Polarization-entangled twin photons from two-photon quantum-dot emission

Heinze, Dirk; Zrenner, A.; Schumacher, Stefan

doi:10.1103/physrevb.95.245306

Cited by 33 publications

(38 citation statements)

References 45 publications

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“…In particular, phonons are known to provide a major source of decoherence [26][27][28][29][30][31][32][33][34][35], which led to the expectation that phonons should always degrade the entanglement. Indeed, recent simulations [24,36,37] are in line with this expectation.…”

supporting

confidence: 71%

“…Which-path information introduced, e.g., by the fine-structure splitting of the excitons, leads to an asymmetric superposition and decreased entanglement. The system can also decay from the biexciton directly to the ground state by simultaneous two-photon emission, a process which is much less affected by which-path information than the sequential single-photon decay [23][24][25].…”

mentioning

confidence: 99%

“…This is realized, e.g., in the limit of weak biexciton binding and finite exciton or cavity mode splitting. In both cases, the phonon-induced enhancement is found in a finite range of binding energies and couplings g. Our studies are based on the Hamiltonian [24,37]:…”

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confidence: 99%

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Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems

et al. 2019

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We report on simulations of the degree of polarization entanglement of photon pairs simultaneously emitted from a quantum dot-cavity system that demand revisiting the role of phonons. Since coherence is a fundamental precondition for entanglement and phonons are known to be a major source of decoherence, it seems unavoidable that phonons can only degrade entanglement. In contrast, we demonstrate that phonons can cause a degree of entanglement that even surpasses the corresponding value for the phonon-free case. In particular, we consider the situation of comparatively small biexciton binding energies and either finite exciton or cavity mode splitting. In both cases, combinations of the splitting and the dot-cavity coupling strength are found where the entanglement exhibits a nonmonotonic temperature dependence which enables entanglement above the phonon-free level in a finite parameter range. This unusual behavior can be explained by phonon-induced renormalizations of the dot-cavity coupling g in combination with a nonmonotonic dependence of the entanglement on g that is present already without phonons.

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confidence: 71%

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confidence: 99%

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Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems

et al. 2019

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“…In order to appreciate our main result, it should be noted that the 2PR configuration with finite biexciton binding energy has attracted a lot of attention 16,17,51 since this configuration has been proposed in order to reach high degrees of entanglement at finite fine-structure splittings. The idea is that two-photon transitions are favored which are much less affected by the which-path information introduced by the fine-structure splitting than sequential single-photon processes.…”

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confidence: 90%

From strong to weak temperature dependence of the two-photon entanglement resulting from the biexciton cascade inside a cavity

et al. 2019

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We investigate the degree of entanglement quantified by the concurrence of photon pairs that are simultaneously emitted in the biexciton-exciton cascade from a quantum dot in a cavity. Four dot-cavity configurations are compared that differ with respect to the detuning between the cavity modes and the quantum dot transitions, corresponding to different relative weights of direct twophoton and sequential single-photon processes. The dependence of the entanglement on the exciton fine-structure splitting δ is found to be significantly different for each of the four configurations. For a finite splitting and low temperatures, the highest entanglement is found when the cavity modes are in resonance with the two-photon transition between the biexciton and the ground state and, in addition, the biexciton has a finite binding energy of a few meV. However, this widely used configuration is rather strongly affected by phonons such that other dot-cavity configurations, that are commonly regarded as less suited for obtaining high degrees of entanglement, become more favorable already at temperatures on the order of 10 K and above. If the cavity modes are kept in resonance with one of the exciton-to-ground-state transitions and the biexciton binding energy is finite, the entanglement drastically drops for positive δ with rising temperatures when T is below 4 K, but is virtually independent of the temperature for higher T .arXiv:1902.01683v2 [cond-mat.mes-hall]

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“…However, two-photon Rabi splitting in a cavity-dot system has not yet been experimentally demonstrated, restricting its applications in multi-photon operation. This is due to that the biexciton binding energy of QDs is too large in general and coupling between two-photon transition and cavity mode is not strong enough [13,14]. To achieve strong-coupling regime in a cavity-dot system, a promising way is to utilize photonic crystal (PC) cavity, due to high quality factor (Q) and small mode volume (V) [15][16][17][18].…”

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confidence: 99%

Two-Photon Rabi Splitting in a Coupled System of a Nanocavity and Exciton Complexes

Qian

Song

et al. 2018

Phys. Rev. Lett.

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Two-photon Rabi splitting in a cavity-dot system provides a basis for multiqubit coherent control in a quantum photonic network. Here we report on two-photon Rabi splitting in a strongly coupled cavity-dot system. The quantum dot was grown intentionally large in size for a large oscillation strength and small biexciton binding energy. Both exciton and biexciton transitions couple to a high-quality-factor photonic crystal cavity with large coupling strengths over 130 μeV. Furthermore, the small binding energy enables the cavity to simultaneously couple with two exciton states. Thereby, two-photon Rabi splitting between the biexciton and cavity is achieved, which can be well reproduced by theoretical calculations with quantum master equations.

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Polarization-entangled twin photons from two-photon quantum-dot emission

Cited by 33 publications

References 45 publications

Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems

Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems

From strong to weak temperature dependence of the two-photon entanglement resulting from the biexciton cascade inside a cavity

Two-Photon Rabi Splitting in a Coupled System of a Nanocavity and Exciton Complexes

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