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Examining non-locality and quantum coherent dynamics induced by a common reservoir.

Chen GY, Chen SL, Li CM, Chen YN - Sci Rep (2013)

Bottom Line: Here, we propose to use the steering inequality to examine the non-locality induced by a common reservoir.Compared with the Bell inequality, we find that the steering inequality has a better tolerance for examining non-locality.In view of the dynamic nature of the entangling process, we also propose to observe the quantum coherent dynamics by using the Leggett-Garg inequalities.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.

ABSTRACT
If two identical emitters are coupled to a common reservoir, entanglement can be generated during the decay process. When using Bell's inequality to examine the non-locality, however, it is possible that the bound cannot be violated in some cases. Here, we propose to use the steering inequality to examine the non-locality induced by a common reservoir. Compared with the Bell inequality, we find that the steering inequality has a better tolerance for examining non-locality. In view of the dynamic nature of the entangling process, we also propose to observe the quantum coherent dynamics by using the Leggett-Garg inequalities. We also suggest a feasible scheme, which consists of two quantum dots coupled to nanowire surface plasmons, for possible experimental realization.

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The ELG inequality for Rabi-oscillations between a qubit and cavity photon.With the state /+, 0c〉 being initially excited, the red curves are the results of the observable /−, 1c〉 〈−, 1c/, while the black curve is the result of the observable /+, 0c〉 〈+, 0c/. Inset: Population dynamics of the state /−, 1c〉. Here, κ and γ are the cavity loss and atomic dissipation rate, respectively, while g is the coupling strength between the qubit and the cavity field.
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f5: The ELG inequality for Rabi-oscillations between a qubit and cavity photon.With the state /+, 0c〉 being initially excited, the red curves are the results of the observable /−, 1c〉 〈−, 1c/, while the black curve is the result of the observable /+, 0c〉 〈+, 0c/. Inset: Population dynamics of the state /−, 1c〉. Here, κ and γ are the cavity loss and atomic dissipation rate, respectively, while g is the coupling strength between the qubit and the cavity field.

Mentions: A proper choice of the observable is the key to see the violation of the ELG inequality. This can be understood by the following example. Consider a qubit in a lossy cavity. Let us choose /+, 0c〉 〈+, 0c/ or /−, 1c〉 〈−, 1c/ as our observables, for which we plot in Fig. 5 the function /LQ/. Here, the state /+, 0c〉 (/−, 1c〉) denotes the qubit is in its excited (ground) state and there is zero (one) photon in the cavity. For the observable /−, 1c〉 〈−, 1c/, it is possible that /LQ/ is not violated (the red-dashed curve) even though the population dynamics is still oscillatory. Therefore, it is very important to choose a proper observable when using the ELG inequality as a tool to indicate the quantumness.


Examining non-locality and quantum coherent dynamics induced by a common reservoir.

Chen GY, Chen SL, Li CM, Chen YN - Sci Rep (2013)

The ELG inequality for Rabi-oscillations between a qubit and cavity photon.With the state /+, 0c〉 being initially excited, the red curves are the results of the observable /−, 1c〉 〈−, 1c/, while the black curve is the result of the observable /+, 0c〉 〈+, 0c/. Inset: Population dynamics of the state /−, 1c〉. Here, κ and γ are the cavity loss and atomic dissipation rate, respectively, while g is the coupling strength between the qubit and the cavity field.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3753592&req=5

f5: The ELG inequality for Rabi-oscillations between a qubit and cavity photon.With the state /+, 0c〉 being initially excited, the red curves are the results of the observable /−, 1c〉 〈−, 1c/, while the black curve is the result of the observable /+, 0c〉 〈+, 0c/. Inset: Population dynamics of the state /−, 1c〉. Here, κ and γ are the cavity loss and atomic dissipation rate, respectively, while g is the coupling strength between the qubit and the cavity field.
Mentions: A proper choice of the observable is the key to see the violation of the ELG inequality. This can be understood by the following example. Consider a qubit in a lossy cavity. Let us choose /+, 0c〉 〈+, 0c/ or /−, 1c〉 〈−, 1c/ as our observables, for which we plot in Fig. 5 the function /LQ/. Here, the state /+, 0c〉 (/−, 1c〉) denotes the qubit is in its excited (ground) state and there is zero (one) photon in the cavity. For the observable /−, 1c〉 〈−, 1c/, it is possible that /LQ/ is not violated (the red-dashed curve) even though the population dynamics is still oscillatory. Therefore, it is very important to choose a proper observable when using the ELG inequality as a tool to indicate the quantumness.

Bottom Line: Here, we propose to use the steering inequality to examine the non-locality induced by a common reservoir.Compared with the Bell inequality, we find that the steering inequality has a better tolerance for examining non-locality.In view of the dynamic nature of the entangling process, we also propose to observe the quantum coherent dynamics by using the Leggett-Garg inequalities.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, National Chung Hsing University, Taichung 402, Taiwan.

ABSTRACT
If two identical emitters are coupled to a common reservoir, entanglement can be generated during the decay process. When using Bell's inequality to examine the non-locality, however, it is possible that the bound cannot be violated in some cases. Here, we propose to use the steering inequality to examine the non-locality induced by a common reservoir. Compared with the Bell inequality, we find that the steering inequality has a better tolerance for examining non-locality. In view of the dynamic nature of the entangling process, we also propose to observe the quantum coherent dynamics by using the Leggett-Garg inequalities. We also suggest a feasible scheme, which consists of two quantum dots coupled to nanowire surface plasmons, for possible experimental realization.

Show MeSH
Related in: MedlinePlus