A study on quantum discord in Gaussian states

Xiong, Yan; Huang, Guo Hui; Fang, Mao Fa

doi:10.1016/j.optcom.2014.11.069

Cited by 8 publications

(5 citation statements)

References 29 publications

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“…Notably, Eq. ( 6 ) is used to calculate the < δa 1 + δa 1 > , < δa 2 + δa 2 > , and < δa 1 δa 2 > as the mean photon number of the first-, second-oscillator, and the phase-sensitive cross-correlation 17 , 21 , 22 , 25 .…”

Section: Theory and Backgroundmentioning

confidence: 99%

“…Some studies show that quantum discord can be defied for both qubits and continuous variable systems 7 , 16 . Therefore, studying the quantum discord for the continuous variables is valuable due to the critical applications of the continuous variables, such as in quantum computation and quantum communications 17 . For some reason mentioned above, and since the circuit designed in this work interacts with the environment as any real quantum systems interact inevitably with the surrounding, we have to focus on the continuous variable and calculate the quantum discord for these variables.…”

Section: Introductionmentioning

confidence: 99%

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Quantum correlation of microwave two-mode squeezed state generated by nonlinearity of InP HEMT

Salmanogli

2023

Sci Rep

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This study significantly concentrates on cryogenic InP HEMT high-frequency circuit analysis using quantum theory to find how the transistor nonlinearity can affect the quantum correlation of the modes generated. Firstly, the total Hamiltonian of the circuit is derived, and the dynamic equation of the motion contributed is examined using the Heisenberg-Langevin equation. Using the nonlinear Hamiltonian, some components are attached to the intrinsic internal circuit of InP HEMT to address the circuit characteristics fully. The components attached are arisen due to the nonlinearity effects. As a result, the theoretical calculations show that the states generated in the circuit are mixed, and no pure state is produced. Accordingly, the modified circuit generates the two-mode squeezed thermal state, which means one can focus on calculating the Gaussian quantum discord to evaluate quantum correlation. It is also found that the nonlinearity factors (addressed as the nonlinear components in the circuit) can intensely influence the squeezed thermal state by which the quantum discord is changed. Finally, as the primary point, it is concluded that although it is possible to enhance the quantum correlation between modes by engineering the nonlinear components; however, attaining quantum discord greater than unity, entangled microwave photons, seems a challenging task since InP HEMT operates at 4.2 K.

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Section: Theory and Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantum correlation of microwave two-mode squeezed state generated by nonlinearity of InP HEMT

Salmanogli

2023

Sci Rep

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“…It is shown that quantum discord is more robust against environment induced decoherence than entanglement [5,6]. Moreover, it has been proven to be an important quantum resource in a plethora of quantum information processing tasks [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Discordlike correlation of bipartite coherence

Guo

Goswami

2017

Phys. Rev. A

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Quantum discord has been studied extensively as a measure of non-classical correlations which includes entanglement as a subset. Although it is well known that non-zero discord can exist without entanglement, the origin of quantum discord is not well understood as compared to entanglement, which manifests itself more simply as inseparable higher dimensional quantum superposition. In this paper we establish the discordlike correlation of bipartite coherence and then compare it to quantum discord. Consequently, we show that the minimum of the discordlike correlation of coherence coincides with the original quantum discord. This demonstrates quantum discord as the irreducible correlated bipartite coherence. In addition, the discordlike correlated coherence is shown to admit the postulates of the quantum resource theory (QRT), although the original quantum discord is not a "good" candidate under the QRT. We also find that the relative entropy measure induced from the discordlike coherence is a well-defined coherence measure for bipartite states.Comment: 6 pages. Some minors are correcte

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“…It has been shown that there are quantum correlations that may arise without entanglement, such as quantum discord (QD) [4], measurement-induced nonlocality (MIN) [6], quantum deficit [7], quantum correlation induced by unbiased bases [8,9] and quantum correlation derived from the distance between the reduced states [10], etc. Among them, quantum discord has aroused great interest in the past decade [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. It is more robust against the effects of decoherence [13] and can be a resource in quantum computation [31,32], quantum key distribution [33] remote state preparation [34,35] and quantum cryptography [36].…”

Section: Introductionmentioning

confidence: 99%

Non-commutativity measure of quantum discord

Guo

2016

Sci Rep

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Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively are proposed in this paper. These two measures can be calculated easily for any state with arbitrary dimension. It is shown by several examples that these measures can reflect the amount of the original quantum discord.

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A study on quantum discord in Gaussian states

Cited by 8 publications

References 29 publications

Quantum correlation of microwave two-mode squeezed state generated by nonlinearity of InP HEMT

Quantum correlation of microwave two-mode squeezed state generated by nonlinearity of InP HEMT

Discordlike correlation of bipartite coherence

Non-commutativity measure of quantum discord

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