Transmitting qubits through relativistic fields

Jonsson, Robert H.; Ried, Katja; Martín-Martínez, Eduardo; Kempf, Achim

doi:10.1088/1751-8121/aae78a

Cited by 34 publications

(34 citation statements)

References 53 publications

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“…This therefore extends the no-quantumbroadcasting result proven in Ref. [14] for identical detectors to the case of spherically symmetric, non-identical detectors, and it therefore gives supporting evidence to the conjecture that it is not possible to send quantum information through a quantum field to multiple disjoint detectors, identical or not.…”

Section: Broadcasting Quantum Informationsupporting

confidence: 85%

“…As such, it gives an idea of the amount of quantum information that can be coherently transmitted by the quantum channel, still taking into account that purposefully using n copies of the channel can be better than n independent uses [31]. Unfortunately however, while the formula (14) provides an intuitive interpretation of the quantum capacity as being the maximal coherent information of many copies of the channel being allowed to work in parallel, it is generally not possible to evaluate this limit and obtain a closed form expression for Q(Ξ). Instead, it is often only possible to compute lower bounds on Q(Ξ), such as [33,34]…”

Section: B Quantum Channel Capacity and Coherent Informationmentioning

confidence: 99%

“…In fact, this question was partially answered in Ref. [14], where the authors showed that, in a flat spacetime of any dimension, it is not possible for Alice to send any amount of quantum information to mul- tiple identical Bobs. 5 In this section we will attempt to circumvent this result by considering non-identical Bobs.…”

Section: Broadcasting Quantum Informationmentioning

confidence: 99%

“…Both Bobs are spherically symmetric, with Bob B 1 covering the region of space given by r < r 0 , and Bob B 2 covering the region r > r 0 . We consider this setup both for its computational simplicity (owing to the fact that spherical symmetry is preserved), as well as the fact that the Bobs in this setup are not identical, thus allowing us to potentially overcome the limitations imposed upon identical Bobs [14], as discussed above. Despite the simplicity of the setup however, it will nevertheless provide us with interesting insights into the broadcasting of quantum information through a relativistic quantum field.…”

Section: Broadcasting Quantum Informationmentioning

confidence: 99%

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Transmission of quantum information through quantum fields

et al. 2020

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We investigate the quantum channel consisting of two localized quantum systems that communicate through a scalar quantum field. We choose a scalar field rather than a tensor or vector field, such as the electromagnetic field, in order to isolate the situation where the qubits are carried by the field amplitudes themselves rather than, for example, by encoding qubits in the polarization of photons. We find that suitable protocols for this type of quantum channel require the careful navigation of several constraints, such as the no-cloning principle, the strong Huygens principle and the tendency of field-matter couplings that are short to be entanglement breaking. We nonperturbatively construct a protocol for such a quantum channel that possesses maximal quantum capacity.

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Section: Broadcasting Quantum Informationsupporting

confidence: 85%

Section: B Quantum Channel Capacity and Coherent Informationmentioning

confidence: 99%

Section: Broadcasting Quantum Informationmentioning

confidence: 99%

Section: Broadcasting Quantum Informationmentioning

confidence: 99%

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Transmission of quantum information through quantum fields

et al. 2020

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“…In fact, this construction does not only apply to mixed states but to bi-linear forms in general. Thus, it may be used to further develop techniques such as [81] to efficiently describe the interaction of several quantum systems with a given bath of harmonic oscillators, with applications ranging from open system dynamics to fundamental quantum communication between local observers via relativistic fields [82][83][84][85][86][87]…”

Section: Outlook: Mixed Statesmentioning

confidence: 99%

Minimal energy cost of entanglement extraction

Hackl

Jonsson

2019

Quantum

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We compute the minimal energy cost for extracting entanglement from the ground state of a bosonic or fermionic quadratic system. Specifically, we find the minimal energy increase in the system resulting from replacing an entangled pair of modes, sharing entanglement entropy ∆S, by a product state, and we show how to construct modes achieving this minimal energy cost. Thus, we obtain a protocol independent lower bound on the extraction of pure state entanglement from quadratic systems. Due to their generality, our results apply to a large range of physical systems, as we discuss with examples.A ⊕ B, we have the unique decompositionwhere the projections P A : V → A and P B : V → B with P A + P B = 1 provide the unique decomposition of a vector v = a + b into its part inGiven such a decomposition, the spectrum of J 2 A and J 2 B is the same except for the number of eigenvalues equal to −1. Put differently, given an eigenvalue λ of J 2 A , we have λ = −1 or J 2 B also has λ as eigenvalue.Proof. We write J 2 = −1 in blocks to find

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Lorentz-covariant sampling theory for fields

Pye

2023

Phys. Scr.

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Sampling theory is a discipline in communications engineering involved with the exact reconstruction of continuous signals from discrete sets of sample points. From a physics perspective, this is interesting in relation to the question of whether spacetime is continuous or discrete at the Planck scale, since in sampling theory we have functions which can be viewed as equivalently residing on a continuous or discrete space. Further, it is possible to formulate analogues of sampling which yield discreteness without disturbing underlying spacetime symmetries. In particular, there is a proposal for how this can be adapted for Minkowski spacetime. Here we will provide a detailed examination of the extension of sampling theory to this context. We will also discuss generally how spacetime symmetries manifest themselves in sampling theory, which at the surface seems in conflict with the fact that the discreteness of the sampling is not manifestly covariant. Specifically, we will show how the symmetry of a function space with a sampling property is equivalent to the existence of a family of possible sampling lattices related by the symmetry transformations.

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Transmitting qubits through relativistic fields

Cited by 34 publications

References 53 publications

Transmission of quantum information through quantum fields

Transmission of quantum information through quantum fields

Minimal energy cost of entanglement extraction

Lorentz-covariant sampling theory for fields

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