on the experimental setting [7,[45][46][47][48], this is usually called a tunneling or a beamsplitter interaction. The sum over j indicates that the tunneling is agnostic to the internal states of the particles.…”

Section: A Continuous Systems: Mode Splittingmentioning

confidence: 99%

Converting Nonclassicality into Entanglement

Killoran¹,

Steinhoff²,

Plenio³

2016

Phys. Rev. Lett.

193

199

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Quantum mechanics exhibits a wide range of non-classical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well-known that nonclassicality (e.g., squeezing, spin-squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting non-classicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are 'symmetric coherent states,' connected with symmetric representations of the group SU (K). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and non-local pictures of non-classicality.Quantum mechanics currently provides our deepest description of nature. Despite this, much of our everyday experience can be accurately captured within a classical description. What is special about the nonclassical states of a physical system, and what distinguishes them from the more commonplace classical states? Certainly, one of the most important manifestations of non-classicality is entanglement of multipartite systems. Schrödinger even viewed entanglement as "the characteristic trait of quantum mechanics" [1]. Yet there are situations where entanglement has no natural role in describing non-classicality, such as Fock states in optics [2]. Particularly for non-composite systems, other notions of non-classicality appear better suited for characterizing quantum states.A key aspect where quantum mechanics departs from classical mechanics is the prominence of the superposition principle. This elementary tenet of quantum theory supplies a very general framework for categorizing classical and non-classical states. Depending on the particular setting, we may specify some important subset of pure states {|c } c∈I to be the 'classical' pure states of the system. We can then directly associate non-classicality with superposition: a state |ψ is non-classical if and only if it is a non-trivial superposition of classical states. In fact, entanglement fits naturally within this superposition framework, by specifying factorized states as the classical states.One famous example of classical states is that of optical coherent states, {|α } α∈C [2][3][4]. A completely different example is found in the resource theories of coherence [5] or reference frames [6], where the classical states are some fixed orthonormal basis {|k } M k=0 . In both examples, there is no distinction of subsystems, and entanglement is not obviously relevant. Nevertheless, there are fundamental connections between these single-system c...

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Section: A Continuous Systems: Mode Splittingmentioning

confidence: 99%

Converting Nonclassicality into Entanglement

Killoran¹,

Steinhoff²,

Plenio³

2016

Phys. Rev. Lett.

193

199

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“…trapped ions, which are effectively interacting due to Coulomb repulsion, give rise to interesting long-range couplings that are likely to result in multipartite states whose nonlocal character can well be studied by the means of our tools [26,37]. Similar considerations hold for ultracold atoms loaded in an intracavity double-well potential where, in the so-called two-mode approximation [38], a tripartite bosonic state of a cavity field and two atomic modes can be established.…”

Section: Physical Settingsmentioning

confidence: 92%

Testing genuine multipartite nonlocality in phase space

et al. 2013

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We demonstrate genuine three-mode nonlocality based on phase-space formalism. A Svetlichny-type Bell inequality is formulated in terms of the s-parametrized quasiprobability function. We test such a tool using exemplary forms of three-mode entangled states, identifying the ideal measurement settings required for each state. We thus verify the presence of genuine three-mode nonlocality that cannot be reproduced by local or nonlocal hidden variable models between any two out of three modes. In our results, GHZ-and W-type nonlocality can be fully discriminated. We also study the behavior of genuine tripartite nonlocality under the effects of detection inefficiency and dissipation induced by local thermal environments. Our formalism can be useful to test the sharing of genuine multipartite quantum correlations among the elements of some interesting physical settings, including arrays of trapped ions and intracavity ultracold atoms. Quantum nonlocality is one of the most fundamental features of quantum mechanics. It refers to the correlations that cannot be explained by local hidden-variable models that satisfy a set of constraints epitomized by so-called Bell inequalities [1]. The violation of a Bell inequality reveals the existence of nonlocality in a given quantum mechanical state [2][3][4].While originally formulated for bipartite systems, Bell-like inequalities have been extended to the multipartite scenario, a noticeable example being embodied by the well-known inequality proposed by Mermin and Klyshko (MK) [5]. However, the violation of a MK-type inequality by a multipartite state does not necessarily imply the existence of genuine multipartite nonlocality, as this test can be flasified by nonlocal correlations in any reduction of the system's components. In order to demonstrate genuine tripartite nonlocality, another type of Bell inequalities should be thus considered such as the one formulated by Svetlichny [6], which rules out both local and nonlocal hidden variable models possibly imposed on any subparties. It was also noted that a stronger violation of the MK type can demonstrate genuine nonlocality for the cases with an even number of parties [7]. Experimental demonstrations of genuine multipartite nonlocality were firstly achieved by strong violations of an MK inquality with four photon polarization entanglements [8]. A violation of Svetlichnytype inequality was experimentally demonstrated recently with GHZ-type photon polarization entangled states [9]. A generalized version of Svetlichny inequality was recently proposed and studied [10].In this paper, motivated by the growing experimental capabilities of controlling and manipulating the state of tripartite quantum systems, in the optical laboratory [11] and beyond, we address the formulation of genuine three-mode continuous variable (CV) nonlocality tests in phase space. While the phase space provides a natural arena for the description of the state of multimode CV systems, it also provides us with powerful tools for the analysis of the quantum correla...

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“…Phase sensitive detection, analogous to homodyning, was implemented by modulating the ion's fluorescence with a retroreflecting mirror. Active control was actuated by acting on the trap electrodes, in general a notable control possibility available in ion traps [84][85][86][87]. In cavity mediated setups, cold damping of a micromechanical resonator down to 5 K was demonstrated in [88] and improved to 100 mK in [89].…”

Section: Quantum Feedback Coolingmentioning

confidence: 99%

Feedback Control in Quantum Optics: An Overview of Experimental Breakthroughs and Areas of Application

Serafini

2012

ISRN Optics

Self Cite

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We present a broad summary of research involving the application of quantum feedback control techniques to optical setups, from the early enhancement of optical amplitude squeezing to the recent stabilisation of photon number states in a microwave cavity, dwelling mostly on the latest experimental advances. Feedback control of quantum optical continuous variables, quantum nondemolition memories, feedback cooling, quantum state control, adaptive quantum measurements, and coherent feedback strategies will all be touched upon in our discussion.

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Manipulating the quantum information of the radial modes of trapped ions: linear phononics, entanglement generation, quantum state transmission and non-locality tests

Cited by 45 publications

References 62 publications

Converting Nonclassicality into Entanglement

Converting Nonclassicality into Entanglement

Testing genuine multipartite nonlocality in phase space

Feedback Control in Quantum Optics: An Overview of Experimental Breakthroughs and Areas of Application

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