General no-go theorem for entanglement extraction

Simidzija, Petar; Jonsson, Robert H.; Martín-Martínez, Eduardo

doi:10.1103/physrevd.97.125002

Cited by 61 publications

(76 citation statements)

References 49 publications

(99 reference statements)

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“…a single use of the channel can transmit at most one qubit), we thus conclude that in the limit λ φ /σ → ∞, the quantum channel capacity Q(Ξ) approaches its maximum value of 1. In other words, we have verified, without the use of any approximations, that the field-mediated quantum channel from Alice to Bob is indeed a perfect quantum channel if the conditions (35) and (36) are satisfied.…”

Section: A Gaussian Detector Smearingmentioning

confidence: 69%

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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: A Gaussian Detector Smearingmentioning

confidence: 69%

“…Additionally, in order for the channel to succeed, the conditions (35) and (36) on the coupling strengths λ φ and λ π must be satisfied. Physically, Eq.…”

Section: Decoding a Qubit Out Of A Fieldmentioning

confidence: 99%

Transmission of quantum information through quantum fields

et al. 2020

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“…Every Hamiltonian gives rise to a unique ground state, but for each state there are plenty of Hamiltonians that share the same ground state. This redundancy is visible in (31) where rescaling h ab with an overall factor (or individually in each frequency sector) leaves G ab unchanged.…”

Section: • Computation Of G Abmentioning

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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“…With this ultimate motivation in mind, it has been shown that a non-zero detector energy gap is crucial in protecting an entanglement harvesting UDW pair against fluctuation induced, entanglement harming, local noise [32,33]. Furthermore, for harmonic oscillator detectors, this noise has been found to increase with field temperature, leading to detrimental effects on the amount of entanglement harvested [18] by oscillator pairs.…”

Section: Introductionmentioning

confidence: 99%

Harvesting correlations from thermal and squeezed coherent states

Simidzija

Martín-Martínez

2018

Phys. Rev. D

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We study the harvesting of entanglement and mutual information by Unruh-DeWitt particle detectors from thermal and squeezed coherent field states. We prove (for arbitrary spatial dimensions, switching profiles and detector smearings) that while the entanglement harvesting ability of detectors decreases monotonically with the field temperature T , harvested mutual information grows linearly with T . We also show that entanglement harvesting from a general squeezed coherent state is independent of the coherent amplitude, but depends strongly on the squeezing amplitude. Moreover, we find that highly squeezed states i) allow for detectors to harvest much more entanglement than from the vacuum, and ii) ensure that the entanglement harvested does not decay with their spatial separation. Finally we analyze the spatial inhomogeneity of squeezed states and its influence on harvesting, and investigate how much entanglement one can actually extract from squeezed states when the squeezing is bandlimited. * psimidzija@uwaterloo.ca † emartinmartinez@uwaterloo.ca arXiv:1809.05547v1 [quant-ph]

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General no-go theorem for entanglement extraction

Cited by 61 publications

References 49 publications

Transmission of quantum information through quantum fields

Transmission of quantum information through quantum fields

Minimal energy cost of entanglement extraction

Harvesting correlations from thermal and squeezed coherent states

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